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I thought about it for a while and proposed a potential solution at the end of the question, do you think it's feasible?
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I'm using Firebase Realtime Database to support chatting in my iOS app. I have a node called "conversations" in database, which is structured like so:
-conversations
-user_id_1 // This is you
-recipient_id_1 // id of the user who's chatting with you
-message_id_1
-message: <some_message>
-date: <some_date>
-message_id_2
-message: <some_message>
-date: <some_date>
-recipient_id_2
-message_id_1
-message: <some_message>
-date: <some_date>
-message_id_2
-message: <some_message>
-date: <some_date>
Whenever a new message is sent to a user, he should get a notification.
I have thought about using Push Notification, i.e. I use Cloud Function Trigger to observe the path:
functions.database.ref('conversations/{uid}/{recipientId}/{messageId}').onCreate((snapshot) => {
// Send push notification to user with "uid"
})
However, there's a problem with this, what if the user blocks the push notification of the app? The user is not gonna receive any message while he's not using the app (which is what he wants by turning off push notification), but he's not gonna get any message even when he's in the app. Therefore, I'm thinking, maybe I should use Firebase SDK in my app to observe database like so:
Database
.database().reference()
.child("conversations").child(<my_user_id>)
.observe(.childAdded) { (snapshot) in
// do stuff with snapshot
}
But then, this only observes newly started conversations, i.e. if the user already had a conversation with, say "person1", and "person1" sends a new message to the user, this observer wouldn't be triggered. Then, I was thinking:
Firstly, Keep the above observer so that I get notified when a new conversation is started
Secondly, Create multiple other observers that listen to my existing conversations:
Database
.database().reference()
.child("conversations").child(<my_user_id>).child(<existing_recipient_id>)
.observe(.childAdded) { (snapshot) in
// do stuff with snapshot
}
But this way, how do I know all my "existing_recipient_id"? I certainly shouldn't fetch them on start up:
Database
.database().reference()
.child("conversations").child(<my_user_id>)
.observeSingleEvent(of: .value) { (snapshot) in
// Extract all "existing_recipient_id"
}
Because this fetches all my conversations and their messages, which could potentially be multi-GBs.
I have the following 2 questions:
If I have 1,000 conversations with 1,000 people, should I have 1,000 observers in-app? If this wouldn't cause any problem, say performance issue, how do I set up these observers so that I could avoid the problems above?
I'm definitely using push notification, in case user is not in the app while a new message is sent to him. But, I don't know whether the user is in app or not, if he is, I already have those observers, push notification seems redundant, and it raises the cost. Is there a way that I can avoid this?
Temp solution
Write a cloud function that fetches all "existing_recipient_id", which is just an array of strings.
In the app, I add a listener that monitors the device's connection state, whenever the device comes back online from offline, also when the app first launches, I call that cloud function to fetch id's of all existing conversations.
Add observers to each of those conversations
Add observer to listen to new conversation
But I still don't know what to do about push notification when user is in-app, I guess I'll do it even though it's redundant
Related
Im trying to find a way to de-authorise users for push notifications when they log out from an app Ive found this function UIApplication.shared.unregisterForRemoteNotifications() which aparently works however I never see notifications being disabled, I also read in the documentation that it should not be used often or something to that effect, I basically want to have a toggle button in my app where the user clicks it one way and gets the standard enable notifications popup and another way to disable notifications on the fly, Im not a native swift developer so any pointers welcome
Also is it possible to attach a callback to this to know if it executes successfully, Im trying the following but get the error Argument passed to call that takes no arguments
UIApplication.shared.unregisterForRemoteNotifications() { (result, error) in
if let error = error {
call.error("Error", error)
} else if let result = result {
call.success([
"deregister": true
])
}
}
Edit: I found this which says its not possible to toggle on and off Change push notifications programmatically in Swift
With that in mind does this mean that the standard for devices is that:
1) when a user log out of their account they can still receive notifications.
2) When a user creates a new account on the same app it uses the same token and so receives notifications from the old account ?
3) when a user sells their phone and another guy/gal downloads the same app that they will receive notifications from that other users account (in terms of 3rd party push service one signal, aparently you dont need to refresh the player id)
I need to keep track of devices that are actively running the app. Right now I have a status field that changes to 1 when the app is first launched or when the device becomes active. When the user presses the home button, I set the status field to 0 upon receiving the notification UIApplicationWillResignActiveNotification
if(self.device) {
[self.realm transactionWithBlock:^{
self.device.status = 0;
}];
}
self.device = nil;
[self.realm refresh];
However, I check the data in Realm Cloud, and it doesn't seem to be updating at all. Is there some way to force update the sync of my Realm data?
