Retrieve push notification after coming back to online status. Firebase/Onesignal

Question

I am using Firebase with OneSignal within an hybrid application (Android + JS with cordova app). In some cases the user may become offline and online while he is still using the application.

Note that you can't retrieve a push notification if you don't have connectivity.

So my question is, is it possible to retrieve a push notification if the another user sends a push notification while the first user is offline, and later on this first user retrieves the connectivity (As a delayed push notification)?

Thanks!

Answer 1

Internally, OneSignal uses Firebase Messaging Service, so the constraints should be looked for there.

Firebase has 2 types of pushes : notification messages and data messages. That matters if you want to show a notification straight when a push comes, or you'd like to do some additional processing beforehand.

Then, you can configure Firebase to store and resend every message up to 28 days . Of course, losing a network connection for some time does not prevent a message to arrive.

There is another limitation though: up to 100 messages can be stored per client. So, if there are more than a hundred, it's better to re-request the diff.

And then, when the device finally comes back to the network, you should decide if you'd like the notification to come immediately even if the app is already minimized or the device is sleeping. Here is a part about push priorities .

Finally, to be able to work with Firebase on this lower level, you may need to configure OneSignal accordingly. Here is an instruction telling how to work with the background notifications, if you need them.