Initiate a service and inject it to all controllers - angularjs

Question

I'm using Facebook connect to login my clients.
I want to know if the user is logged in or not.
For that i use a service that checks the user's status.
My Service:
angular.module('angularFacebbokApp')
.service('myService', function myService($q, Facebook) {
return {
getFacebookStatus: function() {
var deferral = $q.defer();
deferral.resolve(Facebook.getLoginStatus(function(response) {
console.log(response);
status: response.status;
}));
return deferral.promise;
}
}
});
I use a promise to get the results and then i use the $q.when() to do additional stuff.
angular.module('angularFacebbokApp')
.controller('MainCtrl', function ($scope, $q, myService) {
console.log(myService);
$q.when(myService.getFacebookStatus())
.then(function(results) {
$scope.test = results.status;
});
});
My problem is that i need to use the $q.when in every controller.
Is there a way to get around it? So i can just inject the status to the controller?
I understand i can use the resolve if i use routes, but i don't find it the best solution.

Answer 1

There is no need to use $q.defer() and $q.when() at all, since the Facebook.getLoginStatus() already return a promise.
Your service could be simpified like this:
.service('myService', function myService(Facebook) {
return {
getFacebookStatus: function() {
return Facebook.getLoginStatus();
}
}
});
And in your controller:
.controller('MainCtrl', function ($scope, myService) {
myService.getFacebookStatus().then(function(results) {
$scope.test = results.status;
});
});
Hope this helps.

Answer 2

As services in angularjs are singleton you can create new var status to cache facebook response. After that before you make new call to Facebook from your controller you can check if user is logged in or not checking myService.status
SERVICE
angular.module('angularFacebbokApp')
.service('myService', function myService($q, Facebook) {
var _status = {};
function _getFacebookStatus() {
var deferral = $q.defer();
deferral.resolve(Facebook.getLoginStatus(function(response) {
console.log(response);
_status = response.status;
}));
return deferral.promise;
}
return {
status: _status,
getFacebookStatus: _getFacebookStatus
}
});
CONTROLLER
angular.module('angularFacebbokApp')
.controller('MainCtrl', function ($scope, $q, myService) {
console.log(myService);
//not sure how do exactly check if user is logged
if (!myService.status.islogged )
{
$q.when(myService.getFacebookStatus())
.then(function(results) {
$scope.test = results.status;
});
}
//user is logged in
else
{
$scope.test = myService.status;
}
});