稳扎稳打Silverlight(24) - 2.0通信之Socket, 开发一个多人聊天室

using System; 
using System.Collections.Generic; 
using System.ComponentModel; 
using System.Data; 
using System.Drawing; 
using System.Linq; 
using System.Text; 
using System.Windows.Forms; 
 
using System.Net.Sockets; 
using System.IO; 
using System.Net; 
 
namespace PolicyServer 
{ 
         public partial  class Main : Form 
        { 
                 // 客户端 socket 发送到服务端的对策略文件的请求信息 
                 private  readonly  string _policyRequestString =  "<policy-file-request/>"; 
 
                 private Socket _listener;  // 服务端监听的 socket 
                 private  byte[] _policyBuffer;  // 服务端策略文件的 buffer 
                 private  byte[] _requestBuffer;  // 客户端 socket 发送的请求信息的 buffer 
 
                 private  int _received;  // 接收到的信息字节数 
 
                 private  bool _flag =  false;  // 标志位。服务端是否要处理传入的连接 
 
                System.Threading.SynchronizationContext _syncContext; 
 
                 public Main() 
                { 
                        InitializeComponent(); 
 
                        _flag =  true; 
 
                        lblStatus.Text =  "PolicyServer状态：启动"; 
                        lblStatus.ForeColor = Color.Green; 
 
                         // 启动 PolicyServer 
                        StartupPolicyServer(); 
 
                         // UI 线程 
                        _syncContext = System.Threading.SynchronizationContext.Current; 
                } 
 
                 private  void btnStartup_Click( object sender, EventArgs e) 
                { 
                        _flag =  true; 
 
                        lblStatus.Text =  "PolicyServer状态：启动"; 
                        lblStatus.ForeColor = Color.Green; 
                } 
 
                 private  void btnPause_Click( object sender, EventArgs e) 
                { 
                        _flag =  false; 
 
                        lblStatus.Text =  "PolicyServer状态：暂停"; 
                        lblStatus.ForeColor = Color.Red; 
                } 
 
                 /// <summary> 
                 /// 启动 PolicyServer 
                 /// </summary> 
                 private  void StartupPolicyServer() 
                { 
                         string policyFile = Path.Combine(Application.StartupPath,  "clientaccesspolicy.xml"); 
 
                         using (FileStream fs =  new FileStream(policyFile, FileMode.Open, FileAccess.Read)) 
                        { 
                                 // 将策略文件的内容写入 buffer 
                                _policyBuffer =  new  byte[fs.Length]; 
                                fs.Read(_policyBuffer, 0, _policyBuffer.Length); 
                        } 
 
                         // 初始化 socket ， 然后与端口绑定， 然后对端口进行监听 
                        _listener =  new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); 
                        _listener.Bind( new IPEndPoint(IPAddress.Any, 943));  // socket 请求策略文件使用 943 端口 
                        _listener.Listen(100); 
 
                         // 开始接受客户端传入的连接 
                        _listener.BeginAccept( new AsyncCallback(OnClientConnect),  null); 
                } 
 
                 private  void OnClientConnect(IAsyncResult result) 
                { 
                         if (!_flag) 
                        { 
                                 // PolicyServer 停用的话，则不再处理传入的连接 
                                _listener.BeginAccept( new AsyncCallback(OnClientConnect),  null); 
                                 return; 
                        } 
                                    
                        Socket client;  // 客户端发过来的 socket 
 
                         try 
                        { 
                                 // 完成接受客户端传入的连接的这个异步操作，并返回客户端连入的 socket 
                                client = _listener.EndAccept(result); 
                        } 
                         catch (SocketException) 
                        { 
                                 return; 
                        } 
 
                        _requestBuffer =  new  byte[_policyRequestString.Length]; 
                        _received = 0; 
 
                         try 
                        { 
                                 // 开始接收客户端传入的数据 
                                client.BeginReceive(_requestBuffer, 0, _policyRequestString.Length, SocketFlags.None,  new AsyncCallback(OnReceive), client); 
                        } 
                         catch (SocketException) 
                        { 
                                 // socket 出错则关闭客户端 socket 
                                client.Close(); 
                        } 
 
                         // 继续开始接受客户端传入的连接 
                        _listener.BeginAccept( new AsyncCallback(OnClientConnect),  null); 
                } 
 
 
                 private  void OnReceive(IAsyncResult result) 
                { 
                        Socket client = result.AsyncState  as Socket; 
 
                         try 
                        { 
                                 // 完成接收数据的这个异步操作，并计算累计接收的数据的字节数 
                                _received += client.EndReceive(result); 
 
                                 if (_received < _policyRequestString.Length) 
                                { 
                                         // 没有接收到完整的数据，则继续开始接收 
                                        client.BeginReceive(_requestBuffer, _received, _policyRequestString.Length - _received, SocketFlags.None,  new AsyncCallback(OnReceive), client); 
                                         return; 
                                } 
 
                                 // 把接收到的数据转换为字符串 
                                 string request = System.Text.Encoding.UTF8.GetString(_requestBuffer, 0, _received); 
 
                                 if (StringComparer.InvariantCultureIgnoreCase.Compare(request, _policyRequestString) != 0) 
                                { 
                                         // 如果接收到的数据不是“<policy-file-request/>”，则关闭客户端 socket 
                                        client.Close(); 
                                         return; 
                                } 
 
                                 // 开始向客户端发送策略文件的内容 
                                client.BeginSend(_policyBuffer, 0, _policyBuffer.Length, SocketFlags.None,  new AsyncCallback(OnSend), client); 
                        } 
 
                         catch (SocketException) 
                        { 
                                 // socket 出错则关闭客户端 socket 
                                client.Close(); 
                        } 
                } 
 
                 private  void OnSend(IAsyncResult result) 
                { 
                        Socket client = result.AsyncState  as Socket; 
 
                         try 
                        { 
                                 // 完成将信息发送到客户端的这个异步操作 
                                client.EndSend(result); 
 
                                 // 获取客户端的ip地址及端口号，并显示 
                                _syncContext.Post(ResultCallback, client.LocalEndPoint.ToString()); 
                        } 
                         finally 
                        { 
                                 // 关闭客户端 socket 
                                client.Close(); 
                        } 
                } 
 
                 void ResultCallback( object result) 
                { 
                         // 输出客户端的ip地址及端口号 
                        txtMsg.Text += result.ToString() +  "\r\n"; 
                } 
        } 
}