How do I implement OAuth authentication in a Node.js Express app?

How do I implement OAuth authentication in a Node.js Express app?

To implement OAuth authentication in a Node.js Express app, you can use the 'passport' library along with 'passport-oauth' strategy.

Can you provide a code example for that?

Sure! First, install the necessary packages: npm install passport passport-oauth. Then, set up your passport strategy like this:

const passport = require('passport');
const OAuthStrategy = require('passport-oauth').OAuthStrategy;

passport.use(new OAuthStrategy({
    requestTokenURL: 'https://provider.com/oauth/request_token',
    accessTokenURL: 'https://provider.com/oauth/access_token',
    userAuthorizationURL: 'https://provider.com/oauth/authorize',
    consumerKey: 'your-consumer-key',
    consumerSecret: 'your-consumer-secret',
    callbackURL: 'http://localhost:3000/auth/callback'
  },
  function(token, tokenSecret, profile, done) {
    // User authentication logic here
  }
));

What do I need to do for user authentication logic?

You typically need to find or create a user in your database based on the profile information returned by the OAuth provider. If the user exists, you can log them in; if not, you may want to create a new user.