How to send Firebase Push notification from device to device in iOS - swift

Question

I integrated firebase successfully. when I send notification using cloud messaging from firebase site just for a test purpose it is received by device. but in my app I need to send notification from one device to another device using firebase.. how to implement that.
Swift 4, Xcode 10
here is some code:
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZ"
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)
}
Messaging.messaging().delegate = self
InstanceID.instanceID().instanceID { (result, error) in
if let error = error {
print("Error fetching remote instance ID: \(error)")
} else if let result = result {
print("Remote instance ID token: \(result.token)")
self.deviceTokenString = result.token as NSString
}
}
application.registerForRemoteNotifications()
registerForPushNotifications()
}
func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
}
private func application(application: UIApplication, didReceiveRemoteNotification userInfo: [NSObject : AnyObject], fetchCompletionHandler completionHandler: (UIBackgroundFetchResult) -> Void) {
print("Recived: \(userInfo)")
completionHandler(.newData)
}
func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any]) {
if let messageID = userInfo[gcmMessageIDKey] {
print("Message ID: \(messageID)")
}
print("Recived: \(userInfo)")
}
#available(iOS 10.0, *)
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)
}
Messaging.messaging().shouldEstablishDirectChannel to true.
func messaging(_ messaging: Messaging, didReceive remoteMessage: MessagingRemoteMessage) {
print("Received data message: \(remoteMessage.appData)")
}
}
#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([.alert])
}
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()
}
}

Answer 1

If you want to send push notifications from device to device you will have to use Firebase Cloud functions. It's not difficult to implement if you follow the sample code. Check the docs here and you can check samples from their github repo.