Android/Firebase - Check to see if you are subscribed to topic

Question

I am wondering if there is a way to test to see if you are subscribed to a topic on the android side of things.

Basically, I am HOPING that all devices will subscribe to a topic during their installation, when the token is first obtained by the device. However, there is always a chance that the device fails to subscribe. The FCM registration token should be installed on the device for a long time, and thus, the onTokenRefresh() method shouldn't be called again without clearing data, uninstall/reinstall, etc.

My idea was to test to see if the device is subscribed to a topic in my MainActivity, and if not, then try to subscribe again. If it fails to subscribe, then get a new token and try again, etc.

    @Override
    public void onTokenRefresh() {
    // Get updated InstanceID token.
    String refreshedToken = FirebaseInstanceId.getInstance().getToken();
    Log.e(TAG, "Refreshed token: " + refreshedToken);

    // Subscribe to a topic
    Log.e(TAG, "Subscribing to topic");
    FirebaseMessaging.getInstance().subscribeToTopic("test");

So, I can subscribe and unsubscribe, but how do I check if the device is subscribed to a topic? I did my fair share of googling, and couldn't find anything, unfortunately.

I would greatly appreciate any/all assistance. Thanks!

Solution

There is currently no way to check on the client side if they are subscribed to a topic.

The behavior for subscribeToTopic is it would immediately subscribe to the specified topic, if it fails, it would retry on it's own (unless your app was killed). See my answer here.

I think that forcing the onTokenRefresh call just to make sure that subscribeToTopic is too much. You could simply just call it in your initial activity if you want, that way, everytime the app starts, it sends the subscription request.