Question

In my app, for first time push notification registration, I call didRegisterForRemoteNotificationsWithDeviceToken and save the device token in persistence as well as update my server list for device token. Now afterwards if somebody turns the push notification settings off from iPhone Settings how can I determine it from my app so that I can remove the device token from server as well. I know APNS provides a feedback list, but other than that is there a way to determine it in App programmatically? Thanks for any help!

Answer 1

I believe you do not want to manage tokens this way.

Your app should always be asking Apple for an APNs token. You should always then send that token to your own server, likely associating the token with your user (if you have one). You do this because the token could change, so you want to make sure you always have up-to-date tokens.

The Feedback service will tell you (actually, you poll it at some interval of your choosing) which tokens have become invalid. At this point, you remove the tokens from your server-side database. To be clear, you need a server-side process that polls Apple’s feedback service and then updates your server-side database.

You will not receive feedback about invalid tokens until you try to send a notification using the token. The notification will (I believe) be accepted by Apple when you send it, but when Apple discovers it’s for an invalid token, the message is dropped, and the token is added to your feedback.

Now, if the user of your app accepts push notifications when your app first asks about it, but later turns off notifications via the Settings app for your app, you will not get any feedback about it. What happens, near as I can tell, is that any notification you send to that device will be sent to the device, but the OS drops it, honoring the user’s ultimate choice in the Settings app for your app and notifications.

Finally, there is an API you can call in your app to get a bitmask of which kinds of notifications are enabled for your app on the device. Here’s a method I wrote for this purpose; adjust as needed:

+(BOOL)acceptsPushNotifications
{
    UIRemoteNotificationType mask = [[UIApplication sharedApplication] enabledRemoteNotificationTypes];

    return (mask & UIRemoteNotificationTypeAlert) == UIRemoteNotificationTypeAlert;
}

But I would not recommend using this to decide if you app should tell your server to delete the token from your database. That’s not how the whole APNs system is intended to work… I believe.