CurrentUserHelper - Ember.js

gistfile1.js

// define

App.CurrentUserHelper = {
  beforeModel: function() {
    if (!this.controllerFor('application').get('currentUser')) {
      var auth_deferred = $.get(App.Host + '/session');

      auth_deferred.then(function(user) {
        this.controllerFor('application').set('currentUser', user);
      }.bind(this));

      return auth_deferred;
    } 
  },
  currentUser: function() {
    return this.controllerFor('application').get('currentUser');
  }.property()
}

// use it in an Ember.Route

App.NewPostRoute = Ember.Route.extend(App.CurrentUserHelper, {
  model: function() {
    if (!this.get('currentUser')) {
      this.transitionTo('posts');
      return;
    }
    return this.store.createRecord('post');
  }
});