Question

我正在使用套接字在.NET中使用代理服务器，我发现代码执行时非常感兴趣：

当我逐步调试代码时 - 代理服务器工作正常
当我在没有调试的情况下启动代理服务器时 - 我在浏览器中出错。

我真的不知道为什么它像我上面描述的那样有效。也许，某人已经解决了这个问题？

以下是我的代理服务器的代码：

using System;
using System.Collections.Generic;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;

namespace Statistiks.Lib
{
    internal class NetworkMonitor
    {
        private readonly IList<string> _denied;
        private readonly Socket _srvSocket;
        private readonly Thread _srvThread;

        public NetworkMonitor(int port, IList<string> deniedList)
        {
            _denied = deniedList;
            _srvSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream,
                                    ProtocolType.Tcp);
            _srvSocket.Bind(new IPEndPoint(IPAddress.Loopback, port));
            _srvThread = new Thread(ProxyServerThread);
            _srvThread.Start(_srvSocket);
        }

        private void ProxyServerThread(object obj)
        {
            var srv = obj as Socket;
            srv.Listen(1024);
            while (true)
            {
                Socket clientSocket = srv.Accept();
                ThreadPool.QueueUserWorkItem(cSocket =>
                    {
                        var client = cSocket as Socket;
                        if (client.Available <= 0)
                        {
                            client.Shutdown(SocketShutdown.Both);
                            client.Close();
                            return;
                        }
                        var recieveBuf = new byte[client.Available];
                        client.Receive(recieveBuf, SocketFlags.None);
                        var ni = new NetworkInfo();
                        try
                        {
                            ni.Url = new Uri(Encoding.ASCII.GetString(recieveBuf)
                                                     .Split(new[] {"\r\n"}, StringSplitOptions.RemoveEmptyEntries)[0]
                                                 .Split(' ')[1]);
                        }
                        catch (ArgumentOutOfRangeException)
                        {
                            client.Shutdown(SocketShutdown.Both);
                            client.Close();
                            return;
                        }
                        var forwardedSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream,
                                                         ProtocolType.Tcp);
                        forwardedSocket.Connect(Dns.GetHostAddresses(ni.Url.Host)[0], ni.Url.Port);
                        forwardedSocket.Send(recieveBuf, SocketFlags.None);
                        recieveBuf = new byte[forwardedSocket.Available];
                        forwardedSocket.Receive(recieveBuf, SocketFlags.None);
                        client.Send(recieveBuf, SocketFlags.None);
                        forwardedSocket.Shutdown(SocketShutdown.Both);
                        forwardedSocket.Disconnect(false);
                        client.Shutdown(SocketShutdown.Both);
                        client.Disconnect(false);
                        forwardedSocket.Close();
                        client.Close();
                    }, clientSocket);
            }
        }
    }

    internal struct NetworkInfo
    {
        internal Uri Url;
    }
}

Answer 1

调试器下的不同结果可能是因为所有数据都适合套接字缓冲区，调试的额外延迟允许所有数据在调用Receive之前到达。

然而，在正常执行情况下，情况并非如此。数据将以数据包形式到达，为了知道数据结尾的位置，您必须解析HTTP请求。套接字的Available属性仅指示当前缓冲区中的数据量，它不是整个消息的长度。虽然使用原始套接字绝对可以读取，但使用NetworkStream：

更容易

IEnumerable<string> ReadRequestHeaders(Socket s)
{
    using (var stream = new NetworkStream(s, false))
    using (var reader = new StreamReader(stream))
    {
        while (true)
        {
            var line = reader.ReadLine();
            if (line == "")
                break;

            yield return line;
        }
    }
}

对于HTTP消息的其余部分也是如此 - 为了正确转发它，您必须知道它的结束位置，这意味着理解Content-Length或Transfer-Encoding字段并相应地解析。

C＃Proxy Server无法正常工作

1 个答案: