From dbb09e4ab936413694faa3f743c8d8f6cd8e5aba Mon Sep 17 00:00:00 2001
From: Marco Rossignoli <marco.rossignoli@gmail.com>
Date: Tue, 28 May 2019 18:36:25 +0200
Subject: [PATCH] User-Agent header is ignored in "CONNECT" requests 
 (dotnet/corefx#37785)

* flow UserAgent on CONNECT

* Apply Stephen feedback

* address PR feedback

* update test

* fix style


Commit migrated from https://github.com/dotnet/corefx/commit/1064d0352c007fd2d8fb32d7f6e286fbb6d41264
---
 .../Http/SocketsHttpHandler/HttpConnectionPool.cs  | 10 ++++-
 .../tests/FunctionalTests/HttpClientHandlerTest.cs | 52 ++++++++++++++++++++++
 2 files changed, 60 insertions(+), 2 deletions(-)

diff --git a/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnectionPool.cs b/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnectionPool.cs
index c747304..ba60505 100644
--- a/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnectionPool.cs
+++ b/src/libraries/System.Net.Http/src/System/Net/Http/SocketsHttpHandler/HttpConnectionPool.cs
@@ -5,6 +5,7 @@
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
+using System.Net.Http.Headers;
 using System.Net.Http.HPack;
 using System.Net.Security;
 using System.Net.Sockets;
@@ -617,7 +618,7 @@ namespace System.Net.Http
                     case HttpConnectionKind.ProxyTunnel:
                     case HttpConnectionKind.SslProxyTunnel:
                         HttpResponseMessage response;
-                        (stream, response) = await EstablishProxyTunnel(cancellationToken).ConfigureAwait(false);
+                        (stream, response) = await EstablishProxyTunnel(request.HasHeaders ? request.Headers : null, cancellationToken).ConfigureAwait(false);
                         if (response != null)
                         {
                             // Return non-success response from proxy.
@@ -666,12 +667,17 @@ namespace System.Net.Http
         }
 
         // Returns the established stream or an HttpResponseMessage from the proxy indicating failure.
-        private async ValueTask<(Stream, HttpResponseMessage)> EstablishProxyTunnel(CancellationToken cancellationToken)
+        private async ValueTask<(Stream, HttpResponseMessage)> EstablishProxyTunnel(HttpRequestHeaders headers, CancellationToken cancellationToken)
         {
             // Send a CONNECT request to the proxy server to establish a tunnel.
             HttpRequestMessage tunnelRequest = new HttpRequestMessage(HttpMethod.Connect, _proxyUri);
             tunnelRequest.Headers.Host = $"{_host}:{_port}";    // This specifies destination host/port to connect to
 
+            if (headers != null && headers.TryGetValues(HttpKnownHeaderNames.UserAgent, out IEnumerable<string> values))
+            {
+                tunnelRequest.Headers.TryAddWithoutValidation(HttpKnownHeaderNames.UserAgent, values);
+            }
+
             HttpResponseMessage tunnelResponse = await _poolManager.SendProxyConnectAsync(tunnelRequest, _proxyUri, cancellationToken).ConfigureAwait(false);
 
             if (tunnelResponse.StatusCode != HttpStatusCode.OK)
diff --git a/src/libraries/System.Net.Http/tests/FunctionalTests/HttpClientHandlerTest.cs b/src/libraries/System.Net.Http/tests/FunctionalTests/HttpClientHandlerTest.cs
index 70ff032..7cb3dbe 100644
--- a/src/libraries/System.Net.Http/tests/FunctionalTests/HttpClientHandlerTest.cs
+++ b/src/libraries/System.Net.Http/tests/FunctionalTests/HttpClientHandlerTest.cs
@@ -449,6 +449,58 @@ namespace System.Net.Http.Functional.Tests
             Assert.True(connectionAccepted);
         }
 
+        [SkipOnTargetFramework(TargetFrameworkMonikers.Uap, "UAP HTTP stack doesn't support .Proxy property")]
+        [Theory]
+        [InlineData(true)]
+        [InlineData(false)]
+        [OuterLoop("Uses external server")]
+        public async Task ProxyTunnelRequest_UserAgentHeaderAdded(bool addUserAgentHeader)
+        {
+            if (!UseSocketsHttpHandler)
+            {
+                return; // Skip test since the fix is only in SocketsHttpHandler.
+            }
+
+            string addressUri = $"https://{Configuration.Http.SecureHost}/";
+            bool connectionAccepted = false;
+
+            await LoopbackServer.CreateClientAndServerAsync(async proxyUri =>
+            {
+                using (HttpClientHandler handler = CreateHttpClientHandler())
+                using (var client = new HttpClient(handler))
+                {
+                    handler.Proxy = new WebProxy(proxyUri);
+                    handler.ServerCertificateCustomValidationCallback = TestHelper.AllowAllCertificates;
+                    if (addUserAgentHeader)
+                    {
+                        client.DefaultRequestHeaders.UserAgent.Add(new ProductInfoHeaderValue("Mozilla", "5.0"));
+                    }
+                    try
+                    {
+                        await client.GetAsync(addressUri); 
+                    }
+                    catch 
+                    {
+                    }
+                }
+            }, server => server.AcceptConnectionAsync(async connection =>
+            {
+                connectionAccepted = true;
+                List<string> headers = await connection.ReadRequestHeaderAndSendResponseAsync();
+                Assert.Contains($"CONNECT {Configuration.Http.SecureHost}:443 HTTP/1.1", headers);
+                if (addUserAgentHeader)
+                {
+                    Assert.Contains("User-Agent: Mozilla/5.0", headers);
+                }
+                else
+                {
+                    Assert.DoesNotContain("User-Agent:", headers);
+                }
+            }));
+
+            Assert.True(connectionAccepted);
+        }
+
         public static IEnumerable<object[]> SecureAndNonSecure_IPBasedUri_MemberData() =>
             from address in new[] { IPAddress.Loopback, IPAddress.IPv6Loopback }
             from useSsl in new[] { true, false }
-- 
2.7.4