CODEWITHSUNDEEP
androidpush-notificationgoogle-cloud-messaging
Manish
Manish

Reputation: 53

Dealing with stored messages in GCM after registration id change

The case here is of using GCM for payload based push notifications. Let's say about 10 odd push notifications are sent to the GCM server in a non-collapsible way so that all of them are queued. The user hasn't got those notifications yet because the user hasn't connected to internet.

If after connecting to internet the user updates the application before receiving those notifications, the registration id for the app is going to change.

Wanted to know, if in this case, would the stored notifications still get delivered to the device or would they be discarded altogether?

I was unable to locate the handling of stored notifications when registration id changes anywhere in the documentation. Could anyone please shed some light over this?

Thank you very much.

Upvotes: 2

Views: 497

Answers (1)

Eran
Eran

Reputation: 393771

I've seen no documentation about this very unlikely scenario either.

The reason it's so unlikely is that once you connect to the internet (in order to udpate the application), it is very likely you'll get the stored messages before you download and install the update.

Now, suppose that you didn't get them before installing the update. When the application is being updated, there's a chance that due to an old bug in GCM, the app will get unregistered automatically if it receives a message while getting upgraded. That's precisely the reason why the GCM docs suggest to re-register to GCM each time the app is updated.

In the unlikely event that this bug happens, you will lose all the undelivered messages stored for your device in GCM server, since your app will become unregistered on this device.

If, on the other hand, the undelivered messages are delayed in the GCM server until after you updated the app, launchd the updated app and re-registered to GCM, it's likely that the stored messages will be delivered, even if the re-registration results in a new registration ID (note that the registration ID won't necessarily change), since old registration IDs continue to work even after a new registration ID is assigned.

All of that being said, you should never rely on all the GCM messages always being delivered. It is never guaranteed. Whenever a user starts your app, you should synchronize it with your server (load whatever data is relevant), and therefore any GCM messages that were not delivered will become irrelevant.

Upvotes: 1

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