Add support for embedded license file

src/BaGetter.Core/Content/DefaultPackageContentService.cs

@@ -88,4 +88,15 @@ public async Task<Stream> GetPackageIconStreamOrNullAsync(string id, NuGetVersio
 
         return await _storage.GetIconStreamAsync(id, version, cancellationToken);
     }
+
+    public async Task<Stream> GetPackageLicenseStreamOrNullAsync(string id, NuGetVersion version, CancellationToken cancellationToken = default)
+    {
+        var package = await _packages.FindPackageOrNullAsync(id, version, cancellationToken);
+        if (package == null || !package.HasEmbeddedLicense)
+        {
+            return null;
+        }
+
+        return await _storage.GetLicenseStreamAsync(id, version, package.LicenseFormatIsMarkdown, cancellationToken);
+    }
 }

src/BaGetter.Core/Content/IPackageContentService.cs

@@ -81,4 +81,13 @@ Task<Stream> GetPackageIconStreamOrNullAsync(
         string id,
         NuGetVersion version,
         CancellationToken cancellationToken);
+
+    /// <summary>
+    /// The package license if the license is an embedded license, or null if the license is a URL or expression.
+    /// </summary>
+    /// <param name="id">The package id.</param>
+    /// <param name="version">The package's version.</param>
+    /// <param name="cancellationToken">A token to cancel the task.</param>
+    /// <returns>The package's license stream, or null if the package license does not exist, or the license type is URL or expression.</returns>
+    Task<Stream> GetPackageLicenseStreamOrNullAsync(string id, NuGetVersion version, CancellationToken cancellationToken);
 }

src/BaGetter.Core/Entities/Package.cs

@@ -4,7 +4,10 @@
 
 namespace BaGetter.Core;
 
-// See NuGetGallery's: https://github.com/NuGet/NuGetGallery/blob/master/src/NuGetGallery.Core/Entities/Package.cs
+/// <remarks>
+/// See: <see href="https://github.com/NuGet/NuGetGallery/blob/master/src/NuGetGallery.Core/Entities/Package.cs"/><br/>
+/// Newer version: <see href="https://github.com/NuGet/NuGetGallery/blob/main/src/NuGet.Services.Entities/Package.cs"/>
+/// </remarks>
 public class Package
 {
     public int Key { get; set; }
@@ -34,10 +37,22 @@ public NuGetVersion Version
     public string Description { get; set; }
     public long Downloads { get; set; }
     public bool HasReadme { get; set; }
+    /// <summary>
+    /// Indicates if the icon is embedded in the package.
+    /// </summary>
     public bool HasEmbeddedIcon { get; set; }
+    /// <summary>
+    /// Indicates if the license is embedded in the package.
+    /// </summary>
+    public bool HasEmbeddedLicense { get; set; }
     public bool IsPrerelease { get; set; }
     public string ReleaseNotes { get; set; }
     public string Language { get; set; }
+    /// <summary>
+    /// Indicates if the license format is Markdown.
+    /// </summary>
+    /// <value><c>true</c> if Markdown, <c>false</c> otherwise.</value>
+    public bool LicenseFormatIsMarkdown { get; set; }
     public bool Listed { get; set; }
     public string MinClientVersion { get; set; }
     public DateTime Published { get; set; }

src/BaGetter.Core/Extensions/PackageArchiveReaderExtensions.cs

@@ -19,9 +19,39 @@ public static bool HasReadme(this PackageArchiveReader package)
     public static bool HasEmbeddedIcon(this PackageArchiveReader package)
         => !string.IsNullOrEmpty(package.NuspecReader.GetIcon());
 
-    public async static Task<Stream> GetReadmeAsync(
-        this PackageArchiveReader package,
-        CancellationToken cancellationToken)
+    /// <summary>
+    /// Indicates if the package has an embedded license file.
+    /// </summary>    
+    /// <returns><c>true</c> if the license file is embedded, otherwise <c>false</c>.</returns>
+    public static bool HasEmbeddedLicense(this PackageArchiveReader package)
+    {
+        var licenseMetadata = package.NuspecReader.GetLicenseMetadata();
+        if (licenseMetadata != null && licenseMetadata.Type == LicenseType.File)
+        {
+            return true;
+        }
+
+        return false;
+    }
+
+    /// <summary>
+    /// Indicates if the license file format is Markdown.
+    /// </summary>    
+    /// <returns><c>true</c> if the license file format is Markdown, otherwise <c>false</c>.</returns>
+    public static bool IsLicenseFormatMarkdown(this PackageArchiveReader package)
+    {
+        var licenseMetadata = package.NuspecReader.GetLicenseMetadata();
+        if (licenseMetadata == null ||
+            licenseMetadata.Type != LicenseType.File ||
+            string.IsNullOrWhiteSpace(licenseMetadata.License))
+        {
+            return false;
+        }
+
+        return Path.GetFileName(licenseMetadata.License).EndsWith(".md", StringComparison.OrdinalIgnoreCase);
+    }
+
+    public static async Task<Stream> GetReadmeAsync(this PackageArchiveReader package, CancellationToken cancellationToken)
     {
         var readmePath = package.NuspecReader.GetReadme();
         if (readmePath == null)
@@ -34,18 +64,28 @@ public async static Task<Stream> GetReadmeAsync(
         return await package.GetStreamAsync(readmePath, cancellationToken);
     }
 
-    public async static Task<Stream> GetIconAsync(
-        this PackageArchiveReader package,
-        CancellationToken cancellationToken)
+    public static async Task<Stream> GetIconAsync(this PackageArchiveReader package, CancellationToken cancellationToken)
     {
         return await package.GetStreamAsync(
             PathUtility.StripLeadingDirectorySeparators(package.NuspecReader.GetIcon()),
             cancellationToken);
     }
 
-    public static Package GetPackageMetadata(this PackageArchiveReader packageReader)
+    public static async Task<Stream> GetLicenseAsync(this PackageArchiveReader package, CancellationToken cancellationToken)
     {
-        var nuspec = packageReader.NuspecReader;
+        var licenseMetadata = package.NuspecReader.GetLicenseMetadata();
+        if (licenseMetadata.Type == LicenseType.File && licenseMetadata.License == null)
+        {
+            throw new InvalidOperationException("Package does not have a license file!");
+        }
+
+        var licensePath = PathUtility.StripLeadingDirectorySeparators(licenseMetadata.License);
+        return await package.GetStreamAsync(licensePath, cancellationToken);
+    }
+
+    public static Package GetPackageMetadata(this PackageArchiveReader package)
+    {
+        var nuspec = package.NuspecReader;
 
         (var repositoryUri, var repositoryType) = GetRepositoryMetadata(nuspec);
 
@@ -55,10 +95,12 @@ public static Package GetPackageMetadata(this PackageArchiveReader packageReader
             Version = nuspec.GetVersion(),
             Authors = ParseAuthors(nuspec.GetAuthors()),
             Description = nuspec.GetDescription(),
-            HasReadme = packageReader.HasReadme(),
-            HasEmbeddedIcon = packageReader.HasEmbeddedIcon(),
+            HasReadme = package.HasReadme(),
+            HasEmbeddedIcon = package.HasEmbeddedIcon(),
+            HasEmbeddedLicense = package.HasEmbeddedLicense(),
             IsPrerelease = nuspec.GetVersion().IsPrerelease,
             Language = nuspec.GetLanguage() ?? string.Empty,
+            LicenseFormatIsMarkdown = package.IsLicenseFormatMarkdown(),
             ReleaseNotes = nuspec.GetReleaseNotes() ?? string.Empty,
             Listed = true,
             MinClientVersion = nuspec.GetMinClientVersion()?.ToNormalizedString() ?? string.Empty,
@@ -75,11 +117,11 @@ public static Package GetPackageMetadata(this PackageArchiveReader packageReader
             Dependencies = GetDependencies(nuspec),
             Tags = ParseTags(nuspec.GetTags()),
             PackageTypes = GetPackageTypes(nuspec),
-            TargetFrameworks = GetTargetFrameworks(packageReader),
+            TargetFrameworks = GetTargetFrameworks(package),
         };
     }
 
