client.js

        var authData = storageService.get('authData');
        var accessToken = authData.token;
        var connection = $.hubConnection(host);
        connection.qs = { 'access_token': accessToken };
        var proxy = connection.createHubProxy(hub);

QueryStringIdProvider.cs

//This solution is based on the code of this tutorial https://github.com/louislewis2/AngularJSAuthentication
using Microsoft.AspNet.SignalR;
namespace Solution.Web.Providers
{
    public class QueryStringIdProvider : IUserIdProvider
    {
        public string GetUserId(IRequest request)
        {
            var token = request.QueryString.Get("access_token");
            var authenticationTicket = Startup.OAuthOptions.AccessTokenFormat.Unprotect(token);
            if (authenticationTicket == null || authenticationTicket.Identity == null ||
                !authenticationTicket.Identity.IsAuthenticated)
                return string.Empty;

            var userId = authenticationTicket.Identity.Name;
            return userId;
        }
    }
}