C#实现多线程的Web代理服务器实例

本文实例讲述了c#实现多线程的web代理服务器。分享给大家供大家参考。具体如下：

/**
proxy.cs：
c# programming tips & techniques
by charles wright, kris jamsa
publisher: osborne/mcgraw-hill (december 28, 2001)
isbn: 0072193794
*/
// proxy.cs -- implements a multi-threaded web proxy server
//
//    compile this program with the following command line:
//     c:>csc proxy.cs
using system;
using system.net;
using system.net.sockets;
using system.text;
using system.io;
using system.threading;
namespace nsproxyserver
{
 public class proxyserver
 {
  static public void main (string [] args)
  {
   int port = 3125;
   if (args.length > 0)
   {
    try
    {
     port = convert.toint32 (args[0]);
    }
    catch
    {
     console.writeline ("please enter a port number.");
     return;
    }
   }
   try
   {
    // create a listener for the proxy port
    tcplistener sockserver = new tcplistener (port);
    sockserver.start ();
    while (true)
    {
     // accept connections on the proxy port.
     socket socket = sockserver.acceptsocket ();
     // when acceptsocket returns, it means there is a connection. create
     // an instance of the proxy server class and start a thread running.
     clsproxyconnection proxy = new clsproxyconnection (socket);
     thread thrd = new thread (new threadstart (proxy.run));
     thrd.start ();
     // while the thread is running, the main program thread will loop around
     // and listen for the next connection request.
    }
   }
   catch (ioexception e)
   {
    console.writeline (e.message);
   }
  }
 }
 class clsproxyconnection
 {
  public clsproxyconnection (socket sockclient)
  {
   m_sockclient = sockclient;
  }
  socket m_sockclient; //, m_sockserver;
  byte [] readbuf = new byte [1024];
  byte [] buffer = null;
  encoding ascii = encoding.ascii;
  public void run ()
  {
   string strfromclient = "";
   try
   {
    // read the incoming text on the socket/
    int bytes = readmessage (m_sockclient,
           readbuf, ref strfromclient);
    // if it's empty, it's an error, so just return.
    // this will termiate the thread.
    if (bytes == 0)
     return;
    // get the url for the connection. the client browser sends a get command
    // followed by a space, then the url, then and identifer for the http version.
    // extract the url as the string betweeen the spaces.
    int index1 = strfromclient.indexof (' ');
    int index2 = strfromclient.indexof (' ', index1 + 1);
    string strclientconnection =
      strfromclient.substring (index1 + 1, index2 - index1);
    if ((index1 < 0) || (index2 < 0))
    {
     throw (new ioexception ());
    }
    // write a messsage that we are connecting.
    console.writeline ("connecting to site " +
         strclientconnection);
    console.writeline ("connection from " +
         m_sockclient.remoteendpoint);
    // create a webrequest object.
    webrequest req = (webrequest) webrequest.create
              (strclientconnection);
    // get the response from the web site.
    webresponse response = req.getresponse ();
    int bytesread = 0;
    byte [] buffer = new byte[32];
    int bytessent = 0;
    // create a response stream object.
    stream responsestream = response.getresponsestream();
    // read the response into a buffer.
    bytesread = responsestream.read(buffer,0,32);
    stringbuilder strresponse = new stringbuilder("");
    while (bytesread != 0)
    {
     // pass the response back to the client
     strresponse.append(encoding.ascii.getstring(buffer,
          0, bytesread));
     m_sockclient.send(buffer, bytesread, 0);
     bytessent += bytesread;
     // read the next part of the response
     bytesread = responsestream.read(buffer, 0, 32);
    }
   }
   catch (filenotfoundexception e)
   {
    senderrorpage (404, "file not found", e.message);
   }
   catch (ioexception e)
   {
    senderrorpage (503, "service not available", e.message);
   }
   catch (exception e)
   {
     senderrorpage (404, "file not found", e.message);
     console.writeline (e.stacktrace);
     console.writeline (e.message);
   }
   finally
   {
    // disconnect and close the socket.
    if (m_sockclient != null)
    {
     if (m_sockclient.connected)
     {
      m_sockclient.close ();
     }
    }
   }
   // returning from this method will terminate the thread.
  }
  // write an error response to the client.
  void senderrorpage (int status, string strreason, string strtext)
  {
   sendmessage (m_sockclient, "http/1.0" + " " +
       status + " " + strreason + "\r\n");
   sendmessage (m_sockclient, "content-type: text/plain" + "\r\n");
   sendmessage (m_sockclient, "proxy-connection: close" + "\r\n");
   sendmessage (m_sockclient, "\r\n");
   sendmessage (m_sockclient, status + " " + strreason);
   sendmessage (m_sockclient, strtext);
  }
  // send a string to a socket.
  void sendmessage (socket sock, string strmessage)
  {
   buffer = new byte [strmessage.length + 1];
   int len = ascii.getbytes (strmessage.tochararray(),
          0, strmessage.length, buffer, 0);
   sock.send (buffer, len, 0);
  }
  // read a string from a socket.
  int readmessage (socket sock, byte [] buf, ref string strmessage)
  {
   int ibytes = sock.receive (buf, 1024, 0);
   strmessage = encoding.ascii.getstring (buf);
   return (ibytes);
  }
 }
}

希望本文所述对大家的c#程序设计有所帮助。