add nuget icon cache

src/SharpIDE.Application/Features/Nuget/NugetPackageIconCacheService.cs

@@ -0,0 +1,52 @@
+namespace SharpIDE.Application.Features.Nuget;
+
+public enum NugetPackageIconFormat
+{
+	Png,
+	Jpg
+}
+public class NugetPackageIconCacheService(IHttpClientFactory httpClientFactory)
+{
+	private readonly IHttpClientFactory _httpClientFactory = httpClientFactory;
+
+	public async Task<(byte[]? bytes, NugetPackageIconFormat?)> GetNugetPackageIcon(string packageId, Uri? iconUrl)
+	{
+		var appdataFolderPath = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData);
+		var cacheFolder = Path.Combine(appdataFolderPath, "SharpIDE", "NugetPackageIconCache");
+		Directory.CreateDirectory(cacheFolder);
+		var packageIconFilePath = Path.Combine(cacheFolder, $"{packageId}.bin");
+		if (File.Exists(packageIconFilePath))
+		{
+			var bytes = await File.ReadAllBytesAsync(packageIconFilePath);
+			return (bytes, GetImageFormat(bytes));
+		}
+		else if (iconUrl is null)
+		{
+			return (null, null);
+		}
+		else
+		{
+			var httpClient = _httpClientFactory.CreateClient();
+			var iconBytes = await httpClient.GetByteArrayAsync(iconUrl);
+			await File.WriteAllBytesAsync(packageIconFilePath, iconBytes);
+			return (iconBytes, GetImageFormat(iconBytes));
+		}
+	}
+
+	private static NugetPackageIconFormat? GetImageFormat(byte[] imageBytes)
+	{
+		// PNG files start with 89 50 4E 47 0D 0A 1A 0A
+		if (imageBytes is [0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A, ..])
+		{
+			return NugetPackageIconFormat.Png;
+		}
+
+		// JPEG files start with FF D8 and end with FF D9
+		if (imageBytes is [0xFF, 0xD8, .., 0xFF, 0xD9])
+		{
+			return NugetPackageIconFormat.Jpg;
+		}
+
+		return null;
+	}
+}

src/SharpIDE.Application/SharpIDE.Application.csproj

@@ -27,6 +27,7 @@
     <PackageReference Include="LibGit2Sharp" />
     <PackageReference Include="Microsoft.Diagnostics.NETCore.Client" PrivateAssets="all" />
     <PackageReference Include="Microsoft.Extensions.FileSystemGlobbing" />
+    <PackageReference Include="Microsoft.Extensions.Http" />
     <PackageReference Include="Microsoft.VisualStudio.Shared.VSCodeDebugProtocol" />
     <!-- If any Microsoft.Build.*.dll (Excluding Locator) ends up in the output, it will be prioritised for loading by MSBuild Nodes  -->
     <PackageReference Include="Ardalis.GuardClauses" />