使用.Net 4.5asynchronousfunction进行套接字编程

我以前使用过BeginAccept()和BeginRead() ，但是在Visual Studio 2012中，我想在我的套接字服务器程序中使用新的asynchronous（ async ， await ）function。

我如何完成AcceptAsync和ReceiveAsyncfunction？

 using System.Net; using System.Net.Sockets; namespace OfficialServer.Core.Server { public abstract class CoreServer { private const int ListenLength = 500; private const int ReceiveTimeOut = 30000; private const int SendTimeOut = 30000; private readonly Socket _socket; protected CoreServer(int port, string ip = "0.0.0.0") { _socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); _socket.Bind(new IPEndPoint(IPAddress.Parse(ip), port)); _socket.Listen(ListenLength); _socket.ReceiveTimeout = ReceiveTimeOut; _socket.SendTimeout = SendTimeOut; _socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.KeepAlive, true); _socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.DontLinger, true); } public void Start() { } } } 

Answer 1

…因为你是如此的坚定，所以我编写了一个非常简单的例子，说明如何编写一个回显服务器来让你走。 收到的任何东西都会回传给客户端。 服务器将保持运行60秒。 尝试在本地端口6666上telnet到它。花点时间来了解这里到底发生了什么。

 void Main() { CancellationTokenSource cts = new CancellationTokenSource(); TcpListener listener = new TcpListener(IPAddress.Any, 6666); try { listener.Start(); //just fire and forget. We break from the "forgotten" async loops //in AcceptClientsAsync using a CancellationToken from `cts` AcceptClientsAsync(listener, cts.Token); Thread.Sleep(60000); //block here to hold open the server } finally { cts.Cancel(); listener.Stop(); } } async Task AcceptClientsAsync(TcpListener listener, CancellationToken ct) { var clientCounter = 0; while (!ct.IsCancellationRequested) { TcpClient client = await listener.AcceptTcpClientAsync() .ConfigureAwait(false); clientCounter++; //once again, just fire and forget, and use the CancellationToken //to signal to the "forgotten" async invocation. EchoAsync(client, clientCounter, ct); } } async Task EchoAsync(TcpClient client, int clientIndex, CancellationToken ct) { Console.WriteLine("New client ({0}) connected", clientIndex); using (client) { var buf = new byte[4096]; var stream = client.GetStream(); while (!ct.IsCancellationRequested) { //under some circumstances, it's not possible to detect //a client disconnecting if there's no data being sent //so it's a good idea to give them a timeout to ensure that //we clean them up. var timeoutTask = Task.Delay(TimeSpan.FromSeconds(15)); var amountReadTask = stream.ReadAsync(buf, 0, buf.Length, ct); var completedTask = await Task.WhenAny(timeoutTask, amountReadTask) .ConfigureAwait(false); if (completedTask == timeoutTask) { var msg = Encoding.ASCII.GetBytes("Client timed out"); await stream.WriteAsync(msg, 0, msg.Length); break; } //now we know that the amountTask is complete so //we can ask for its Result without blocking var amountRead = amountReadTask.Result; if (amountRead == 0) break; //end of stream. await stream.WriteAsync(buf, 0, amountRead, ct) .ConfigureAwait(false); } } Console.WriteLine("Client ({0}) disconnected", clientIndex); } 

Answer 2

您可以使用TaskFactory.FromAsync将Begin / End对包装到async -ready操作中。

Stephen Toub在他的博客上有一个值得称道的Socket ，它包装了更高效的*Async端点。 我build议将它与TPL Dataflow结合起来，以创build一个完全async兼容的Socket组件。