Google Strategy Setup

Google Strategy Setup

To use Google OAuth, you need to register your application with Google and get authentication credentials. Let us walk through the setup.

Step 1: Google Developer Console

1. Go to console.developers.google.com
2. Create a new project (e.g., "OAuth Tutorial")
3. Go to Credentials in the left sidebar
4. Click Create Credentials → OAuth client ID
5. Select Web application
6. Add http://localhost:3000 to Authorized JavaScript origins
7. Add http://localhost:3000/auth/google/redirect to Authorized redirect URIs
8. Click Create

Google gives you a Client ID and Client Secret. Keep the secret safe — never commit it to version control.

Step 2: Enable the API

1. Go to Library in the sidebar
2. Search for "Google+ API" or "Google People API"
3. Click Enable

Step 3: Configure the Strategy

// config/passport-setup.js
const passport = require('passport');
const GoogleStrategy = require('passport-google-oauth20').Strategy;
const keys = require('./keys');

passport.use(
    new GoogleStrategy({
        clientID: keys.google.clientID,
        clientSecret: keys.google.clientSecret,
        callbackURL: '/auth/google/redirect'
    }, function(accessToken, refreshToken, profile, done) {
        console.log(profile);
    })
);

Step 4: Update the Auth Route

// routes/auth-routes.js
const passport = require('passport');

// Auth with Google
router.get('/google', passport.authenticate('google', {
    scope: ['profile', 'email']
}));

// Callback
router.get('/google/redirect', passport.authenticate('google'),
    function(req, res) {
        res.send('You reached the callback');
    }
);

The scope array tells Google what data you want access to. profile gives you the user's name and photo; email gives you their email address.

Key Takeaways

• Register your app in the Google Developer Console to get a Client ID and Secret
• The Redirect URI must match exactly — including the path and protocol
• Enable the Google+ API or People API for profile access
• passport.authenticate('google', { scope }) triggers the redirect to Google