Utilizzando. Net 4.5 Funzione asincrona per la programmazione di socket

Ho già utilizzato BeginAccept() e BeginRead() , ma con Visual Studio 2012 voglio sfruttare le nuove funzionalità asincrone ( async , await ) nel mio programma per server socket.

Come posso completare le funzioni AcceptAsync e ReceiveAsync ?

 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() { } } } 

… perché sei così determinato, ho messo insieme un esempio molto semplice di come scrivere un server echo per farti arrivare. Qualsiasi cosa ricevuta viene riportata al cliente. Il server rimarrà in esecuzione per 60 secondi. Prova a collegarti alla porta localhost 6666. Prenditi del tempo per capire esattamente cosa sta succedendo qui.

 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); } 

È ansible utilizzare TaskFactory.FromAsync per racchiudere le coppie Begin / End in operazioni async -ready.

Stephen Toub ha un Socket attendibile sul suo blog che racchiude i più efficienti endpoint *Async . Raccomando di combinare questo con TPL Dataflow per creare un componente Socket completamente async compatibile.