Firebase Push Notifications with Swift not working

I am trying to set up push notifications using Firebase on ios 11.4 using Swift and its currently not working (i.e. not even the message to allow notifications comes up). Does it have to do with the fact that I am writing code for ios 10 (this is what they have in the Firebase website) or should this code work for ios 10 and up. Can anyone please help me with this. Thanks a lot!

I have the following AppDelegate code:

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

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


func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    // Override point for customization after application launch.
    FirebaseApp.configure()

    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 })
    } else {
        let settings: UIUserNotificationSettings =
            UIUserNotificationSettings(types: [.alert, .badge, .sound], categories: nil)
        application.registerUserNotificationSettings(settings)
    }

    application.registerForRemoteNotifications()

    let token = Messaging.messaging().fcmToken
    print("***** MY FCM token: \(token ?? "")")

    return FBSDKApplicationDelegate.sharedInstance().application(application, didFinishLaunchingWithOptions: launchOptions)
}

func applicationWillResignActive(_ application: UIApplication) {
    // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
    // Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game.
    FBSDKAppEvents.activateApp()
}

func applicationDidEnterBackground(_ application: UIApplication) {
    // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
    // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
}

func applicationWillEnterForeground(_ application: UIApplication) {
    // Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
}

func applicationDidBecomeActive(_ application: UIApplication) {
    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
}

func applicationWillTerminate(_ application: UIApplication) {
    // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
}

func application(_ application: UIApplication, open url: URL, sourceApplication: String?, annotation: Any) -> Bool {
    return FBSDKApplicationDelegate.sharedInstance().application(application, open: url, sourceApplication: sourceApplication, annotation: annotation)
}


}

// [START ios_10_message_handling]
@available(iOS 10, *)
extension AppDelegate : UNUserNotificationCenterDelegate {

// Receive displayed notifications for iOS 10 devices.
func userNotificationCenter(_ center: UNUserNotificationCenter,
                            willPresent notification: UNNotification,
                            withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
    let userInfo = notification.request.content.userInfo

    // With swizzling disabled you must let Messaging know about the message, for Analytics
    // Messaging.messaging().appDidReceiveMessage(userInfo)

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

    // Print full message.
    print(userInfo)

    // Change this to your preferred presentation option
    completionHandler([.alert, .badge, .sound])
}

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

    // Print full message.
    print(userInfo)

    completionHandler()
}
}

// [END ios_10_message_handling]

extension AppDelegate : MessagingDelegate {
// [START refresh_token]
func messaging(_ messaging: Messaging, didRefreshRegistrationToken fcmToken: String) {
    print("Firebase registration token: \(fcmToken)")
}
// [END refresh_token]

// [START ios_10_data_message]
// Receive data messages on iOS 10+ directly from FCM (bypassing APNs) when the app is in the foreground.
// To enable direct data messages, you can set Messaging.messaging().shouldEstablishDirectChannel to true.
func messaging(_ messaging: Messaging, didReceive remoteMessage: MessagingRemoteMessage) {
    print("Received data message: \(remoteMessage.appData)")
}
// [END ios_10_data_message]
}

And the following in my ViewController:

class ViewController: UIViewController, WKNavigationDelegate, WKScriptMessageHandler {

var webView: WKWebView!
let userContentController = WKUserContentController()

override func loadView() {
    super.loadView()

    let preferences = WKPreferences()
    preferences.javaScriptEnabled=true

    let configuration = WKWebViewConfiguration()
    configuration.preferences=preferences
    configuration.userContentController=userContentController

    webView = WKWebView(frame: self.view.frame, configuration: configuration)
    //webView = WKWebView(frame: self.view.frame)
    let token = Messaging.messaging().fcmToken

    let userScript = WKUserScript(
        source: "change_me(\"\(token ?? "")\")",
        injectionTime: WKUserScriptInjectionTime.atDocumentEnd,
        forMainFrameOnly: true
    )

    userContentController.addUserScript(userScript)
    webView?.configuration.userContentController.add(self, name: "scriptHandler")
    webView.navigationDelegate=self

