Angular ui-router: How to defer rendering the template until authorization is complete?

Question

My ui-router configuration is this:

$stateProvider
  .state('app', {
    url: '/app',
    abstract: true,
    templateUrl: 'sidemenu/sidemenu.html',
    controller: 'SideMenuCtrl'
  })
  .state('login', {
    url: '/login',
    templateUrl: 'login/login.html',
    controller: 'LoginCtrl'
  })
  .state('app.dashboard', {
    url: '/dashboard', 
    views: {
      menuContent: {
        templateUrl: 'dashboard/dashboard.html',
        controller: 'DashboardCtrl'
      }
    }
  })
  [More states here]

$urlRouterProvider.otherwise('/app/dashboard');

When user navigates to /app/dashboard I would like to check if they are authorized, and then:

• redirect to /login if they are not authorized, or
• allow to see the dashboard if they are authorized

This seems to do the trick: (based on this example)

$rootScope.$on('$stateChangeSuccess', function(event) {
  var path = $location.path();

  if (path === '/login') {
    return;
  }

  // Halt state change from even starting
  event.preventDefault();

  Auth.getCurrentUser().then(function(currentUser) {
    if (currentUser === null) {
      $state.go('login');
    } else {
      // Continue with the update and state transition
      $urlRouter.sync();
    }
  });
});

The only problem with this solution is that, if a non-authorized user navigates to the dashboard, the dashboard template is visible first. Only when the authorization response is coming back it changes to the login template.

Is there a way not to show the dashboard while we authorize the user?

I also tried to change $stateChangeSuccess to $stateChangeStart, but it didn't really work (routing seems to be completely broken then).

Answer 1

What about using a resolve-block?

.state('app.dashboard', {
    url: '/dashboard', 
    views: {
        menuContent: {
            templateUrl: 'dashboard/dashboard.html',
            controller: 'DashboardCtrl',
            resolve: {
                login: function($q, Auth) {
                    var deferred = $q.defer();
                    Auth.getCurrentUser().then(function(currentUser) {
                        if (currentUser == null) {
                            deferred.reject();
                        } else {
                            deferred.resolve();
                        }
                    });
                    return deferred.promise;
                }
            }
        }
    }
})

The state-change won't happed untill the promise is resolved so the template should not be showing. Rejecting the promise will raise a $stateChangeError according to this answer so you would need to handle that error and redirect to the login-page.