We are already done with the initial setup for implementing Push notifications and are able to send/receive notifications successfully.
Now, we have been looking for the possible solutions to handle badge count increment from ios app (especially when app is not in foreground) -
1. Delegate the badge count calculation to server side.
- If we think of offloading the task of badge calculation to app server, then question arises is that, how server side will get to know about the count of viewed notifications so that badge can be decremented accordingly.
2. Use UIBackgroundModes and call 'didReceiveRemoteNotification:fetchCompletionHandler' method.
- Apple says, this method will get called when my app is either in foreground or background state. With this we should be able to track the count/notification info even when the app is in background & thus it probably enables us to do the necessary calculation in iOS app itself.
However, we have noticed that this method doesn't invoke when app is in background. Does it work only for iOS Silent notifications.
Any guidance/help in this regard will be greatly appreciated.
Thanks.
Option 1 is done by most apps (WhatsApp, Mail). It means you have to send a lot of 'notification read' messages to the server.
As for option 2, it works only for silent notifications (as you already noted) and in my experience, it is not entirely reliable. There even seems to be a rate limit on these.
Related
I am building an iOS application in SWIFT where user location is fetched and sent to the server after every 30 mins. When the app is opened it keeps sending the location lat/long to the server but when the app is closed or suspended it won't send. I want to send the location even the app is closed. Is this somehow possible? I just want to send the location to server no need to open the app again and again?
You app needs to support Background Tasks for being able to run in background.
I believe this has been answered multiple times. Here is the documentation link
Since you are using location, I would recommend you to use UIBackgroundModes as locations.But be sure you don't drain the users battery.
Also usage of background fetch (UIBackgroundModes - fetch) and silent notification can be a great way to get you app running after equal interval of time.
Update
For performing operations you can use silent notification - refer this apple documentation
As per documentation - the system wakes your app in the background and calls the application(_:didReceiveRemoteNotification:fetchCompletionHandler:)
Update 2
For local notification along with scheduling custom action refer this apple documentation. But I really doubt this will help you achieve your desired result. Mainly because you app would get an event only when the user performs any action on your local notification and if he ignores it, you app will remain in background.
As stated clearly in Apple docs, beacon ranging can be done in background for a short period of time only, say up to 10 seconds by default or up to 3 minutes with the help of background task expiration handler. As per my app's use case, app needs to do beacon ranging for every 15 mins until user exits the region. I am thinking of using background push notification(silent push notification) for this purpose(assuming data connection is available on the device always). So the flow goes like this, upon user entering the region, app calls the server with device token, server sends silent push notification for every 15 minutes. Once app received push notification, it does beacon ranging within allowed period of time if needed. Question I have here is whether using push notification in background mode to do ranging is legal, will I face any issues during app store submission.
Note: Also I need to enable BLE background mode for the app, to read some characteristics from some BLE devices.
Technically you can do it, but Apple mostly rejects such app. One important thing you have to consider is that, if the app is manually killed by the user and not running in the background, then the app won't wake up with silent push notification. There is a workaround if you have VoIP push notifications it will wake the app even from the terminated state. But you might need strong reason while pushing it to AppStore.
If you misuse one of the background modes, the app will probably be rejected, saying that, I don't think silent push notifications were meant for: keep an iOS app in "Background" state by sending it a silent push notification every few minutes.
another thing is that silent push notifications are rate limited as described http://asciiwwdc.com/search?q=push+notification, so I'm not sure if they will be sent every few minutes.
Apple says that;
Silent notifications are not meant as a way to keep your app awake in
the background, nor are they meant for high priority updates. APNs
treats silent notifications as low priority and may throttle their
delivery altogether if the total number becomes excessive. The actual
limits are dynamic and can change based on conditions, but try not to
send more than a few notifications per hour.
You might want to see this article. The user talks about apps that use silent notification for triggering location tracking. But eventually it's a hack that Apple may reject some time in the future, so it's best to have a contingency plan. FWIW so far I haven't heard anyone reporting rejection.
So the official answer is don't do it, as for the why you can refer to Ashish's answer. The unofficial answer is if you can't change your business logic then do it at your own risk.
The iOS application I'm working on does the exact same thing with the exception that I'm using recording instead of a Beacon. Recording by iOS standards gives more issues in pushing the app to the app store.
But Apple did not reject this app. Although we still are facing some issues but they don't relate to your problem.
You can follow such a tutorial for further help apart from the answer you were looking for : iOS Push Notification Demysitfied
Also, I've done firing of local notifications, while the application is in the background. BLE even works if the app is killed by the system, when the OS receives some communication from your peripheral or central, iOS wakes your app up and executes the desired function, before putting your app back to sleep.
I'm developing a great feature for my app which requires HTTP requests to be sent periodically in background.
I have read already many articles and discussions here, but haven't come up with a solution because all suggestions I met on stackoverflow.com solve the problem only partially.
Let me explain in details what do I want my application to do.
Consider there is a website with API and I want to send requests (when app is in background mode) periodically to check the state of data on the website. And if the state of data is acceptable I would send Push Notification to user to notify him that data is correct at the moment.
Could someone propose a solution how to implement this idea in iOS app?
