Remove unregistered FCM tokens

[mtrezza]

New Feature / Enhancement Checklist

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Current Limitation

Google notified in April 2024 that:

Starting May 15, 2024, the stale tokens and topic subscriptions for devices, which have not been connected to FCM in over 270 days, will be considered as expired and invalid. If a request is sent to an invalid token, it will be rejected with a 404 (UNREGISTERED) error.

We recommend you to confirm that your service handles 404 error codes from FCM correctly. Please delete your record of any tokens with a 404 response code because they will not be valid again.

It doesn't seem that Parse Server would be properly handling this UNREGISTERED error, but it's hard to tell how these errors provided by the push adapter translate to the existing error strings:

parse-server/src/StatusHandler.js

Lines 240 to 243 in 2420024

	// GCM errors
	if (error === 'NotRegistered' || error === 'InvalidRegistration') {
	devicesToRemove.push(token);
	}

Feature / Enhancement Description

Ensure that Parse Server deletes "unregistered" tokens.

3rd Party References

• https://firebase.google.com/docs/cloud-messaging/manage-tokens#stale-and-expired-tokens

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[jimnor0xF]

Would very much like this feature merged in, so I think I'll look into this soon.

FCM returns the following error object when not registered:
{"code":"messaging/registration-token-not-registered","message":"Requested entity was not found."}

So could perhaps simply add an additional check on the code key there.

[mtrezza]

Yes, the errors are passed in an array from the push adapter to Parse Server, which then removes the tokens based on the error message. You could just add the error text to that logic I've mentioned above.

Side note: the current solution is not elegant, because the logic in which the errors are parsed is in Parse Server, but it seems that it should be in the push adapter, since these errors are push API specific. Opened parse-community/parse-server-push-adapter#244.