iOS critical alert through FCM

Question

iOS 12 has added critical alerts. The APNS payload has the sound dictionary to support critical alerts. Is there an equivalent sound dictionary support in FCM payload to sen

Answer 1

Answering my own question.

I had to rely on notification extension to do the magic as the FCM payload doesn't support the iOS sound dictionary. I send the "critical" flag set to 1 as part of FCM data payload and use it in notification extension to mark a notification as critical.

class NotificationService: UNNotificationServiceExtension {
    var contentHandler: ((UNNotificationContent) -> Void)?
    var bestAttemptContent: UNMutableNotificationContent?

    override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) {
       self.contentHandler = contentHandler
       bestAttemptContent = (request.content.mutableCopy() as? UNMutableNotificationContent)
       let userInfo: [AnyHashable : Any] = (bestAttemptContent?.userInfo)!
       if let apsInfo = userInfo["aps"] as? [AnyHashable: Any], let bestAttemptContent = bestAttemptContent, let critical =  userInfo["critical"] as? String, Int(critical)! == 1 {
            //critical alert try to change the sound if sound file is sent in notificaiton.
            if let sound = apsInfo["sound"] as? String {
                //sound file is present in notification. use it for critical alert..
                bestAttemptContent.sound =
                    UNNotificationSound.criticalSoundNamed(UNNotificationSoundName.init(sound),
                                                           withAudioVolume: 1.0)
            } else {
                //sound file not present in notifiation. use the default sound.
                bestAttemptContent.sound =
                                UNNotificationSound.defaultCriticalSound(withAudioVolume: 1.0)
            }
            contentHandler(bestAttemptContent)
        }
    }
}