express_passport_google_oauth2_authentication_quickstart.ts

1import express, { Request, Response } from 'express';
2import passport from 'passport';
3import { Strategy as GoogleStrategy, Profile, VerifyCallback } from 'passport-google-oauth20';
4import session from 'express-session';
5
6const app = express();
7
8// Configure Passport to use Google Strategy
9passport.use(new GoogleStrategy({
10    clientID: process.env['GOOGLE_CLIENT_ID'] || 'YOUR_GOOGLE_CLIENT_ID',
11    clientSecret: process.env['GOOGLE_CLIENT_SECRET'] || 'YOUR_GOOGLE_CLIENT_SECRET',
12    callbackURL: "http://www.example.com/auth/google/callback"
13  },
14  (accessToken: string, refreshToken: string, profile: Profile, cb: VerifyCallback) => {
15    // In a real application, you would find or create a user in your database here
16    // User.findOrCreate({ googleId: profile.id }, function (err, user) {
17    //   return cb(err, user);
18    // });
19    return cb(null, profile);
20  }
21));
22
23// Configure session middleware (required for persistent login sessions)
24app.use(session({ secret: 'keyboard cat', resave: false, saveUninitialized: true }));
25app.use(passport.initialize());
26app.use(passport.session());
27
28// Used to stuff a piece of user profile ID into a cookie
29passport.serializeUser((user: any, done) => {
30  done(null, user);
31});
32
33// Used to decode the received cookie and find user from DB
34passport.deserializeUser((user: any, done) => {
35  done(null, user);
36});
37
38// Route to start authentication with Google
39app.get('/auth/google',
40  passport.authenticate('google', { scope: ['profile', 'email'] }));
41
42// Callback route where Google redirects after authentication
43app.get('/auth/google/callback', 
44  passport.authenticate('google', { failureRedirect: '/login' }),
45  (req: Request, res: Response) => {
46    // Successful authentication, redirect home.
47    res.redirect('/');
48  });
49
50app.listen(3000, () => {
51  console.log('Server started on http://localhost:3000');
52});