Setting Up a Firebase Cloud Messaging Client App on iOS

For iOS client apps, you can implement Firebase Cloud Messaging in two complementary ways:

• Receive basic push messages up to 4KB over the Firebase Cloud Messaging APNs interface.

• Send messages upstream and/or receive downstream data payloads up to 4KB in foregrounded apps.

To write your client code in Objective-C or Swift, we recommend that you use the FIRMessaging API. The quickstart example provides sample code for both languages.

Method swizzling in Firebase Cloud Messaging

The FCM SDK performs method swizzling in two key areas: mapping your APNs token to the FCM registration token and capturing analytics data during downstream message callback handling. Developers who prefer not to use swizzling can disable it by adding the flag FirebaseAppDelegateProxyEnabled in the app’s Info.plist file and setting it to NO (boolean value). Relevant areas of the guides provide code examples, both with and without method swizzling enabled.

Add Firebase to your iOS project

This section covers tasks you may have completed if you have already enabled other Firebase features for your app. For FCM specifically, you'll need to upload your APNs authentication key and register for remote notifications.

Prerequisites

Before you begin, you need a few things set up in your environment:

• Xcode 9.2 or later
• An Xcode project targeting iOS 8 or above
• Swift projects must use Swift 3.0 or later
• The bundle identifier of your app
• CocoaPods 1.4.0 or later
• For Cloud Messaging:
  • A physical iOS device
  • An Apple Push Notification Authentication Key for your Apple Developer account
  • In Xcode, enable Push Notifications in App > Capabilities

If you don't have an Xcode project already, you can download one of our quickstart samples if you just want to try a Firebase feature. If you're using a quickstart, remember to get the bundle identifier from the project settings, you'll need it for the next step.

Add Firebase to your app

It's time to add Firebase to your app. To do this you'll need a Firebase project and a Firebase configuration file for your app.

To create a Firebase project:

1. Create a Firebase project in the Firebase console, if you don't already have one. Click Add project. If you already have an existing Google project associated with your mobile app, select it from the Project name drop down menu. Otherwise, enter a project name to create a new project.
2. Optional: Edit your Project ID. Your project is given a unique ID automatically, and it's used in publicly visible Firebase features such as database URLs and your Firebase Hosting subdomain. You can change it now if you want to use a specific subdomain.
3. Follow the remaining setup steps and click Create project (or Add Firebase if you're using an existing project) to begin provisioning resources for your project. This typically takes a few minutes. When the process completes, you'll be taken to the project overview.

Now that you have a project, you can add your iOS app to it:

1. Click Add Firebase to your iOS app and follow the setup steps. If you're importing an existing Google project, this may happen automatically and you can just download the config file.
2. When prompted, enter your app's bundle ID. It's important to enter the bundle ID your app is using; this can only be set when you add an app to your Firebase project.
3. During the process, you'll download a GoogleService-Info.plist file. You can download this file again at any time.
4. After you add the initialization code, run your app to send verification to the Firebase console that you've successfully installed Firebase.

Add the SDK

If you are setting up a new project, you need to install the SDK. You may have already completed this as part of creating a Firebase project.

We recommend using CocoaPods to install the libraries. You can install Cocoapods by following the installation instructions. If you'd rather not use CocoaPods, you can integrate the SDK frameworks directly without using CocoaPods.

If you are planning to download and run one of the quickstart samples, the Xcode project and Podfile are already present, but you'll still need to install the pods and download the GoogleService-Info.plist file. If you would like to integrate the Firebase libraries into one of your own projects, you will need to add the pods for the libraries that you want to use.

1. If you don't have an Xcode project yet, create one now.

2. Create a Podfile if you don't have one:

   $ cd your-project directory
   $ pod init
   

3. Add the pods that you want to install. You can include a Pod in your Podfile like this:

   pod 'Firebase/Core'
   pod 'Firebase/Messaging'
   

   This will add the prerequisite libraries needed to get Firebase up and running in your iOS app, along with Google Analytics for Firebase. A list of currently available pods and subspecs is provided below. These are linked in feature specific setup guides as well.

4. Install the pods and open the .xcworkspace file to see the project in Xcode.

   $ pod install
   $ open your-project.xcworkspace
   

5. Download a GoogleService-Info.plist file from Firebase console and include it in your app.

Upload your APNs authentication key

Upload your APNs authentication key to Firebase. If you don't already have an APNs authentication key, see Configuring APNs with FCM.

1. Inside your project in the Firebase console, select the gear icon, select Project Settings, and then select the Cloud Messaging tab.

2. In APNs authentication key under iOS app configuration, click the Upload button.

3. Browse to the location where you saved your key, select it, and click Open. Add the key ID for the key (available in Certificates, Identifiers & Profiles in the Apple Developer Member Center) and click Upload.

