Check if user is logged in before template load - angularjs

Question

I use angularjs with ui-router library. Lets say I have some routes for admin and some routes for user. If admin or user is logged in I want to show some page for them (admin.html for admin and user.html for user, for example), otherwise login.html
On the backend I have a special url, like /auth/status/, which gives me information about the user (if he's logged and which role he has)
There are some situations I can't figure out how to handle:
I go to '/' url. The application loads. I have a run method for my app module. But how can I check if the user is logged in, when it happens asynchronously? Well, I have this and it works somehow, but I'm not sure if this is a good solution:
app.config(['$stateProvider', '$routeProvider',
function($stateProvider, $routeProvider) {
$stateProvider
.state('admin', {
abstract: true,
url: '/',
templateUrl: 'templates/admin.html'
})
.state('admin.desktop', {
url: 'desktop',
templateUrl: 'templates/desktop.html'
});
}]);
app.run([
'$http',
'$rootScope',
'$location',
'$state',
'userRoles',
function($http, $rootScope, $location, $state, userRoles) {
var DEFAULT_ADMIN_STATE = 'admin.desktop';
var promise = $http.get('/auth/status/');
promise.then(function(response) {
$rootScope.isLogged = response.data.logged;
$rootScope.userRole = userRoles[response.data.role];
if (!$rootScope.isLogged) {
$state.transitionTo('login');
} else {
switch (response.data.role) {
case 'admin': $state.transitionTo(DEFAULT_ADMIN_STATE); break;
}
}
}, function(response) {
$location.path('/login');
});
}]);
Though I don't understand: if I go to / url I should get an error because it's abstract. Instead when $http.get request is resolved (I put 2 seconds sleep in backend to check that) I transition to admin.desktop state. I'm confused what happens in which order: state loads template or app.run function with some ajax requests...
The main question is, when I go to /#/desktop how can I first check if user is logged (send a request to /admin/auth/ and check what it returns) and only then decide what to do (transition to login or desktop state)?
I found Delaying AngularJS route change until model loaded to prevent flicker this, but again still a little fuzzy for me. Resolve property seems like a solution when I want to load a list of entities and then show the template. But I want to have some "before" function for ALL states which just checks if user is logged and has a correspond role (one moment: I do not want to use /admin/entites or /user/entities urls, want to have just /entitites. As I get it several states may have the same url). So basically it looks like if I go to /someurl I want to run method wait until it gets ajax response and after that transition to some state. Instead the state corresponding to /someurl load a template...
Also I found an article about authentication in angular but author uses cookies which is not async thing
Update: when I use cookies for checking if user is logged and I go to /#/desktop I still have it rendered, and $state.transitionTo doesn't work..

Answer 1

You should check it before page load:
I cannot write full example now, but in common you should do like this:
.run([ ..., function(....) {
$scope.$on('$routeChangeStart', function(next, current) {
... check cookie here ...
});
}]);