🔗 d50.in | Cloud-Deployed URL Shortener

🚀 A full-stack URL shortening service built with Spring Boot (Java) and deployed on AWS EC2 using Nginx as a reverse proxy and MySQL (RDS) for persistence. Convert long URLs into short, manageable aliases under the custom d50.in domain.

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✨ Key Features

• 🔗 URL Shortening: Converts long, cumbersome URLs into neat short links.
• ✍️ Custom Aliases: Allows users to suggest a preferred short alias (e.g., d50.in/r/my-project).
• 🎲 Random Aliases (Base62): Generates unique, 5-character Base62 ([0-9a-zA-Z]) aliases automatically if no custom alias is provided.
• ♻️ Duplicate URL Handling: If a long URL has already been shortened, the existing short link is returned, preventing duplicate entries.
• ➡️ Secure Redirection: Uses HTTP 301 Permanent Redirects for optimal SEO and performance when redirecting from the short link (/r/{alias}) to the original URL.
• 🖥️ Simple Frontend: A clean web interface built with HTML, CSS, and Vanilla JavaScript for easy submission of URLs.
• 🔒 HTTPS Enforced: All traffic is automatically redirected to HTTPS, secured using Nginx and free SSL certificates from Let's Encrypt.
• ☁️ Cloud Native: Designed and deployed on AWS infrastructure (EC2, RDS, Route 53).

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💻 Technology Stack

☕ Backend (Server-Side Logic)

✨ Frontend (User Interface)

💾 Database & Persistence

(Note: H2 Database is used for local development/testing.)

☁️ Deployment, Networking, Proxy & Security

🛠️ Build Tools

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🏗️ Architecture Overview

The application follows a standard client-server architecture enhanced by a reverse proxy:

1. User's Browser: Interacts with the static frontend (HTML/CSS/JS).
2. Nginx (on EC2):
   • Listens on ports 80 (HTTP) & 443 (HTTPS).
   • Redirects all HTTP traffic to HTTPS.
   • Terminates SSL for HTTPS traffic using Let's Encrypt certificates.
   • Forwards valid HTTPS requests for /api/* or /r/* to the Spring Boot application running internally on port 8080.
   • Adds crucial X-Forwarded-* headers.
3. Spring Boot Application (on EC2):
   • Listens internally on localhost:8080.
   • Handles API requests (/api/shorten) and redirection logic (/r/{alias}).
   • Interacts with the database via Spring Data JPA.
   • Configured to understand X-Forwarded-* headers.
4. AWS RDS (MySQL Database):
   • Stores the alias -> long URL mappings persistently.
   • Accessible only from the EC2 instance via internal VPC networking (secured by Security Groups).

(Diagram Recommendation: Insert a clear architecture diagram image here showing the flow: User -> Browser -> Route 53 -> EC2 (Nginx -> Spring Boot) -> RDS)

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🔌 API Endpoints

Method	Endpoint	Request Body / Path Params	Success Response	Error Response(s)	Description
POST	/api/shorten	JSON (CreateRedirectRequest DTO)	201 Created - JSON (RedirectResponse DTO)	400 Bad Request (Validation, Alias Exists), 503 (Alias Gen)	Creates a new short URL or returns existing one.
GET	/r/{alias}	Path Variable: alias (String)	301 Moved Permanently (Location Header)	404 Not Found	Redirects the user to the original long URL.

DTOs:

• CreateRedirectRequest: { "url": "string (required)", "alias": "string (optional, max 10 chars, [a-zA-Z0-9-])" }
• RedirectResponse: { "alias": "string", "originalUrl": "string", "shortUrl": "string (full https://d50.in/r/alias)" }

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🗄️ Database Schema

Table: redirects

Column Name	Data Type	Constraints	Description
id	BIGINT	Primary Key, Auto Increment	Unique record identifier.
alias	VARCHAR(10)	Unique, Not Null	The short alias string.
url	VARCHAR(2048)	Not Null	The original long URL.
created_at	TIMESTAMP	Not Null, Defaults to Current Time	Timestamp of record creation.

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📝 Blog Post

Read more about the development process, challenges faced, and deployment details in my blog post:

➡️ [Link to Your Blog Post Here] (Coming Soon!)