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Cloud Messaging

Installation and getting started with Cloud Messaging.

Installation

This module requires that the @react-native-firebase/app module is already setup and installed. To install the "app" module, view the Getting Started documentation.

# Install & setup the app module
yarn add @react-native-firebase/app

# Install the messaging module
yarn add @react-native-firebase/messaging

# If you're developing your app using iOS, run this command
cd ios/ && pod install

iOS requires further configuration before you can start receiving and sending messages through Firebase. Read the documentation on how to setup iOS with Firebase Cloud Messaging.

If you're using an older version of React Native without auto-linking support, or wish to integrate into an existing project, you can follow the manual installation steps for iOS and Android.

What does it do

React Native Firebase provides native integration of Firebase Cloud Messaging (FCM) for both Android & iOS. FCM is a cost free service, allowing for server-device and device-device communication. The React Native Firebase Messaging module provides a simple JavaScript API to interact with FCM.

The module also provides basic support for displaying local notifications, to learn more view the Notifications documentation.

Usage

iOS - Requesting permissions

iOS prevents messages containing notification (or 'alert') payloads from being displayed unless you have received explicit permission from the user.

To learn more about local notifications, view the Notifications documentation.

This module provides a requestPermission method which triggers a native permission dialog requesting the user's permission:

import messaging, { AuthorizationStatus } from '@react-native-firebase/messaging';

async function requestUserPermission() {
  const authStatus = await messaging().requestPermission();
  const enabled =
    authStatus === AuthorizationStatus.AUTHORIZED ||
    authStatus === AuthorizationStatus.PROVISIONAL;

  if (enabled) {
    console.log('Authorization status:', authStatus);
  }
}

The permissions API for iOS provides much more fine-grain control over permissions and how they're handled within your application. To learn more, view the advanced iOS Permissions documentation.

On Android, you do not need to request user permission. This method can still be called on Android devices; however, and will always resolve successfully.

Receiving messages

FCM messages can be sent to devices via a number of methods (see below). A message is simply a payload of data which can be used however you see fit within your application. Common use-cases for handling messages could be:

  • Displaying a notification (see Notifications).
  • Syncing message data silently on the device (e.g. via AsyncStorage).
  • Updating the application's UI.

To learn about how to send messages to devices from your own server setup, view the Server Integration documentation.

Depending on the devices state, incoming messages are handled differently by the device and module. To understand these scenarios, it is first important to establish the various states a device can be in:

StateDescription
ForegroundWhen the application is open and in view.
BackgroundWhen the application is open, however in the background (minimised). This typically occurs when the user has pressed the "home" button on the device or has switched to another app via the app switcher.
QuitWhen the device is locked or application is not active or running. The user can quit an app by "swiping it away" via the app switcher UI on the device.

The user must have opened the app before messages can be received. If the user force quits the app from the device settings, it must be re-opened again before receiving messages.

Depending on the contents of the message, it's important to understand both how the device will handle the message (e.g. display a notification, or even ignore it) and also how the library sends events to your own listeners.

Message handlers

The device state and message contents determines which handler will be called:

ForegroundBackgroundQuit
NotificationonMessagesetBackgroundMessageHandlersetBackgroundMessageHandler
Notification + DataonMessagesetBackgroundMessageHandlersetBackgroundMessageHandler
DataonMessagesetBackgroundMessageHandler (see below)setBackgroundMessageHandler (see below)
  • In cases where the message is data-only and the device is in the background or quit, both Android & iOS treat the message as low priority and will ignore it (i.e. no event will be sent). You can however increase the priority by setting the priority to high (Android) and content-available to true (iOS) properties on the payload.

To learn more about how to send these options in your message payload, view the Firebase documentation for your FCM API implementation.

Notifications

The device state and message contents can also determine whether a Notification will be displayed:

ForegroundBackgroundQuit
NotificationNotification: ❌Notification: ✅Notification: ✅
Notification + DataNotification: ❌Notification: ✅Notification: ✅
DataNotification: ❌Notification: ❌Notification: ❌

Foreground state messages

To listen to messages in the foreground, call the onMessage method inside of your application code. Code executed via this handler has access to React context and is able to interact with your application (e.g. updating the state or UI).

