中文
devexamples

Firebase Auth Session Token Refresh

Subscribe to Firebase auth state, read the current ID token before each API call, and let the SDK refresh expired tokens transparently.

JavascriptAuth Jwt

Code

snippet
import { initializeApp } from 'firebase/app';
import {
  getAuth, onAuthStateChanged, signInAnonymously,
} from 'firebase/auth';

const app = initializeApp({
  apiKey: process.env.FIREBASE_API_KEY,
  authDomain: 'demo.firebaseapp.com',
  projectId: 'demo-project',
});

const auth = getAuth(app);

onAuthStateChanged(auth, (user) => {
  if (user) {
    console.log('signed in as', user.uid, 'anonymous:', user.isAnonymous);
  } else {
    console.log('signed out');
  }
});

await signInAnonymously(auth);

async function authorizedFetch(path) {
  const user = auth.currentUser;
  if (!user) throw new Error('auth required');

  // getToken 强制刷新已过期的 ID 令牌，保持短期凭证语义
  const token = await user.getIdToken(true);
  const res = await fetch('https://api.example.com' + path, {
    headers: { Authorization: 'Bearer ' + token },
  });
  if (res.status === 401) throw new Error('token rejected upstream');
  return res.json();
}

const profile = await authorizedFetch('/me');
console.log('profile loaded:', Object.keys(profile).length, 'fields');

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