Node.js and express - Authenticating through OAuth

From github for oAuth2 with Passport https://github.com/jaredhanson/passport-oauth2

Configure the startegy

passport.use(new OAuth2Strategy({
    authorizationURL: 'https://www.example.com/oauth2/authorize',
    tokenURL: 'https://www.example.com/oauth2/token',
    clientID: EXAMPLE_CLIENT_ID,
    clientSecret: EXAMPLE_CLIENT_SECRET,
    callbackURL: "http://localhost:3000/auth/example/callback"
  },
  function(accessToken, refreshToken, profile, cb) {
    User.findOrCreate({ exampleId: profile.id }, function (err, user) {
      return cb(err, user);
    });
  }
));

Now you can authenticate the endpoints either on a global scope

express.use(passport.authenticate('oauth2'));

or on a route specific location

app.get('/auth/example',
        passport.authenticate('oauth2'),
        function(req, res) {
   // Your code here
 });