How do I implement OAuth authentication in an Express app?

How do I implement OAuth authentication in an Express app?

To implement OAuth authentication in an Express app, you can use the 'passport' library along with 'passport-oauth' strategies.

What are the steps to set up Passport for OAuth?

First, install Passport and the required OAuth strategy. Then, configure Passport with your OAuth provider's credentials.

Can you show me a code example?

Sure! Here's a basic example:

const passport = require('passport');
const OAuth2Strategy = require('passport-oauth2');

passport.use(new OAuth2Strategy({
  authorizationURL: 'https://provider.com/oauth2/authorize',
  tokenURL: 'https://provider.com/oauth2/token',
  clientID: 'your-client-id',
  clientSecret: 'your-client-secret',
  callbackURL: 'http://localhost:3000/auth/provider/callback'
}, function(accessToken, refreshToken, profile, done) {
  // User authentication logic here
}));

This sets up the OAuth strategy.

What if I want to use Google as my OAuth provider?

You can use 'passport-google-oauth20' for Google. Just install it and configure it similarly with your Google credentials.