How to make firebase push notifications work

Question

I have spent about 2 days going through firebases documentation, asking questions and looking at others and following youtube/medium tutorials and more. Here is a github project with my full app delegate, so that all my code is visible.

But I am yet to figure out how to be able to send a notification message from firebase cloud messaging. I have setup Apple push services have gotten and inputed auth key into firebase and written code in my app delegate seen here

Can someone let me know what I need to do to make it work? What have I missed?

Here is my didRegisterForRemoteNotificationsWithDeviceToken method:

    func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
    Messaging.messaging().apnsToken = deviceToken
    let tokenParts = deviceToken.map { data in String(format: "%02.2hhx", data) }
    let token = tokenParts.joined()
    print("Device Token: \(token)")

}

Update:

I have followed again this whole documentation by firebase and still sending notifications from fire cloud messaging does not work.

Clearly however the code is running given that 2 lines I have which save the token to firebase successfully save the token.

Answer 1

I have had a problem like this in the past, what fixed it for me was checking the bundle ID is the same on both the auth key and fire project as well as in Xcode.

Also to make sure your app delegate code is correct just use Firebase's example:

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: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {

        FirebaseApp.configure()

        // [START set_messaging_delegate]
        Messaging.messaging().delegate = self
        // [END set_messaging_delegate]

        // Register for remote notifications. This shows a permission dialog on first run, to
        // show the dialog at a more appropriate time move this registration accordingly.
        // [START register_for_notifications]
        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()

        // [END register_for_notifications]

        return true
    }

    // [START receive_message]
    func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable: Any]) {
        // If you are receiving a notification message while your app is in the background,
        // this callback will not be fired till the user taps on the notification launching the application.
        // TODO: Handle data of notification

        // 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)
    }

    func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable: Any],
                     fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {
        // If you are receiving a notification message while your app is in the background,
        // this callback will not be fired till the user taps on the notification launching the application.
        // TODO: Handle data of notification

        // 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)

        completionHandler(UIBackgroundFetchResult.newData)
    }
    // [END receive_message]

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

    // This function is added here only for debugging purposes, and can be removed if swizzling is enabled.
    // If swizzling is disabled then this function must be implemented so that the APNs token can be paired to
    // the FCM registration token.
    func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
        print("APNs token retrieved: \(deviceToken)")

        // With swizzling disabled you must set the APNs token here.
        // Messaging.messaging().apnsToken = deviceToken
    }
}

// [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([])
    }

    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, didReceiveRegistrationToken fcmToken: String) {
        print("Firebase registration token: \(fcmToken)")

        let dataDict:[String: String] = ["token": fcmToken]
        NotificationCenter.default.post(name: Notification.Name("FCMToken"), object: nil, userInfo: dataDict)
        // TODO: If necessary send token to application server.
        // Note: This callback is fired at each app startup and whenever a new token is generated.
    }
    // [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]
}

Answer 2

Assuming you have the APNS Auth Key correctly configured in the firebase console, and considering your appDelegate implementation you have provided, the only piece of code i see missing is the FIRInstanceId creation.

According to Firebase documentation here :

Instance ID provides a unique identifier for each app instance and a mechanism >to authenticate and authorize actions (for example, sending an FCM message).

Once an InstanceID is generated, the library periodically sends information >about the application and the device where it’s running to the Firebase >backend.

And here

To send or receive messages, the app must get a registration token from >FIRInstanceID. This token authorizes an app server to send messages to an app >instance.

Just before where you register for remote notification in your application didFinishLaunching..., add this before the application.registerForRemoteNotifications()

InstanceID.instanceID().instanceID { (result, error) in
    if let error = error {
        print("Error fetching remote instange ID: \(error)")
    } else if let result = result {
        print("Remote instance ID token: \(result.token)")
    }
}

Let me know if this helps :)