21 | April | 2012 | LongSheng

C# Socket实例

public string Hello{ Response.Write("test"); Response.End9() } 客户端:2 1 using System; 2 using System.Net; 3 using System.Net.Sockets; 4 using System.Text; 5 6 public class SynchronousSocketClient { 7 8 public static void StartClient() { 9 // Data buffer for incoming data. 10 byte[] bytes = new byte[1024]; 11 12 // Connect to a remote device. 13 try { 14 // Establish the remote endpoint for the socket. 15 // This example uses port 11000 on the local computer. 16 IPHostEntry ipHostInfo = Dns.Resolve(Dns.GetHostName()) 17 IPAddress ipAddress = ipHostInfo.AddressList[0]; 18 IPEndPoint remoteEP = […]

龙生 21 Apr 2012

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c#进制转换

/// <summary>/// 十进制转换为二进制/// </summary>/// <param name="x"></param>/// <returns></returns> public static string DecToBin(string x){string z = null;int X = Convert.ToInt32(x);int i = 0;long a, b = 0;while (X > 0){a = X%2;X = X/2;b = b + a*Pow(10, i);i++;}z = Convert.ToString(b);return z;} /// <summary>/// 16进制转ASCII码/// </summary>/// <param name="hexString"></param>/// <returns></returns> public static string HexToAscii(string hexString){StringBuilder sb = new StringBuilder();for (int i = 0; i <= hexString.Length – 2; i += 2){sb.Append(Convert.ToString(Convert.ToChar(Int32.Parse(hexString.Substring(i, 2),System.Globalization.NumberStyles.HexNumber))));}return sb.ToString();} /// <summary>/// 十进制转换为八进制/// </summary>/// <param name="x"></param>/// <returns></returns> public static string DecToOtc(string x){string z = null;int X = Convert.ToInt32(x);int […]

龙生 21 Apr 2012

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深入探析c# Socket

　　最近浏览了几篇有关Socket发送消息的文章，发现大家对Socket Send方法理解有所偏差，现将自己在开发过程中对Socket的领悟写出来，以供大家参考。　　（一）架构　　基于TCP协议的Socket通信，架构类似于B/S架构，一个Socket通信服务器，多个Socket通信客户端。Socket通信服务器启动时，会建立一个侦听Socket，侦听Socket将侦听到的Socket连接传给接受Socket，然后由接受Socket完成接受、发送消息，当Socket存在异常时，断开连接。在实际开发项目中，往往要求Socket通信服务器能提供高效、稳定的服务，一般会用到以下技术：双工通信、完成端口、SAEA、池、多线程、异步等。特别是池，用的比较多，池一般包括一下几种： 1）Buffer池，用于集中管控Socket缓冲区，防止内存碎片。 2）SAEA池，用于集中管控Socket，重复利用Socket。 3）SQL池，用于分离网络服务层与数据访问层（SQL的执行效率远远低于网络层执行效率）。 4）线程池，用于从线程池中调用空闲线程执行业务逻辑，进一步提高网络层运行效率。（二）Send 　　主服务器接受Socket为一端口，客户端Socket为一端口，这两个端口通过TCP协议建立连接，通信基础系统负责管理此连接，它有两个功能：　　1）发送消息　　2）接受消息　　Socket的Send方法，并非大家想象中的从一个端口发送消息到另一个端口，它仅仅是拷贝数据到基础系统的发送缓冲区，然后由基础系统将发送缓冲区的数据到连接的另一端口。值得一说的是，这里的拷贝数据与异步发送消息的拷贝是不一样的，同步发送的拷贝，是直接拷贝数据到基础系统缓冲区，拷贝完成后返回，在拷贝的过程中，执行线程会IO等待, 此种拷贝与Socket自带的Buffer空间无关，但异步发送消息的拷贝，是将Socket自带的Buffer空间内的所有数据，拷贝到基础系统发送缓冲区，并立即返回，执行线程无需IO等待，所以异步发送在发送前必须执行SetBuffer方法，拷贝完成后，会触发你自定义回调函数ProcessSend，在ProcessSend方法中，调用SetBuffer方法，重新初始化Buffer空间。　　口说无凭，下面给个例子：　　服务器端：客户端：解释：客户端第一次发送数据：1234567890。客户端第一个接受数据：1234567890，该数据由服务端用Send同步方法发送返回。客户端第二个接受数据：1234567890，该数据由服务端用Send异步方法发送返回。以上似乎没什么异常，好，接下来，我只发送abc。客户端第一个接受数据：abc，理所当然，没什么问题。客户端第二个接受数据：abc4567890！为什么呢？应该是abc才对呀！好，现在为大家解释一下：异步发送是将其Buffer空间中所有数据拷贝到基础系统发送缓冲区，第一次拷贝1234567890到发送缓冲区，所以收到1234567890，第二次拷贝abc到发送缓冲区，替换了先前的123，所以收到abc4567890，大家明白的？源码： BufferManager

