App Check from Firebase in Flutter doesn't work

Question

I'm trying to use App Check from Firebase with Flutter (on Android only for now), but the documentation is just terrible and I don't understand the errors I get when I try to access a Firebase service with an App Check token.

I run my app on my personal Android device through the terminal using the following command: flutter run --no-sound-null-safety.

I want to access data on Firebase Storage with that app. I have enforced App Check on that feature, I have also enabled SafetyNet for my app and I have created a debug token entitled "tests" that I don't even know how to use.

Here is the error I get:

Here is my main() function:

import 'package:firebase_core/firebase_core.dart';
import 'package:firebase_app_check/firebase_app_check.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  await FirebaseAppCheck.instance.activate();

  // ... not related code

  runApp(MyWidget())
}

Here is my build.gradle in /android/app/:

// ...

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'com.google.firebase:firebase-appcheck-safetynet:16.0.0-beta03'
}

Here is my MainActivity.kt in /android/app/src/main/kotlin/com/example/my_app/:

// the package

import io.flutter.embedding.android.FlutterActivity
import android.os.Bundle
import com.google.firebase.FirebaseApp
import com.google.firebase.appcheck.FirebaseAppCheck
import com.google.firebase.appcheck.safetynet.SafetyNetAppCheckProviderFactory

class MainActivity: FlutterActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        FirebaseApp.initializeApp(/*context=*/ this);
        val firebaseAppCheck = FirebaseAppCheck.getInstance()
        firebaseAppCheck.installAppCheckProviderFactory(SafetyNetAppCheckProviderFactory.getInstance())
        super.onCreate(savedInstanceState)
    }
}

Please help me guys, nothing works now.

Answer 1

FirebaseApp.initializeApp(/*context=*/ this);

You have a semicolon, It's Kotlin code; in Kotlin we don't use semicolons.

Answer 2

in my main.dart

  await FirebaseAppCheck.instance.activate();  

Here is my build.gradle

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'com.google.firebase:firebase-appcheck-debug:16.0.0-beta06'
}

MainActivity.kt

 import io.flutter.embedding.android.FlutterActivity
    import android.os.Bundle
    import com.google.firebase.FirebaseApp
    import com.google.firebase.appcheck.FirebaseAppCheck;
    import com.google.firebase.appcheck.debug.DebugAppCheckProviderFactory
    
    
class MainActivity: FlutterActivity() {
 override fun onCreate(savedInstanceState: Bundle?) {
        FirebaseApp.initializeApp(/*context=*/this)
        val firebaseAppCheck = FirebaseAppCheck.getInstance()
        firebaseAppCheck.installAppCheckProviderFactory(
            DebugAppCheckProviderFactory.getInstance()
        )
        super.onCreate(savedInstanceState)
    }
}