Initialize Firebase in your app

You'll need to add Firebase initialization code to your application. Import the Firebase module and configure a shared instance as shown:

1. Import the Firebase module in your UIApplicationDelegate:

   Swift

   import Firebase
   

   Objective-C

   @import Firebase;
   

2. Configure a FirebaseApp shared instance, typically in your application's application:didFinishLaunchingWithOptions: method:

   Swift

   // Use Firebase library to configure APIs
   FirebaseApp.configure()
   

   Objective-C

   // Use Firebase library to configure APIs
   [FIRApp configure];
   

Register for remote 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()
AppDelegate.swift

if ([UNUserNotificationCenter class] != nil) {
  // iOS 10 or later
  // For iOS 10 display notification (sent via APNS)
  [UNUserNotificationCenter currentNotificationCenter].delegate = self;
  UNAuthorizationOptions authOptions = UNAuthorizationOptionAlert |
      UNAuthorizationOptionSound | UNAuthorizationOptionBadge;
  [[UNUserNotificationCenter currentNotificationCenter]
      requestAuthorizationWithOptions:authOptions
      completionHandler:^(BOOL granted, NSError * _Nullable error) {
        // ...
      }];
} else {
  // iOS 10 notifications aren't available; fall back to iOS 8-9 notifications.
  UIUserNotificationType allNotificationTypes =
  (UIUserNotificationTypeSound | UIUserNotificationTypeAlert | UIUserNotificationTypeBadge);
  UIUserNotificationSettings *settings =
  [UIUserNotificationSettings settingsForTypes:allNotificationTypes categories:nil];
  [application registerUserNotificationSettings:settings];
}

[application registerForRemoteNotifications];
AppDelegate.m

Access the registration token

By default, the FCM SDK generates a registration token for the client app instance on app launch. Similar to the APNs device token, this token allows you to send targeted notifications to any particular instance of your app.

In the same way that iOS typically delivers an APNs device token on app start, FCM provides a registration token via FIRMessagingDelegate's messaging:didReceiveRegistrationToken: method. The FCM SDK retrieves a new or existing token during initial app launch and whenever the token is updated or invalidated. In all cases, the FCM SDK calls messaging:didReceiveRegistrationToken: with a valid token.

The registration token may change when:

• The app is restored on a new device
• The user uninstalls/reinstall the app
• The user clears app data.

Set the messaging delegate

To receive registration tokens, implement the messaging delegate protocol and set FIRMessaging's delegate property after calling [FIRApp configure]. For example, if your application delegate conforms to the messaging delegate protocol, you can set the delegate on application:didFinishLaunchingWithOptions: to itself.

Messaging.messaging().delegate = self

[FIRMessaging messaging].delegate = self;

Fetching the current registration token

Registration tokens are delivered via the method messaging:didReceiveRegistrationToken:. This method is called generally once per app start with an FCM token. When this method is called, it is the ideal time to:

• If the registration token is new, send it to your application server.
• Subscribe the registration token to topics. This is required only for new subscriptions or for situations where the user has re-installed the app.

You can retrieve the token directly using instanceIDWithHandler:. This callback provides an InstanceIDResult, which contains the token. A non null error is provided if the InstanceID retrieval failed in any way.

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)")
    self.instanceIDTokenMessage.text  = "Remote InstanceID token: \(result.token)"
  }
}

[[FIRInstanceID instanceID] instanceIDWithHandler:^(FIRInstanceIDResult * _Nullable result,
                                                    NSError * _Nullable error) {
  if (error != nil) {
    NSLog(@"Error fetching remote instance ID: %@", error);
  } else {
    NSLog(@"Remote instance ID token: %@", result.token);
    NSString* message =
      [NSString stringWithFormat:@"Remote InstanceID token: %@", result.token];
    self.instanceIDTokenMessage.text = message;
  }
}];

Generally, the token is available locally, so this method does not open a network connection. You can use this method at any time to access the token instead of storing it.

Monitor token refresh

To be notified whenever the token is updated, supply a delegate conforming to the messaging delegate protocol. The following example registers the delegate and adds the proper delegate method:

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.
}
AppDelegate.swift

- (void)messaging:(FIRMessaging *)messaging didReceiveRegistrationToken:(NSString *)fcmToken {
    NSLog(@"FCM registration token: %@", fcmToken);
    // Notify about received token.
    NSDictionary *dataDict = [NSDictionary dictionaryWithObject:fcmToken forKey:@"token"];
    [[NSNotificationCenter defaultCenter] postNotificationName:
     @"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.
}
AppDelegate.m

Alternatively, you can listen for an NSNotification named kFIRMessagingRegistrationTokenRefreshNotification rather than supplying a delegate method. The token property always has the current token value.

Swizzling disabled: mapping your APNs token and registration token

If you have disabled method swizzling, you'll need to explicitly map your APNs token to the FCM registration token. Override the methods didRegisterForRemoteNotificationsWithDeviceToken to retrieve the APNs token, and then set FIRMessaging's APNSToken property:

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

// With "FirebaseAppDelegateProxyEnabled": NO
- (void)application:(UIApplication *)application
    didRegisterForRemoteNotificationsWithDeviceToken:(NSData *)deviceToken {
    [FIRMessaging messaging].APNSToken = deviceToken;
}

After the FCM registration token is generated, you can access it and listen for refresh events using the same methods as with swizzling enabled.

Import existing user APNs tokens

If you have an existing user base that you want to onboard to an FCM client app, use the batchImport API provided by Instance ID. With this API, you can bulk import existing iOS APNs tokens into FCM, mapping them to new, valid registration tokens.

Prevent auto initialization

FCM generates an Instance ID, which is used as a registration token within FCM. When an Instance ID is generated the library will upload the identifier and configuration data to Firebase.If you want to get an explicit opt-in before using Instance ID, you can prevent generation at configure time by disabling FCM. To do this, add a metadata value to your Info.plist (not your GoogleService-Info.plist):

FirebaseMessagingAutoInitEnabled = NO

To re-enable FCM, you can make a runtime call:

Messaging.messaging().autoInitEnabled = true

[FIRMessaging messaging].autoInitEnabled = YES;

This value persists across app restarts once set.

Next steps

After you have set up your iOS client, you're ready to add message handling and other, more advanced behavior to your app. See these guides for more information:

• Receive messages in an iOS app
• Send topic messages
• Send to device groups
• Send upstream messages