/// <summary>
/// Invoke before response if it is set.
/// </summary>
/// <param name="args"></param>
/// <returns></returns>
protected async Task onBeforeResponse(SessionEventArgs args)
{
if (BeforeResponse != null)
{
await BeforeResponse.InvokeAsync(this, args, ExceptionFunc);
}
}
/// <summary>
/// Invoke before response if it is set.
/// </summary>
/// <param name="args"></param>
/// <returns></returns>
private async Task invokeBeforeResponse(SessionEventArgs args)
{
if (BeforeResponse != null)
{
await BeforeResponse.InvokeAsync(this, args, ExceptionFunc);
}
}
/// <summary>
/// This is the core request handler method for a particular connection from client
/// Will create new session (request/response) sequence until
/// client/server abruptly terminates connection or by normal HTTP termination
/// </summary>
/// <param name="client"></param>
/// <param name="clientStream"></param>
/// <param name="clientStreamReader"></param>
/// <param name="clientStreamWriter"></param>
/// <param name="httpsConnectHostname"></param>
/// <param name="endPoint"></param>
/// <param name="connectRequest"></param>
/// <param name="isTransparentEndPoint"></param>
/// <returns></returns>
private async Task HandleHttpSessionRequest(TcpClient client, CustomBufferedStream clientStream,
CustomBinaryReader clientStreamReader, HttpResponseWriter clientStreamWriter, string httpsConnectHostname,
ProxyEndPoint endPoint, ConnectRequest connectRequest, bool isTransparentEndPoint = false)
{
TcpConnection connection = null;
try
{
//Loop through each subsequest request on this particular client connection
//(assuming HTTP connection is kept alive by client)
while (true)
{
// read the request line
string httpCmd = await clientStreamReader.ReadLineAsync();
if (string.IsNullOrEmpty(httpCmd))
{
break;
}
var args = new SessionEventArgs(BufferSize, endPoint, ExceptionFunc)
{
ProxyClient = { TcpClient = client },
WebSession = { ConnectRequest = connectRequest }
};
try
{
Request.ParseRequestLine(httpCmd, out string httpMethod, out string httpUrl, out var version);
//Read the request headers in to unique and non-unique header collections
await HeaderParser.ReadHeaders(clientStreamReader, args.WebSession.Request.Headers);
Uri httpRemoteUri;
if (uriSchemeRegex.IsMatch(httpUrl))
{
try
{
httpRemoteUri = new Uri(httpUrl);
}
catch (Exception ex)
{
throw new Exception($"Invalid URI: '{httpUrl}'", ex);
}
}
else
{
string host = args.WebSession.Request.Host ?? httpsConnectHostname;
string hostAndPath = host;
if (httpUrl.StartsWith("/"))
{
hostAndPath += httpUrl;
}
string url = string.Concat(httpsConnectHostname == null ? "http://" : "https://", hostAndPath);
try
{
httpRemoteUri = new Uri(url);
}
catch (Exception ex)
{
throw new Exception($"Invalid URI: '{url}'", ex);
}
}
args.WebSession.Request.RequestUri = httpRemoteUri;
args.WebSession.Request.OriginalUrl = httpUrl;
args.WebSession.Request.Method = httpMethod;
args.WebSession.Request.HttpVersion = version;
args.ProxyClient.ClientStream = clientStream;
args.ProxyClient.ClientStreamReader = clientStreamReader;
args.ProxyClient.ClientStreamWriter = clientStreamWriter;
//proxy authorization check
if (!args.IsTransparent && httpsConnectHostname == null && await CheckAuthorization(clientStreamWriter, args) == false)
{
break;
}
if (!isTransparentEndPoint)
{
PrepareRequestHeaders(args.WebSession.Request.Headers);
args.WebSession.Request.Host = args.WebSession.Request.RequestUri.Authority;
}
//if win auth is enabled
//we need a cache of request body
//so that we can send it after authentication in WinAuthHandler.cs
if (isWindowsAuthenticationEnabledAndSupported && args.WebSession.Request.HasBody)
{
await args.GetRequestBody();
}
//If user requested interception do it
if (BeforeRequest != null)
{
await BeforeRequest.InvokeAsync(this, args, ExceptionFunc);
}
var response = args.WebSession.Response;
if (args.WebSession.Request.CancelRequest)
{
await HandleHttpSessionResponse(args);
if (!response.KeepAlive)
{
break;
}
continue;
}
//create a new connection if hostname/upstream end point changes
if (connection != null &&
(!connection.HostName.Equals(args.WebSession.Request.RequestUri.Host, StringComparison.OrdinalIgnoreCase) ||
(args.WebSession.UpStreamEndPoint != null &&
!args.WebSession.UpStreamEndPoint.Equals(connection.UpStreamEndPoint))))
{
connection.Dispose();
connection = null;
}
if (connection == null)
{