1

<div>using System.Collections.Generic; using System.Net.Sockets; // This class creates a single large buffer which can be divided up // and assigned to SocketAsyncEventArgs objects for use with each // socket I/O operation. // This enables bufffers to be easily reused and guards against // fragmenting heap memory. // // The operations exposed on the BufferManager class are not thread safe. class BufferManager { int m_numBytes; // the total number of bytes controlled by the buffer pool byte[] m_buffer; // the underlying byte array maintained by the Buffer Manager Stack<int> m_freeIndexPool; // int m_currentIndex; int m_bufferSize; public BufferManager(int totalBytes, int bufferSize) { m_numBytes = totalBytes; m_currentIndex = 0; m_bufferSize = bufferSize; m_freeIndexPool = new Stack<int>(); } // Allocates buffer space used by the buffer pool public void InitBuffer() { // create one big large buffer and divide that // out to each SocketAsyncEventArg object m_buffer = new byte[m_numBytes]; } // Assigns a buffer from the buffer pool to the // specified SocketAsyncEventArgs object // // <returns>true if the buffer was successfully set, else false</returns> public bool SetBuffer(SocketAsyncEventArgs args) { if (m_freeIndexPool.Count > 0) { args.SetBuffer(m_buffer, m_freeIndexPool.Pop(), m_bufferSize); } else { if ((m_numBytes - m_bufferSize) < m_currentIndex) { return false; } args.SetBuffer(m_buffer, m_currentIndex, m_bufferSize); m_currentIndex += m_bufferSize; } return true; } // Removes the buffer from a SocketAsyncEventArg object. // This frees the buffer back to the buffer pool public void FreeBuffer(SocketAsyncEventArgs args) { m_freeIndexPool.Push(args.Offset); args.SetBuffer(null, 0, 0); } } </div>

SocketAsyncEventArgsPool

1

<div>using System; using System.Collections.Generic; using System.Net.Sockets; // Represents a collection of reusable SocketAsyncEventArgs objects. class SocketAsyncEventArgsPool { Stack<SocketAsyncEventArgs> m_pool; // Initializes the object pool to the specified size // // The "capacity" parameter is the maximum number of // SocketAsyncEventArgs objects the pool can hold public SocketAsyncEventArgsPool(int capacity) { m_pool = new Stack<SocketAsyncEventArgs>(capacity); } // Add a SocketAsyncEventArg instance to the pool // //The "item" parameter is the SocketAsyncEventArgs instance // to add to the pool public void Push(SocketAsyncEventArgs item) { if (item == null) { throw new ArgumentNullException("Items added to a SocketAsyncEventArgsPool cannot be null"); } lock (m_pool) { m_pool.Push(item); } } // Removes a SocketAsyncEventArgs instance from the pool // and returns the object removed from the pool public SocketAsyncEventArgs Pop() { lock (m_pool) { return m_pool.Pop(); } } // The number of SocketAsyncEventArgs instances in the pool public int Count { get { return m_pool.Count; } } }</div>

1

<div>using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Net.Sockets; class AsyncUserToken { public Socket Socket; } </div>

