Should i backup GCM registration ID with google cloud? - google-cloud-messaging

Is it advised to backup GCM id using android cloud back up ? i am storing the GCM id in a sharedpreferences so i dont have to keep registering.
if i backup this GCM sharedpref and user changes devices do i need to update it to a new registration id ? Is the registration ID device specific ? What happens when user changes devices and backs up ?
I tried and read this from the docs:
You must exclude any device specific identifiers, either issued by a server or generated on the device. This includes the Google Cloud Messaging (GCM) registration token which, when restored to another device, can render your app on that device unable to receive GCM messages.

From the docs i found my answer that the reason this should not be done is that it can intrefer in the apps intialization of gcm and it will not try to get the GCM id if its already restored from a new device that restored a old registration id.
Handle Google Cloud Messaging
For apps that use Google Cloud Messaging (GCM) for push notifications,
backing up the registration token that Google Cloud Messaging
registration returned can cause unexpected behavior in notifications
for the restored app. This is because when a user installs your app on
a new device, the app must query the GCM API for a new registration
token. If the old registration is present, because the system had
backed it up and restored it, the app doesn't seek the new token. To
prevent this issue from arising, exclude the registration token from
the set of backed-up files.

Related

APNS handle obtained by Expo in React Native is incorrect

EXPO SDK Version: 42.0.01
Developing for: iOS
Our goal: successfully send a test notification from Test Send tool in Azure Notification Hub to a registered physical iPhone which is running a local instance of an EXPO app.
Progress: we're able to successfully register a physical iPhone with Azure Notification Hub without using a 3rd party library. We can see that registration in the Hub.
Issues: when using the Azure's Test Send tool we're getting an error "The Push Notification System handle for the registration is invalid" and the test notification does not get delivered.
Debugging:
we're using EXPO's Notifications.getDevicePushTokenAsync() API to obtain the push token.
Azure support team analysed the logs and concluded that the problem is the PNS handle i.e. Apple's ID of the phone registered for notifications.
the phone's PNS handle remains the same at all times.
by using "expo credentials:manager" I've added a new Push Notification Key using KeyID, TeamID and .p8 certificate - the PNS handle didn't change after doing that and notifications were failing too.
I haven't found any tools to validate the APNS handle. I'm currently awaiting a .p12 certificate from our corporate team to test notifications by using https://pushtry.com/.
How do we validate the APNS handle and if found that it's invalid - how do we cycle it / request another?
The PNS Handle from APNs does not change that often as it is tied to the device and app installation. See this answer for more details Does the APNS device token ever change, once created?

Developer payload (external data) in App Store server notifications

We are using server-to-server purchase notifications for Google Play and App Store mobile apps. User can pay for subscription in several ways: in web broswer (via third-party billing provider), in android application (via google play) and in ios/macos application (via app store). That is why we use custom user/subscription ids - it should be equal across all platforms/devices within single account.
Now, everhing went just fine with other billing providers until we came to App Store. We configured server side notification with callback at our server as we did it before. And now it turns out, that there is no user information in App Store receipt data. And it seems to be no way to pass that data from mobile application. For example, Google Play have so called "developer payload" field for this purposes, other providers also have possibility to add external data into server notification request. Is there any analog for App Store notifications?
Another question is about notifications itself. If there is no user information in the receipt - that means that there is no way to bind user id and receipt id data. Then what is the purpose of such notfications with external server scenario?

PushSharp - GCM Authorization Failed

Using v4.0.10 of Pushsharp (nuget package), I am getting error GCM Authorization Failed when sending push notifications to Android devices.
Seems the bug raised in issue 574 (https://github.com/Redth/PushSharp/issues/574 ) has been compiled into the nuget package, yet I'm still getting this error.
Could this be related to the introduction of Firebase Cloud Messaging?
Does anyone still have success using GCM?
As of right now, GCM is still usable. However, it is highly encouraged for new users to use FCM instead. Either way, for both GCM and FCM, you must use a Server Key generated from the Firebase Console. There is a visible note in the GCM docs saying:
Starting from Sept. 2016 new server key can only be created in the Firebase Console using the Cloud Messaging tab of the Settings panel. Existing projects that need to create a new server key can be imported in the Firebase console without affecting their existing configuration.
The Authorization error has been encountered by number of users, some also had an old project. See my answer here for more details.
The sender id used in the app code needs to match the sender id Firebase Cloud Message Console and its corresponding "Firebase Cloud Messaging token".
Thank you #AL for your help.

