do not change headers in transparent mode

Author: honfika

Titanium.Web.Proxy/EventArguments/SessionEventArgs.cs

@@ -96,7 +96,9 @@ public bool ReRequest
         /// </summary>
         public event EventHandler<MultipartRequestPartSentEventArgs> MultipartRequestPartSent;
 
-        public ProxyEndPoint LocalEndPoint;
+        public ProxyEndPoint LocalEndPoint { get; }
+
+        public bool IsTransparent => LocalEndPoint is TransparentProxyEndPoint;
 
         /// <summary>
         /// Constructor to initialize the proxy

Titanium.Web.Proxy/Helpers/HttpResponseWriter.cs

@@ -20,7 +20,6 @@ public HttpResponseWriter(Stream stream, int bufferSize) : base(stream, bufferSi
         public async Task WriteResponseAsync(Response response, bool flush = true)
         {
             await WriteResponseStatusAsync(response.HttpVersion, response.StatusCode, response.StatusDescription);
-            response.Headers.FixProxyHeaders();
             await WriteHeadersAsync(response.Headers, flush);
         }
 

Titanium.Web.Proxy/Http/HttpWebClient.cs

@@ -79,7 +79,7 @@ internal void SetConnection(TcpConnection connection)
         /// Prepare and send the http(s) request
         /// </summary>
         /// <returns></returns>
-        internal async Task SendRequest(bool enable100ContinueBehaviour)
+        internal async Task SendRequest(bool enable100ContinueBehaviour, bool isTransparent)
         {
             var upstreamProxy = ServerConnection.UpStreamProxy;
 
@@ -89,12 +89,12 @@ internal async Task SendRequest(bool enable100ContinueBehaviour)
 
             //prepare the request & headers
             await writer.WriteLineAsync(Request.CreateRequestLine(Request.Method,
-                useUpstreamProxy ? Request.OriginalUrl : Request.RequestUri.PathAndQuery,
+                useUpstreamProxy || isTransparent ? Request.OriginalUrl : Request.RequestUri.PathAndQuery,
                 Request.HttpVersion));
 
 
             //Send Authentication to Upstream proxy if needed
-            if (upstreamProxy != null
+            if (!isTransparent && upstreamProxy != null
                 && ServerConnection.IsHttps == false
                 && !string.IsNullOrEmpty(upstreamProxy.UserName)
                 && upstreamProxy.Password != null)
@@ -106,7 +106,7 @@ await writer.WriteLineAsync(Request.CreateRequestLine(Request.Method,
             //write request headers
             foreach (var header in Request.Headers)
             {
-                if (header.Name != KnownHeaders.ProxyAuthorization)
+                if (isTransparent || header.Name != KnownHeaders.ProxyAuthorization)
                 {
                     await header.WriteToStreamAsync(writer);
                 }

Titanium.Web.Proxy/ProxyAuthorizationHandler.cs

@@ -76,6 +76,7 @@ private async Task<Response> SendAuthentication407Response(HttpResponseWriter cl
             response.Headers.AddHeader(KnownHeaders.ProxyAuthenticate, $"Basic realm=\"{ProxyRealm}\"");
             response.Headers.AddHeader(KnownHeaders.ProxyConnection, KnownHeaders.ProxyConnectionClose);
 
+            response.Headers.FixProxyHeaders();
             await clientStreamWriter.WriteResponseAsync(response);
             return response;
         }

Titanium.Web.Proxy/RequestHandler.cs

@@ -106,8 +106,11 @@ private async Task HandleClient(ExplicitProxyEndPoint endPoint, TcpClient tcpCli
                     }
 
                     //write back successfull CONNECT response
-                    connectArgs.WebSession.Response = ConnectResponse.CreateSuccessfullConnectResponse(version);
-                    await clientStreamWriter.WriteResponseAsync(connectArgs.WebSession.Response);
+                    var response = ConnectResponse.CreateSuccessfullConnectResponse(version);
+                    response.Headers.FixProxyHeaders();
+                    connectArgs.WebSession.Response = response;
+
+                    await clientStreamWriter.WriteResponseAsync(response);
 
                     var clientHelloInfo = await SslTools.PeekClientHello(clientStream);
                     bool isClientHello = clientHelloInfo != null;
@@ -401,14 +404,14 @@ private async Task HandleHttpSessionRequest(TcpClient client, CustomBufferedStre
                         args.ProxyClient.ClientStreamWriter = clientStreamWriter;
 