Server

1

<div>using System; using System.Threading; using System.Net.Sockets; using System.Net; using System.Text; // Implements the connection logic for the socket server. // After accepting a connection, all data read from the client // is sent back to the client. The read and echo back to the client pattern // is continued until the client disconnects. class Server { private int m_numConnections; // the maximum number of connections the sample is designed to handle simultaneously private int m_receiveBufferSize;// buffer size to use for each socket I/O operation BufferManager m_bufferManager; // represents a large reusable set of buffers for all socket operations const int opsToPreAlloc = 2; // read, write (don't alloc buffer space for accepts) Socket listenSocket; // the socket used to listen for incoming connection requests // pool of reusable SocketAsyncEventArgs objects for write, read and accept socket operations SocketAsyncEventArgsPool m_readWritePool; int m_totalBytesRead; // counter of the total # bytes received by the server int m_numConnectedSockets; // the total number of clients connected to the server Semaphore m_maxNumberAcceptedClients; // Create an uninitialized server instance. // To start the server listening for connection requests // call the Init method followed by Start method // // <param name="numConnections">the maximum number of connections the sample is designed to handle simultaneously</param> // <param name="receiveBufferSize">buffer size to use for each socket I/O operation</param> public Server(int numConnections, int receiveBufferSize) { m_totalBytesRead = 0; m_numConnectedSockets = 0; m_numConnections = numConnections; m_receiveBufferSize = receiveBufferSize; // allocate buffers such that the maximum number of sockets can have one outstanding read and //write posted to the socket simultaneously m_bufferManager = new BufferManager(receiveBufferSize * numConnections * opsToPreAlloc, receiveBufferSize); m_readWritePool = new SocketAsyncEventArgsPool(numConnections); m_maxNumberAcceptedClients = new Semaphore(numConnections, numConnections); } // Initializes the server by preallocating reusable buffers and // context objects. These objects do not need to be preallocated // or reused, but it is done this way to illustrate how the API can // easily be used to create reusable objects to increase server performance. // public void Init() { // Allocates one large byte buffer which all I/O operations use a piece of. This gaurds // against memory fragmentation m_bufferManager.InitBuffer(); // preallocate pool of SocketAsyncEventArgs objects SocketAsyncEventArgs readWriteEventArg; for (int i = 0; i < m_numConnections; i++) { //Pre-allocate a set of reusable SocketAsyncEventArgs readWriteEventArg = new SocketAsyncEventArgs(); readWriteEventArg.Completed += new EventHandler<SocketAsyncEventArgs>(IO_Completed); readWriteEventArg.UserToken = new AsyncUserToken(); // assign a byte buffer from the buffer pool to the SocketAsyncEventArg object m_bufferManager.SetBuffer(readWriteEventArg); // add SocketAsyncEventArg to the pool m_readWritePool.Push(readWriteEventArg); } } // Starts the server such that it is listening for // incoming connection requests. // // <param name="localEndPoint">The endpoint which the server will listening // for connection requests on</param> public void Start(IPEndPoint localEndPoint) { // create the socket which listens for incoming connections listenSocket = new Socket(localEndPoint.AddressFamily, SocketType.Stream, ProtocolType.Tcp); listenSocket.Bind(localEndPoint); // start the server with a listen backlog of 100 connections listenSocket.Listen(100); // post accepts on the listening socket StartAccept(null); //Console.WriteLine("{0} connected sockets with one outstanding receive posted to each....press any key", m_outstandingReadCount); Console.WriteLine("Press any key to terminate the server process...."); Console.ReadKey(); } // Begins an operation to accept a connection request from the client // // <param name="acceptEventArg">The context object to use when issuing // the accept operation on the server's listening socket</param> public void StartAccept(SocketAsyncEventArgs acceptEventArg) { if (acceptEventArg == null) { acceptEventArg = new SocketAsyncEventArgs(); acceptEventArg.Completed += new EventHandler<SocketAsyncEventArgs>(AcceptEventArg_Completed); } else { // socket must be cleared since the context object is being reused acceptEventArg.AcceptSocket = null; } m_maxNumberAcceptedClients.WaitOne(); bool willRaiseEvent = listenSocket.AcceptAsync(acceptEventArg); if (!willRaiseEvent) { ProcessAccept(acceptEventArg); } } // This method