Set up a Firebase Cloud Messaging client app with C++ (original) (raw)

To write your cross-platform Firebase Cloud Messaging client app with C++, use theFirebase Cloud Messaging API. The C++ SDK works for both Android and Apple platforms, with some additional setup required for each platform.

Set up Firebase and the FCM SDK

Android

1. If you haven't already,add Firebase to your C++ project.
   • In the linked setup instructions, review the device and app requirements for using the Firebase C++ SDK, including the recommendation to use CMake to build your app.
   • In your project-level build.gradle file, make sure to include Google's Maven repository in both your buildscript andallprojects sections.
2. Create a Firebase App object, passing in the JNI environment and Activity:
   app = ::firebase::App::Create(::firebase::AppOptions(), jni_env, activity);
3. Define a class that implements the firebase::messaging::Listenerinterface.
4. Initialize FCM, passing in the App and a constructed Listener:
   ::firebase::messaging::Initialize(app, listener);
5. Apps that rely on the Google Play services SDK should check the device for a compatible Google Play services APK before accessing the features. To learn more, refer toCheck for Google Play services APK.

iOS+

1. If you haven't already,add Firebase to your C++ project. Then, to set up your project for FCM:
   1. In your project's Podfile, add the FCM dependency:
      pod 'FirebaseMessaging'
   2. Drag the firebase.framework and firebase_messaging.frameworkframeworks into your Xcode project from the Firebase C++ SDK.
2. Upload your APNs authentication key to Firebase. If you don't already have an APNs authentication key, make sure to create one in theApple Developer Member Center.
   1. Inside your project in the Firebase console, select the gear icon, selectProject Settings, and then select theCloud 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 clickOpen. Add the key ID for the key (available in the Apple Developer Member Center) and clickUpload.
3. Configure your Xcode project to enable Push Notifications:
   1. Select the project from the Navigator area.
   2. Select the project target from the Editor area.
   3. Select the General tab from the Editor area.
      1. Scroll down to Linked Frameworks and Libraries, then click the + button to add frameworks.
      2. In the window that appears, scroll toUserNotifications.framework, click on that entry, then clickAdd.
         This framework only appears in Xcode v8 and later and is required by this library.
   4. Select the Capabilities tab from the Editor area.
      1. Switch Push Notifications to On.
      2. Scroll down to Background Modes, then switch it to On.
      3. Select Remote notifications under Background Modes.
4. Create a Firebase App object:
   app = ::firebase::App::Create(::firebase::AppOptions());
5. Define a class that implements the firebase::messaging::Listenerinterface.
6. Initialize Firebase Cloud Messaging, passing in the App and a constructed Listener:
   ::firebase::messaging::Initialize(app, listener);

Access the device registration token

Upon initializing the Firebase Cloud Messaging library, a registration token is requested for the client app instance. The app will receive the token with theOnTokenReceived callback, which should be defined in the class that implementsfirebase::messaging::Listener.

If you want to target that specific device, you'll need access to this token.

Note about message delivery on Android

When the app is not running at all and a user taps on a notification, the message is not, by default, routed through FCM's built in callbacks. In this case, message payloads are received through an Intentused to start the application. To have FCM forward these incoming messages to the C++ library callback, you need to override the methodonNewIntent in your Activity and pass the Intent to theMessageForwardingService.

import com.google.firebase.messaging.MessageForwardingService;

class MyActivity extends Activity { private static final String TAG = "MyActvity";

@Override protected void onNewIntent(Intent intent) { Log.d(TAG, "A message was sent to this app while it was in the background."); Intent message = new Intent(this, MessageForwardingService.class); message.setAction(MessageForwardingService.ACTION_REMOTE_INTENT); message.putExtras(intent); message.setData(intent.getData()); // For older versions of Firebase C++ SDK (< 7.1.0), use startService. // startService(message); MessageForwardingService.enqueueWork(this, message); } }

Messages received while the app is in the background have the content of their notification field used to populate the system tray notification, but that notification content will not be communicated to FCM. That is,Message::notification will be a null.

