C＃异步服务器/客户端体系结构

堆叠溢出的第一篇文章！

无论如何……我正在尝试在业余时间自学网络编程，但我已经陷入困境，我无法绕过头脑。 在使用同步网络方法几天后，我决定制作一个客户端/服务器程序，该程序可以：

• 处理多个并发连接
• 处理多个通信流
• 有真正的双向沟通

在更一般的层面上，我想制作一个聊天程序。 多个客户端连接到服务器，可以单独发送和接收数据而没有任何问题……但是服务器也可以将数据从每个客户端发送给其他客户端。

现在我还没有达到目标，所以我在这里寻求一点指导。 我似乎无法使我的循环正常工作，我确信它与代码的异步性质有关……无论出于何种原因，我似乎无法弄清楚什么是错误的。 这是代码块：

Server.cs

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 { // 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 class AsynchronousSocketListener { // 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]; IPAddress ipAddress = System.Net.IPAddress.Loopback; IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 3000); // 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("\nPress 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 asynchronous 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("") > -1) { // All the data has been read from the // client. Display it on the console. Console.WriteLine("Read {0} bytes from socket. \n Data : {1}", content.Length, content); // Echo the data back to the client. Send(handler, content); } else { // Not all data received. Get more. handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReadCallback), state); } } } private static void Send(Socket handler, String data) { // Convert the string data to byte data using ASCII encoding. byte[] byteData = Encoding.ASCII.GetBytes(data); // Begin sending the data to the remote device. handler.BeginSend(byteData, 0, byteData.Length, 0, new AsyncCallback(SendCallback), handler); } private static void SendCallback(IAsyncResult ar) { try { // Retrieve the socket from the state object. Socket handler = (Socket)ar.AsyncState; // Complete sending the data to the remote device. int bytesSent = handler.EndSend(ar); Console.WriteLine("Sent {0} bytes to client.", bytesSent); handler.Shutdown(SocketShutdown.Both); handler.Close(); } catch (Exception e) { Console.WriteLine(e.ToString()); } } public static int Main(String[] args) { StartListening(); return 0; } } 

Client.cs

 using System; using System.Net; using System.Net.Sockets; using System.Text; using System.Threading; public class StateObject { // Client socket. public Socket workSocket = null; // Size of receive buffer. public const int BufferSize = 256; // Receive buffer. public byte[] buffer = new byte[BufferSize]; // Received data string. public StringBuilder sb = new StringBuilder(); } public class Program { public static ManualResetEvent connectDone = new ManualResetEvent(false); public static ManualResetEvent sendDone = new ManualResetEvent(false); public static ManualResetEvent receiveDone = new ManualResetEvent(false); public static void Connect(EndPoint remoteEP, Socket client) { client.BeginConnect(remoteEP, new AsyncCallback(ConnectCallback), client); connectDone.WaitOne(); } private static void ConnectCallback(IAsyncResult ar) { try { // Retrieve the socket from the state object. Socket client = (Socket)ar.AsyncState; // Complete the connection. client.EndConnect(ar); Console.WriteLine("Socket connected to {0}", client.RemoteEndPoint.ToString()); // Signal that the connection has been made. connectDone.Set(); } catch (Exception e) { Console.WriteLine(e.ToString()); } } private static void Send(Socket client, String data) { // Convert the string data to byte data using ASCII encoding. byte[] byteData = Encoding.ASCII.GetBytes(data); // Begin sending the data to the remote device. client.BeginSend(byteData, 0, byteData.Length, SocketFlags.None, new AsyncCallback(SendCallback), client); } private static void SendCallback(IAsyncResult ar) { try { // Retrieve the socket from the state object. Socket client = (Socket)ar.AsyncState; // Complete sending the data to the remote device. int bytesSent = client.EndSend(ar); Console.WriteLine("Sent {0} bytes to server.", bytesSent); // Signal that all bytes have been sent. sendDone.Set(); } catch (Exception e) { Console.WriteLine(e.ToString()); } } private static void Receive(Socket client) { try { // Create the state object. StateObject state = new StateObject(); state.workSocket = client; // Begin receiving the data from the remote device. client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReceiveCallback), state); } catch (Exception e) { Console.WriteLine(e.ToString()); } } private static void ReceiveCallback(IAsyncResult ar) { try { // Retrieve the state object and the client socket // from the asynchronous state object. StateObject state = (StateObject)ar.AsyncState; Socket client = state.workSocket; // Read data from the remote device. int bytesRead = client.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)); // Get the rest of the data. client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReceiveCallback), state); } else { // All the data has arrived; put it in response. if (state.sb.Length > 1) { string response = state.sb.ToString(); Console.WriteLine(response); } // Signal that all bytes have been received. receiveDone.Set(); } } catch (Exception e) { Console.WriteLine(e.ToString()); } } static void Main(string[] args) { IPAddress ipAddress = System.Net.IPAddress.Loopback; IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 3000); Socket sock = new Socket(AddressFamily.InterNetwork,SocketType.Stream,ProtocolType.Tcp); Connect(localEndPoint, sock); string packet; while (true) { packet = Console.ReadLine(); packet += ""; Send(sock, packet); Receive(sock); connectDone.WaitOne(); } } } 

Answer 1

当你异步时，你不需要任何循环或等待句柄。 只需在AcceptCallback中激活另一个beginAccept，服务器将在接受客户端后再次开始监听。

如果您的问题是服务器只响应一次然后关闭，那么，那就是您在SendCallback中所说的 – 它发送内容然后关闭。 调用handler.beginReceive而不是handler.shutdown（你必须将StateObject一直带到这个回调，而不仅仅是处理程序）。