Do you need to manually remove a connection from a SignalR group on disconnect?

Question

In a SignalR hub, I am adding connections to groups in the OnConnected method:

public override Task OnConnected()
{
    this.Groups.Add(this.Context.ConnectionId, "aGroup");
    this.Groups.Add(this.Context.ConnectionId, "bGroup");
}

Do I need to manually remove the connection from these groups upon disconnect? Given the pub-sub model, I don't see how I could easily do this, except to keep track of connections and groups in a separate data structure.

I am experiencing a rather large memory leak in an MVC project using SignalR, and am wondering if this could be the culprit.

Answer 1

No, you don't.

You don't have to explicitly create groups. In effect, a group is automatically created the first time you specify its name in a call to Groups.Add, and it is deleted when you remove the last connection from membership in it.

Source, and read further: http://www.asp.net/signalr/overview/guide-to-the-api/working-with-groups