[Feature Request] List topic Cloud Messaging

[jimlyas]

What feature would you like to see?

It would be good if we can list all the FCM topics that the device subscribed.

How would you use it?

For example, if we have authentication and FCM topics based on it. So when the user log out, we need to unsubscribe certain topics programmatically.

It would help a lot if the SDK could provide list of FCM topics

[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

[argzdev]

Hi @jimlyas, thanks for reporting. I've marked this as a feature request, so our engineers have take a look and discuss this further when they have the time.

[rohan20]

This is a very important requirement. This was earlier possible using the https://iid.googleapis.com/iid/info/<fcm_device_token>?details=true which has now been deprecated.

Let's say I'm building a fantasy sports app like Fantasy Premier League where the user can pick 15 players from the league every week. Each player has their own FCM topic such as topic_player_1. Every week, the user can pick a new set of 15 players. So each week, I want to subscribe the user to 15 new topics and unsubscribe them from the 15 topics of last week.

This was quite straightforward to do using the now deprecated iid endpoint:

1. First week: Subscribe the user to 15 topics
2. Each week thereafter: Fetch the topics' list that the user is subscribed to
3. Calculate the diff and subscribe the user to new topics
4. Calculate the diff and unsubscribe the user from obsolete topics

This is no longer possible now that the endpoint has been deprecated.

Even if I manage the FCM topics per user on my server, there can be instances where the unsubscription doesn't go through. In that case, the user keeps receiving notifications for an obsolete topic and it is a pain to manage this.

Please re-consider providing this API.