✨ Gateway proxy for contained frontend to access other services

2025-07-25 22:24:02 +08:00
parent a4b84f0717
commit d13fb8b0e4
8 changed files with 109 additions and 5 deletions
--- a/DysonNetwork.Shared/Registry/GatewayReverseProxy.cs
+++ b/DysonNetwork.Shared/Registry/GatewayReverseProxy.cs
@@ -0,0 +1,83 @@
+using System.Diagnostics;
+using System.Net;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.DependencyInjection;
+using Yarp.ReverseProxy.Forwarder;
+
+namespace DysonNetwork.Shared.Registry;
+
+public static class GatewayReverseProxy
+{
+    /// <summary>
+    /// Provides reverse proxy for DysonNetwork.Gateway.
+    /// Give the ability to the contained frontend to access other services via the gateway.
+    /// </summary>
+    /// <param name="app">The asp.net core application</param>
+    /// <returns>The modified application</returns>
+    public static WebApplication MapGatewayProxy(this WebApplication app)
+    {
+        var httpClient = new HttpMessageInvoker(new SocketsHttpHandler
+        {
+            UseProxy = false,
+            AllowAutoRedirect = true,
+            AutomaticDecompression = DecompressionMethods.All,
+            UseCookies = true,
+            EnableMultipleHttp2Connections = true,
+            ActivityHeadersPropagator = new ReverseProxyPropagator(DistributedContextPropagator.Current),
+            ConnectTimeout = TimeSpan.FromSeconds(15),
+        });
+
+        var transformer = new GatewayReverseProxyTransformer();
+        var requestConfig = new ForwarderRequestConfig();
+
+        app.Map("/cgi/{**catch-all}", async (HttpContext context, IHttpForwarder forwarder) =>
+        {
+            var registry = context.RequestServices.GetRequiredService<ServiceRegistry>();
+            var gatewayUrl = await registry.GetServiceUrl("DysonNetwork.Gateway");
+            if (gatewayUrl is null)
+            {
+                context.Response.StatusCode = 404;
+                await context.Response.WriteAsync("Gateway not found");
+                return;
+            }
+
+            var error = await forwarder.SendAsync(
+                context,
+                gatewayUrl,
+                httpClient,
+                requestConfig,
+                transformer
+            );
+            if (error != ForwarderError.None)
+            {
+                var errorFeature = context.GetForwarderErrorFeature();
+                var exception = errorFeature?.Exception;
+                context.Response.StatusCode = 502;
+                context.Response.ContentType = "text/plain";
+                await context.Response.WriteAsync($"Gateway remote error: {exception?.Message}");
+            }
+        });
+
+        return app;
+    }
+}
+
+public class GatewayReverseProxyTransformer : HttpTransformer
+{
+    private const string Value = "/cgi";
+    
+    public override ValueTask TransformRequestAsync(
+        HttpContext httpContext,
+        HttpRequestMessage proxyRequest,
+        string destinationPrefix,
+        CancellationToken cancellationToken
+    )
+    {
+        httpContext.Request.Path = httpContext.Request.Path.StartsWithSegments(Value, out var remaining)
+            ? remaining
+            : httpContext.Request.Path;
+        
+        return Default.TransformRequestAsync(httpContext, proxyRequest, destinationPrefix, cancellationToken);
+    }
+}