IOS FCM 未收到数据消息

Question

我正在使用 FCM 向 iOS 移动应用程序发送自定义数据消息，如果负载是这样的，我没有收到任何消息：

{
content_available: true,

data : {
    title   : message_title,
    body    : message_body, 
       }
}

但如果我添加这样的有效负载，我会收到通知：

{
content_available: true,
notification : {
    title   : message_title,
    body    : message_body,         
 },
data : {
    title   : message_title,
    body    : message_body, 
    }
}

但我不想发送通知我想发送数据消息。

我的 appDelegate 是：

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

    FirebaseApp.configure()

    application.registerForRemoteNotifications()

    UNUserNotificationCenter.current().delegate = self
    let authOptions: UNAuthorizationOptions = [.alert, .badge, .sound]
    UNUserNotificationCenter.current().requestAuthorization(options: authOptions, completionHandler: {_, _ in })
    application.applicationIconBadgeNumber = 0

    return true
}

func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
    Messaging.messaging().apnsToken = deviceToken
}

func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {

    UIApplication.shared.applicationIconBadgeNumber = 0
    let userInfo = notification.request.content.userInfo
    print("[UserNotificationCenter] applicationState: \(applicationStateString) willPresentNotification: \(userInfo)")

    NotificationCenter.default.post(name: .didReceiveData, object: nil, userInfo: userInfo)
}

func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {

    UIApplication.shared.applicationIconBadgeNumber = 0
    let userInfo = response.notification.request.content.userInfo
    print("[UserNotificationCenter] applicationState--: \(applicationStateString) didReceiveResponse: \(userInfo)")
    completionHandler()
}

为什么数据消息不起作用？

我在这个帖子https://stackoverflow.com/a/51954446/1747440找到了解决方案

Answer 1

 Messaging.messaging().delegate = self  

Messaging.messaging().shouldEstablishDirectChannel = true

//在didFinishLaunchingWithOptions中调用这个，然后检查token是否来了

// 打印(deviceToken)

// 如果仍然没有令牌，那么您必须确保您的密钥链中的 APNS 证书必须在 FireBase 云消息传递设置中，除了您的代码看起来很好之外，只有后端设置会出现问题，即您如何在 Firebase 上配置您的应用。

Firebase APNS cer