My goal is to implement a function where, when a user (lets call him User1) sends a message to another user (User2), a notification is sent to User2´s device, so he can see the message right on the lock screen. I have already implemented a function where this works. My only problem now is that when I send the push Notification from User1´s device to User2´s device, I don't know if User2 is on the account that he should receive the message on.
If User2 has logged into a different account and User1 sends him a message, he sees this message, although User2 is in a different account and shouldn't see this message. Is there any way to know if a user logged into a different account and to then block the notification from showing on User2´s device?
Firebase Cloud Messaging has no concept of a user. It only knows about devices, or more explicitly app instances (a specific app on a specific device is an app instance).
If your use-case is based around users, your application logic is making a mapping from a user to their FCM instance ID/IDs. If you want the user to not receive a message anymore on a specific app instance, you need to remove the mapping you made.
The most common way to do this is to remove the mapping when the user signs out from your application on a specific device.
Since this is all rather abstract, I recommend also checking out:
When to register an FCM token for a user
Removing a user from Firebase
How to send FCM messages to a different user
Android: How to handle user logout Firebase Cloud Messaging in 2021
How to get Firebase user id from FCM token? (in admin code on server)
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I use push notifications in my iOS application but the problem is - several users with different IDs in the system can use the same device and I want to send push notification only to the user which is logged in, but now notifications arrive to the device even if other user is logged in. I know that APNS identifies pushes only by device tokens...
But is there some way to send push notifications based on user ID or other information not only device token?
You'll have to manage it yourself.
Whenever a user logs-in to your app, notify your server (send the user-id to the server).
Do the same whenever a user logs-off.
In your server, based on the currently logged-in user (you'll have to manage a database that contains for each device token the currently logged-in user), you can decide
which push notification to send to the device.
I don't think iOS push notification is right for your problem. here is why
consider you have an app with multiple users using the same device. you have a simple scenario where users can assign tasks to other users and they would like to get notifications when a task has been assigned to them
you do 'user to device token' mapping yourself on the server. consider user A and user B. both registered to receive notifications. so on the server both of them will have an entry in the mapping of what their device tokens are
Now, user B is logged out -- you will update on the server by removing the token for user B? or say use a flag to update the status that he is logged out?
user A now assigns a task to user B. on the server, you can see that user B has no mapping or mapping status is not active?
what happens to the notification?
you will end up queuing a notification for user b until he logs in? and push again? but again how do you know when to push again?
It is better you provide some UX in the app to get the notifications on a tap or periodically poll the server for any notifications
I’m looking at the designing and developing a service for Push notifications, and am trying to understand the order of processing in the Apple App when it comes to Registering for Push Notifications and storage of the Token.
What I’m developing currently is a service that allows subscription to individual changes that happen to particular processing on our server.
When they happen, the phone user may receive a message of type “A”, “B”, or “C”.
The phone user has to “subscribe” to each of these types individually if they want them. Otherwise they can ignore it and not subscribe.
So User Fred, on Phone #4, starts our App, logs in, and then has the ability to turn on or off subscriptions to events that are sent as Push Notifications.
So I need to tie details from Fred’s login, to Phone #4’s device Token, with particular subscriptions.
So my particularly important questions are.
When the Phone connects to the APNS server to get its device token, is this automatic on app start? Or can this be initiated at a later step? Ie, after going through a loging screen on our app.
Can we (are we allowed to) store the device token on the phone in the App's data store?. Or, should the App be connecting to the APNS server every time the app is run?
How does the App know if it as already called the APNS server and retrieved a token, or as above, should it call the APNS server time the app is run?
Can we (are we allowed to) store the token in the App’s memory as it runs, so we can properly subscribe and unsubscribe for particular messages?
We need also to be able to list all the subscriptions that a particular user may have across all their devices so the user can remove old devices (if they change phones). Or can we rely upon data back from calls to the APNS – when we attempt to push a notification - to inform us that a device token is no longer valid?
Or is there some better way of tying this all together?
When the Phone connects to the APNS server to get its device token, is
this automatic on app start? Or can this be initiated at a later step?
Ie, after logging into our app.
After the app has started, the app gets the token by calling registerForRemoteNotificationTypes. This will prompt the user for permission, and call a callback with the device token if permission is granted.
Can we (are we allowed to) store the device token on the phone in the
Apps data store?. Or, should the App be connecting to the APNS server
every time the app is run?
You'll need to build an APN provider, which is a web server that calls apple to send the pushes. The thing to do with the token is post it to your server that uses the APN provider. The app doesn't connect to APNS, your provider does, and it does it when it has pushes to send.
Can we (are we allowed to) store the token in the App’s memory as it
runs, so we can properly subscribe and unsubscribe for particular
messages?
