How to fix 'Multiple push notification' error in swift? - ios

Question

I'm going through process of adding push notification on my iOS app by following a book and some docs on push notification.
Push notification was working fine for few days and then all of a sudden I started getting 3 push notification at a time and then it gradually increased to 7.
// this function is called from didFinishLaunchingWithOptions function
func requestForNotification(_ application: UIApplication){
UNUserNotificationCenter.current().requestAuthorization(options: [.badge,.sound,.alert]) { (granted, _) in
guard granted else {return}
DispatchQueue.main.async {
UIApplication.shared.registerForRemoteNotifications()
}
}
}
func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
let token = deviceToken.reduce(""){$0 + String(format: "%02x",$1) }
sendTokenToService(token: token)
print("device token is:::::::::: \(token)")
}
//Send token to local server
func sendTokenToService(token:String){
var params = [String:AnyObject]()
params["token"] = token as AnyObject
APIManager.shared.request(apiRouter: APIRouter.init(endpoint: .addAdminToken(param: params))) { (response, success) in
if success, let response = response["response"] {
print(response)
}
}
}
registerForRemoteNotifications() is being called only once but I found this on apple's official docs:
registerForRemoteNotifications() method: UIKit might call it in other rare circumstances. For example, UIKit calls the method when the user launches an app after having restored a device from data that is not the device’s backup data. In this exceptional case, the app won’t know the new device’s token until the user launches it.
Any idea how to resolve this issue ?

Answer 1

Push notifications are delivered once per device token. If you have access to your push notification server (or push provider if you are not managing it yourself), you can verify that is the case. When you are building the app and installing on a device, the new build will most likely be generating a new token. This also happens when the user uninstalls/installs the app. This could be the reason you're getting multiple notifications. Apple is supposed to invalidate old device tokens and send feedback back to your server. For more information on how Apple sends you feedback, here's a link to their Apple APNS docs.