Optimal way to retrieve hub context in SignalR 3.0 from anywhere

Question

I am working on a Asp .NET 3.1 application using SignalR 3.0 and I need the ability to access the hubcontext at any time. I regularly and receiving data and processing it to push out to the clients when a timer event fires. This means I can rely on the ability to access the hubcontext when the client calls a hub method or through the controllers or middleware. Since I cannot use GlobalHost in this version of signalR, what is the optimum way to do this?

I have tried several different things, I originally thought to keep a static reference to the hubcontext but I don't think that is a very reliable method. I thought to keep a static reference to an IServiceProvider, but by the time my timers fired, the service provider had been disposed. Any suggestions?

Answer 1

If you are using standard Asp.Net Core Dependency Injection (IServiceCollection) you can inject IHubContext<ChatHub> in constructor of your service:

    public class NotificationsHub : Hub
    {
    }

    public class NotificationService(IHubContext<NotificationsHub> notificationsHub) : INotificationService
    {
    }

    // ***** At Startup ********

    // SignalR registration
    private static void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
      app.UseSignalR(routes =>
      {
        routes.MapHub<NotificationsHub>(hubRoute);
      });
    }

    // dependencies registration
    public static IServiceCollection RegisterServices(IServiceCollection services)
    {
      services.AddSingleton<INotificationsService, NotificationService>();
    }

Does it work for you ?