UserController.js

/**
 * UserController
 *
 * @description :: Server-side logic for managing users
 * @help        :: See http://links.sailsjs.org/docs/controllers
 */
 /*
  |--------------------------------------------------------------------------
  | Login with Twitter
  |--------------------------------------------------------------------------
  */

var qs = require('querystring');
var request = require('request');
var jwt = require('jwt-simple');
var moment = require('moment');

module.exports = {
	login: function (req, res) {

   var requestTokenUrl = 'https://api.twitter.com/oauth/request_token';
   var accessTokenUrl = 'https://api.twitter.com/oauth/access_token';
   var profileUrl = 'https://api.twitter.com/1.1/users/show.json?screen_name=';

   // Part 1 of 2: Initial request from Satellizer.
   if (!req.body.oauth_token || !req.body.oauth_verifier) {
     var requestTokenOauth = {
       consumer_key: config.TWITTER_KEY,
       consumer_secret: config.TWITTER_SECRET,
       callback: config.TWITTER_CALLBACK
     };

     // Step 1. Obtain request token for the authorization popup.
     request.post({ url: requestTokenUrl, oauth: requestTokenOauth }, function(err, response, body) {
       var oauthToken = qs.parse(body);

       // Step 2. Send OAuth token back to open the authorization screen.
       res.send(oauthToken);
     });
   } else {
     // Part 2 of 2: Second request after Authorize app is clicked.
     var accessTokenOauth = {
       consumer_key: config.TWITTER_KEY,
       consumer_secret: config.TWITTER_SECRET,
       token: req.body.oauth_token,
       verifier: req.body.oauth_verifier
     };

     // Step 3. Exchange oauth token and oauth verifier for access token.
     request.post({ url: accessTokenUrl, oauth: accessTokenOauth }, function(err, response, accessToken) {

       accessToken = qs.parse(accessToken);

       var profileOauth = {
         consumer_key: config.TWITTER_KEY,
         consumer_secret: config.TWITTER_SECRET,
         oauth_token: accessToken.oauth_token
       };

       // Step 4. Retrieve profile information about the current user.
       request.get({
         url: profileUrl + accessToken.screen_name,
         oauth: profileOauth,
         json: true
       }, function(err, response, profile) {

         // Step 5a. Link user accounts.
         if (req.headers.authorization) {
           User.findOne({ twitter: profile.id }, function(err, existingUser) {
             if (existingUser) {
               return res.status(409).send({ message: 'There is already a Twitter account that belongs to you' });
             }

             var token = req.headers.authorization.split(' ')[1];
             var payload = jwt.decode(token, config.TOKEN_SECRET);

             User.findById(payload.sub, function(err, user) {
               if (!user) {
                 return res.status(400).send({ message: 'User not found' });
               }

               user.twitter = profile.id;
               user.displayName = user.displayName || profile.name;
               user.save(function(err) {
				 if (err) return res.negotiate(err);
                 res.send({
					token: createJWT(user)
				 });
               });
             });
           });
         } else {
           // Step 5b. Create a new user account or return an existing one.
           User.findOne({ twitter: profile.id }, function(err, existingUser) {
             if (existingUser) {
               return res.send({ token: createJWT(existingUser) });
             }

             User.create({
	             twitter: profile.id,
	             displayName: profile.name,
						 }).exec(function (err, user) {
	               res.send({ token: createJWT(user) });
	           });
           });
         }
       });
     });
   }
 }
}

function createJWT(user) {
  var payload = {
    sub: user._id,
    iat: moment().unix(),
    exp: moment().add(14, 'days').unix()
  };
  return jwt.encode(payload, config.TOKEN_SECRET);
}