在.Net中,System.Net.Sockets 命名空間為需要嚴密控製網路存取的開發人員提供了 Windows Sockets (Winsock) 介面的託管實作。 System.Net 命名空間中的所有其他網路存取類別都建立在該套接字Socket實作之上,如TCPClient、TCPListener 和UDPClient 類別封裝有關建立到Internet 的TCP 和UDP 連接的詳細資訊;NetworkStream類別則提供用於網路存取的基礎資料流等,常見的許多Internet服務都可以見到Socket的蹤影,如Telnet、Http、Email、Echo等,這些服務儘管通訊協定Protocol的定義不同,但是其基礎的傳輸都是採用的Socket。
其實,Socket可以像流Stream一樣被視為一個資料通道,這個通道架設在應用程式端(客戶端)和遠端伺服器端之間,而後,資料的讀取(接收)和寫入(傳送)均針對這個通道來進行。
可見,在應用程式端或伺服器端建立了Socket物件之後,就可以使用Send/SentTo方法將資料傳送到連線的Socket,或使用Receive/ReceiveFrom方法接收來自連線Socket的資料;
針對Socket編程,.NET 框架的Socket 類別是Winsock32 API 提供的套接字服務的託管程式碼版本。其中為實現網路程式設計提供了大量的方法,大多數情況下,Socket 類別方法只是將資料封送到它們的本機 Win32 副本中並處理任何必要的安全檢查。如果你熟悉Winsock API函數,那麼用Socket類編寫網頁程式會非常容易,當然,如果你不曾接觸過,也不會太困難,跟隨下面的解說,你會發覺使用Socket類開發windows 網路應用程式原來有規可尋,它們在大多數情況下遵循大致相同的步驟。
本節介紹使用Socket來實作一個同步的UDP伺服器。
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Net.Sockets; using System.Net; using System.Threading; namespace NetFrame.Net.UDP.Sock.Synchronous { /// <summary> /// Socket 实现同步UDP服务器 /// </summary> public class SocketUDPServer { #region Fields /// <summary> /// 服务器程序允许的最大客户端连接数 /// </summary> private int _maxClient; /// <summary> /// 当前的连接的客户端数 /// </summary> private int _clientCount; /// <summary> /// 服务器使用的同步socket /// </summary> private Socket _serverSock; /// <summary> /// 客户端会话列表 /// </summary> private List<SocketUDPState> _clients; private bool disposed = false; /// <summary> /// 数据接受缓冲区 /// </summary> private byte[] _recvBuffer; #endregion #region Properties /// <summary> /// 服务器是否正在运行 /// </summary> public bool IsRunning { get; private set; } /// <summary> /// 监听的IP地址 /// </summary> public IPAddress Address { get; private set; } /// <summary> /// 监听的端口 /// </summary> public int Port { get; private set; } /// <summary> /// 通信使用的编码 /// </summary> public Encoding Encoding { get; set; } #endregion #region 构造函数 /// <summary> /// 异步Socket UDP服务器 /// </summary> /// <param name="listenPort">监听的端口</param> public SocketUDPServer(int listenPort) : this(IPAddress.Any, listenPort,1024) { } /// <summary> /// 异步Socket UDP服务器 /// </summary> /// <param name="localEP">监听的终结点</param> public SocketUDPServer(IPEndPoint localEP) : this(localEP.Address, localEP.Port,1024) { } /// <summary> /// 异步Socket UDP服务器 /// </summary> /// <param name="localIPAddress">监听的IP地址</param> /// <param name="listenPort">监听的端口</param> /// <param name="maxClient">最大客户端数量</param> public SocketUDPServer(IPAddress localIPAddress, int listenPort, int maxClient) { this.Address = localIPAddress; this.Port = listenPort; this.Encoding = Encoding.Default; _maxClient = maxClient; _clients = new List<SocketUDPState>(); _serverSock = new Socket(localIPAddress.AddressFamily, SocketType.Dgram, ProtocolType.Udp); _recvBuffer=new byte[_serverSock.ReceiveBufferSize]; } #endregion #region Method /// <summary> /// 启动服务器 /// </summary> /// <returns>异步TCP服务器</returns> public void Start() { if (!IsRunning) { IsRunning = true; _serverSock.Bind(new IPEndPoint(this.Address, this.Port)); //启动一个线程监听数据 new Thread(ReceiveData).Start(); } } /// <summary> /// 停止服务器 /// </summary> public void Stop() { if (IsRunning) { IsRunning = false; _serverSock.Close(); //TODO 关闭对所有客户端的连接 CloseAllClient(); } } /// <summary> /// 同步数据接收方法 /// </summary> private void ReceiveData() { int len = -1; EndPoint remote = null; while (true) { try { len = _serverSock.ReceiveFrom(_recvBuffer, ref remote); //if (!