connection = await GetServerConnection(args, false);
}
//if upgrading to websocket then relay the requet without reading the contents
if (args.WebSession.Request.UpgradeToWebSocket)
{
//prepare the prefix content
var requestHeaders = args.WebSession.Request.Headers;
await connection.StreamWriter.WriteLineAsync(httpCmd);
await connection.StreamWriter.WriteHeadersAsync(requestHeaders);
string httpStatus = await connection.StreamReader.ReadLineAsync();
Response.ParseResponseLine(httpStatus, out var responseVersion, out int responseStatusCode, out string responseStatusDescription);
response.HttpVersion = responseVersion;
response.StatusCode = responseStatusCode;
response.StatusDescription = responseStatusDescription;
await HeaderParser.ReadHeaders(connection.StreamReader, response.Headers);
if (!args.IsTransparent)
{
await clientStreamWriter.WriteResponseAsync(response);
}
//If user requested call back then do it
if (BeforeResponse != null && !args.WebSession.Response.ResponseLocked)
{
await BeforeResponse.InvokeAsync(this, args, ExceptionFunc);
}
await TcpHelper.SendRaw(clientStream, connection.Stream, BufferSize,
(buffer, offset, count) => { args.OnDataSent(buffer, offset, count); },
(buffer, offset, count) => { args.OnDataReceived(buffer, offset, count); },
ExceptionFunc);
break;
}
//construct the web request that we are going to issue on behalf of the client.
await HandleHttpSessionRequestInternal(connection, args);
//if connection is closing exit
if (!response.KeepAlive)
{
break;
}
}
catch (Exception e) when(!(e is ProxyHttpException))
{
throw new ProxyHttpException("Error occured whilst handling session request", e, args);
}
finally
{
args.Dispose();
}
}
}
finally
{
connection?.Dispose();
}
}
/// <summary>
/// Called asynchronously when a request was successfully and we received the response
/// </summary>
/// <param name="args"></param>
/// <returns>true if client/server connection was terminated (and disposed) </returns>
private async Task HandleHttpSessionResponse(SessionEventArgs args)
{
try
{
//read response & headers from server
await args.WebSession.ReceiveResponse();
var response = args.WebSession.Response;
//check for windows authentication
if (isWindowsAuthenticationEnabledAndSupported && response.StatusCode == (int)HttpStatusCode.Unauthorized)
{
await Handle401UnAuthorized(args);
}
args.ReRequest = false;
//If user requested call back then do it
if (BeforeResponse != null && !response.ResponseLocked)
{
await BeforeResponse.InvokeAsync(this, args, ExceptionFunc);
}
//if user requested to send request again
//likely after making modifications from User Response Handler
if (args.ReRequest)
{
//clear current response
await args.ClearResponse();
await HandleHttpSessionRequestInternal(args.WebSession.ServerConnection, args);
return;
}
response.ResponseLocked = true;
var clientStreamWriter = args.ProxyClient.ClientStreamWriter;
//Write back to client 100-conitinue response if that's what server returned
if (response.Is100Continue)
{
await clientStreamWriter.WriteResponseStatusAsync(response.HttpVersion, (int)HttpStatusCode.Continue, "Continue");
await clientStreamWriter.WriteLineAsync();
}
else if (response.ExpectationFailed)
{
await clientStreamWriter.WriteResponseStatusAsync(response.HttpVersion, (int)HttpStatusCode.ExpectationFailed, "Expectation Failed");
await clientStreamWriter.WriteLineAsync();
}
//Write back response status to client
await clientStreamWriter.WriteResponseStatusAsync(response.HttpVersion, response.StatusCode, response.StatusDescription);
if (!args.IsTransparent)
{
response.Headers.FixProxyHeaders();
}
if (response.IsBodyRead)
{
bool isChunked = response.IsChunked;
string contentEncoding = response.ContentEncoding;
if (contentEncoding != null)
{
response.Body = await GetCompressedResponseBody(contentEncoding, response.Body);
if (isChunked == false)
{
response.ContentLength = response.Body.Length;
}
else
{
response.ContentLength = -1;
}
}
await clientStreamWriter.WriteHeadersAsync(response.Headers);
await clientStreamWriter.WriteBodyAsync(response.Body, isChunked);
}
else
{
await clientStreamWriter.WriteHeadersAsync(response.Headers);
//Write body if exists
if (response.HasBody)
{
await args.CopyResponseBodyAsync(clientStreamWriter, false);
}
}
}
catch (Exception e) when(!(e is ProxyHttpException))
{
throw new ProxyHttpException("Error occured whilst handling session response", e, args);
}
}