Do you need to register your APNS device token with GCM every time via:
tokenWithAuthorizedEntity:scope:options:handler
every time the app is launched, EVEN IF the device token is identical.
According to a sample app for GCM, every time the app is launched, [[GGLInstanceID sharedInstance] tokenWithAuthorizedEntity:_gcmSenderID [1] is called. This is because the registration is invoked from didRegisterForRemoteNotificationsWithDeviceToken which does need to be called every time the app is launched - "Device tokens can change, so your app needs to reregister every time it is launched and pass the received token back to your server." [2]
Can I store the registrationToken and deviceToken and only reregister when the deviceToken changes? The presence of GGLInstanceIDDelegate#onTokenRefresh seems to suggest that there is a mechanism to be notified when the registrationToken changes for your deviceToken, but I would like this to be confirmed.
[1]https://github.com/googlesamples/google-services/blob/master/ios/gcm/GcmExample/AppDelegate.m#L151
[2]https://developer.apple.com/library/ios/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/Chapters/IPhoneOSClientImp.html
In Google's official GCM Client Demo App, registering every time the app starts ensures that your servers gets the Registration ID even if it lost it somehow, but that shouldn't be an issue if your Registration IDs are persisted properly in the server.
Note that google may periodically refresh the registration ID, so you should design your app that be called multiple times. Your app needs to be able to respond accordingly.
To summarize, you should always treat the Token as if it may change any time you restart your application.
Related
When I install app for the first time and it asks for the permission for getting notification, if I press yes then the Device token is generated, but whenever I relaunch the app, I get the error:
Failed to fetch APNS token Error Domain=com.firebase.iid Code=1001 "(null)
Can anyone tell whether the device token is generated every time the app is launched?
Nope. A (new) token is not generated every time the app is launched. It is generated on initial launch (i.e. first launch after app install). From the docs:
By default, the FCM SDK generates a registration token for the client app instance on initial startup of your app.
But it may change because of the following scenarios (also from the docs):
The registration token may change when:
The app deletes Instance ID
The app is restored on a new device
The user uninstalls/reinstall the app
The user clears app data.
Today the doc says https://firebase.google.com/docs/cloud-messaging/ios/client#access_the_registration_token
The app is restored on a new device
The user uninstalls/reinstall the app
The user clears app data.
Seems like FCM Token is not generated when we delete the instance ID.
I want to make sure my server always has the up to date APNS device token, which can change under specific circumstances.
Should I save it to the Keychain, and on launch check if it's different, and then update the server if so?
Is that the best way to be doing this?
Apple actually say NOT to store the device token locally. You call registerForRemoteNotifications() when you need the device token. From Apple:
Never cache a device token; always get the token from the system whenever you need it. If your app previously registered for remote notifications, calling the registerForRemoteNotifications method again does not incur any additional overhead, and iOS returns the existing device token to your app delegate immediately. In addition, iOS calls your delegate method any time the device token changes, not just in response to your app registering or re-registering.
So what you need to do is register for remote notifications on launch, and send that token to your server. From Apple:
Device tokens can change, so your app needs to reregister every time it is launched and pass the received token back to your server.
You can find more documentation here: https://developer.apple.com/library/ios/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/Chapters/IPhoneOSClientImp.html#//apple_ref/doc/uid/TP40008194-CH103-SW25
Sure thing, you need to register for push notifications every time the app is launched. Like the documentation from Apple says, you never know when and why the token can/will change.
Second, indeed you can have some code to store locally the token in case of a server error or loss of internet when you try to send it to your server. And this logic can retry with a delay and max try count. But this is pretty overkill and not KISS-like.
What you can do is send it as soon as you get it from didRegisterForPushNotification and store it locally and every time the user of your app does an "update settings" call send it at the same time also.
We are using remote notifications in our iOS application and we are registering to APNS server inside application: didFinishLaunching: delegate method. That means it will be registered with APNS server every time the application launched freshly. Below is the code snippet.
[[UIApplication sharedApplication] registerForRemoteNotifications]
We have noticed that the device token (which is delivered to us by APNS server) is same every time. So, we thought that we can save the token in NSUserDefaults and use it later. In application: didFinishLaunching: method, we can give a check if the device token is present in NSUserDefaults or not. If it's available, we can use the same instead of registering to APNS. Otherwise, we can opt to register with APNS.