_clients.Contains(remote)) //{ // _clients.Add(remote); //} } catch (Exception) { //TODO 异常处理操作 RaiseOtherException(null); } } } /// <summary> /// 同步发送数据 /// </summary> public void Send(string msg, EndPoint clientip) { byte[] data = Encoding.Default.GetBytes(msg); try { _serverSock.SendTo(data, clientip); //数据发送完成事件 RaiseCompletedSend(null); } catch (Exception) { //TODO 异常处理 RaiseOtherException(null); } } #endregion #region 事件 /// <summary> /// 接收到数据事件 /// </summary> public event EventHandler<SocketUDPEventArgs> DataReceived; private void RaiseDataReceived(SocketUDPState state) { if (DataReceived != null) { DataReceived(this, new SocketUDPEventArgs(state)); } } /// <summary> /// 数据发送完毕事件 /// </summary> public event EventHandler<SocketUDPEventArgs> CompletedSend; /// <summary> /// 触发数据发送完毕的事件 /// </summary> /// <param name="state"></param> private void RaiseCompletedSend(SocketUDPState state) { if (CompletedSend != null) { CompletedSend(this, new SocketUDPEventArgs(state)); } } /// <summary> /// 网络错误事件 /// </summary> public event EventHandler<SocketUDPEventArgs> NetError; /// <summary> /// 触发网络错误事件 /// </summary> /// <param name="state"></param> private void RaiseNetError(SocketUDPState state) { if (NetError != null) { NetError(this, new SocketUDPEventArgs(state)); } } /// <summary> /// 异常事件 /// </summary> public event EventHandler<SocketUDPEventArgs> OtherException; /// <summary> /// 触发异常事件 /// </summary> /// <param name="state"></param> private void RaiseOtherException(SocketUDPState state, string descrip) { if (OtherException != null) { OtherException(this, new SocketUDPEventArgs(descrip, state)); } } private void RaiseOtherException(SocketUDPState state) { RaiseOtherException(state, ""); } #endregion #region Close /// <summary> /// 关闭一个与客户端之间的会话 /// </summary> /// <param name="state">需要关闭的客户端会话对象</param> public void Close(SocketUDPState state) { if (state != null) { _clients.Remove(state); _clientCount--; //TODO 触发关闭事件 } } /// <summary> /// 关闭所有的客户端会话,与所有的客户端连接会断开 /// </summary> public void CloseAllClient() { foreach (SocketUDPState client in _clients) { Close(client); } _clientCount = 0; _clients.Clear(); } #endregion #region 释放 /// <summary> /// Performs application-defined tasks associated with freeing, /// releasing, or resetting unmanaged resources. /// </summary> public void Dispose() { Dispose(true); GC.SuppressFinalize(this); } /// <summary> /// Releases unmanaged and - optionally - managed resources /// </summary> /// <param name="disposing"><c>true</c> to release /// both managed and unmanaged resources; <c>false</c> /// to release only unmanaged resources.</param> protected virtual void Dispose(bool disposing) { if (!this.disposed) { if (disposing) { try { Stop(); if (_serverSock != null) { _serverSock = null; } } catch (SocketException) { //TODO RaiseOtherException(null); } } disposed = true; } } #endregion } }
客戶狀態封裝類別
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Net.Sockets; using System.Net; namespace NetFrame.Net.UDP.Sock.Synchronous { public class SocketUDPState { // Client socket. public Socket workSocket = null; // Size of receive buffer. public const int BufferSize = 1024; // Receive buffer. public byte[] buffer = new byte[BufferSize]; // Received data string. public StringBuilder sb = new StringBuilder(); public EndPoint remote = new IPEndPoint(IPAddress.Any, 0); } }
伺服器事件參數類別
using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace NetFrame.Net.UDP.Sock.Synchronous { /// <summary> /// Socket实现同步UDP服务器 /// </summary> public class SocketUDPEventArgs:EventArgs { /// <summary> /// 提示信息 /// </summary> public string _msg; /// <summary> /// 客户端状态封装类 /// </summary> public SocketUDPState _state; /// <summary> /// 是否已经处理过了 /// </summary> public bool IsHandled { get; set; } public SocketUDPEventArgs(string msg) { this._msg = msg; IsHandled = false; } public SocketUDPEventArgs(SocketUDPState state) { this._state = state; IsHandled = false; } public SocketUDPEventArgs(string msg, SocketUDPState state) { this._msg = msg; this._state = state; IsHandled = false; } } }
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