Firebase User Stream

A Package for subscribing to User reload updates.

ATTENTION

Since firebase_auth version 0.18.0 this library is mostly pointless as firebase_auth (finally) adds authStateChanges() which mostly substitutes this package, fixing the problem described below.

I mean mostly because here we can have further functionality like:

Reloading based on a predicate
Reload and get the user in the same line.

Although that's not useful to most people.

The (old, pre firebase_auth version 0.18.0) problem

The FirebaseAuth Flutter plugin provides a Stream<FirebaseUser> with onAuthStateChanged, which is useful for getting updates when a user signs-in or signs-out, but it fails to provide an update when the user data itself changes.

A common problem is when we want to detect if the user has just verified his e-mail address, in other words get if FirebaseUser.isEmailVerified changed its value, as this is updated server-side and not pushed to the app.

FirebaseAuth.currentUser() will only detect changes made locally to the user, but if any server-side changes occur, it won't detect them, unless FirebaseUser.reload() is called first, then we need to call FirebaseAuth.currentUser() again to get the reloaded user, but still this user won't be emitted by onAuthStateChanged.

The solution

There are two ways we can get a new FirebaseUser, with the latest information on the server:

Do it manually:

Future<FirebaseUser> reloadCurrentUser() async {
  FirebaseUser oldUser = await FirebaseAuth.instance.currentUser();    
  oldUser.reload();
  FirebaseUser newUser = await FirebaseAuth.instance.currentUser();
  // Add newUser to a Stream, maybe merge this Stream with onAuthStateChanged?
  return newUser; 
}

Let us do it for you!

Getting Started

After you install this package you can use FirebaseUserReloader to get reload updates using the onUserReloaded and onAuthStateChangedOrReloaded streams.

FirebaseUserReloader internally uses the FirebaseAuth instance returned by FirebaseAuth.instance, so your entire App will have the same Singleton instance, you don't have to configure anything, it just works out of the box.

In order to get reload updates just do:

var subscription = FirebaseUserReloader.onUserReloaded.listen((user) {
  // A new user will be printed each time there's a reload
  print(user);
});

// This will trigger a reload and the reloaded user will be emitted by onUserReloaded
FirebaseUserReloader.reloadCurrentUser();

subscription.cancel();

Each time you call reloadCurrentUser() a reloaded user will be emitted by onUserReloaded.

Keep in mind that onUserReloaded will emit reloaded users, they might be new, or just the current one if the user data didn't change.

As a bonus, you can provide a predicate to reloadCurrentUser(), in order to only get reloaded users that matter to you:

var subscription = FirebaseUserReloader.onUserReloaded.listen((user) {
  // A new user will be printed each time there's a reload
  print(user);
});

// This will trigger a reload and the reloaded user will be emitted by onUserReloaded
// only if isEmailVerified == true
FirebaseUserReloader.reloadCurrentUser((user) => user.isEmailVerified);

subscription.cancel();

You also can get the reloaded user as the return value of reloadCurrentUser, but in this case, the predicate will be ignored, and the reloaded user will always be returned.

var user = await FirebaseUserReloader.reloadCurrentUser();

If you want to listen for updates on sign-ins, sign-outs and user reloads, use onAuthStateChangedOrReloaded instead, it's just a convenient merge of onUserReloaded and FirebaseAuth.onAuthStateChanged and it works as a broadcast Behavior Subject:

var subscription = FirebaseUserReloader.onAuthStateChangedOrReloaded.listen((user) {
  // A new user will be printed each time there's a reload, login or logout
  print(user);
});

// This will trigger a reload and the reloaded user will be emitted by onUserReloaded
// only if isEmailVerified == true
FirebaseUserReloader.reloadCurrentUser((user) => user.isEmailVerified);

subscription.cancel();

Both onAuthStateChangedOrReloaded and onUserReloaded are broadcast streams.

Testing

This library uses static methods for easiness of usage, but this doesn't limit its testability.

FirebaseUserReloader can be injected with a mocked instance of FirebaseAuth for unit testing.

For any examples on how to control its behavior under tests, please take a look at our own tests inside the test folder.

Skquark / firebase_user_stream