But, from the Apple documentation, it's observed that "they encourage us to register for remote notifications each time the application is launched freshly". Below is the screenshot from docs.
When does the device token value change actually? Can I afford to store the device token in NSUserDefaults and use it later instead of registering every time? Please help!! Thanks in advance!!
To answer your question with some apple documentation:
The form of this phase of token trust ensures that only APNs generates the token which it will later honor, and it can assure
itself that a token handed to it by a device is the same token that it
previously provisioned for that particular device—and only for that
device.
If the user restores backup data to a new device or reinstalls the
operating system, the device token changes.
This means you shouldn't really store the token in your NSUserDefaults.
However if you want to save it anyway I recommend to save it in the Keychain.
See this example how to do so:
Store Device Token in Keychain
Another quote from apple documentation:
"By requesting the device token and passing it to the provider every time your application launches, you help to ensure that the provider has the current token for the device. If a user restores a backup to a device other than the one that the backup was created for (for example, the user migrates data to a new device), he or she must launch the application at least once for it to receive notifications again. If the user restores backup data to a new device or reinstalls the operating system, the device token changes. Moreover, never cache a device token and give that to your provider; always get the token from the system whenever you need it. If your application has previously registered, calling registerForRemoteNotificationTypes: results in iOS passing the device token to the delegate immediately without incurring additional overhead."
EDIT:
Looks like the above links to Apple's documentation are broken by now. Here is a updated link (thanks to #Enrico Cupellini): https://developer.apple.com/library/content/technotes/tn2265/_index.html
Most documentation advises to register for remote notifications on launch, and on receipt of the token, push this to a server with any other app-specific settings (e.g. user, in-app Push settings). However, I am not sure how to handle the following corner case.
If the user launches the app without connectivity, no token will be received. Moments later, connectivity is restored. The user attempts to change some setting in the app, which should prompt a post to my server including the setting and the token. However, the token is still nil.
Would it not be better, instead, to register for notifications every time before attempting to post the setting? It seems unnecessary to request this token on launch since it might not be needed, and even worse, might be nil when it is needed.
I think it's still best to register for push notifications when the app is launched. When you get the device token, you don't have to immediately send it to your server. You can store it locally on the device. When your logic requires to send the device token (as well as other settings) to your server, get the locally saved token. If the saved token is null, try registering again, and send the token to your server once you get it.
Note that when the app is launched you should register for push notifications even if you a have a previous locally stored device token (due to the remote chance that Apple would decide to change the device token).
Apple recommends you should call register every time the app comes to the foreground ( either when you open it or when it comes back from background).
This call does not serve only as a way to get the push notification token but also to let Apple know that this application is still interested in receiving push notification. If you call this method only once, or rarely and you don't send push notifications that often, you could run into a scenario where the token you have been using, that is stored on the server is no longer a valid token (after enough time has passed without a token being acknowledged by a device apple will no longer consider the token valid. )
I'm developing an iOS app that enables the user to observe technical devices and be notified if there are problems.
What I know so far:
My app requests a token from the APNs.
My app sends this token to my server.
My server notifies the APNs in case of an event.
The APNs pushes a message onto the device.
What I want to know:
I read the token may change, therefor I need to request it on every app launch. Is this true?
If I get a new token from time to time I have to register at my server from time to time to make sure it uses the current token. Do I have to store and manually send the old token with the new one if the token changes to allow my server to delete the old one?
How can I detect that a user removed the app to remove his device on the server?
Highest priority in my case is for the server to know which devices are registered with the service. Old devices (old tokens that is) need to be removed immediately.
Thanks for your help.
You should register for the remote notification on every app launch and send the token to your server.
To check if the user removed the app or disabled notifications you have to check the feedback service. Look for it on this page:
https://developer.apple.com/library/content/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/BinaryProviderAPI.html#//apple_ref/doc/uid/TP40008194-CH13-SW1
Note: APNs monitors providers for their diligence in checking the feedback service and refraining from sending push notifications to nonexistent applications on devices.