ApiHubController.cs

using System;
using System.Linq;
using System.Threading.Tasks;
using System.Web.Http;

using SignalR.Client;
using SignalR.Client.Hubs;
using SignalR.Hubs;

namespace EventDay.Web.Api.Controllers
{
    public abstract class ApiHubController<THub> : ApiController where THub : IHub
    {
        private readonly HubConnection _connection;
        private readonly Task<HubProxy> _proxyTask;

        protected ApiHubController()
        {
            var url = string.Format("http://app.{0}", Application.TopLevelDomain);

            _connection = new HubConnection(url);
            var proxy = new HubProxy(_connection, GetHubName());
            _proxyTask = _connection.Start().ContinueWith(t => proxy);
        }

        protected IHubProxy Hub
        {
            get { return _proxyTask.Result; }
        }

        private string GetHubName()
        {
            Type type = typeof (THub);
            HubNameAttribute attribute =
                type.GetCustomAttributes(typeof (HubNameAttribute), false).Cast<HubNameAttribute>().SingleOrDefault();
            return attribute != null ? attribute.HubName : type.Name;
        }

        protected override void Dispose(bool disposing)
        {
            if(disposing && _connection.State != ConnectionState.Disconnected)
                _connection.Stop();

            base.Dispose(disposing);
        }
    }
}