If you want to achieve this by only using realm platform, I think you should implement a data updating logic, for example, every 5-second client should update a value, it can be the current timestamp and you can recognize online users by the last timestamp value.
in my opinion, a simple socket.io implementation can be a better solution, you can save users connection status by saving them in the socket server. you just need to save timestamp when the client has connected to the server and when he has disconnected.
I believe you can do same with ROS but I'm not sure they provide public API for user connection event or status ...
I'm using Firebase Messaging to send out notifications to users of my iPhone app. My database is structured like this:
- Users
- user1
- user2
- Groups
- group1
- members
- user1
- user2
When a user joins a group they get subscribed to a topic corresponding to that group. I have a cloud function that listens for writes in that group, and sends a notification to the groups topic when a write happens:
exports.sendNotifs = functions.database
.ref('pets/{petId}/events/{eventId}').onWrite(event => {
const pet_Id = event.params.petId;
const payload = {
'notification': {
'title': `${toTitleCase(name)} just logged an event`,
'body': `${events[eventType]} for ${toTitleCase(petName)}`,
'sound': 'default',
}
};
admin.messaging().sendToTopic(pet_Id, payload);
});
However, this results in everybody getting a notification including the person who did the write that triggered the notification. I only want other people in the group to display a notification since the triggering user doesn't need to see one. I tried appending the sending user's uid as extra data of the notification and only displaying the notification if the recieving user's uid doesn't match the notification data's uid. This works when the application is in the foreground but not if its in the background, so if the user writes then closes the application before he receives the notification it'll display for him when he receives it, something I'm trying to avoid.
How can I make sure only other members of a group get a notification? Are messaging topics not good for this?
If you use Topics it's not possible to send to everyone except one.
If you are Ok sending to everyone, and then filtering on the client, you will need to use the data messages, and not notification messages, to avoid the problem with background/foreground you described.
https://firebase.google.com/docs/cloud-messaging/concept-options
i guess that the solution is:
each iOS client from group1 will subscribe to topic /topics/group1.selfUserId
the server already have the list with all users that are part of group1
the iOS client ask server to send notification to group1.members beside selfUserId (make a http post request)
server send gets all group1.members beside selfUserId and send notification to all /topics/group1.memberX
As already mentioned, you cannot exclude someone who has been registered to a Topic.
So what you can do is sending a message to a single device. So for example you have a group of ten persons, one person posts a message, you have to send nine single messages to the other nine persons of the group.
What you need to do is to store the registration token of every single user into your database and you have to take into account that registration tokens will change after some time.
I have a coaching app that has a section where I can push realtime updates out to the players like: "No Practice - Do to inclement weather, practice will be pushed until Friday"
I have been trying to figure out how to send automatic notifications when I update this UpdatesTableView with a new post. Like "New Update Posted".
I post my updates to the Firebase Database. There must be a way to listen for changes and when there is to push a notification out to all the users?
I already have firebase notifications set up in my app but I have to utilize the Firebase console to push these notifications every time i push an update. Does anyone know how to automate this? Thanks!
You can easily do that by listening/Observing to any data change at a particular location in firebase. If new child is added to that path, associated block will be called.
In your case, you can observe UpdatesTableView. and whenever you post any update, call the block which will send notification to all users.
If you are using Swift:
func observe(_ eventType: FIRDataEventType, with block: #escaping (FIRDataSnapshot) -> Void) -> UInt
If you are using Objective C:
- (FIRDatabaseHandle)
observeEventType:(FIRDataEventType)eventType
withBlock:(nonnull void (^)(FIRDataSnapshot *_Nonnull))block;
According to official firebase documentation :
observeEventType:withBlock: is used to listen for data changes at a particular location. This is the primary way to read data from the
Firebase Database. Your block will be triggered for the initial data
and again whenever the data changes.
And, Whenever you would like to stop listening to data changes, you can Use removeObserverWithHandle
Use removeObserverWithHandle: to stop receiving updates. - parameter:
eventType The type of event to listen for. - parameter: block The
block that should be called with initial data and updates. It is
passed the data as a FIRDataSnapshot. - returns: A handle used to
unregister this block later using removeObserverWithHandle:
For more and detailed information, Read iOS firebase#Attaching Observers to read data Documentation.
Also, For sending Notifications to users effieciently, you can use Firebase Notification. Have a look at it. i dont know about your usecase properly, But i think this will help.
I also stucked with same problem where I wanted to show notification to users whenever data changes in Firebase irrespective of application in foreground or background.
I achieved it by binding ChildEventListener with a service which keeps running in background. At every childAdded event data is stored in sqlited db and a new notification object is created and shown to user.