You can keep the token on the client, but you don't really need to. It's your web service that calls APN, so it needs to be kept aware of your users' subscription prefs.
We need also to be able to list all the subscriptions that a
particular user may have across all their devices so the user can
remove old devices (if they change phones). Or can we rely upon data
back from calls to the APNS – when we attempt to push a notification -
to inform us that a device token is no longer valid?
APN also provides a feedback service that you call in batch which returns the device tokens that are no longer valid. Not only can you use this service, but you must. Apple will get mad at apps that repeatedly send to no longer valid devices.
Or is there some better way of tying this all together?
Yes! Parse.com provides a nice wrapper on the client code, does the provider and feedback service, abstracts the idea of single devices to the idea of a "channel" which sounds like just what you need for multiple notification types A, B, C, provides a super-easy step by step setup, and loads of other useful cloud services for iOS. (I'm not affiliated, but a big fan).
This is the first time that I approach the push notification service and I'm little bit confused. I 'd like to have just some conceptual help, not code.
I need to build an app that should receive and register for different kind of notifications. For instance in my app I'd like that users could register for PROMO notifications category and NEWS notifications category, I'd like that they could choose which one they want to be notified.
Reading the Apple doc, that was not so clear to me, it seems that once the app device is registered I receive just one token and seems impossible to receive more tokens for different kind of registration(NEWS and PROMO for instance), because the token is related to the app and the device. Is that correct?
The other thing that is not so clear to me is, if a device is registered for a specific notification is it possible to send the notification only to a set o devices?
If nothing of that is offered by Apple Push services do you think that is possible to manage everything like that:
-I register the app device for notification if (PROMO || NEWS) are selected
-I get the token
-I send the token to my server giving also as additional info about the service which the user wants to subscribe
-The server (provider) register the token and the kind of subscription (PROMO || NEWS)
-Later when I have a notification to push I ask the server all the tokens registered for that specific category and then I send the notification only to those devices registered for that category.
Thanks for helping me out I'm really confused.
"Reading the Apple doc, that was not so clear to me, it seems that once the app device is registered I receive just one token and seems impossible to receive more tokens for different kind of registration(NEWS and PROMO for instance), because the token is related to the app and the device. Is that correct?"
YES
The other thing that is not so clear to me is, if a device is registered for a specific notification is it possible to send the notification only to a set o devices?
YES, you need a DB where you connect a Push Token with the related Services (promo | news). If you have a new Promo Push Message you send the message to all related token. on the app site, everytime the user change the categorie (promo / news) you should prpvide these infos to your service with the push token.
These are all problems that you have to solve yourself on the server side. The push service simply provides a means to send a single message to a single device. You have to figure out yourself which messages you want to send to which devices. Each message has to be sent individually, there's no way to "broadcast" a message to all your users directly.
You could think of the push tokens as email addresses – of course, one email address might be subscribed to different newsletters from the same publisher, but it's the publisher's job (yours) to figure out whom to send which newsletters, not the email provider's (Apple's).
You should think of the push notification registration like my I send the user push notifications. Not what kind of push notification can I send the user.
Then you need to do serverside filtering on you categories, like the ones in your example promo and news.
The perferance of the user should be stored on your server, so you will know what kind of notification to send to which user.
I have an app where I would like to select a user in my contacts. If that person has my app installed, then I would like to send some data that is relevant for this app using a notification. The other user gets the notification, and acts on it within this app. Is that possible? I am thinking that if I can identify that users device, I can store this message in a server. When the user connects to the app, it will retrieve and get this users message from the server. But question is can I identify other devices like this, from my contact list. Can I send this notification using phone number instead of device id?
Please help.
Thank you,
Anks
No, you cannot. You have to have the Apple Push Token for a device and the user has to have notifications turned on to be able to receive notifications from Apple Push.
You would need to maintain a server side database linking the APNS Token to a specific user account. There are a lot of dots to connect with this kind of implmentation. Your better bet would be maintaining a "list of contacts" within your App to link contacts to.
The app is for a Gym. I would like it to allow individual push notifications to be sent from trainers to their clients. Is this possible? Would registering the app with user name and trainer after downloading have any effect?
If your goal is to initiate a push message from one iphone app and have it delivered to another iphone, then yes it is possible. Typically in this type of scenario, your application would upload an APN device token to a backend server for each client that logs into your application. The backend server would then associate that token to that particular user. If you want to be able to handle multiple devices per user, then you will want to also include a unique device id with this registration.
When the trainers are using the application, they would tell the backend server to send a push message to one or more clients. Your backend would then retrieve the tokens associated with the clients to which the message is to be sent and use the retrieved token to send the message(s) to Apple's APN interface.
Remember the APN token is specific to the mobile device and application.