SignalR: Using the caller method outside of the hub context

Question

I am trying to use the Caller method outside my Hub Context. I have a helper class which works fine when broadcasting a message to all users like so:

hub.Clients.All.newLessonAlert(notif);

It won't allow me to use the Caller method within this class but this works fine in the hub context class. Why is this? I have also tried to move all of my functions inside the context class but I now get this unhanded exception:

Using a Hub instance not created by the HubPipeline is unsupported

Is there a straightforward way to continue to use my helper class and identify connections to the hub?

Answer 1

I solved this in the following way:

1. I created a OnConnected method in my Hub class. This assigned the currently connected user to a group.

   [HubName("NotificationsHub")]
   public class NotificationHub : Hub
   {
       private static IHubContext hubContext = GlobalHost.ConnectionManager.GetHubContext<NotificationHub>();
   
       public override Task OnConnected()
       {
           string userid = Context.Request.User.Identity.GetUserId();
           Groups.Add(Context.ConnectionId, userid);
           return base.OnConnected();
       }
   }
   

2. Modified my HubHelper class to now broadcast this alert to the currently connected user (specified by the user's ID)

   public void HighScoreAlert(int gameid, int score, string userID)
   {
       string message = "High Score achieved on " + gameid;
   
       hub.Clients.Group(userID).score(message);
   }
   

3. For the controller action I pass in the user's ID and then call the HubHelper method featured above.

Hope this helps someone