    self.view.addSubview(webView!)
}

public func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
    print("********Message received: \(message.name) with body: \(message.body)")

    let loginManager = LoginManager()
    loginManager.loginBehavior = LoginBehavior.native
    loginManager.logIn( readPermissions: [ReadPermission.publicProfile], viewController: self) { loginResult in
        switch loginResult {
        case .failed(let error):
            print(error)
        case .cancelled:
            print("User cancelled login.")
        case .success(let grantedPermissions, let declinedPermissions, let accessToken):
            print("Logged in!")
            print("\(accessToken)")
        }
    }


}

@IBAction func button(_ sender: UIButton) {

    print("Result: ")
}

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    let taskershopURL = URL(string: "https://www.taskershop.ca")
    let taskershopURLRequest = URLRequest(url:taskershopURL!,cachePolicy: NSURLRequest.CachePolicy.reloadIgnoringLocalCacheData)
    webView?.load(taskershopURLRequest)


    let token = Messaging.messaging().fcmToken
    print("-------- FCM token: \(token ?? "")")

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


}

first make sure you have a paid developer account, activate notification from the project capabilities section, set up all the certificate with apple member center and add this certificate to gcm (see this How to use Apple's new .p8 certificate for APNs in firebase console) , you also must test with a real device

I assume that you already have these 3 Pods

import FirebaseInstanceID
import FirebaseMessaging
import UserNotifications

first you need to add this to didfinishlaunchingwithoptions

FirebaseApp.configure()
Messaging.messaging().delegate = self
registerForPushNotifications()

then add this two func to get the user permission

func getNotificationSettings() {
    if #available(iOS 10.0, *) {
        UNUserNotificationCenter.current().getNotificationSettings { (settings) in
            guard settings.authorizationStatus == .authorized else { return }
            DispatchQueue.main.async(execute: {
                UIApplication.shared.registerForRemoteNotifications()
            })
        }
    } else {
        // Fallback on earlier versions
    }
}

func registerForPushNotifications() {
    if #available(iOS 10.0, *) {
        UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound, .badge]) {
            (granted, error) in 
            guard granted else { return }
            self.getNotificationSettings()
        }
    } else {
        let settings = UIUserNotificationSettings(types: [.sound, .alert, .badge], categories: nil)
        UIApplication.shared.registerUserNotificationSettings(settings)
        UIApplication.shared.registerForRemoteNotifications()
    }
}

to get the firebase token add this

func messaging(_ messaging: Messaging, didReceiveRegistrationToken fcmToken: String) {
    print(fcmToken)
}

from now you should be able to see the permission prompt and to push notification from the Firebase console

if you need to perform a notification from code here is what I do (make sure to replace with your api key from firebase)

func sendPushNotification(notData: [String: Any]) {
    let url = URL(string: "https://fcm.googleapis.com/fcm/send")!
    var request = URLRequest(url: url)
    request.setValue("application/json", forHTTPHeaderField: "Content-Type")
    request.setValue("key=YOUR-SERVER-API-KEY", forHTTPHeaderField: "Authorization")
    request.httpMethod = "POST"

    request.httpBody = try? JSONSerialization.data(withJSONObject: notData, options: [])
    let task = URLSession.shared.dataTask(with: request) { data, response, error in
        guard let data = data, error == nil else {
            print(error ?? "")
            return
        }

        if let httpStatus = response as? HTTPURLResponse, httpStatus.statusCode != 200 {         
            print("statusCode should be 200, but is \(httpStatus.statusCode)")
            print(response ?? "")
        }

        let responseString = String(data: data, encoding: .utf8)
        print(responseString ?? "")
    }
    task.resume()
}

then call this func when you need

let notifMessage: [String: Any] = [
        "to" : "fcm token you need to send the notification",
        "notification" :
            ["title" : "title you want to display", "body": "content you need to display", "badge" : 1, "sound" : "default"]
    ]

sendPushNotification(notData: notifMessage)