For example, the React Native Alert API could be used to display a new Alert each time a message is delivered'

import React, { useEffect } from 'react';
import { Alert } from 'react-native';
import messaging from '@react-native-firebase/messaging';

function App() {
  useEffect(() => {
    const unsubscribe = messaging().onMessage(async remoteMessage => {
      Alert.alert('A new FCM message arrived!', JSON.stringify(remoteMessage));
    });

    return unsubscribe;
  }, []);
}

The remoteMessage property contains all of the information about the message sent to the device from FCM, including any custom data (via the data property) and notification data. To learn more, view the RemoteMessage API reference.

If the RemoteMessage payload contains a notification property when sent to the onMessage handler, the device will not show any notification to the user. Instead, you could trigger a local notification or update the in-app UI to signal a new notification.

Background & Quit state messages

When the application is in a background or quit state, the onMessage handler will not be called when receiving messages. Instead, you need to setup a background callback handler via the setBackgroundMessageHandler method.

To setup a background handler, call the setBackgroundMessageHandler outside of your application logic as early as possible:

// index.js
import { AppRegistry } from 'react-native';
import messaging from '@react-native-firebase/messaging';
import App from './App';

// Register background handler
messaging().setBackgroundMessageHandler(async remoteMessage => {
  console.log('Message handled in the background!', remoteMessage);
});

AppRegistry.registerComponent('app', () => App);

The handler must return a promise once your logic has completed to free up device resources. It must not attempt to update any UI (e.g. via state) - you can however perform network requests, update local storage etc.

The remoteMessage property contains all of the information about the message sent to the device from FCM, including any custom data via the data property. To learn more, view the RemoteMessage API reference.

If the RemoteMessage payload contains a notification property when sent to the setBackgroundMessageHandler handler, the device will have displayed a notification to the user.

Data-only messages

When an incoming message is "data-only" (contains no notification option), both Android & iOS regard it as low priority and will prevent the application from waking (ignoring the message). To allow data-only messages to trigger the background handler, you must set the "priority" to "high" on Android, and enable the content-available flag on iOS. For example, if using the Node.js firebase-admin package to send a message:

admin.messaging().sendToDevice(
  [], // device fcm tokens...
  {
    data: {
      owner: JSON.stringify(owner),
      user: JSON.stringify(user),
      picture: JSON.stringify(picture),
    },
  },
  {
    // Required for background/quit data-only messages on iOS
    contentAvailable: true,
    // Required for background/quit data-only messages on Android
    priority: 'high',
  },
);

These options can be applied to all FCM messages. View the Server Integration documentation to learn more about other available SDKs.

Background Application State

Although the library supports handling messages in background/quit states, the underlying implementation on how this works is different on Android & iOS.

On Android, a Headless JS task (an Android only feature) is created that runs separately to your main React component; allowing your background handler code to run without mounting your root component.

On iOS however, when a message is received the device silently starts your application in a background state. At this point, your background handler (via setBackgroundMessageHandler) is triggered, but your root React component also gets mounted. This can be problematic for some users since any side-effects will be called inside of your app (e.g. useEffects, analytics events/triggers etc). To get around this problem, the messaging module injects a isHeadless prop to your root component which you can conditionally use to render/do "nothing" if your app is launched in the background:

// index.js
import { AppRegistry } from 'react-native';
import messaging from '@react-native-firebase/messaging';

messaging().setBackgroundMessageHandler(async remoteMessage => {
  console.log('Message handled in the background!', remoteMessage);
});

function HeadlessCheck({ isHeadless }) {
  if (isHeadless) {
    // App has been launched in the background by iOS, ignore
    return null;
  }

  return <App />;
}

function App{) {
  // Your application
}

AppRegistry.registerComponent('app', () => HeadlessCheck);

On Android, this prop will not exist.

