Flutter Firebase Authentication emulator enabling - flutter

Question

I'm trying to hook the Firebase Authentication emulator to my Flutter mobile project to perform some local testing. Unfortunately it seems it is not possible to do with the FlutterFire plugin.
There is no problem whatsoever to enable Firestore or Cloud Functions emulators, but I can not find a way for Authentication.
Is there someone with ideas or best practices to follow?

Answer 1

It looks like the method to connect to the Authentication emulator hasn't made it to the FlutterFire libraries yet.
An issue was logged for it in the Github repo, so you can follow its status there.
Update: It looks like this has now landed in version 0.20 (and later) of the firebase_auth package. The syntax should be something like:
FirebaseAuth.instance.useEmulator('http://localhost:9099');

Answer 2

It is now available in the latest stable release (^0.20.1).
To use it, call FirebaseAuth.instance.useEmulator('http://localhost:9099')
It must be called prior to accessing any auth methods.

Answer 3

Configuring flutter app to work with firebase authentication in local emulators.
First:
Add one of the below lines before authentication function call see which one working for me loopback IP worked:
firebaseAuth.useAuthEmulator('127.0.0.1',9099);
//firebaseAuth.useAuthEmulator('http://localhost',9099);
Sample:
Future<LocalUser?> signInAnonymously({required BuildContext context}) async {
firebaseAuth.useAuthEmulator('127.0.0.1',9099);
//firebaseAuth.useAuthEmulator('http://localhost',9099);
UserCredential userCredential = await firebaseAuth.signInAnonymously();
return LocalUser(user: userCredential.user);
}
If you get network error do as follow.
Second-1: For Android.
Add android:usesCleartextTraffic="true" in AndroidManifest.xml path: android/app/src/main/AndroidManifest.xml.
<application
android:usesCleartextTraffic="true" //<========
android:name="io.flutter.app.FlutterApplication"
android:label="firebaseauthexample"
android:icon="#mipmap/ic_launcher">
Second-2: For IOS.
Add bellow code here ios/Runner/Info.plist
<key>NSAppTransportSecurity</key>
<dict>
<key>NSAllowsArbitraryLoads</key>
<true/>
</dict>

Answer 4

Firebase emulator has support to connect to web apps. *As a workaround, you can use the beta version of flutter to convert your mobile app to web app and test your it in your browser. You would have to add support for firebase services explicitly in index.html file.
See: -
https://flutter.dev/web
https://flutter.dev/docs/get-started/web

Answer 5

"localhost" may be easier to use as follows:
Flutter has updated useEmulator with useAuthEmulator. To use local Authentication emulator, you can use useAuthEmulator method by passing Firebase emulator port and "localhost" keyword as follows:
await FirebaseAuth.instance.useAuthEmulator('localhost', 9099);
Please be sure to pass this line before all auth methods as mentioned by #frank-van-puffelen before.