Gcm with appodeal

I am using gcm with appodeal in my app and when I am sending the push notification the for the first push was successful but phone is not receiving the notification and after that error is there while sending push that device is not register. What to do in this situation please help me.
Is it iOS or Android ? I had the exact same issue just yesterday with iOS and all I had to was to create a development provisioning profile and set it up properly in xCode. I hope that helps you.
I think for you to verify that your app can send and receive messages, client apps must register with GCM.
To register with GCM:
1.The client app obtains a registration token using the Instance ID API. The call to this API must have the authorized entity set to your app server's sender ID, and the scope set to the appropriate value for GCM (depending on your platform). Refer to the API reference for full detail on this API.
2.The client app passes the registration token to the app server.
3. The app server saves the registration token and acknowledges to the client app that the process completed successfully.
This thread may also provide further insight as to why you are receiving the device not registered error.

Does the APNS device token ever change, once created?

Once created does the push notification device token ever change?
Example when the app is updated? or in any other case it can change??
Apple's official documentation is unclear on this point. What I have observed is this: the token is invariant for a given device, application, and domain (production vs. sandbox). I believe that this must remain true in order for the system to work reliably. Consider the situation where an application update triggers a new APN token; if I were using the greatest new Twitter-like app, with notifications enabled, what would happen when I update my app from iTunes? Should I have the expectation that it will continue to be sent notifications even though I have not run the applications since I "sync" the update onto me device? The act of changing the application cannot affect the APN system since the OS can receive notifications on your behalf even though you haven't run the updated app.
To be clear, Apple states "An application should register [with APN servers] every time it launches and give its provider the current token". I wholeheartedly agree; doing so will protect your application from bad assumptions or unusual situations.
One of the answers to Are push notification tokens unique across all apps for a single device? indicates that device tokens are unique per "operating system install"; and that restoring from backup to a device would maintain the token but wiping a device will cause it to get a new token. This would be entirely consistent with Apple's intentions of seamless operation and privacy: wiping a device is severe enough that perhaps it warrants a new association, but a user restoring an image after an OS update would want to preserve their existing notifications. If I recall the recent iOS5 update on my iPad, I restored the most recent backup after upgrading, so this would have maintained my notification token's consistency. [Edit: restoring a backup to a different device will NOT duplicate the token.]
caveat:
I do not have definitive knowledge on the subject, just some reasonable experience working with APN (as a third-party developer). As always, it is best to verify your assumptions.
Update (June 2012):
I recently had a chance to a> talk to Apple engineers and b> run some real world tests, and I wanted to present the results:
To be complete, when I talk about returning an APN token, I am assuming the context of a single bundle identifier/application.
First, the Apple engineers said that it should not be possible for two devices to return the same APN. Notwithstanding the comments below, I have not been able to identify a circumstance where this fails.
Second, here is the upgrade test sequence and results:
Start with iOS4 installed on iPhone4; backup device in iTunes
Upgrade to iOS5
From a previous test, I know that the APN token is now different
Restore the backup to the device
The APN token is now the same as step 1.
Reset iOS (clean device)
The APN Token changes
Backup a different phone to iTunes and restore that backup to test device; basically, I'm restoring the "wrong" backup, as if I were switching phones.
The APN token changes again; further it is distinct and does not match the tokens either the original token or the "cloned" token.
Restore the "correct" backup to the device.
The APN token is now the same as step 1.
Lastly, I upgraded the phone to iOS6 (beta2), restored my backup, and re-tested. As expected, the token continued to match the token in step 1.
At this point, I'm pretty confident that APN tokens can't be duplicated between different devices; perhaps this may have happened as a bug in earlier versions of iOS, but I'm confident that iOS5 (and presumably iOS6) are handling APN tokens correctly.
Update (August 2012)
I just realized I had not added this: device tokens will change. One of the Apple devs shared with me that tokens do actually expire (after 2 years, I think). For many purposes, this is long enough that can be thought of as invariant.
[I'm not worried if I have to update my test scripts with new tokens every two years, especially since I change phones every year.]
From [Apple Documentation ApplePushService]2
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.
I've just tested it with iOS9 and APN Push token changes if I reinstall an app.
YES, device tokens can change.
Anytime your app receives a token, it should store it. Then, whenever a new token is received (which will happen, eventually), compare the new token to the stored token and, if they are different:
Update the device's local storage, (including possibly to nil)
Update anything on the device which uses the token to be aware of the new token
Update any APIs which are aware of this token to the new token.
