Calling SignalR hub clients from elsewhere in system

Question

I\'ve set up a SignalR hub to communicate between the server and client. The hub server side code is stored in a class called Hooking.cs. What I want is to be able to call a

Answer 1

You can easily use a hub by following this 2 step-

1. Instantiating by dependency injection like this-

   public class ClassName
   {
       ........
       ........
       private IHubContext _hub;
   
       public BulletinSenderController(IConnectionManager connectionManager)
       {
           _hub = connectionManager.GetHubContext<McpHub>();
           ........
           ........
       }
   
       ............
       ............
   }
   

2.Using the hub object like this-

_hub.Clients.All.onBulletinSent(bulletinToSend);

More can be found here.

Example code can be found in this git repo.

Answer 2

This is the correct way for SignalR 2.x:

var context = GlobalHost.ConnectionManager.GetHubContext<MyHub>();
context.Clients.All.addMessage(message);

Basically, you can use the dependency resolver for the current host to resolve the IConnectionManager interface which allows you to get ahold of the context object for a hub.

Further information can be found in the official documentation.

Answer 3

Hub.GetClients has disappeared in version 0.4.0.

From the wiki you can now use:

IConnectionManager connectionManager = AspNetHost.DependencyResolver.Resolve<IConnectionManager>();
dynamic clients = connectionManager.GetClients<MyHub>();

Answer 4

Have a look at how it's done in Chat.cs in SignalR.Samples.Hubs.Chat from https://github.com/SignalR/SignalR.

I can see in there that static Dictionary<TKey, TValue>'s are being instantiated at the top, so I imagine they are being maintained persistently too, either with the Chat class being a persisted instance (?) or that array being updated somehow.

Check it out, David Fowler would probably be the best on this.

Answer 5

This has changed in .NET Core 2, now you can use dependency injection like this:

    private readonly IHubContext<MyHub,IMyHubInterface> _hubContext;

    public MyController(MyHub,IMyHubInterface hubContext)
    {
        _hubContext = hubContext;
    }

    public bool SendViaSignalR()
    {
        _hubContext.Clients.All.MyClientSideSignalRMethod(new MyModel());
        return true;
    }