Push Notifications

FCM and Tokens

Fireflutter uses FCM to send messages to devices.

The tokens are saved under /user-fcm-tokens/<token> { uid: [user uid], platform: [android or ios]}. So, if you want to get the tokens of a user, you must get the tokens by searching the uid.

Subscription

Messages are sent to each user token individually without using topics. Therefore, information about whether a user is subscribed or not needs to be stored in the database. Please refer to the documentation for each feature. Refer to: Board Subscription Refer to: Chat Room Subscription

Sending messages to user

One user may use multiple devices and one device may have multiple tokens. So, if the app sends a message to A, the app must query to get the tokens of A in /user-fcm-tokens

The code below shows how send a message to multiple users.

final List<String> uids = some.users;

//sending notification to the list of uids
await MessagingService.instance.sendTo(
  uids: uids,
  title: '... message title ...',
  body: '... message body ...',
  image: url,
);

To use this method, The firebase cloud function named sendPushNotifications in firebase/functions/src/messaging/functions.ts must be installed. See installation on how to install firebase functions.

Sending messages for forum category subscription and chat room subscription

There are firebase cloud functions that work with Fireflutter for sending messages to subscribers on forum categories and chat rooms.

You will need to install sendMessagesToCategorySubscribers and sendMessagesToChatRoomSubscribers in firebase/functions/src/messaging/functions.ts to make it work.

The source code is under firebase/functions and the test code is under firebase/functions/tests.

Unit testing

See firebase/functions/tests folder for unit testing on push notification. To run the unit test code, you need to set the environment variable - GOOGLE_APPLICATION_CREDENTIAILS

Opening Screen When Message is Tapped in System Tray

When a user taps on a message in the system tray, the app should open pages such as chats, posts, or user profiles.

Internally, when a message is tapped, the push notification data is modeled through parseData.

The screen to which the push notification message is routed will vary depending on each app. You can refer to the example below and modify it accordingly for your use case.

Future<void> _onMessageTapped(RemoteMessage message) async {
  dog("onMessageTapped trigged.");
  dog("onMessageTapped: ${message.data.toString()}");

  final data = MessagingService.instance.parseData(message.data);

  if (data is ChatMessagingModel) {
    ChatService.instance.showChatRoom(
      context: globalContext,
      roomId: data.roomId,
    );
    return;
  }

  if (data is PostMessagingModel) {
    Post? post =
        await Post.get(category: data.category, id: data.id);
    if (post == null) return;
    if (globalContext.mounted) {
      ForumService.instance.showPostViewScreen(
        globalContext,
        post: post,
      );
    }
    return;
  }

  if (data is UserMessagingModel) {
    UserService.instance.showPublicProfileScreen(
      context: globalContext,
      uid: data.uid,
    );
    return;
  }
}