Correct way to retrieve token for FCM - iOS 10 Swift 3

Question

i had implement Firebase with FirebaseAuth/FCM etc and did sent notification successfully through Firebase Console.

However i would need to push the notification from my own app server.

i am wondering below which way is correct way to retrieve the registration id for the device:-

1) retrieve registration id token from didRegisterForRemoteNotificationWithDeviceToken

func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {     var token = ""      for i in 0..<deviceToken.count {         token += String(format: "%02.2hhx", arguments: [deviceToken[i]])     }      print("Registration succeeded!")     print("Token: ", token)     Callquery(token)  } 

2) Retrieve Registration token from firebase (Based on Firebase document which retrieve the current registration token)

let token = FIRInstanceID.instanceID().token()! 

i was using the first way, the push notification is not being received even the registration id is stored on my app server database accordingly and i get this CURL session result :-

{"multicast_id":6074293608087656831,"success":0,"failure":1,"canonical_ids":0,"results":[{"error":"InvalidRegistration"}]} 

i had also tried the second way and get fatal error while running the app as below:-

appreciated if anyone could point me the right way, thanks!

Answer 1

The tokenRefreshNotification function doesn't always get called when launching the app.

However, when placing the code inside the regular didRegisterForRemoteNotificationsWithDeviceToken delegate function, I can get the token every time:

func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {     if let refreshedToken = InstanceID.instanceID().token() {         print("InstanceID token: \(refreshedToken)")     } } 

(Swift 3 + Firebase 4.0.4)

Answer 2

The recommended way by Firebase:

let token = Messaging.messaging().fcmToken 

Reference : Setting Up a Firebase Cloud Messaging Client App on iOS