$firebase with userid reference, init after user login best practice? - firebase

Question

Just like firefeed, i'm storing user-meta under /users/userid.
I only need the meta for the currently logged in user, so my thinking is to grab a reference only for the logged in user. So instead of
usersRef = new Firebase(firebase/users/) && users = $firebase(usersRef)
i'm waiting until the login service sets the current user, and then created the reference based on that user's id. This is inside of a service.
var userRef = undefined;
var user = undefined;
var _setCurrentUser = function (passedUser) {
console.log(passedUser);
currentUser = passedUser;
if (!currentUser) {
userRef = new Firebase(FIREBASE_URI + 'users/' + currentUser.id);
user = $firebase(userRef);
}
};
My question is: Is this a good idea? If i don't need a reference to the entire users object, does it make sense performance-wise to specify a specific user. How so/in what way? Is there a better way to wait until we have the current user's id to create the firebase instance for the user?

Answer 1

Ideally, if you don't need all users, you would fetch the specific reference. Something like the following:
var app = angular.module('myApp', ['firebase']);
// a little abstraction to manage establishing a $firebaseSimpleLogin instance
app.factory('loginService', function($firebaseSimpleLogin, Firebase) {
var fb = new Firebase(URL);
var auth = $firebaseSimpleLogin(fb);
return auth;
});
// a little abstraction to reduce the deps involved in creating a $firebase object
app.factory('syncData', function($firebase, Firebase) {
return function(pathToData) {
return $firebase(new Firebase(URL).child(pathToData));
}
});
app.factory('logInAndReturnUser', function(loginService, syncData) {
return function(provider) {
// call the login service
return loginService.$login(provider)
.then(function(user) {
// resolve to a $firebase object for the specific user
return syncData('users/'+user.uid);
});
}
});
Angular-ui's ui-router is ideal for this sort of use case and I highly recommend this approach for dealing with auth. Simply set up a resolve that returns the user:
var app = angular.module('myApp', ['firebase']);
app.factory('loginService', function($firebaseSimpleLogin, Firebase) {
var fb = new Firebase(URL);
var auth = $firebaseSimpleLogin(fb);
return auth;
});
app.configure(function($stateProvider) {
$stateProvider.state('home', {
url: '/',
resolve: {
'user': function(loginService) {
// getCurrentUser returns a promise that resolves to the user object
// or null if not logged in
return loginService.$getCurrentUser();
}
},
controller: 'homeCtrl'
})
});
app.controller('homeCtrl', function(user) {
// assumes we've logged in already, that can be part of router
// processing or we could check for user === null here and send to login page
console.log('user is ' + user.uid);
});