Just in case you find a use for some web proxy code…
I wrote a HttpListener proxy based on the HttpListener MSDN docs, and the web request code I did for something else. I had to do this because I needed to use the X-Plane updater from work which let me specify only an anonymous proxy, not the authenticated type that is at work. Here’s the code I got working for streaming binary data (note the HttpListener MSDN code only works for text as I discovered).
To test it I guess you could set a proxy in your web browser as 127.0.0.1:8080. The code below is the complete program.
using System;
using System.Net;
using System.Collections.Generic;
using System.Text;
using System.IO;
namespace HttpListenerProxy
{
class RequestData
{
public HttpWebRequest WebRequest;
public HttpListenerContext Context;
public RequestData(HttpWebRequest request, HttpListenerContext context)
{
WebRequest = request;
Context = context;
}
}
class Program
{
static void Main(string[] args)
{
// Create a listener.
HttpListener listener = new HttpListener();
listener.Prefixes.Add("http://*:8080/");
listener.Start();
try
{
while (true)
{
Console.WriteLine("Listening…");
// Note: The GetContext method blocks while waiting for a request.
HttpListenerContext context = listener.GetContext();
string requestString = context.Request.RawUrl;
Console.WriteLine("Got request for " + requestString);
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(requestString);
request.KeepAlive = false;
request.Proxy.Credentials = CredentialCache.DefaultCredentials;
request.Timeout = 200000;
RequestData requestData = new RequestData(request, context);
IAsyncResult result = (IAsyncResult)request.BeginGetResponse(new AsyncCallback(RespCallback), requestData);
}
}
catch (Exception e)
{
Console.WriteLine("\nMain Exception raised!");
Console.WriteLine("Source :{0} ", e.Source);
Console.WriteLine("Message :{0} ", e.Message);
}
listener.Stop();
}
static void RespCallback(IAsyncResult asynchronousResult)
{
try
{
// State of request is asynchronous.
RequestData requestData = (RequestData)asynchronousResult.AsyncState;
Console.WriteLine("Got back response from " + requestData.Context.Request.Url.AbsoluteUri);
using(HttpWebResponse response = (HttpWebResponse)requestData.WebRequest.EndGetResponse(asynchronousResult))
using (Stream receiveStream = response.GetResponseStream())
{
HttpListenerResponse responseOut = requestData.Context.Response;
// Need to get the length of the response before it can be forwarded on
responseOut.ContentLength64 = response.ContentLength;
int bytesCopied = CopyStream(receiveStream, responseOut.OutputStream);
responseOut.OutputStream.Close();
Console.WriteLine("Copied {0} bytes", bytesCopied);
}
}
catch (Exception e)
{
Console.WriteLine("\nMain Exception raised!");
Console.WriteLine("Source :{0} ", e.Source);
Console.WriteLine("Message :{0} ", e.Message);
}
}
public static int CopyStream(Stream input, Stream output)
{
byte[] buffer = new byte[32768];
int bytesWritten = 0;
while (true)
{
int read = input.Read(buffer, 0, buffer.Length);
if (read <= 0)
break;
output.Write(buffer, 0, read);
bytesWritten += read;
}
return bytesWritten;
}
}
}
