Swift3 can't receive background FCM push notification

Question

I'm new in IOS development.

I've searched google 2days.

I can't receive background push notification through FCM.

In foreground, received but In background, not called delegate.

checked capabilities->Push Notifications, Background Modes.

I set priority to high and content_available to true.

using swift3, ios10.3, firebase.

here's my code.

import UIKit
import UserNotifications
import Firebase

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?
    let gcmMessageIDKey = "gcm.message_id"

func application(_ application: UIApplication,
                 didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    FirebaseApp.configure()

    Messaging.messaging().delegate = self
    if #available(iOS 10.0, *) {
        UNUserNotificationCenter.current().delegate = self

        let authOptions: UNAuthorizationOptions = [.alert, .badge, .sound]
        UNUserNotificationCenter.current().requestAuthorization(
            options: authOptions,
            completionHandler: {_, _ in })
    } else {
        let settings: UIUserNotificationSettings =
            UIUserNotificationSettings(types: [.alert, .badge, .sound], categories: nil)
        application.registerUserNotificationSettings(settings)
    }

    application.registerForRemoteNotifications()
    return true
}
func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable: Any]) {
    if let messageID = userInfo[gcmMessageIDKey] {
        print("Message ID: \(messageID)")
    }

    print(userInfo)
}
    func applicationDidBecomeActive(_ application: UIApplication)
    {
        Messaging.messaging().shouldEstablishDirectChannel = true

        application.applicationIconBadgeNumber = 0;
    }

    func applicationDidEnterBackground(_ application: UIApplication)
    {
        Messaging.messaging().shouldEstablishDirectChannel = false
        print("Disconnected from FCM.")
    }
func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable: Any],
                 fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {
    if let messageID = userInfo[gcmMessageIDKey] {
        print("Message ID: \(messageID)")
    }

    print(userInfo)

    completionHandler(UIBackgroundFetchResult.newData)
}
func application(_ application: UIApplication, didFailToRegisterForRemoteNotificationsWithError error: Error) {
    print("Unable to register for remote notifications: \(error.localizedDescription)")
}

func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
    print("APNs token retrieved: \(deviceToken)")

}
}

@available(iOS 10, *)
extension AppDelegate : UNUserNotificationCenterDelegate {

func userNotificationCenter(_ center: UNUserNotificationCenter,
                            willPresent notification: UNNotification,
                            withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
    let userInfo = notification.request.content.userInfo

    if let messageID = userInfo[gcmMessageIDKey] {
        print("Message ID: \(messageID)")
    }

    print(userInfo)

    completionHandler([])
}

func userNotificationCenter(_ center: UNUserNotificationCenter,
                            didReceive response: UNNotificationResponse,
                            withCompletionHandler completionHandler: @escaping () -> Void) {
    let userInfo = response.notification.request.content.userInfo
    if let messageID = userInfo[gcmMessageIDKey] {
        print("Message ID: \(messageID)")
    }

    print(userInfo)

    completionHandler()
}
}

extension AppDelegate : MessagingDelegate {
func messaging(_ messaging: Messaging, didRefreshRegistrationToken fcmToken: String) {
    print("Firebase registration token: \(fcmToken)")
}
func messaging(_ messaging: Messaging, didReceive remoteMessage: MessagingRemoteMessage) {
    print("Received data message: \(remoteMessage.appData)")
}
}

Answer 1

Add in appdelegate :

func application(_ application: UIApplication,
                   didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
    Messaging.messaging().apnsToken = deviceToken as Data
  }

Answer 2

In your function:

func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data)

You are receiving the deviceToken but doing nothing with it, you need to send it to Firebase.

Import Instance ID:

import FirebaseInstanceID

And try this:

func application(
   _ application:UIApplication,
   didRegisterForRemoteNotificationsWithDeviceToken deviceToken:Data)
{
   FIRInstanceID.instanceID().setAPNSToken(
      deviceToken as Data,
      type:.unknown)
}