Firebase token is generated every time new

Question

We are using Firebase Cloud Messaging in our app to displaying push notifications. According to FirebaseInstanceId doc, Instance ID is stable except when:

• App deletes Instance ID
• App is restored on a new device
• User uninstalls/reinstall the app
• User clears app data

However every time we launch the app (previously stopped, not resumed), a different Token is returned through the FirebaseInstanceIdService onTokenRefreshed() callback.

I was wondering if this is the normal behaviour of the service or there is a bug in the code.

---

Update

Dependency in root build gradle file:

classpath 'com.google.gms:google-services:3.0.0'

Dependency in app build gradle file:

"com.google.firebase:firebase-messaging:9.2.1"
"com.google.android.gms:play-services-base:9.2.1"

// defined at the bottom of the same file: plugin for firebase
apply plugin: 'com.google.gms.google-services'

FirebaseInstanceIdService:

@Override
public void onTokenRefresh() {
  // Get the saved token from the shared preferences
  final String oldToken = PrefsHelper.getStringValue(PREF_DEVICE_TOKEN);
       
  Log.d(TAG, "Old token: " + oldToken);
        
  // Get updated InstanceID token.
  final String refreshedToken = FirebaseInstanceId.getInstance().getToken();

  Log.d(TAG, "Refreshed token: " + refreshedToken);

  if (TextUtils.isEmpty(oldToken)) {
    handleNewToken(refreshedToken);
  } else {
    handleTokenUpdate(oldToken, refreshedToken);
  }
}

Answer 1

We are using Firebase Cloud Messaging in a project too.

We use firebase in android app with:

compile 'com.google.firebase:firebase-core:9.0.2'

The token we receipt persist whenever we relaunch the app.

It's better to make sure if each time you launch the app, token get refreshed in your FirebaseInstanceService:

public class MyFirebaseInstanceIDService extends FirebaseInstanceIdService {

  private static final String TAG = "MyFirebaseIIDService";

  @Override public void onTokenRefresh() {
    ...

    // Get updated InstanceID token.
    String refreshedToken = FirebaseInstanceId.getInstance().getToken();
    // check here.
    Log.d(TAG, "Refreshed token: " + refreshedToken);

    ...
  }
}

Then make sure in your server you have correctly set the Firebase Server.

It could be a bug if you getting a different token every time you launching your app. But make sure you have tested your android project with the newest Firebase Library.

This questions could be related to your problem:
Firebase Android Authentication failed: expired_token (Auth token is expired)