-    // Based off https://github.com/NuGet/NuGetGallery/blob/master/src/NuGetGallery.Core/SemVerLevelKey.cs
+    /// <remarks>Based off: <see href="https://github.com/NuGet/NuGetGallery/blob/master/src/NuGetGallery.Core/SemVerLevelKey.cs"/></remarks>
     private static SemVerLevel GetSemVerLevel(NuspecReader nuspec)
     {
         if (nuspec.GetVersion().IsSemVer2)
@@ -104,7 +146,10 @@ private static SemVerLevel GetSemVerLevel(NuspecReader nuspec)
 
     private static Uri ParseUri(string uriString)
     {
-        if (string.IsNullOrEmpty(uriString)) return null;
+        if (string.IsNullOrEmpty(uriString))
+        {
+            return null;
+        }
 
         return new Uri(uriString);
     }
@@ -113,14 +158,20 @@ private static Uri ParseUri(string uriString)
 
     private static string[] ParseAuthors(string authors)
     {
-        if (string.IsNullOrEmpty(authors)) return Array.Empty<string>();
+        if (string.IsNullOrEmpty(authors))
+        {
+            return Array.Empty<string>();
+        }
 
         return authors.Split(Separator, StringSplitOptions.RemoveEmptyEntries);
     }
 
     private static string[] ParseTags(string tags)
     {
-        if (string.IsNullOrEmpty(tags)) return Array.Empty<string>();
+        if (string.IsNullOrEmpty(tags))
+        {
+            return Array.Empty<string>();
+        }
 
         return tags.Split(Separator, StringSplitOptions.RemoveEmptyEntries);
     }
@@ -204,9 +255,9 @@ private static List<PackageType> GetPackageTypes(NuspecReader nuspec)
         return packageTypes;
     }
 
-    private static List<TargetFramework> GetTargetFrameworks(PackageArchiveReader packageReader)
+    private static List<TargetFramework> GetTargetFrameworks(PackageArchiveReader package)
     {
-        var targetFrameworks = packageReader
+        var targetFrameworks = package
             .GetSupportedFrameworks()
             .Select(f => new TargetFramework
             {

src/BaGetter.Core/IUrlGenerator.cs

@@ -101,4 +101,12 @@ public interface IUrlGenerator
     /// <param name="id">The package's ID</param>
     /// <param name="version">The package's version</param>
     string GetPackageIconDownloadUrl(string id, NuGetVersion version);
+
+    /// <summary>
+    /// Get the URL to download a package's license.
+    /// </summary>
+    /// <param name="id">The package's ID</param>
+    /// <param name="version">The package's version</param>
+    /// <param name="licenseFormatIsMarkdown">Is the format of the license Markdown?</param>
+    string GetPackageLicenseDownloadUrl(string id, NuGetVersion version, bool licenseFormatIsMarkdown);
 }

src/BaGetter.Core/Indexing/PackageIndexingService.cs

@@ -40,6 +40,7 @@ public async Task<PackageIndexingResult> IndexAsync(Stream packageStream, Cancel
         Stream nuspecStream;
         Stream readmeStream;
         Stream iconStream;
+        Stream licenseStream;
 
         try
         {
@@ -70,6 +71,16 @@ public async Task<PackageIndexingResult> IndexAsync(Stream packageStream, Cancel
                 {
                     iconStream = null;
                 }
+
+                if (package.HasEmbeddedLicense)
+                {
+                    licenseStream = await packageReader.GetLicenseAsync(cancellationToken);
+                    licenseStream = await licenseStream.AsTemporaryFileStreamAsync(cancellationToken);
+                }
+                else
+                {
+                    licenseStream = null;
+                }
             }
         }
         catch (Exception e)
@@ -108,6 +119,7 @@ await _storage.SavePackageContentAsync(
                 nuspecStream,
                 readmeStream,
                 iconStream,
+                licenseStream,
                 cancellationToken);
         }
         catch (Exception e)

