How to Determine Server Disconnection from Signalr Client

How to determine server disconnection from SignalR client?

The provided answers will no longer work.
This is the new way to stop/disconnect connections.

myHub.stop().then(() => {
  alert('Server has disconnected');
});

Detect on disconnect user signalr

Add this overriden method into your Hub class:

public override Task OnDisconnected(bool stopCalled)
{
    // do the logging here
    Trace.WriteLine(Context.ConnectionId + ' - disconnected');
    return base.OnDisconnected(stopCalled);
}

This will handle and log disconects on server side while I think it doesn't make much sense to track it on client side as it's unlikely your SignalR session would be terminated from server side - see here.

Edit in regard to @stuartd comment:
you could also override

public override Task OnReconnected()
{
    Trace.WriteLine(Context.ConnectionId + ' - reconnected');
    return base.OnReconnected();
}

so you'll be able to track cases when Client tried reconnect to Server and succeed.

Edit#2:
Then you can of course use same mechanism for tracking of OnConnected event

public override Task OnConnected()
{
    Trace.WriteLine(Context.ConnectionId + ' - reconnected');
    return base.OnConnected();
}

So all tracking code is conveniently kept just on server-side which is more robust in cases when client is logged into hub but for some reason failed to execute method you're using to track logged state.

SignalR - Server side method to detect if a client disconnects from a hub?

SignalR has OnConnected, OnDisconnected, and OnReconnected that are called every time the client does one of those actions. You can simply override them:

public override Task OnConnected()
{
    return base.OnConnected();
}

public override Task OnDisconnected()
{
    //custom logic here
    return base.OnDisconnected();
}

public override Task OnReconnected()
{
    return base.OnReconnected();
}

I've found them to be extremely useful also for debugging purposes. If you're wanting to set a timer for each person, you should use some sort of connectionMapping along with the above functions to keep track of your users.

SignalR: client disconnection

If a user refreshes the page, that is treated as a new connection. You are correct that the disconnect is based on a timeout.

You can handle the Connect/Reconnect and Disconnect events in a Hub by implementing SignalR.Hubs.IConnected and SignalR.Hubs.IDisconnect.

The above referred to SignalR 0.5.x.

From the official documentation (currently for v1.1.3):

public class ContosoChatHub : Hub
{
    public override Task OnConnected()
    {
        // Add your own code here.
        // For example: in a chat application, record the association between
        // the current connection ID and user name, and mark the user as online.
        // After the code in this method completes, the client is informed that
        // the connection is established; for example, in a JavaScript client,
        // the start().done callback is executed.
        return base.OnConnected();
    }

    public override Task OnDisconnected()
    {
        // Add your own code here.
        // For example: in a chat application, mark the user as offline, 
        // delete the association between the current connection id and user name.
        return base.OnDisconnected();
    }

    public override Task OnReconnected()
    {
        // Add your own code here.
        // For example: in a chat application, you might have marked the
        // user as offline after a period of inactivity; in that case 
        // mark the user as online again.
        return base.OnReconnected();
    }
}

Notify SignalR Server On Client Disconnected Accidentally (Disgracefully)

Since WebSocketTransport is not available at Xamarin, I advice to use "Ping" workaround.

1. Implement Ping() method at server-side.
2. Call this method from clients periodically (say 1/2 of the timeout interval).
3. Within this method save ConnectionId : DateTime key/value pair to static ConcurrentDictionary at server-side.
4. Run background Task at server-side and check DateTime for all dictionary keys.
5. Remove old-ones and call appropriate code.

---

Related Topics