在.Net中,System.Net.Sockets 命名空间为需要严密控制网络访问的开发人员提供了 Windows Sockets (Winsock) 接口的托管实现。System.Net 命名空间中的所有其他网络访问类都建立在该套接字Socket实现之上,如TCPClient、TCPListener 和 UDPClient 类封装有关创建到 Internet 的 TCP 和 UDP 连接的详细信息;NetworkStream类则提供用于网络访问的基础数据流等,常见的许多Internet服务都可以见到Socket的踪影,如Telnet、Http、Email、Echo等,这些服务尽管通讯协议Protocol的定义不同,但是其基础的传输都是采用的Socket。 其实,Socket可以象流Stream一样被视为一个数据通道,这个通道架设在应用程序端(客户端)和远程服务器端之间,而后,数据的读取(接收)和写入(发送)均针对这个通道来进行。
可见,在应用程序端或者服务器端创建了Socket对象之后,就可以使用Send/SentTo方法将数据发送到连接的Socket,或者使用Receive/ReceiveFrom方法接收来自连接Socket的数据;
针对Socket编程,.NET 框架的 Socket 类是 Winsock32 API 提供的套接字服务的托管代码版本。其中为实现网络编程提供了大量的方法,大多数情况下,Socket 类方法只是将数据封送到它们的本机 Win32 副本中并处理任何必要的安全检查。如果你熟悉Winsock API函数,那么用Socket类编写网络程序会非常容易,当然,如果你不曾接触过,也不会太困难,跟随下面的解说,你会发觉使用Socket类开发windows
网络应用程序原来有规可寻,它们在大多数情况下遵循大致相同的步骤。
本节介绍使用Socket来实现一个高性能的异步UDP服务器,实际上UDP是不分客户机和服务器的,但是我们有的时候和服务器通讯就是使用UDP来进行的。
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Net; using System.Net.Sockets; namespace NetFrame.Net.UDP.Sock.Asynchronous { /// <summary> /// SOCKET实现异步UDP服务器 /// </summary> public class AsyncSocketUDPServer { #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<AsyncUDPSocketState> _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 AsyncSocketUDPServer(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 AsyncSocketUDPServer(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 AsyncSocketUDPServer(IPAddress localIPAddress, int listenPort, int maxClient) { this.Address = localIPAddress; this.Port = listenPort; this.Encoding = Encoding.Default; _maxClient = maxClient; //_clients = new List<AsyncUDPSocketState>(); _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)); //_serverSock.Connect(new IPEndPoint(IPAddress.Any, 0)); AsyncSocketUDPState so = new AsyncSocketUDPState(); so.workSocket = _serverSock; _serverSock.BeginReceiveFrom(so.buffer, 0, so.buffer.Length, SocketFlags.None, ref so.remote, new AsyncCallback(ReceiveDataAsync), null); //EndPoint sender = new IPEndPoint(IPAddress.Any, 0); //_serverSock.BeginReceiveFrom(_recvBuffer, 0, _recvBuffer.Length, SocketFlags.None, // ref sender, new AsyncCallback(ReceiveDataAsync), sender); //BeginReceive 和 BeginReceiveFrom的区别是什么 /*_serverSock.BeginReceive(_recvBuffer, 0, _recvBuffer.Length, SocketFlags.None, new AsyncCallback(ReceiveDataAsync), null);*/ } } /// <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 } } /// <summary> /// 接收数据的方法 /// </summary> /// <param name="ar"></param> private void ReceiveDataAsync(IAsyncResult ar) { AsyncSocketUDPState so = ar.AsyncState as AsyncSocketUDPState; //EndPoint sender = new IPEndPoint(IPAddress.Any, 0); int len = -1; try { len = _serverSock.EndReceiveFrom(ar, ref so.remote); //len = _serverSock.EndReceiveFrom(ar, ref sender); //EndReceiveFrom 和 EndReceive区别 //len = _serverSock.EndReceive(ar); //TODO 处理数据 //触发数据收到事件 RaiseDataReceived(so); } catch (Exception) { //TODO 处理异常 RaiseOtherException(so); } finally { if (IsRunning && _serverSock != null) _serverSock.BeginReceiveFrom(so.buffer, 0, so.buffer.Length, SocketFlags.None, ref so.remote, new AsyncCallback(ReceiveDataAsync), so); } } /// <summary> /// 发送数据 /// </summary> /// <param name="msg"></param> /// <param name="remote"></param> public void Send(string msg,EndPoint remote) { byte[] data = Encoding.Default.GetBytes(msg); try { RaisePrepareSend(null); _serverSock.BeginSendTo(data, 0, data.Length, SocketFlags.None, remote, new AsyncCallback(SendDataEnd), _serverSock); } catch (Exception) { //TODO 异常处理 RaiseOtherException(null); } } private void SendDataEnd(IAsyncResult ar) { ((Socket)ar.AsyncState).EndSendTo(ar); RaiseCompletedSend(null); } #endregion #region 事件 /// <summary> /// 接收到数据事件 /// </summary> public event EventHandler<AsyncSocketUDPEventArgs> DataReceived; private void RaiseDataReceived(AsyncSocketUDPState state) { if (DataReceived != null) { DataReceived(this, new AsyncSocketUDPEventArgs(state)); } } /// <summary> /// 发送数据前的事件 /// </summary> public event EventHandler<AsyncSocketUDPEventArgs> PrepareSend; /// <summary> /// 触发发送数据前的事件 /// </summary> /// <param name="state"></param> private void RaisePrepareSend(AsyncSocketUDPState state) { if (PrepareSend != null) { PrepareSend(this, new AsyncSocketUDPEventArgs(state)); } } /// <summary> /// 数据发送完毕事件 /// </summary> public event EventHandler<AsyncSocketUDPEventArgs> CompletedSend; /// <summary> /// 触发数据发送完毕的事件 /// </summary> /// <param name="state"></param> private void RaiseCompletedSend(AsyncSocketUDPState state) { if (CompletedSend != null) { CompletedSend(this, new AsyncSocketUDPEventArgs(state)); } } /// <summary> /// 网络错误事件 /// </summary> public event EventHandler<AsyncSocketUDPEventArgs> NetError; /// <summary> /// 触发网络错误事件 /// </summary> /// <param name="state"></param> private void RaiseNetError(AsyncSocketUDPState state) { if (NetError != null) { NetError(this, new AsyncSocketUDPEventArgs(state)); } } /// <summary> /// 异常事件 /// </summary> public event EventHandler<AsyncSocketUDPEventArgs> OtherException; /// <summary> /// 触发异常事件 /// </summary> /// <param name="state"></param> private void RaiseOtherException(AsyncSocketUDPState state, string descrip) { if (OtherException != null) { OtherException(this, new AsyncSocketUDPEventArgs(descrip, state)); } } private void RaiseOtherException(AsyncSocketUDPState 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(AsyncSocketUDPState 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 (AsyncUDPSocketState 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 } }
会话封装类
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Net; using System.Net.Sockets; namespace NetFrame.Net.UDP.Sock.Asynchronous { public class AsyncSocketUDPState { // 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); } }
Socket异步UDP服务器事件参数类
using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace NetFrame.Net.UDP.Sock.Asynchronous { /// <summary> /// SOCKET 异步UDP 事件类 /// </summary> public class AsyncSocketUDPEventArgs : EventArgs { /// <summary> /// 提示信息 /// </summary> public string _msg; /// <summary> /// 客户端状态封装类 /// </summary> public AsyncSocketUDPState _state; /// <summary> /// 是否已经处理过了 /// </summary> public bool IsHandled { get; set; } public AsyncSocketUDPEventArgs(string msg) { this._msg = msg; IsHandled = false; } public AsyncSocketUDPEventArgs(AsyncSocketUDPState state) { this._state = state; IsHandled = false; } public AsyncSocketUDPEventArgs(string msg, AsyncSocketUDPState state) { this._msg = msg; this._state = state; IsHandled = false; } } }
以上就是C#网络编程系列文章(五)之Socket实现异步UDP服务器的内容,更多相关内容请关注PHP中文网(www.php.cn)!