I am trying to make an app where you could send a warning to other users which then will trigger an alarm on the receivers phone.
So my plan is to send a silent warning to the receiver, which then triggers sounds and vibrations on the receivers phone from the app.
So basically my question is, is it possible to open an app on a phone through a silent push?
This is done with push notifications in iOS. See Apple's description.
Apps must be configured appropriately before they can receive local or remote notifications. The configuration process differs slightly on iOS and OS X, but the basic principles are the same. At launch time, your app registers to receive notifications and works with the system to configure that notification support. Once registration is complete, you can start creating notifications for delivery to your app. Your app then handles these incoming notifications and provides an appropriate response.
But note that it is up to the receiving user to determine how he wants to be alerted.
Related
While working with APNS, I was able to have push notifications work flawlessly while device is online.
For any APNS push I send while device is offline, only the last one is received once the device is back online. This seems to be coherent with Apple's Store-and-Forward design.
However - I did notice, that when sending WhatsApp messages to an offline device, once this device goes online it receives all push notifications (one for each message). This is not something based on collapse identifier, but rather independent push notification for each message.
So how did WhatsApp do it?
Tried using Notification Extension and attempt to post multiple local notifications, but this also fails as extensions are not allowed to do that.
Instead of a normal push notification, use a Background Notification, which will not show anything visible, but wake up your app in background. Use this event, to make api call, get relevant data and generate multiple local notifications.
Note the following from the documentation when you implement application(_:didReceiveRemoteNotification:fetchCompletionHandler:) :
system calls this method when your app is running in the foreground or background
system does not automatically launch your app if the user has force-quit it
you must call the block in the handler parameter (fetchCompletionHandler) or your app will be terminated. Your app
has up to 30 seconds of wall-clock time to process the notification
and call the specified completion handler block
Apps that use significant amounts of power when processing remote notifications may not always be woken up early to process future
notifications
Please read relevant documentation completely before making ANY assumptions about how you think this should work.
I have an application which has communication with a remote server. The server should push data into it using remote notification silently, and I need to get and store these data into a CoreData database. The user won't be aware of the whole process.
I can successfully get notified when the app receives a remote notification, while it is either in the foreground or background mode. However, I need to get data while the app is terminated as well.
I searched for the possible solutions. For example, this SO question was good if I don't tend to use silent notification. I also saw the PushKit capability, but I am not sure about the Apple Review result.
What is the possible solution?
If I want to use VoIP and PushKit to get notified when the app is terminated, would Apple reject my application?
If you’re not creating a VoIP app and you want your app to be in the App Store then the correct answer is: it is not possible. The only thing that can be done is adjusting your requirements in some way.
For instance you can send some notifications that will be visible for user in the Notification Center and wait until the user taps the notification or starts the app the usual way. Then the app will be able to do all the operations you need.
The delivery of push notifications is not guaranteed, so you should not rely on them to synchronise data.
For example, if multiple push notifications are sent while the device is offline, only the last notification is delivered when the device comes back online; the earlier notifications are lost.
When your app launches one of the first things it should do is check with your server for new data.
We need to calculate some numbers and display the calculations in local notification on receiving a silent push message from the server.
This works when the app is active/open in background.
This does not work if the app is killed/not in background.
So is there anyway to perform tasks when app is closed and the silent push arrives?
FYI I have enabled background fetch.
Apple's Documentation states:
Note: The ability of APNs to deliver remote notifications to a nonrunning
app requires the app to have been launched at least once.
On an iOS device, if a user force-quits your app using the app
multitasking UI, the app does not receive remote notifications until
the user relaunches it.
The second sentence pertains directly to your question; likely not the answer you hoped for...
↳ Configuring Remote Notification Support
Display my push notification message is "Message from: +919687335565"
attached screenshot :
I just want to fetch the name of this +919687335565 contact number from the Address book and display name of this contact instead of a phone number in push notification.
Before displaying notification i want to replace phone number +919687335565 with its contact name Chandresh in push notification.
like attached screenshot :
There are various possibilities for preprocessing and modify the payload of a notification on iOS.
Before iOS 10
You could be sending Silent Notifications, what will not be not shown to the user. Will wake our application when it is terminated or in background, and you will be able to do preprocessing on the notification content. See more info here, how to set it up. However, this notification type is not 100% reliable, and should not be abused, e.g. used for all notifications to be delivered, because Apple could stop the notifications to be sent after a number of messages.
The other option is, if your application supports VoIP. This way your app will pretty much always listen to push notifications, and you will be always available to preprocess the notifications, before you would be displaying them. However, if your app does not have real VoIP capabilities, e.g. phone calls, your app will be rejected by Apple on the review. Here is a great tutorial, how to set it up.
From iOS 10
With the introduction of iOS 10, we are finally able to do preprocessing on our notifications, even, when the app is in background or terminated. No VoIP capabilities or special type of notifications needed to be sent. Here is a great tutorial, how to set it up.
This is possible, except:
want to fetch name of this +91********* contact number from Address book
because Address Book is not accessible when app is in background!
You have to write separate logic in app itself to replace mobile no by appropriate name.
How other than this is possible:
Before iOS 10 and iOS 8+:
Use PushKit to send silent push notifications, app will be woken up by iOS, change the mobile no by name, show local notification.
iOS 10+:
Use Notification Service Extension to alter notification content before it'll shown to user.
Look at this official documentation
Using this service extension, iOS gives you a way to first receive notification directly to app, modify content and then deliver to user.
Here you can change mobile no by name.
No this is not possible.
Because the push notification is handle by server.
This message is only change by server not from app because that time
app is in background or terminated.
But you can change message when app is in foreground and background fetch is
enable then you can customize your message and can show it.
My app makes use of push notifications to alert the user when they receive a message. Due to the nature of my server and also due to encryption, the server does not know what the message is, only the iPhone is able to decrypt it. However, i would like the message to show in the notification. So i need processing time after a silent push to download and decrypt the message then use a local notification to tell the user
However, iOS doesn't allow processing time for killed apps, only for foreground ones or ones still in the app switcher. How can i workaround this issue?
One solution i have found is PushKit. This seems to relaunch apps even if they've been force quit. However, it only does this for VoIP apps, my app is not a VoIP app and I think App Review will reject it if I use PushKit
It is exactly as you described it and there is nothing to add. If the app is killed, you have no way of processing a silent push notification other than PushKit, but if you use PushKit, your app won't go through the review if it doesn't implement VoIP.
Your best option is to send push notification with a generic text (e.g. "You have a new message") instead of a silent push notification, that will serve as a fallback for the case that the app was killed. If the app was not killed, you can discard/remove the remote notification, download and decrypt the message and show a local notification with the actual message. If the app was killed, the remote notification with the generic text will be shown instead and the user will at least be notified that there is a new message.
Add this behavior to the FAQ of your app to encourage users to not kill the app. There is no reason to do this on iOS anyways, so if a user kills an app, he shouldn't expect that it works as desired.
Addition on misusing PushKit for this:
If you misuse a functionality/service for something it is not intended to be used for, your app will probably be rejected. So if you enable VoIP background mode, but your app doesn't provide any VoIP functionality, it is pretty obvious.
From the App Store Review Guidelines:
2.16 Multitasking Apps may only use background services for their intended purposes: VoIP, audio playback, location, task completion,
local notifications, etc.