关闭客户端时出现SignalR Websocket异常

Question

当启动和停止连接到基本自托管服务器的SignalR客户端时，可以像这样：

async public void Start(string url)
{
    _connection = new HubConnection(url);
    _proxy = _connection.CreateHubProxy("hubname");
    await _connection.Start().ContinueWith((task) => IsRunning = true);
}
public void Stop()
{
    _connection.Stop();
}

当调用“Stop”方法时，我收到以下异常信息（包括跟踪消息）:

SignalR.Transports.TransportHeartBeat Verbose: 0 : KeepAlive(c75fe282-a86d-406a-935b-5981b47bd472)
SignalR.Transports.TransportHeartBeat Information: 0 : Connection 1bdabc19-e0a7-4649-aabb-bade071ad6d0 is New.
SignalR.Transports.WebSocketTransport Information: 0 : Abort(1bdabc19-e0a7-4649-aabb-bade071ad6d0)
SignalR.Transports.TransportHeartBeat Information: 0 : Removing connection 1bdabc19-e0a7-4649-aabb-bade071ad6d0
SignalR.Transports.WebSocketTransport Information: 0 : End(1bdabc19-e0a7-4649-aabb-bade071ad6d0)
SignalR.Transports.WebSocketTransport Verbose: 0 : DrainWrites(1bdabc19-e0a7-4649-aabb-bade071ad6d0)
SignalR.Transports.WebSocketTransport Information: 0 : CloseSocket(1bdabc19-e0a7-4649-aabb-bade071ad6d0)
App.vshost.exe Error: 0 : Error while closing the websocket: System.Net.WebSockets.WebSocketException (0x80004005): An internal WebSocket error occurred. Please see the innerException, if present, for more details.  ---> System.Net.Sockets.SocketException (0x80004005): An existing connection was forcibly closed by the remote host
   at System.Net.WebSockets.WebSocketConnectionStream.WebSocketConnection.WriteAsync(Byte[] buffer, Int32 offset, Int32 count, CancellationToken cancellationToken)
   at System.Net.WebSockets.WebSocketConnectionStream.<WriteAsync>d__11.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Net.WebSockets.WebSocketBase.<SendFrameAsync>d__11.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Net.WebSockets.WebSocketBase.WebSocketOperation.<Process>d__47.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Net.WebSockets.WebSocketBase.<CloseOutputAsyncCore>d__17.MoveNext()
   at System.Net.WebSockets.WebSocketBase.ThrowIfConvertibleException(String methodName, Exception exception, CancellationToken cancellationToken, Boolean aborted)
   at System.Net.WebSockets.WebSocketBase.<CloseOutputAsyncCore>d__17.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNet.SignalR.WebSockets.WebSocketHandler.<<CloseAsync>b__6>d__8.MoveNext()
App.vshost.exe Error: 0 : Error while closing the websocket: System.Net.WebSockets.WebSocketException (0x80004005): An internal WebSocket error occurred. Please see the innerException, if present, for more details.  ---> System.Net.Sockets.SocketException (0x80004005): An existing connection was forcibly closed by the remote host
   at System.Net.WebSockets.WebSocketConnectionStream.WebSocketConnection.WriteAsync(Byte[] buffer, Int32 offset, Int32 count, CancellationToken cancellationToken)
   at System.Net.WebSockets.WebSocketConnectionStream.<WriteAsync>d__11.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Net.WebSockets.WebSocketBase.<SendFrameAsync>d__11.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Net.WebSockets.WebSocketBase.WebSocketOperation.<Process>d__47.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Net.WebSockets.WebSocketBase.<CloseOutputAsyncCore>d__17.MoveNext()
   at System.Net.WebSockets.WebSocketBase.ThrowIfConvertibleException(String methodName, Exception exception, CancellationToken cancellationToken, Boolean aborted)
   at System.Net.WebSockets.WebSocketBase.<CloseOutputAsyncCore>d__17.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNet.SignalR.WebSockets.WebSocketHandler.<<CloseAsync>b__6>d__8.MoveNext()
SignalR.Transports.WebSocketTransport Information: 0 : CompleteRequest (1bdabc19-e0a7-4649-aabb-bade071ad6d0)
SignalR.Transports.TransportHeartBeat Verbose: 0 : KeepAlive(c75fe282-a86d-406a-935b-5981b47bd472)
SignalR.Transports.TransportHeartBeat Verbose: 0 : KeepAlive(c75fe282-a86d-406a-935b-5981b47bd472)

设置本身似乎运行良好，设备可以连接、发送、接收和断开连接。但每次断开连接时，我都会收到上述不友好的异常信息。有任何想法是什么问题吗？我正在使用SignalR 2.2.0和Owin 1.2.2。

- dsfgsho

Answer 1

看起来是一个已知问题，可能会在v3中得到修复。

- Miha Markic

Answer 2

尝试向关闭方法提供一个TimeSpan，以便在等待可能正在进行的任何异步进程时，给予其足够的时间来实际关闭：

public void Stop()
{
    _connection.Stop(new TimeSpan(1000));
}

这对我很有帮助。

- user3241900

---

这个对我起作用了 - 在上面添加TimeSpan(1000)后，不再收到websocketexceptions。使用SignalR Client 2.1.2框架4.5。 - Neal Davis

Answer 3

好的，伙计们，我知道这很糟糕。我正在尝试在主窗口关闭时关闭SignalR客户端，但我得到了很多无法捕获的异常，导致我的进程挂起。因此，我决定在窗体关闭时杀死主进程。

private void OnClose(object sender, CancelEventArgs e){
        try
        {
            var process = Process.GetCurrentProcess();
            process.Kill();
            //HubConnection.Stop();
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex);
        }

}

- axu

Answer 4

我用以下方法解决了这个问题

connection.Reconnecting += connection.Stop;

因为我发现连接状态总是在重新连接

- Ma Wang

Answer 5

如果我理解正确，您想在客户端断开连接时停止广播消息。因此，我的方法是在SignalR中使用连接生命周期事件。

这是官方页面：SignalRLifeTimeEvents

public override System.Threading.Tasks.Task OnDisconnected()
{
    //-- When any client will close the browser or page this event will fire

    return base.OnDisconnected();
}

- Fatih Ayyildiz

---

我没有做任何特殊处理。我只是在连接的SignalR客户端上使用默认的Stop()方法，这会导致服务器抛出异常。 - dsfgsho