SignalR doesn't push message to client

Question

I am implementing functionality to notify the user of long running job completions using SignalR in an AngularJS application.I have created groups of user based on their name,so for each user a group of his name and different connectionids which he has opened up will be created and he would be notified by his group. I want to notify the user on two pages i.e. landing Page and Job Run Page as even if the user is on landing page and job run completes he should be notified of it.

For the same reason i am creating group by his name on both the pages,so that if he is on any page he would be nofied through the group.

On landing page controller js file i have written code to add the user in group as follow...

$rootScope.signalRHub = $.connection.signalRHub;

$rootScope.hubStart = null;

$rootScope.startHub = function () {

    if ($rootScope.hubStart == null)
    {
        $rootScope.hubStart = $.connection.hub.start();
    }
    return $rootScope.hubStart;
}

$scope.$on('$locationChangeStart', function (event) {

        if ($rootScope.userName != "") {
            $rootScope.signalRHub.server.leaveGroup($rootScope.userName);
        }
});

// Start the connection
$rootScope.startHub().done(function () {

        $rootScope.signalRHub.server.joinGroup($rootScope.userName);
});

on Job Run controller js file i have written following code....

$rootScope.signalRHub.client.showNotification = function (message) {
    notify('Your notification message');//notify is the angular js directive injected in this controller which runs fine
};

$scope.$on('$locationChangeStart', function (event) {
        $rootScope.signalRHub.server.leaveGroup($rootScope.studyid);
});

// Start the connection    
$rootScope.startHub().done(function () {

    $rootScope.signalRHub.server.joinGroup($rootScope.userName
});

My Hub File.....

[EnableCors(origins: "*", headers: "*", methods: "*")]
    public class SignalRHub : Hub
    {        
        public Task JoinGroup(string groupName)
        {
            return Groups.Add(Context.ConnectionId, groupName);
        }       

        public Task LeaveGroup(string groupName)
        {
            return Groups.Remove(Context.ConnectionId, groupName);
        }

        public void ShowNotification(string jobRunDetailId, string userName)
        {
            if (!string.IsNullOrEmpty(userName))
            {
                var context = GlobalHost.ConnectionManager.GetHubContext<SignalRHub>();

                context.Clients.Group(userName).showNotification(jobRunDetailId);
            }
        }
    }

The issue is when i run the application the group add functionality for both pages works fine.but when i call "showNotification" from Hub it doesn't show any message.

But strange thing is if i comment the "$rootScope.startHub().done...." function on landing page then the jobrun page notify functionality works fine.I am not sure if writing "$rootScope.startHub().done()..." on two places is creating this problem.please help.

Answer 1

You need to wire up all callbacks before calling start. If you turn client side logging on, it'll tell you what hubs you are subscribed to.

Aside: [EnableCors] is a webapi specific attribute that does not work in SignalR.