Simple Http Socket Proxy: Questions

Question

I am trying to find out how sockets work in C #. My idea was to program a simple HTTP proxy: Here is my code:

using System;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading;

class Program
{
    static void Main(string[] args)
    {
        ThreadPool.SetMaxThreads(1000, 500);
        ThreadPool.SetMinThreads(500, 250);

        TcpListener listener = new TcpListener(IPAddress.Any, 8282);
        listener.Start();

        while (true)
        {
            Socket client = listener.AcceptSocket();
            ThreadPool.QueueUserWorkItem(ProcessSocket, client);
        }
    }

    private static readonly string patternHostPort = @"(Host:\s)(\S+)(:)(\d+)";
    private static readonly string patternHost = @"(Host:\s)(\S+)";
    private static Regex regexHostPort = new Regex(patternHostPort);
    private static Regex regexHost = new Regex(patternHost);

    static void ProcessSocket(object request)
    {
        string requestString = string.Empty;
        MemoryStream mStream = new MemoryStream();
        int bytesReceived;
        int bytesSended;
        byte[] buffer;
        byte[] byteOriginalRequest;

        Socket socketClient = (Socket)request;
        Console.WriteLine("Incoming connection: " + socketClient.RemoteEndPoint.ToString());

        buffer = new byte[4096];

        bytesReceived = socketClient.Receive(buffer, 0, buffer.Length, SocketFlags.None);
        mStream.Write(buffer, 0, bytesReceived);
        while (socketClient.Available > 0)
        {
            bytesReceived = socketClient.Receive(buffer, 0, buffer.Length, SocketFlags.None);
            mStream.Write(buffer, 0, bytesReceived);
        }

        mStream.Close();

        byteOriginalRequest = mStream.ToArray();
        requestString = Encoding.ASCII.GetString(byteOriginalRequest);
        //Console.WriteLine(requestString);

        #region Get requested Host and Port
        string srvHost = string.Empty;
        string srvPort = string.Empty;

        Match matchHostPort = regexHostPort.Match(requestString);
        if (matchHostPort.Success)
        {
            srvHost = matchHostPort.Groups[2].Value;
            srvPort = matchHostPort.Groups[4].Value;
        }
        else
        {
            Match matchHost = regexHost.Match(requestString);
            if (matchHost.Success)
            {
                srvHost = matchHost.Groups[2].Value;
                srvPort = "80";
            }
            else
            {
                Console.WriteLine("Invalid request?");
            }
        }
        #endregion

        Console.WriteLine(string.Format("Request to {0} on port {1}", srvHost, srvPort));

        IPAddress[] ipAddress = Dns.GetHostAddresses(srvHost);
        IPEndPoint endPoint = new IPEndPoint(ipAddress[0], int.Parse(srvPort));

        using (Socket socketProxy = new Socket(endPoint.AddressFamily, SocketType.Stream, ProtocolType.Tcp))
        {
            socketProxy.Connect(endPoint);

            bytesSended = socketProxy.Send(byteOriginalRequest, byteOriginalRequest.Length, SocketFlags.None);

            MemoryStream m2Stream = new MemoryStream();
            bytesReceived = 1;
            while (bytesReceived > 0)
            {
                bytesReceived = socketProxy.Receive(buffer, 0, buffer.Length, SocketFlags.None);
                m2Stream.Write(buffer, 0, bytesReceived);
            }

            m2Stream.Close();
            byte[] finalResponse = m2Stream.ToArray();
            string stringFinalResponse = Encoding.ASCII.GetString(finalResponse);

            bytesSended = socketClient.Send(finalResponse, finalResponse.Length, SocketFlags.None);

            socketProxy.Close();
        }

        socketClient.Close();
    }
}

Here are a few questions:

1) Why if I replace this

bytesReceived = 1;
while (bytesReceived > 0)
{
    bytesReceived = socketProxy.Receive(buffer, 0, buffer.Length, SocketFlags.None);
    m2Stream.Write(buffer, 0, bytesReceived);
}

with this

while (socketProxy.Available > 0)
{
    bytesReceived = socketProxy.Receive(buffer, 0, buffer.Length, SocketFlags.None);
    m2Stream.Write(buffer, 0, bytesReceived);
}

Am I only getting a blank page (in browser)?

2) Perhaps it is connected with 1), but ... with the current code it takes some time to load any simple page (for example, google), debugging I found that the problem may be in socketProxy.Receive ... but I do not know why .

3) Is there a difference between

socketProxy.Send(byteOriginalRequest, byteOriginalRequest.Length, SocketFlags.None);

or

socketProxy.Send(byteOriginalRequest);

? (More parameters invalid answer :)

4) Any recommended reading? book, textbook, ...?

5) Any other suggestion to learn about sockets?

. .

Answer 1

1) Socket.Available , , , . Socket.Read (), , . . , . , . , , , .

2) , , , , . .

3) .

4) 5), API- CLR- API- API, C, , # .

, Shutdown Close. Close, , , , , - , . Shutdown (SocketShutdown.Send) Read ( , ). , Read , , , , Shutdown. Close.

, "" , , . , , , .

Answer 2

Sockets, "". , - WinsockTool.

, .MSI , :

http://www.isatools.org/tools/winsocktool.msi

Google : isatools.org WinsockTool

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