As a practical matter, the last step is the most likely to be non-trivial. For example, if you have a service which is sending weather alerts to a device token based on what zip code that device has subscribed to, then you need to pass the old_token and the new_token to said service so it can update delivery.
Ergo, generally speaking 100% of APIs accepting a "device token" must also have some kind of UPDATE facility for that token. To not build for this is to build for mis-delivered and non-delivered notifications.
Device token does change from iOS 8 and later
Please see text below from Apple website. Registering, Scheduling, and Handling User Notifications
The device token is your key to sending push notifications to your app on a specific device. Device tokens can change, so your app needs to reregister every time it is launched and pass the received token back to your server. If you fail to update the device token, remote notifications might not make their way to the user’s device. Device tokens always change when the user restores backup data to a new device or computer or reinstalls the operating system. When migrating data to a new device or computer, the user must launch your app once before remote notifications can be delivered to that device.
I think it is worth mentioning as nobody did it that the token changes after you have called unregisterForRemoteNotifications. When you call registerForRemoteNotifications next time the token is different. I failed to find any confirmation of this in the Apple docs but I witnessed such a behavior myself. Please keep this in mind
Links quickly become obsolete with apple! so i'm quoting what seems to be quite clear now :
Never cache device tokens in your app; instead, get them from the system when you need them. APNs issues a new device token to your app when certain events happen. The device token is guaranteed to be different, for example, when a user restores a device from a backup, when the user installs your app on a new device, and when the user reinstalls the operating system. Fetching the token, rather than relying on a cache, ensures that you have the current device token needed for your provider to communicate with APNs. When you attempt to fetch a device token but it has not changed, the fetch method returns quickly.
From this guide
It shouldn't change, unless your app is restored onto a new device (at which point it won't be asked to accept push notifications again, and will simply send you the registered call at which point you should accept the new token).
But Apple doesn't guarantee that it never changes (hence the documentation never mentions it). You better program for the worst and assume it may change one day. Also, sending a token to your server regularly enables you to remove tokens that haven't registered for a while, and have probably deinstalled your app or lost interest a while ago (and the documentation does specify this as wanted behavior!).
From - Apple Docs
APNs can issue a new device token for a variety of reasons:
User installs your app on a new device
User restores device from a backup
User reinstalls the operating system
Other system-defined events
As a result, apps must request the device token at launch time.
Additionally:
I M P O R T A N T
APNs device tokens are of variable length. Do not hard-code their
size.
As reference to
Apple push notification stuff
The device token is your key to sending push notifications to your app on a specific device. Device tokens can change, so your app needs to reregister every time it is launched and pass the received token back to your server. If you fail to update the device token, remote notifications might not make their way to the user’s device. Device tokens always change when the user restores backup data to a new device or computer or reinstalls the operating system. When migrating data to a new device or computer, the user must launch your app once before remote notifications can be delivered to that device.
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.
According to this link the device token
The device token included in each request represents the identity of
the device receiving the notification. APNs uses device tokens to
identify each unique app and device combination. It also uses them to
authenticate the routing of remote notifications sent to a device.
Each time your app runs on a device, it fetches this token from APNs
and forwards it to your provider. Your provider stores the token and
uses it when sending notifications to that particular app and device.
The token itself is opaque and persistent, changing only when a
device’s data and settings are erased. Only APNs can decode and read a
device token.
Yes it can change.
Ideally when ever we receive a token via the callback method
(void)application:(UIApplication *)application didRegisterForRemoteNotificationsWithDeviceToken:(NSData *)deviceToken
The app should register / refresh the token on the remote server. This will ensure that the token on the APNS and your server is kept in sync.
As per Apple documentation,
Obtaining and handling an app-specific device token works as follows:
Your app registers with APNs for remote notifications When a new
device token is needed, APNs generates one using information contained
in the device’s certificate. It encrypts the token using a token key
and returns it to the device, as shown in the middle, right-pointing
arrow. The system delivers the device token back to your app by
calling your
application:didRegisterForRemoteNotificationsWithDeviceToken: delegate
method. Upon receiving the token, your app (within the delegate
method) must forward it to your provider in either binary or
hexadecimal format. Your provider cannot send notifications to the
device without this token. For details, see Registering to Receive
Remote Notifications in Configuring Remote Notification Support.
The device token relay on the installation of the app.
It means that if you reinstall the application, it changes; it doesn't metter if you do it from a backup, an iOS upgrade ecc..
The right way to use it, to avoid any problem, is to get the one given on the NSPAppDelegate at each application launch, in the method didRegisterForRemoteNotificationsWithDeviceToken