index.js

/*
Copyright 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance with the License. A copy of the License is located at

    http://aws.amazon.com/apache2.0/

or in the "license" file accompanying this file. This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

*/

// Define our dependencies
var express        = require('express');
var session        = require('express-session');
var passport       = require('passport');
var OAuth2Strategy = require('passport-oauth').OAuth2Strategy;
var request        = require('request');
var handlebars     = require('handlebars');

// Define our constants, you will change these with your own
const TWITCH_CLIENT_ID = process.env.TWITCH_CLIENT_ID
const TWITCH_SECRET    = process.env.TWITCH_SECRET
const SESSION_SECRET   = 'mybattlebitsecret';
const CALLBACK_URL     = 'http://localhost:3000/auth/twitch/callback';
const port             = process.env.PORT;

// Initialize Express and middlewares
var app = express();
app.use(session({secret: SESSION_SECRET, resave: false, saveUninitialized: false}));
app.use(express.static("public"));
app.use(passport.initialize());
app.use(passport.session());
app.set("view engine", "ejs");

// Override passport profile function to get user profile from Twitch API
OAuth2Strategy.prototype.userProfile = function(accessToken, done) {
  var options = {
    url: 'https://api.twitch.tv/helix/users',
    method: 'GET',
    headers: {
      'Client-ID': TWITCH_CLIENT_ID,
      'Accept': 'application/vnd.twitchtv.v5+json',
      'Authorization': 'Bearer ' + accessToken
    }
  };

  request(options, function (error, response, body) {
    if (response && response.statusCode == 200) {
      done(null, JSON.parse(body));
    } else {
      done(JSON.parse(body));
    }
  });
}

passport.serializeUser(function(user, done) {
    done(null, user);
});

passport.deserializeUser(function(user, done) {
    done(null, user);
});

passport.use('twitch', new OAuth2Strategy({
    authorizationURL: 'https://id.twitch.tv/oauth2/authorize',
    tokenURL: 'https://id.twitch.tv/oauth2/token',
    clientID: TWITCH_CLIENT_ID,
    clientSecret: TWITCH_SECRET,
    callbackURL: CALLBACK_URL,
    state: true
  },
  function(accessToken, refreshToken, profile, done) {
    profile.accessToken = accessToken;
    profile.refreshToken = refreshToken;


    done(null, profile);
  }
));

// Set route to start OAuth link, this is where you define scopes to request
app.get('/auth/twitch', passport.authenticate('twitch', { scope: 'user_read' }));

// Set route for OAuth redirect
app.get('/auth/twitch/callback', passport.authenticate('twitch', { successRedirect: '/', failureRedirect: '/' }));

// If user has an authenticated session, display it, otherwise display link to authenticate
app.get('/', function (req, res) {
  if(req.session && req.session.passport && req.session.passport.user) {
    const userData = req.session.passport.user;
    console.log(JSON.stringify(userData));
    res.render("index",{userData});
  }
});

app.listen(port, function () {
  console.log('Twitch auth sample listening on port '+port+'!')
});