I’m working on a kind of “notification observer” service which uses SignalR to collect connected users from an Angular application (this app uses Azure Entra as auth). This “observer” service would detect (by Service Bus or a call to the Hub) that a new notification has been created by other application for a specific group of user ids (list of Entra user ids, so GUIDs), and then it should be able to send this notification only to these specific users if they are connected to a Hub instance.

Thing is, I don’t really know if this is feasible, I know that you can configure SignalR to require authentication with Azure Entra, but I’m struggling to find information about if SignalR can distinguish between these connected users by their Azure Entra Id, something like:

foreach(var entraUserId in notification.Users)
  await this.hubContext.Client(entraUserId).SendAsync(message);

Or if I have to do something special, I know .Client() expects a connectionId which maps to a specific connection, but I have the feeling that there is a link that I don’t know about that would be able to map the Entra User Ids to connectionIds.