In summary:

Custom Message Handling on Android

By default, notifications sent to the app are passed to::firebase::messaging::Listener::OnMessageReceived, but in some cases you may want to override the default behavior. To do this on Android you will need to write custom classes that extendcom.google.firebase.messaging.cpp.ListenerService as well as update your project's AndroidManifest.xml.

Override ListenerService Methods.

The ListenerService is the Java class that intercepts incoming messages sent to the app and routes them to the C++ library. When the app is in the foreground (or when the app is the background and it receives a data-only payload), messages will pass through one of the callbacks provided on this class. To add custom behavior to the message handling, you will need to extend FCM's default ListenerService:

import com.google.firebase.messaging.cpp.ListenerService;

class MyListenerService extends ListenerService {

By overriding the method ListenerService.onMessageReceived, you can perform actions based on the receivedRemoteMessageobject and get the message data:

@Override public void onMessageReceived(RemoteMessage message) { Log.d(TAG, "A message has been received."); // Do additional logic... super.onMessageReceived(message); }

ListenerService also has a few other methods that are used less frequently. These can be overridden as well, for more information see theFirebaseMessagingServicereference.

@Override public void onDeletedMessages() { Log.d(TAG, "Messages have been deleted on the server."); // Do additional logic... super.onDeletedMessages(); }

@Override public void onMessageSent(String messageId) { Log.d(TAG, "An outgoing message has been sent."); // Do additional logic... super.onMessageSent(messageId); }

@Override public void onSendError(String messageId, Exception exception) { Log.d(TAG, "An outgoing message encountered an error."); // Do additional logic... super.onSendError(messageId, exception); }

Update AndroidManifest.xml

Once your custom classes have been written, they must be included in theAndroidManifest.xml to take effect. Ensure that the manifest includes the merge tools by declaring the appropriate attribute inside the <manifest> tag, like so:

In the firebase_messaging_cpp.aar archive there is an AndroidManifest.xmlfile which declares FCM's default ListenerService. This manifest is normally merged with the project specific manifest which is how theListenerService is able to run. This ListenerService needs to replaced with the cusom listener service. That is accomplished by removing the defaultListenerService and adding the custom Service, which can be done with the following lines your projects AndroidManifest.xml file:

New versions of Firebase C++ SDK (7.1.0 onwards) use JobIntentService which requires additional modifications in AndroidManifest.xml file.

Prevent auto initialization

FCM generates a registration token for device targeting. When a token is generated, the library uploads the identifier and configuration data to Firebase. If you want to get an explicit opt-in before using the token, you can prevent generation at configure time by disabling FCM (and on Android, Analytics). To do this, add a metadata value to your Info.plist (not your GoogleService-Info.plist) on Apple platforms, or your AndroidManifest.xml on Android:

Android

Swift

FirebaseMessagingAutoInitEnabled = NO

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

::firebase::messaging::SetTokenRegistrationOnInitEnabled(true);

This value persists across app restarts once set.

Handling Messages with Deep Links on Android

FCM allows messages to be sent containing a deep link into your app. To receive messages that contain a deep link, you must add a new intent filter to the activity that handles deep links for your app. The intent filter should catch deep links of your domain. If your messages do not contain a deep link, this configuration is not necessary. In AndroidManifest.xml:

It is also possible to specify a wildcard to make the intent filter more flexible. For example:

When users tap a notification containing a link to the scheme and host you specify, your app will start the activity with this intent filter to handle the link.

Next steps

After setting up the client app, you are ready to send downstream and topic messages with the Firebase. To learn more, see this functionality demonstrated in thequickstart samplewhich you can download, run, and review.

To add other, more advanced behavior to your app see the guides for sending messages from an app server:

• Send topic messages
• Send to device groups

Keep in mind that you'll need aserver implementation to make use of these features.