is the callback method associated with Socket.AcceptAsync // operations and is invoked when an accept operation is complete // void AcceptEventArg_Completed(object sender, SocketAsyncEventArgs e) { ProcessAccept(e); } private void ProcessAccept(SocketAsyncEventArgs e) { Interlocked.Increment(ref m_numConnectedSockets); Console.WriteLine("Client connection accepted. There are {0} clients connected to the server", m_numConnectedSockets); // Get the socket for the accepted client connection and put it into the //ReadEventArg object user token SocketAsyncEventArgs readEventArgs = m_readWritePool.Pop(); ((AsyncUserToken)readEventArgs.UserToken).Socket = e.AcceptSocket; // As soon as the client is connected, post a receive to the connection bool willRaiseEvent = e.AcceptSocket.ReceiveAsync(readEventArgs); if (!willRaiseEvent) { ProcessReceive(readEventArgs); } // Accept the next connection request StartAccept(e); } // This method is called whenever a receive or send operation is completed on a socket // // <param name="e">SocketAsyncEventArg associated with the completed receive operation</param> void IO_Completed(object sender, SocketAsyncEventArgs e) { // determine which type of operation just completed and call the associated handler switch (e.LastOperation) { case SocketAsyncOperation.Receive: ProcessReceive(e); break; case SocketAsyncOperation.Send: ProcessSend(e); break; default: throw new ArgumentException("The last operation completed on the socket was not a receive or send"); } } // This method is invoked when an asynchronous receive operation completes. // If the remote host closed the connection, then the socket is closed. // If data was received then the data is echoed back to the client. // private void ProcessReceive(SocketAsyncEventArgs e) { // check if the remote host closed the connection AsyncUserToken token = (AsyncUserToken)e.UserToken; if (e.BytesTransferred > 0 && e.SocketError == SocketError.Success) { //increment the count of the total bytes receive by the server Interlocked.Add(ref m_totalBytesRead, e.BytesTransferred); Console.WriteLine("The server has read a total of {0} bytes", m_totalBytesRead); Int32 BytesToProcess = e.BytesTransferred; Byte[] bt = new Byte[BytesToProcess]; Buffer.BlockCopy(e.Buffer, e.Offset, bt, 0, BytesToProcess); string strReceive = Encoding.Default.GetString(bt); Send(token.Socket, bt, 0, bt.Length, 1000); Thread.Sleep(1000); //echo the data received back to the client //e.SetBuffer(e.Offset, e.BytesTransferred); bool willRaiseEvent = token.Socket.SendAsync(e); if (!willRaiseEvent) { ProcessSend(e); } } else { CloseClientSocket(e); } } public static void Send(Socket socket, byte[] buffer, int offset, int size, int timeout) { socket.SendTimeout = 0; int startTickCount = Environment.TickCount; int sent = 0; // how many bytes is already sent do { if (Environment.TickCount > startTickCount + timeout) //throw new Exception("Timeout."); try { sent += socket.Send(buffer, offset + sent, size - sent, SocketFlags.None); } catch (SocketException ex) { if (ex.SocketErrorCode == SocketError.WouldBlock || ex.SocketErrorCode == SocketError.IOPending || ex.SocketErrorCode == SocketError.NoBufferSpaceAvailable) { // socket buffer is probably full, wait and try again Thread.Sleep(30); } else throw ex; // any serious error occurr } } while (sent < size); } // This method is invoked when an asynchronous send operation completes. // The method issues another receive on the socket to read any additional // data sent from the client // // <param name="e"></param> private void ProcessSend(SocketAsyncEventArgs e) { if (e.SocketError == SocketError.Success) { //e.SetBuffer(e.Offset, 10); // done echoing data back to the client AsyncUserToken token = (AsyncUserToken)e.UserToken; // read the next block of data send from the client bool willRaiseEvent = token.Socket.ReceiveAsync(e); if (!willRaiseEvent) { ProcessReceive(e); } } else { CloseClientSocket(e); } } private void CloseClientSocket(SocketAsyncEventArgs e) { AsyncUserToken token = e.UserToken as AsyncUserToken; // close the socket associated with the client try { token.Socket.Shutdown(SocketShutdown.Send); } // throws if client process has already closed catch (Exception) { } token.Socket.Close(); // decrement the counter keeping track of the total number of clients connected to the server Interlocked.Decrement(ref m_numConnectedSockets); m_maxNumberAcceptedClients.Release(); Console.WriteLine("A client has been disconnected from the server. There are {0} clients connected to the server", m_numConnectedSockets); // Free the SocketAsyncEventArg so they can be reused by another client m_readWritePool.Push(e); } }</div>

