NotRegistered repsonse from GCM server

[alexislg2]

Hey all,
I use your plugin with the node-gcm plugin for sending notifications from a Node.js server. It works fine, I can send notifications to devices and they receive it instantly. But after few days, I receive notRegistered answer from GCM. I looked at the GCM documentation and NotRegistered mean that either the device unregistered or that the app is no longer installed on the device

But I never unregistered neither uninstalled the app. If I launch the app again, then the app registers again and then I can receive notifications again but during the time between the first notRegistered response appears and the time I lauch the app, device does not receive any notification and server always get the NotRegistered response.

Anyone else experienced this?

[alexislg2]

I think it is because the app always registers at startup even if the app is already registered. This cause GCM to generate a new regId. But if the app has no time to transmit this new regId to the server, then the server has an old regId in its DB.

i think the app should first check that the app is not already registered and that there is internet access.

[fredgalvao]

AFAIK multiple and consecutive calls to the register service on GCM do not generate new regIds, and this has been the case since always the apps I have that use pushNotification plugins (be it PushPlugin or phonegap-plugin-push), so that might not be the root of this issue.

[alexislg2]

Could this be related?
phonegap-build/PushPlugin#497

[macdonst]

@alexislg2 good hint, I will look into it.

[alexislg2]

Other hypothesis: Does regId is modified when the user updates the app through the Google Play Store?

If so then any notification sent between the app auto update moment and the first launch would throw a notRegistered error. I will try to investigate this

[fredgalvao]

@alexislg2 , that's not the case. RegistrationIDs do not change inbetween different app versions.

[alexislg2]

Hey. I still have this annoying issue.

I foud something that might be linked http://stackoverflow.com/questions/17893117/gcm-registration-id-changed

So, for handling that you should have a Broadcast Listener which could handle com.google.android.c2dm.intent.REGISTRATION intent, which Google send to the app when it has to refresh the registration ID. The broadcast receiver will have the onReceive method with an Intent. From the intent you can get the Bundle using which you can extract the new registration ID from Google. You can save that and send it to the 3rd part server to replace your previous registered ID for that user.

Is this possibel to implement this with your plugin?

[macdonst]

@alexislg2 that's out of date now as the plugin uses Google's new Instance ID API for registration ID's. It has a service com.adobe.phonegap.push.PushInstanceIDListenerService that will listen for any changes on the registration ID and throw a new registration event.

[alexislg2]

I'm not sure I get this. You mean that Google might decide to unregister some regId for whatever reason and that your app will automatically re-register to GCM?
What about when the app is not running? The app cannot send its new regId to the server.

[fredgalvao]

@alexislg2 please read up on my comment here for the part where I talk about android.

Regarding your last question, if for some reason Google decides to refresh your instance-id (or invalidate it) while your app is in background or completely shut down, as soon as it's up again the plugin code will check for the current values and trigger the 'registration' event if it's different than what it has saved previously, so you'll always be guaranteed to be notified about any changes in the instance-id as soon as possible.

[alexislg2]

OK thanks!

So it means that if Google refreshs the instance-id, my backend won't be able to send notifications to the device as long as the user does not start its app. This is very annoying. I send ~300 notifications a day to 40 differents users and I got 1-2 notRegistered errors per day.

On my mobile phone I have some app like Pushbullet, Pushover or News app that I never open and they keep sending me notifications. I wounder how they do that. Or maybe this is because they are not based on Cordova so they can send their new regId without starting the app.

[fredgalvao]

This has close to nothing to do with cordova itself: remember, any native code is agnostic to cordova and it's shells or bridges by default (plugins only make that code aware of the shells and bridges).

Being literal, the only way to guarantee a valid token "forever" is to use the old registrationId instead of the new instance-id, as the former didn't have documented events on which it could change by itself, although I know for a fact that software updates (e.g. android 4.4 -> 5.0) do change the device UUID and sometimes the registrationId.

We also need to remember that the frequency of these events (which change the instance-id) have not been documented, so it might just as well be the case that they rarely, if at all, occur.

However, I'd take a long shot and guess that Google isn't naïve and somehow handles these dead intervals. They wouldn't upgrade the management of tokens to something less efficient. Something like:

This is pure speculation and guessing

• Google creates token "123abc_1"
• Application receives and stores "123abc_1"
• Google for some reason invalidates "123abc_1" and creates "123abc_2"
• Google still accepts push events sent for "123abc_1" until com.adobe.phonegap.push.PushInstanceIDListenerService receives a new event with the new instance-id
• Application receives and updates "123abc_2"
• Google frees the previous token permanently

[alexislg2]

OK, that would make totally sense.

I updated the plugin so that now my users have instance-id instead of register-id. I don't have any notRegistered anymore (let's wait a couple of weeks to be 100% sure).

But I noticed someting weird: With some users after some time, GCM returns me canonical_id for some users. So I update the instance-id in my database and replace with that canonical_id. I can send notifications successfully with this canonical_id. But then when the user starts the app again, the app sends the "old" instance-id (the one that is working but that tiggers canonical_ids from GCM).

Is that normal?

[fredgalvao]

I don't get what you mean by the difference between canonical_id and old instance-id.