Topics

Topics are a mechanism which allow a device to subscribe and unsubscribe from named PubSub channels, all managed via FCM. Rather than sending a message to a specific device by FCM token, you can instead send a message to a topic and any devices subscribed to that topic will receive the message.

Topics allow you to simplify FCM server integration as you do not need to keep a store of device tokens. There are however some things to keep in mind about topics:

  • Messages sent to topics should not contain sensitive or private information. Do not create a topic for a specific user to subscribe to.
  • Topic messaging supports unlimited subscriptions for each topic.
  • One app instance can be subscribed to no more than 2000 topics.
  • The frequency of new subscriptions is rate-limited per project. If you send too many subscription requests in a short period of time, FCM servers will respond with a 429 RESOURCE_EXHAUSTED ("quota exceeded") response. Retry with exponential backoff.
  • A server integration can send a single message to multiple topics at once. This however is limited to 5 topics.

To learn more about how to send messages to devices subscribed to topics, view the Send messages to topics documentation.

Subscribing to topics

To subscribe a device, call the subscribeToTopic method with the topic name:

messaging()
  .subscribeToTopic('weather')
  .then(() => console.log('Subscribed to topic!'));
Unsubscribing to topics

To unsubscribe from a topic, call the unsubscribeFromTopic method with the topic name:

messaging()
  .unsubscribeFromTopic('weather')
  .then(() => console.log('Unsubscribed fom the topic!'));

firebase.json

Messaging can be further configured to provide more control over how FCM is handled internally within your application.

Auto Registration (iOS)

React Native Firebase Messaging automatically registers the device with APNs to receive remote messages. If you need to manually control registration you can disable this via the firebase.json file:

// <projectRoot>/firebase.json
{
  "react-native": {
    "messaging_ios_auto_register_for_remote_messages": false
  }
}

Once auto-registration is disabled you must manually call registerDeviceForRemoteMessages in your JavaScript code as early as possible in your application startup;

import messaging from '@react-native-firebase/messaging';

async function registerAppWithFCM() {
  await messaging().registerDeviceForRemoteMessages();
}

Auto initialization

Firebase generates an Instance ID, which FCM uses to generate a registration token and which Analytics uses for data collection. When an Instance ID is generated, the library will upload the identifier and configuration data to Firebase. In most cases, you do not need to change this behavior.

If you prefer to prevent Instance ID auto-generation, disable auto initialization for FCM and Analytics:

// <projectRoot>/firebase.json
{
  "react-native": {
    "analytics_auto_collection_enabled": false,
    "messaging_auto_init_enabled": false
  }
}

To re-enable initialization (e.g. once requested permission) call the messaging().setAutoInitEnabled(true) method.

Background handler timeout (Android)

On Android, a background event sent to setBackgroundMessageHandler has 60 seconds to resolve before it is automatically canceled to free up device resources. If you wish to override this value, set the number of milliseconds in your config:

// <projectRoot>/firebase.json
{
  "react-native": {
    "messaging_android_headless_task_timeout": 30000
  }
}

Notification Channel ID

On Android, any message which displays a Notification use a default Notification Channel (created by FCM called "Miscellaneous"). This channel contains basic notification settings which may not be appropriate for your application. You can change what Channel is used by updating the messaging_android_notification_channel_id property:

// <projectRoot>/firebase.json
{
  "react-native": {
    "messaging_android_notification_channel_id": "high-priority"
  }
}

Creating and managing Channels is outside of the scope of the React Native Firebase library, however external libraries such as Notifee can provide such functionality.

Notification Color

On Android, any messages which display a Notification do not use a color to tint the content (such as the small icon, title etc). To provide a custom tint color, update the messaging_android_notification_color property with a Android color resource name.

The library provides a set of default HTML colors (in lowercase) for ease, for example:

// <projectRoot>/firebase.json
{
  "react-native": {
    "messaging_android_notification_color": "@color/hotpink"
  }
}