我正在尝试使用CancellationTokenSource取消等待网络IO的任务,但我必须等到TcpClient连接:
try
{
while (true)
{
token.Token.ThrowIfCancellationRequested();
Thread.Sleep(int.MaxValue); //simulating a TcpListener waiting for request
}
}
有什么想法吗?
其次,可以在单独的任务中启动每个客户端吗?
答案 0 :(得分:3)
当您启动任务时,您可以使用StartNew的重载来传递取消令牌,您的任务将检查取消令牌。
或者你可以使用AcceptAsync继续做其他工作。 AcceptAsync将通过您定义的SocketAsyncEventArgs参数调用附加的OnCompleted方法。
internal class Program
{
private static EventWaitHandle _signalFromClient;
private static readonly string NameThatClientKnows = Guid.NewGuid().ToString();
private static readonly CancellationTokenSource CancellationTokenSource = new CancellationTokenSource();
private const int PingSendTimeout = 30000;
private static Socket _connectedClientSocket;
private static Socket _tcpServer;
private static void Main(string[] args)
{
_signalFromClient = new EventWaitHandle(false, EventResetMode.AutoReset, NameThatClientKnows);
_tcpServer = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
_tcpServer.Bind(new IPEndPoint(IPAddress.Loopback, 0));
_tcpServer.Listen(1);
var asyncOpInfo = new SocketAsyncEventArgs();
asyncOpInfo.Completed += CompletedConnectRequest;
_tcpServer.AcceptAsync(asyncOpInfo);
Console.WriteLine("Console stays open, connecting client will say something.");
Console.ReadLine();
}
private static void CompletedConnectRequest(object sender, SocketAsyncEventArgs e)
{
Console.WriteLine("Client connected");
_connectedClientSocket = e.AcceptSocket;
Task.Factory.StartNew(SendSimpleMessage, CancellationTokenSource.Token);
}
private static void SendSimpleMessage()
{
while (!CancellationTokenSource.Token.IsCancellationRequested && _connectedClientSocket.Connected)
{
try
{
_connectedClientSocket.Send(Encoding.UTF8.GetBytes("PING"));
_signalFromClient.WaitOne(PingSendTimeout);
}
catch (SocketException) { Dispose(); }
}
}
private static void Dispose()
{
CancellationTokenSource.Cancel();
_connectedClientSocket.Close();
_tcpServer.Close();
}
}
当然,使用缓冲区和其他必要的项目/行为设置SocketAsyncEventArgs。 在Dispose()中,我取消了该任务,并通过在客户端和服务器ø_Ø上调用Socket.Close来捕获可能抛出的任何SocketExceptions。
答案 1 :(得分:0)
我使用了CancellationToken句柄而不是创建一个新句柄,它使代码更简单
var task = Listener.AcceptTcpClientAsync();
task.Wait(MainToken.Token);
MainToken.Token.ThrowIfCancellationRequested();