On iOS you can't do this, as you've described it. You don't get to schedule tasks to happen at regular intervals when your app is in the background or not running. You also don't get to control whether iOS decides to terminate your app when it's running in the background, so "not running" is a case you'd need to handle (you can't just keep running in the background as for long as you want).
I'm not sure I understand the server side of things though. If your server is manipulating the data until it's acceptable, and it can send push notifications, why does it need to wait for an incoming request from the phone? Why not just send the push when the data is ready? If the app decides what's "acceptable", maybe have the app tell the server what it wants so that the server knows when to send a push.
There are a couple of options that would get close to what you describe. If you implement the "background fetch" feature in your app, iOS will launch the app when it's not running and let it make network calls in the background. There's no guarantee of how often this happens, though. This is described in Apple's background execution docs
The other option is the "silent" push notification. If your server sends one of these, iOS can launch the app in the background to handle the notification. The app could make a network call if necessary. You can send these at whatever time you like, but Apple warns to not overdo it:
Silent notifications are not meant as a way to keep your app awake in the background, nor are they meant for high priority updates. APNs treats silent notifications as low priority and may throttle their delivery altogether if the total number becomes excessive. The actual limits are dynamic and can change based on conditions, but try not to send more than a few notifications per hour.
Silent pushes are described in Apple's push notification docs.
iOS Background Execution Limits
Questions
How do I keep my app running continuously in the background?
If I schedule a timer, how do I get it to fire when the screen is locked?
How do I run code in the background every 15 minutes?
How do I set up a network server that runs in the background?
How can my app provide an IPC service to another one of my app while it’s in the background?
Answer from Apple:
The short answer to all of these is You can’t. iOS puts strict limits on background execution. Its default behavior is to suspend your app shortly after the user has moved it to the background; this suspension prevents the process from running any code.
Official: https://developer.apple.com/forums/thread/685525
I'm developing a great feature for my app which requires HTTP requests to be sent periodically in background.
I have read already many articles and discussions here, but haven't come up with a solution because all suggestions I met on stackoverflow.com solve the problem only partially.
Let me explain in details what do I want my application to do.
Consider there is a website with API and I want to send requests (when app is in background mode) periodically to check the state of data on the website. And if the state of data is acceptable I would send Push Notification to user to notify him that data is correct at the moment.
Could someone propose a solution how to implement this idea in iOS app?
On iOS you can't do this, as you've described it. You don't get to schedule tasks to happen at regular intervals when your app is in the background or not running. You also don't get to control whether iOS decides to terminate your app when it's running in the background, so "not running" is a case you'd need to handle (you can't just keep running in the background as for long as you want).
I'm not sure I understand the server side of things though. If your server is manipulating the data until it's acceptable, and it can send push notifications, why does it need to wait for an incoming request from the phone? Why not just send the push when the data is ready? If the app decides what's "acceptable", maybe have the app tell the server what it wants so that the server knows when to send a push.
There are a couple of options that would get close to what you describe. If you implement the "background fetch" feature in your app, iOS will launch the app when it's not running and let it make network calls in the background. There's no guarantee of how often this happens, though. This is described in Apple's background execution docs
The other option is the "silent" push notification. If your server sends one of these, iOS can launch the app in the background to handle the notification. The app could make a network call if necessary. You can send these at whatever time you like, but Apple warns to not overdo it:
Silent notifications are not meant as a way to keep your app awake in the background, nor are they meant for high priority updates. APNs treats silent notifications as low priority and may throttle their delivery altogether if the total number becomes excessive. The actual limits are dynamic and can change based on conditions, but try not to send more than a few notifications per hour.
Silent pushes are described in Apple's push notification docs.
iOS Background Execution Limits
Questions
How do I keep my app running continuously in the background?
If I schedule a timer, how do I get it to fire when the screen is locked?
How do I run code in the background every 15 minutes?
How do I set up a network server that runs in the background?
How can my app provide an IPC service to another one of my app while it’s in the background?
Answer from Apple:
The short answer to all of these is You can’t. iOS puts strict limits on background execution. Its default behavior is to suspend your app shortly after the user has moved it to the background; this suspension prevents the process from running any code.
Official: https://developer.apple.com/forums/thread/685525
I've seen a bunch of questions about getting the correct iOS app badge number in response to a remote notification (like this, this, and this). They all hinge on realizing that the OS will badge the app with the number in the payload before your app does anything. I get that, but my question is a bit different.
Assume the following series of events for an app that's enabled the "remote-notification" background mode (and otherwise properly configured for remote notifications):
The server sends a remote notification. The payload says the badge number should be 7.
The OS gets this, badges the app with "7", shows the alert/banner to the user, and launches/wakes my app into the background to start processing data.
Shortly after running, the app realizes the server is wrong and the correct badge number should be 3.
Maybe no big deal if the user comes into the app right away, but I'd like the badge to be correct if they don't. Can I set the badge number from within application:didReceiveRemoteNotification:fetchCompletionHandler: while executing in the background?
This article suggests you can change the badge if you asked for the "background fetch" background mode and the OS granted your wish. Any reason it shouldn't work if you're backgrounded to handle a notification?
For anyone who stumbles upon this later: I managed to get everything setup to actually try this out. Yes, you can mess with the app icon badge while in the background to handle a remote notification. At least when it comes to the badge, there's nothing special or restrictive about executing in the background due to a notification as opposed to any other background mode.