Program

1

<div>using System; using System.Net; using System.Collections.Generic; using System.IO; class Program { static void Main(string[] args) { IPEndPoint iep = new IPEndPoint(IPAddress.Parse("10.1.20.6"), 1333); Server objServer = new Server(1000, 10); objServer.Init(); objServer.Start(iep); } } </div>

http://www.cnblogs.com/tianzhiliang/archive/2010/09/08/1821623.html

龙生 21 Apr 2012

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C#的Socket程序（TCP）

其实只要用到Socket联接，基本上就得使用Thread，是交叉使用的。C#封装的Socket用法基本上不算很复杂，只是不知道托管之后的Socket有没有其他性能或者安全上的问题。在C#里面能找到的最底层的操作也就是socket了，概念不做解释。程序模型如下：WinForm程序：启动端口侦听；监视Socket联接情况；定期关闭不活动的联接；Listener：处理Socket的Accept函数，侦听新链接，建立新Thread来处理这些联接（Connection）。Connection：处理具体的每一个联接的会话。 1：WinForm如何启动一个新的线程来启动Listener：//start the serverprivate void btn_startServer_Click(object sender, EventArgs e){//this.btn_startServer.Enabled = false;Thread _createServer = new Thread(new ThreadStart(WaitForConnect));_createServer.Start();}//wait all connectionsprivate void WaitForConnect(){SocketListener listener = new SocketListener(Convert.ToInt32(this.txt_port.Text));listener.StartListening();}因为侦听联接是一个循环等待的函数，所以不可能在WinForm的线程里面直接执行，不然Winform也就是无法继续任何操作了，所以才指定一个新的线程来执行这个函数，启动侦听循环。这一个新的线程是比较简单的，基本上没有启动的参数，直接指定处理函数就可以了。2：Listener如何启动循环侦听，并且启动新的带有参数的线程来处理Socket联接会话。先看如何建立侦听：（StartListening函数）IPEndPoint localEndPoint = new IPEndPoint(_ipAddress, _port);// 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(20);//20 trucks // Start listening for connections. while (true){// here will be suspended while waiting for a new connection. Socket connection = listener.Accept();Logger.Log("Connect", connection.RemoteEndPoint.ToString());//log it, new connection……}}……基本步骤比较简单：建立本机的IPEndPoint对象，表示以本机为服务器，在指定端口侦听；然后绑定到一个侦听Socket上；进入while循环，等待新的联接；如果有新的联接，那么建立新的socket来对应这个联接的会话。值得注意的就是这一句联接代码：listener.Accept()。执行这一句的时候，程序就在这个地方等待，直到有新的联检请求的时候程序才会执行下一句。这是同步执行，当然也可以异步执行。新的联接Socket建立了（Accept之后），对于这些新的socket该怎么办呢？他们依然是一个循环等待，所以依然需要建立新的Thread给这些Socket去处理会话（接收/发送消息），而这个Thread就要接收参数了。Thread本身是不能接收参数的，为了让它可以接收参数，可以采用定义新类，添加参数作为属性的方法来解决。因为每一个Socket是一个Connection周期，所以我定义了这么一个类public class Connection。这个类至少有这样一个构造函数public Connection(Socket socket); 之所以这么做，就是为了把Socket参数传给这个Connection对象，然后好让Listener启动这个Thread的时候，Thread可以知道他正在处理哪一个Socket。具体处理的方法：（在Listener的StartListening函数，ocket connection […]

龙生 21 Apr 2012

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TCP与UDP区别

TCP与UDP区别 TCP—传输控制协议,提供的是面向连接、可靠的字节流服务。当客户和服务器彼此交换数据前，必须先在双方之间建立一个TCP连接，之后才能传输数据。TCP提供超时重发，丢弃重复数据，检验数据，流量控制等功能，保证数据能从一端传到另一端。 UDP—用户数据报协议，是一个简单的面向数据报的运输层协议。UDP不提供可靠性，它只是把应用程序传给IP层的数据报发送出去，但是并不能保证它们能到达目的地。由于UDP在传输数据报前不用在客户和服务器之间建立一个连接，且没有超时重发等机制，故而传输速度很快 Overview TCP (Transmission Control Protocol) is the most commonly used protocol on the Internet. The reason for this is because TCP offers error correction. When the TCP protocol is used there is a "guaranteed delivery." This is due largely in part to a method called "flow control." Flow control determines when data needs to be re-sent, and stops the flow of data until previous packets are successfully transferred. This works because if a packet of data is sent, a collision may occur. When this […]

龙生 21 Apr 2012

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