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使用.NET访问Internet(5) Paul_Ni(原作)(补充)

来源: 作者: 出处:巧巧读书 2006-09-12 进入讨论组

异步服务器套接字示例


下面的示例程序创建一个接收来自客户端的连接请求的服务器。该服务器是用异步套接字生成的,因此在等待来自客户端的连接时不挂起服务器应用程序的执行。该应用程序接收来自客户端的字符串,在控制台显示该字符串,然后将该字符串回显到客户端。
来自客户端的字符串必须包含字符串“<EOF>”,以发出表示消息结尾的信号。
 [C#]
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
 
// State object for reading client data asynchronously
public class StateObject {
   public Socket workSocket = null;       // Client  socket.
   public const int BufferSize = 1024;       // Size of receive buffer.
   public byte[] buffer = new byte[BufferSize]; // Receive buffer.
   public StringBuilder sb = new StringBuilder();  // Received data string.
}
 
public class AsynchronousSocketListener {
   
   // Incoming data from client.
   public static string data = null;
 
   // Thread signal.
   public static ManualResetEvent allDone = new ManualResetEvent(false);
 
   public AsynchronousSocketListener() {
   }
 
   public static void StartListening() {
      // Data buffer for incoming data.
      byte[] bytes = new Byte[1024];
 
      // Establish the local endpoint for the  socket.
      //   The DNS name of the computer
      //  running the listener is "host.contoso.com".
      IPHostEntry ipHostInfo = Dns.Resolve(Dns.GetHostName());
      IPAddress ipAddress = ipHostInfo.AddressList[0];
      IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 11000);
 
      // Create a TCP/IP  socket.
      Socket listener = new Socket(AddressFamily.InterNetwork,
         SocketType.Stream, ProtocolType.Tcp );
 
      // Bind the  socket to the local endpoint and listen for incoming connections.
      try {
         listener.Bind(localEndPoint);
         listener.Listen(100);
 
         while (true) {
            // Set the event to  nonsignaled state.
            allDone.Reset();
 
            // Start  an asynchronous socket to listen for connections.
            Console.WriteLine("Waiting for a connection...");
            listener.BeginAccept( 
               new AsyncCallback(AcceptCallback),
               listener );
 
            // Wait until a connection is made before continuing.
            allDone.WaitOne();
         }
 
      } catch (Exception e) {
         Console.WriteLine(e.ToString());
      }
 
      Console.WriteLine("\nHit enter to continue...");
      Console.Read();
      
   }
 
   public static void AcceptCallback(IAsyncResult ar) {
      // Signal the main thread to continue.
      allDone.Set();
 
      // Get the socket that handles the client request.
      Socket listener = (Socket) ar.AsyncState;
      Socket handler = listener.EndAccept(ar);
 
      // Create the state object.
      StateObject state = new StateObject();
      state.workSocket = handler;
      handler.BeginReceive( state.buffer, 0, StateObject.BufferSize, 0,
         new AsyncCallback(ReadCallback), state);
   }
 
   public static void ReadCallback(IAsyncResult ar) {
      String content = String.Empty;
      
      // Retrieve the state object and the handler socket
      // from the async state object.
      StateObject state = (StateObject) ar.AsyncState;
      Socket handler = state.workSocket;
 
      // Read data from the client socket. 
      int bytesRead = handler.EndReceive(ar);
 
      if (bytesRead > 0) {
         // There  might be more data, so store  the data received so far.
         state.sb.Append(Encoding.ASCII.GetString(
            state.buffer,0,bytesRead));
 
         // Check for end-of-file tag. If  it is not there, read 
         // more data.
         content = state.sb.ToString();
         if (content.IndexOf("<EOF>") > -1) {
            // All the data has been read from the 
            // client. Display it on the console.
           保留地址 http://www.qqread.com/dotnet/u236930.html 更多文章 更多内容请看.NET移动与嵌入式技术.NET开发手册.NET实用开发专题,或进入讨论组讨论。
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