Demander l'autorisation et obtenir un jeton push
Utilisez expo-notifications pour demander l'autorisation d'envoyer des notifications, récupérez le jeton push Expo, puis envoyez-le à votre serveur principal pour le stocker.
Demander l'autorisation et obtenir un jeton push est une leçon React Native Academy gratuite sur CoddyKit. Ceci est la leçon 1 sur 4. Tu peux lire la leçon complète ci-dessous gratuitement — puis la pratiquer en direct dans le navigateur avec un éditeur de code intégré et un tuteur IA 24/7. Elle fait partie du parcours d'apprentissage React Native Academy, et ta progression se synchronise sur le web et l'application CoddyKit. Le cours React Native Academy comprend 4 leçons au total.
Certaines parties de cette leçon n'ont pas encore été traduites et s'affichent en anglais.
What Are Push Notifications?
Push notifications are messages sent from your server to a user's device even when the app is closed. They appear in the device's notification center, show on the lock screen, and can trigger a badge count on the app icon. On mobile they are one of the most powerful re-engagement tools available.
The flow for push notifications involves three parties: your app (registers the device), your server (decides when to send), and a push gateway (Apple APNs for iOS, Google FCM for Android). Expo wraps both gateways with a unified push service.
Installing expo-notifications
The expo-notifications package provides a unified API for push notifications on both iOS and Android. Install it with the Expo CLI, which handles installing the correct native version for your Expo SDK.
Push notifications require a development build (not Expo Go) because they need APNs entitlements embedded in the iOS app binary. Android push works in Expo Go but iOS does not. For production, EAS Build handles the certificate configuration automatically.
// Install:
// npx expo install expo-notifications
// In app.json, configure notification appearance:
{
'expo': {
'notification': {
'icon': './assets/notification-icon.png',
'color': '#ffffff',
'androidMode': 'default',
'androidCollapsedTitle': '#{unread_notifications} new updates'
}
}
}Requesting Notification Permission
Before sending or receiving notifications, you must request permission from the user. On iOS this shows the system permission dialog the first time. On Android 13+ (API 33+) you must also explicitly request permission; on older Android versions it's granted automatically.
Use Notifications.requestPermissionsAsync() and check the returned status. The status is 'granted', 'denied', or 'undetermined'. If denied, the user must manually re-enable in Settings — you cannot show the dialog again.
import * as Notifications from 'expo-notifications';
async function requestPushPermission() {
const { status: existingStatus } = await Notifications.getPermissionsAsync();
let finalStatus = existingStatus;
if (existingStatus !== 'granted') {
const { status } = await Notifications.requestPermissionsAsync();
finalStatus = status;
}
if (finalStatus !== 'granted') {
console.log('Push permission denied');
return false;
}
return true;
}Getting the Expo Push Token
An Expo Push Token is a unique identifier for the app+device+user combination. It looks like ExponentPushToken[xxxxxxxxxxxxxxxxxxxxxx]. You pass this token to your server so it can send notifications to this specific device later.
Use Notifications.getExpoPushTokenAsync() to retrieve the token. This must be called after permission is granted. For production (non-Expo) builds you also need to provide the projectId from your Expo project.
import * as Notifications from 'expo-notifications';
import Constants from 'expo-constants';
async function getExpoPushToken() {
const token = await Notifications.getExpoPushTokenAsync({
projectId: Constants.expoConfig.extra.eas.projectId,
});
console.log('Push token:', token.data);
// 'ExponentPushToken[AbCdEfGhIjKl...]'
return token.data;
}Storing the Token on Your Server
The push token is only useful if your server has it. After retrieving the token, send it to your backend via an API call and store it associated with the user account. A user might use multiple devices — store one token per device per user.
Tokens can change — when a user reinstalls the app or resets their device. Build your server to handle token updates: either overwrite the old token for the same user, or store multiple tokens per user and handle invalid token responses from the push gateway by removing stale tokens.
async function registerForPushNotifications(userId) {
const hasPermission = await requestPushPermission();
if (!hasPermission) return;
const token = await getExpoPushToken();
// Send to your backend:
await fetch('https://api.myapp.com/users/' + userId + '/push-token', {
method: 'POST',
headers: { 'Content-Type': 'application/json' },
body: JSON.stringify({ token }),
});
}Calling Registration at the Right Time
Call the registration function at an appropriate moment in the user journey — typically right after the user logs in or completes onboarding. Requesting push permission too early (on app first launch) before the user understands the app's value reduces acceptance rates.
Use a useEffect in your authenticated root component to trigger registration once when the user is authenticated. Persist the registration status in AsyncStorage to avoid requesting permission on every launch.
import { useEffect } from 'react';
import AsyncStorage from '@react-native-async-storage/async-storage';
function usePostLoginPushRegistration(userId) {
useEffect(() => {
if (!userId) return;
AsyncStorage.getItem('pushRegistered').then((registered) => {
if (!registered) {
registerForPushNotifications(userId).then(() => {
AsyncStorage.setItem('pushRegistered', 'true');
});
}
});
}, [userId]);
}Android-Specific: Notification Channels
Android 8+ requires notification channels — logical groupings that give users fine-grained control over which types of notifications they receive. Create channels with Notifications.setNotificationChannelAsync() before sending any notifications. On iOS this is not needed.