src/BaGetter.Core/Metadata/RegistrationBuilder.cs

@@ -74,7 +74,9 @@ private BaGetRegistrationIndexPageItem ToRegistrationIndexPageItem(Package packa
                     ? _url.GetPackageIconDownloadUrl(package.Id, package.Version)
                     : package.IconUrlString,
                 Language = package.Language,
-                LicenseUrl = package.LicenseUrlString,
+                LicenseUrl = package.HasEmbeddedLicense
+                    ? _url.GetPackageLicenseDownloadUrl(package.Id, package.Version, package.LicenseFormatIsMarkdown)
+                    : package.LicenseUrlString,
                 Listed = package.Listed,
                 MinClientVersion = package.MinClientVersion,
                 ReleaseNotes = package.ReleaseNotes,

src/BaGetter.Core/Search/SearchResponseBuilder.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using BaGetter.Protocol.Models;
@@ -25,6 +25,9 @@ public SearchResponse BuildSearch(IReadOnlyList<PackageRegistration> packageRegi
             var iconUrl = latest.HasEmbeddedIcon
                 ? _url.GetPackageIconDownloadUrl(latest.Id, latest.Version)
                 : latest.IconUrlString;
+            var licenseUrl = latest.HasEmbeddedLicense
+                ? _url.GetPackageLicenseDownloadUrl(latest.Id, latest.Version, latest.LicenseFormatIsMarkdown)
+                : latest.LicenseUrlString;
 
             result.Add(new SearchResult
             {
@@ -33,7 +36,7 @@ public SearchResponse BuildSearch(IReadOnlyList<PackageRegistration> packageRegi
                 Description = latest.Description,
                 Authors = latest.Authors,
                 IconUrl = iconUrl,
-                LicenseUrl = latest.LicenseUrlString,
+                LicenseUrl = licenseUrl,
                 ProjectUrl = latest.ProjectUrlString,
                 RegistrationIndexUrl = _url.GetRegistrationIndexUrl(latest.Id),
                 Summary = latest.Summary,

src/BaGetter.Core/Storage/IPackageStorageService.cs

@@ -6,8 +6,8 @@
 namespace BaGetter.Core;
 
 /// <summary>
-/// Stores packages' content. Packages' state are stored by the
-/// <see cref="IPackageDatabase"/>.
+/// Stores packages' content.<br/>
+/// Packages' state are stored by the <see cref="IPackageDatabase"/>.
 /// </summary>
 public interface IPackageStorageService
 {
@@ -20,6 +20,7 @@ public interface IPackageStorageService
     /// <param name="nuspecStream">The package's nuspec stream.</param>
     /// <param name="readmeStream">The package's readme stream, or null if none.</param>
     /// <param name="iconStream">The package's icon stream, or null if none.</param>
+    /// <param name="licenseStream">The package's license stream, or null if none.</param>
     /// <param name="cancellationToken"></param>
     /// <returns></returns>
     Task SavePackageContentAsync(
@@ -28,6 +29,7 @@ Task SavePackageContentAsync(
         Stream nuspecStream,
         Stream readmeStream,
         Stream iconStream,
+        Stream licenseStream,
         CancellationToken cancellationToken);
 
     /// <summary>
@@ -57,8 +59,25 @@ Task SavePackageContentAsync(
     /// <returns>The package's readme stream.</returns>
     Task<Stream> GetReadmeStreamAsync(string id, NuGetVersion version, CancellationToken cancellationToken);
 
+    /// <summary>
+    /// Retrieve a package's icon stream if the icon is an embedded file.
+    /// </summary>
+    /// <param name="id">The package's id.</param>
+    /// <param name="version">The package's version.</param>    
+    /// <param name="cancellationToken"></param>
+    /// <returns>The package's icon stream.</returns>
     Task<Stream> GetIconStreamAsync(string id, NuGetVersion version, CancellationToken cancellationToken);
 
+    /// <summary>
+    /// Retrieve a package's license stream if the license is an embedded file.
+    /// </summary>
+    /// <param name="id">The package's id.</param>
+    /// <param name="version">The package's version.</param>
+    /// <param name="licenseFormatIsMarkdown">Is the format of the license Markdown?</param>
+    /// <param name="cancellationToken"></param>
+    /// <returns>The package's license stream.</returns>
+    Task<Stream> GetLicenseStreamAsync(string id, NuGetVersion version, bool licenseFormatIsMarkdown, CancellationToken cancellationToken);
+
     /// <summary>
     /// Remove a package's content from storage. This operation SHOULD succeed
     /// even if the package does not exist.