Fix outgoing format of the forwarding appended by the reverse proxy for IPv6 (#726)

Author: Kaliumhexacyanoferrat

Modules/ReverseProxy/Provider/ReverseProxyProvider.cs

@@ -1,6 +1,7 @@
 using System.Globalization;
 using System.Net;
 using System.Net.Http.Headers;
+using System.Net.Sockets;
 using System.Web;
 
 using GenHTTP.Api.Content;
@@ -260,7 +261,14 @@ private static string GetForwarding(Forwarding forwarding)
 
         if (forwarding.For is not null)
         {
-            result.Add($"for={forwarding.For}");
+            if (forwarding.For.AddressFamily == AddressFamily.InterNetworkV6)
+            {
+                result.Add($"for=[{forwarding.For}]");
+            }
+            else
+            {
+                result.Add($"for={forwarding.For}");
+            }
         }
 
         if (forwarding.Host is not null)

Testing/Acceptance/Modules/ReverseProxy/ReverseProxyTests.cs

@@ -1,10 +1,15 @@
 using System.Net;
+
 using GenHTTP.Api.Content;
 using GenHTTP.Api.Protocol;
+
 using GenHTTP.Modules.IO;
 using GenHTTP.Modules.Layouting;
 using GenHTTP.Modules.ReverseProxy;
+
+
 using Microsoft.VisualStudio.TestTools.UnitTesting;
+
 using Cookie = GenHTTP.Api.Protocol.Cookie;
 
 namespace GenHTTP.Testing.Acceptance.Modules.ReverseProxy;
@@ -266,7 +271,6 @@ public async Task TestBadGateway(TestEngine engine)
         await response.AssertStatusAsync(HttpStatusCode.BadGateway);
     }
 
-
     [TestMethod]
     [MultiEngineTest]
     public async Task TestCompression(TestEngine engine)