How can I dry up Angularfire session authorization ($onAuthStateChanged) - angularjs

Question

Currently I have an authorization system to track user log in/out status using angularfire. The guide I'm looking at suggests using $onAuthStateChanged in every controller as so.
$rootScope.authObj.$onAuthStateChanged(function(firebaseUser) {
if (firebaseUser) {
console.log("Signed in as:", firebaseUser.uid);
});
} else {
console.log("Signed out");
}
});
Instead I've been using a $rootScope.session variable to keep track of my currently logged in user. This works great for the most part, but I can't access this session variable at the start of other controllers since the object is not instantiated at that point. Is there a clean way to access this session variable in the scope of the controller so that I don't have to make an new reference to database in each and every function (as those functions are called after the session variable is set).
To make things a bit more clear.
ref = firebase.database().ref("users/" + $rootScope.session.id + '/meetings');
list = $firebaseArray(ref);
At the top of my controller does not work as $rootScope.session.id is not set yet.
But
$scope.addMeeting = function() {
ref = firebase.database().ref("users/" + $rootScope.session.id + '/meetings');
list = $firebaseArray(ref);
list.$add({
name: $scope.meetingname,
date: firebase.database.ServerValue.TIMESTAMP
});
};
Does work as the function called on a button click which will always be after the page has already loaded, thus meaning $rootScope.session.id is set by that point.
-------------Update-----------------
I've gotten it to work using the firebases suggested methodology, but it doesn't look pretty. It involves nesting everything within a listener on firebase's Auth object and then using an if statement to ensure user object is not null.
myApp.controller('MeetingsController', ['$scope', '$rootScope', '$firebaseAuth', '$firebaseArray', function($scope, $rootScope, $firebaseAuth, $firebaseArray){
var authObj = $firebaseAuth();
authObj.$onAuthStateChanged(function(firebaseUser) {
if (firebaseUser) {
var ref = firebase.database().ref("users/" + firebaseUser.uid + '/meetings');
var meetings = $firebaseArray(ref);
$scope.addMeeting = function() {
meetings.$add({
name: $scope.meetingname,
date: firebase.database.ServerValue.TIMESTAMP
});
};
$scope.deleteMeeting = function(key) {
meetings.$remove(meetings.$getRecord(key)).then(function(ref) {
})
.catch(function(error){
console.log(error);
});
};
}
}); //onAuthStateChange
}]);

Answer 1

$rootScope is a bad option for this kind of storage since it gets cleaned up every time you refresh your page.
You should be lookign into ngStorage. It comes with $localStorage and $sessionStorage, take a read to see what fits better to your needs.
Then add ngStorage to your module and inject $localStorage to the controllers.
$localstorage.sessionId = id;
This will store the id in your browser.

Answer 2

angularfire will track the sessions for you and maintain the current user information. If you are checking for auth in the resolve of each of your states, you can pass the authenticated user into each of the controllers... there is no need for local storage since the underlying firebase SDK is handling that for you.
it might be helpful to provide additional information on the guide you are using.
this documentation here https://github.com/firebase/angularfire/blob/master/docs/guide/user-auth.md#authenticating-with-routers is old, but the pattern can still be used effectively

Answer 3

Create a factory to store the auth properties. Something like this.
app.factory('authService', function(){
return{
authenticated: false
};
});
and then check for it in the controllers:
$scope.authenticated = authService.authenticated;
Hope this somehow helps
P.S controller only used to display model to view and any functionalities should be moved in separate directives or services. Your controller needs a clean up in the future.