                         //proxy authorization check
-                        if (httpsConnectHostname == null && await CheckAuthorization(clientStreamWriter, args) == false)
+                        if (!args.IsTransparent && httpsConnectHostname == null && await CheckAuthorization(clientStreamWriter, args) == false)
                         {
                             break;
                         }
 
-                        PrepareRequestHeaders(args.WebSession.Request.Headers);
                         if (!isTransparentEndPoint)
                         {
+                            PrepareRequestHeaders(args.WebSession.Request.Headers);
                             args.WebSession.Request.Host = args.WebSession.Request.RequestUri.Authority;
                         }
 
@@ -447,6 +450,8 @@ private async Task HandleHttpSessionRequest(TcpClient client, CustomBufferedStre
                             connection = await GetServerConnection(args, false);
                         }
 
+                        var response = args.WebSession.Response;
+
                         //if upgrading to websocket then relay the requet without reading the contents
                         if (args.WebSession.Request.UpgradeToWebSocket)
                         {
@@ -457,13 +462,16 @@ private async Task HandleHttpSessionRequest(TcpClient client, CustomBufferedStre
                             string httpStatus = await connection.StreamReader.ReadLineAsync();
 
                             Response.ParseResponseLine(httpStatus, out var responseVersion, out int responseStatusCode, out string responseStatusDescription);
-                            args.WebSession.Response.HttpVersion = responseVersion;
-                            args.WebSession.Response.StatusCode = responseStatusCode;
-                            args.WebSession.Response.StatusDescription = responseStatusDescription;
+                            response.HttpVersion = responseVersion;
+                            response.StatusCode = responseStatusCode;
+                            response.StatusDescription = responseStatusDescription;
 
-                            await HeaderParser.ReadHeaders(connection.StreamReader, args.WebSession.Response.Headers);
+                            await HeaderParser.ReadHeaders(connection.StreamReader, response.Headers);
 
-                            await clientStreamWriter.WriteResponseAsync(args.WebSession.Response);
+                            if (!args.IsTransparent)
+                            {
+                                await clientStreamWriter.WriteResponseAsync(response);
+                            }
 
                             //If user requested call back then do it
                             if (BeforeResponse != null && !args.WebSession.Response.ResponseLocked)
@@ -483,7 +491,7 @@ await TcpHelper.SendRaw(clientStream, connection.Stream, BufferSize,
                         await HandleHttpSessionRequestInternal(connection, args);
 
                         //if connection is closing exit
-                        if (args.WebSession.Response.KeepAlive == false)
+                        if (response.KeepAlive == false)
                         {
                             break;
                         }
@@ -522,7 +530,7 @@ private async Task HandleHttpSessionRequestInternal(TcpConnection connection, Se
                 if (request.ExpectContinue)
                 {
                     args.WebSession.SetConnection(connection);
-                    await args.WebSession.SendRequest(Enable100ContinueBehaviour);
+                    await args.WebSession.SendRequest(Enable100ContinueBehaviour, args.IsTransparent);
                 }
 
                 //If 100 continue was the response inform that to the client
@@ -546,7 +554,7 @@ private async Task HandleHttpSessionRequestInternal(TcpConnection connection, Se
                 if (!request.ExpectContinue)
                 {
                     args.WebSession.SetConnection(connection);
-                    await args.WebSession.SendRequest(Enable100ContinueBehaviour);
+                    await args.WebSession.SendRequest(Enable100ContinueBehaviour, args.IsTransparent);
                 }
 
                 //check if content-length is > 0

Titanium.Web.Proxy/ResponseHandler.cs

@@ -70,7 +70,11 @@ private async Task HandleHttpSessionResponse(SessionEventArgs args)
                 //Write back response status to client
                 await clientStreamWriter.WriteResponseStatusAsync(response.HttpVersion, response.StatusCode, response.StatusDescription);
 
-                response.Headers.FixProxyHeaders();
+                if (!args.IsTransparent)
+                {
+                    response.Headers.FixProxyHeaders();
+                }
+
                 if (response.IsBodyRead)
                 {
                     bool isChunked = response.IsChunked;