FCM推送通知在iOS 12上不起作用

Question

在IOS 12之前的所有IOS版本中，我都收到通知，而没有任何问题。在IOS 12中，我没有收到任何通知。
我知道我在某个地方读到Firebase中存在一个错误，但现在找不到该帖子了。该应用已投入生产，用户开始报告他们未收到通知。

Using Firebase (5.11.0)
Using FirebaseAnalytics (5.3.0)
Using FirebaseAnalyticsInterop (1.1.0)
Using FirebaseAuth (5.0.4)
Using FirebaseAuthInterop (1.0.0)
Using FirebaseCore (5.1.6)
Using FirebaseDatabase (5.0.3)
Using FirebaseDynamicLinks (3.1.1)

Using FirebaseInstanceID (3.3.0)
Using FirebaseMessaging (3.2.1)

Using FirebaseStorage (3.0.2)
Using FirebaseUI (5.2.0)



import UIKit
import Firebase
import FirebaseAuth
import FirebaseDatabase

import FirebaseCore
import FirebaseMessaging
import FirebaseInstanceID
import UserNotifications



class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterDelegate {

    var window: UIWindow?

    let badgeCountKey = "badgeCountKey" //the app badge count for notification


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


        FirebaseApp.configure()


        // iOS 10 support
        if #available(iOS 10, *) {
            UNUserNotificationCenter.current().delegate = self
            UNUserNotificationCenter.current().requestAuthorization(options:[.badge, .alert, .sound]){ (granted, error) in
            }
            application.registerForRemoteNotifications()
        }
            // iOS 9 support
        else if #available(iOS 9, *) {
            UIApplication.shared.registerUserNotificationSettings(UIUserNotificationSettings(types: [.badge, .sound, .alert], categories: nil))
            UIApplication.shared.registerForRemoteNotifications()
        }
            // iOS 8 support
    else if #available(iOS 8, *) {
          UIApplication.shared.registerUserNotificationSettings(UIUserNotificationSettings(types: [.badge, .sound, .alert], categories: nil))
            UIApplication.shared.registerForRemoteNotifications()
        }
            // iOS 7 support
        else {
            application.registerForRemoteNotifications(matching: [.badge, .sound, .alert])
        }
           NotificationCenter.default.addObserver(self, selector: #selector(self.tokenRefreshNotification(notification:)), name: NSNotification.Name.InstanceIDTokenRefresh, object: nil)

        // - check if app is launched from notification
        // - If  app wasn’t running and user launches it by tapping the push notification
        if let notification = launchOptions?[.remoteNotification] as? [String: AnyObject] {
            prepareToParse(notification: notification)
        }

        return true
    } //end of didFinishLaunchingWithOptions

   func tokenRefreshNotification(notification: NSNotification) {

        connectToFcm()

        let refereshToken = InstanceID.instanceID().token()

        guard let token = refereshToken else {return}    } //end tokenRefreshNotification

    func connectToFcm() {

        Messaging.messaging().connect { (error) in
            if error != nil  {
                print("unable to connect to FCM")
            }else {
                print("connected to FCM")
            }
        }
    }


    func application(_ application: UIApplication,
                     didFailToRegisterForRemoteNotificationsWithError error: Error) {
        print("Failed to register: \(error)")
    }



   func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any],
                     fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {


        guard let aps = userInfo["aps"] as? [String:Any] else {
            printsNow(message: "notification not received")
            return
        }

        guard let alert = aps["alert"] as? [String : Any] else {
            printsNow(message: "alert does not contain any info ")
            return
        }
        _ = NewsItem.makeNewsItem(alert)

        let previousCount = UserDefaults.standard.value(forKey: badgeCountKey) as! Int
        let currentCount = previousCount + 1
        UserDefaults.standard.setValue(currentCount, forKey: badgeCountKey)
        UIApplication.shared.applicationIconBadgeNumber = currentCount

        (window?.rootViewController as? UITabBarController)?.selectedIndex = 1
    }



    //display notifications when app is in foreground
    func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {

        let userInfo =  notification.request.content.userInfo

        guard let aps = userInfo["aps"] as? [String:Any] else {
            printsNow(message: "notification not received")
            return
        }

        guard let alert = aps["alert"] as? [String : Any] else {
            printsNow(message: "alert does not contain any info ")
            return
        }
       let _  = NewsItem.makeNewsItem(alert)

        let previousCount = UserDefaults.standard.value(forKey: badgeCountKey) as! Int
        let currentCount = previousCount + 1
        UserDefaults.standard.setValue(currentCount, forKey: badgeCountKey)
        UIApplication.shared.applicationIconBadgeNumber = currentCount



        if let tabBarController = window?.rootViewController as? UITabBarController {
           if let selectedVC = tabBarController.selectedViewController as? UINavigationController {

            if let lastVC = selectedVC.viewControllers.last as? ChatViewController {

                for (key, val) in userInfo {
                    if key as? String == "gcm.notification.chatUID" {
                        guard let chatID = val as? String else {return}
                        if lastVC.chatSelected.chatUID == chatID {
                            print("chatUID  \(chatID) is true")
                            completionHandler([]) //don't show notification because the message is for the current presented viewController
                            return
                       }
                    }
                }
             }
          }
        }

        completionHandler([.alert, .badge, .sound])
    }

    //when app is in foreground and you click on notification
    func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {

         (window?.rootViewController as? UITabBarController)?.selectedIndex = 1
    }




} //end appDelegate