SignalR: client disconnection

Question

How does the SignalR handle client disconnection? Am I right if I state the following?

• SignalR will detect browser page close/refresh via Javascript event hand

Answer 1

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();
    }
}

Answer 2

In SignalR 1.0, the SignalR.Hubs.IConnected and SignalR.Hubs.IDisconnect are no longer implemented, and now it's just an override on the hub itself:

public class Chat : Hub
{
    public override Task OnConnected()
    {
        return base.OnConnected();
    }

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

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