Use descriptive channel IDs and names that mean something to users in the Settings notification page. For example, messages, promotions, and system. Assign appropriate importance levels — HIGH for urgent notifications, DEFAULT for standard ones.
import * as Notifications from 'expo-notifications';
import { Platform } from 'react-native';
async function setupNotificationChannels() {
if (Platform.OS === 'android') {
await Notifications.setNotificationChannelAsync('messages', {
name: 'Messages',
importance: Notifications.AndroidImportance.HIGH,
vibrationPattern: [0, 250, 250, 250],
lightColor: '#FF231F7C',
});
await Notifications.setNotificationChannelAsync('promotions', {
name: 'Promotions',
importance: Notifications.AndroidImportance.DEFAULT,
});
}
}Configuring Notification Presentation
By default, expo-notifications does not show notifications when the app is in the foreground. Configure the default notification handler with Notifications.setNotificationHandler to control this behavior. Set at the top level of your app, before any components mount.
The handler function receives each notification and returns a config object specifying whether to play a sound, show an alert, and set the badge count. Set up this handler once in your app entry file (App.js or index.js).
import * as Notifications from 'expo-notifications';
// At app root level (outside components):
Notifications.setNotificationHandler({
handleNotification: async () => ({
shouldShowAlert: true,
shouldPlaySound: true,
shouldSetBadge: true,
}),
});
export default function App() {
return <NavigationContainer>...</NavigationContainer>;
}Getting a Native Device Token
For production apps not using Expo's push service (e.g., integrating directly with APNs or FCM), use Notifications.getDevicePushTokenAsync() instead of the Expo push token. This returns the raw APNs or FCM device token that you can pass directly to those services.
The native token is a hexadecimal string (iOS) or registration token (Android). Handle both cases on your server. When using native tokens you must also handle the certificate/key setup for APNs and the google-services.json for FCM separately.
// For direct APNs/FCM integration (not Expo push service):
const nativeToken = await Notifications.getDevicePushTokenAsync();
console.log('Native token type:', nativeToken.type); // 'ios' or 'android'
console.log('Native token data:', nativeToken.data); // raw APNs/FCM token
// Send to your server for direct gateway integration:Handling Token Refresh
Push tokens can be invalidated and refreshed by the OS — for example when the user restores from a backup, reinstalls the app, or resets their device. Listen for token changes with Notifications.addPushTokenListener and update your server with the new token when this fires.
A robust push notification system always handles token refresh. Unregistered tokens cause silent delivery failures on your server. Clean up stale tokens from your database when the push gateway returns a DeviceNotRegistered error.
useEffect(() => {
const tokenSubscription = Notifications.addPushTokenListener(
async ({ data: newToken }) => {
console.log('Push token refreshed:', newToken);
// Update server with new token
await fetch('/api/push-token/refresh', {
method: 'PUT',
body: JSON.stringify({ token: newToken }),
});
}
);
return () => tokenSubscription.remove();
}, []);Privacy and Best Practices
Push token management best practices:
- Never log tokens in production — they are credentials that identify specific devices.
- Encrypt tokens at rest on your server — a leaked token database can enable notification spam.
- Associate tokens with users — delete tokens when users delete their account or opt out of notifications.
- Batch token updates — don't call the server on every app launch, only when the token changes or at first registration.
- Respect user preferences — provide in-app notification settings and honor them on your server.
Quick Check
Test your understanding of React Native Mobile Development concepts from this lesson.
Lesson Recap
In this lesson you learned: Notifications.requestPermissionsAsync() requests OS permission and must be granted before getting a push token, Notifications.getExpoPushTokenAsync() returns a token like ExponentPushToken[...] that identifies the device to your backend, and tokens must be stored on your server and updated when they change to maintain reliable delivery. Next up we send push notifications to devices using the Expo Push API from a server.
Questions Fréquemment Posées
La leçon « Demander l'autorisation et obtenir un jeton push » est-elle gratuite ?
Oui — le texte complet de « Demander l'autorisation et obtenir un jeton push » est gratuit à lire ici sur le web. Pour la pratiquer de manière interactive (un éditeur de code intégré et un tuteur IA 24/7) et déverrouiller le reste du cours React Native Academy, passe à CoddyKit PRO. Le cours React Native Academy comprend 4 leçons au total.
Qu'est-ce que j'apprendrai dans « Demander l'autorisation et obtenir un jeton push » ?
Utilisez expo-notifications pour demander l'autorisation d'envoyer des notifications, récupérez le jeton push Expo, puis envoyez-le à votre serveur principal pour le stocker. Tu pratiques React Native Academy avec du code pratique que tu exécutes directement dans le navigateur, et un tuteur IA 24/7 répond à tes questions au fur et à mesure que tu avances dans la leçon.
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Aucune expérience préalable n'est requise. React Native Academy sur CoddyKit est structuré pour les débutants jusqu'aux apprenants avancés, donc tu peux commencer ici ou depuis le début et avancer à ton rythme. Ceci est la leçon 1 sur 4.
Combien de temps prend la leçon « Demander l'autorisation et obtenir un jeton push » ?
La plupart des leçons CoddyKit prennent environ 5–10 minutes. Chacune est courte et interactive, tu progresses régulièrement et tu repiques exactement où tu t'es arrêté sur le web et l'app.
Peux-tu écrire et exécuter du code dans cette leçon React Native Academy ?
Oui. Chaque leçon React Native Academy inclut un éditeur de code intégré, tu écris et exécutes du vrai code directement dans ton navigateur et tu reçois des retours IA instantanés — aucune configuration locale requise.
Toutes les leçons de ce cours
- Demander l'autorisation et obtenir un jeton push
- Envoyer des notifications via l'API Push d'Expo
- Gérer les notifications au premier plan et en arrière-plan
- Canaux de notification et contenu enrichi