Function didReceive remoteMessage not being called Swift 5

Question

So I've been reading the other posts on this subject here and elsewhere, but I'm still struggling. My app is doing device to device notifications using "Fireabase FCM" . I am able to send and receive the messages. However the method "didReceive remoteMessage" is never called. I would like to use this func to update the application and tabbar item badge numbers.

I've tried adding others methods to indicate a message was received but those haven't worked either. I think I'm missing something fundamental. I'm using Swift 5 with Xcode 10 .

import Foundation
import UIKit
import Firebase
import FirebaseFirestore
import FirebaseMessaging
import UserNotifications

class PushNotificationManager : NSObject, MessagingDelegate, UNUserNotificationCenterDelegate  {

    static let shared = PushNotificationManager( )

    var userID: String = ""
    var instanceIDToken : String = ""
    let defaults = UserDefaults.standard

    override init( ) {
        super.init()
    }

    func setUserId(identifier: String) {
        userID = identifier
    }

    func registerForPushNotifications() {
        if #available(iOS 10.0, *) {
            // For iOS 10 display notification (sent via APNS)
            UNUserNotificationCenter.current().delegate = self
            let authOptions: UNAuthorizationOptions = [.alert, .badge, .sound]
            UNUserNotificationCenter.current().requestAuthorization(
                options: authOptions,
                completionHandler: {_, _ in })
            // For iOS 10 data message (sent via FCM)
            Messaging.messaging().delegate = self
        } else {
            let settings: UIUserNotificationSettings =
                UIUserNotificationSettings(types: [.alert, .badge, .sound], categories: nil)
            UIApplication.shared.registerUserNotificationSettings(settings)
        }

        UIApplication.shared.registerForRemoteNotifications()
        UNMutableNotificationContent().sound = UNNotificationSound.default


        Messaging.messaging().shouldEstablishDirectChannel = true

        updateFirestorePushTokenIfNeeded()
    }


    func getNotificationSettings( ) {
        UNUserNotificationCenter.current().getNotificationSettings { (settings) in
            print("Notification settings: \(settings)")
            guard settings.authorizationStatus == .authorized else {return}
            DispatchQueue.main.async{UIApplication.shared.registerForRemoteNotifications()}
        }
    }

    func updateFirestorePushTokenIfNeeded( ) {
      //  let mytoken = Messaging.messaging().fcmToken
        if let token = Messaging.messaging().fcmToken {
            let usersRef = Firestore.firestore().collection("users_table").document(userID)
            usersRef.setData(["fcmToken": token], merge: true)
        }
    }

    func messaging(_ messaging: Messaging, didReceive remoteMessage: MessagingRemoteMessage) {
        print(remoteMessage.appData)
    }

    func application(received remoteMessage: MessagingRemoteMessage) {
        print("applicationReceivedRemoteMessage")
        print(remoteMessage.appData)
    }

    func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any]) {
        print("REMOTE NOTIFICATION RECEIVED")
    }

    func messaging(_ messaging: Messaging, didReceiveRegistrationToken fcmToken: String) {
        print("Firebase registration token: \(fcmToken)")
        updateFirestorePushTokenIfNeeded()
    }

    func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {
        print(response)
    }


    func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        completionHandler([.alert, .sound])
    }

    func getTokenDirectly( ) {
        InstanceID.instanceID().instanceID { (result, error) in
            if let error = error {
                print("Error fetching remote instance ID: \(error)")
            } else if let result = result {
                print("Remoted instance ID token: \(result.token)")
                self.instanceIDToken = result.token
                self.updateFirestorePushTokenIfNeeded()
            }
        }
    }
}

Again, I'm getting the notifications across the devices I'm using to test but

func messaging(_ messaging: Messaging, didReceive remoteMessage: MessagingRemoteMessage) {
    print(remoteMessage.appData)
}

is never called.

Answer 1

It seems you aren't calling this method:

registerForPushNotifications()

Since that is where you set your delegate as self the delegate's methods won't be called upon