I've implemented an iPhone application that has around 50k users. Switching from iOS7 to iOS8 a lot of these users have experienced a terrible feeling when they thought that they data get lost.
I've implemented the first-import behaviour that I thought was the one suggested by Apple
1) Users launch the App
2) iCloud, automatically, starts synching data previously stored on iCloud
3) At some point user get notified that data from iCloud is ready thanks to NSPersistentStoreUbiquitousTransitionTypeInitialImportCompleted
The problem is with 3) At some point:
Users that have to sync a lot of data need minutes to get the synch completed and in the meanwhile they think that their data is lost.
I really don't know how to let my users know that they have to wait to see their data synched, because I don't know when this operation starts.
I'm thinking about a possible solution:
During the first launch of the App, asking to the user if he wants to use iCloud. If he chooses to use it, building the database with iCloud options, so I know exactly that the synch is starting here (I suppose...)
I'm really not sure about how to implement this behaviour since I've always seen Core Data settings into the AppDelegate but to achieve this behaviour I suppose I need to move all the CoreData settings in a Controller.
What do you think about this solution? how are you working around this problem in you Apps?
Your idea is right, at least it is that what we do. But leave it in the appDelegate.
Differentiate between with iCloud and without iCloud when doing the "addPersistentStoreWithType". If you do it with iCloud options, it will directly start to build the local store which is a kind of a placeholder ( I'm sure you know that, but just to make my thoughts clear). As soon as this is done, the sync starts from iCloud. So this is the starting point I understood you were looking for.
You can watch that process using the notifications by NSPersistentStoreCoordinatorStoresDidChangeNotification and inform you user accordingly triggered by that notification.
If you look at "Reacting to iCloud Events" in the docs https://developer.apple.com/library/ios/documentation/DataManagement/Conceptual/UsingCoreDataWithiCloudPG/UsingSQLiteStoragewithiCloud/UsingSQLiteStoragewithiCloud.html#//apple_ref/doc/uid/TP40013491-CH3-SW5 there is a detailed desc.
To summarize, the event you're describing is part of the account transitions process. An account transition occurs when one of the following four events is triggered:
Initial import
the iCloud account used did change
iCloud is disabled
your application's data is deleted
During this event, Core Data will post the NSPersistentStoreCoordinatorStoresWillChangeNotification and NSPersistentStoreCoordinatorStoresDidChangeNotification notifications to let you know that an account transition is happening. The transition type we're interested in is NSPersistentStoreUbiquitousTransitionTypeInitialImportCompleted.
For information, I've moved all Core Data related code to my own Manager for simplicity and use it with a singleton design pattern. While setting up the singleton, I register the Manager for all relevant notifications (NSPersistentStoreDidImportUbiquitousContentChangesNotification, NSPersistentStoreCoordinatorStoresWillChangeNotification, NSPersistentStoreCoordinatorStoresDidChangeNotification, NSPersistentStoreCoordinatorWillRemoveStoreNotification).
I store several informations in my settings (NSUserDefaults or anything) like the last iCloud state (enabled, disabled, unknown), if the initial import is done or not, etc.
What I end up doing was having a prompt (UIAlertController or anything) to get a confirmation if the user wants to use iCloud or not. I have a displayICloudDialogAndForce:completion: method to do that and only do that if my iCloud state setting is unknown or I use the force parameter.
Then, after the user input, I call a setupCoreDataWithICloud: method, the iCloud boolean parameter depending on the user choice. I would then setup my Core Data stack, on the cloud or not according to the iCloud parameter.
If I'm setting up using iCloud, I would check my settings for the value of an iCloud imported key (boolean). If the value is NO, then I'm presenting a new modal to warn the user about the incoming import that could take some time.
I've registered my manager for different notifications and specially NSPersistentStoreCoordinatorStoresDidChangeNotification. In my storeDidChange: callback, I'm checking the transition type and if it's NSPersistentStoreUbiquitousTransitionTypeInitialImportCompleted, I'm changing the content of my modal to show the user that the import was successful and removing it a few seconds later, saving in my settings that the initial import is done.
- (void)storeDidChange:(NSNotification *)notification
{
NSPersistentStoreUbiquitousTransitionType transitionType = [notification.userInfo[NSPersistentStoreUbiquitousTransitionTypeKey] integerValue];
if (transitionType == NSPersistentStoreUbiquitousTransitionTypeInitialImportCompleted) {
[settings setDefaults:#(YES) forKey:kSettingsICloudImportedKey];
[ICloudModal dismissWithSuccess];
// ...
}
// Do other relevant things...
}