Local Twitter Auth

tw-auth.js

var open = require('open');
var url = require('url');
var http = require('http');
var twitterAPI = require('node-twitter-api');
var Q = require('q');

var authObject = (function () {
  var deferred = Q.defer();
  var twitter = {};
  var token = {};

  var options = {
    host: 'twitter.com',
    path: '/oauth/authenticate?oauth_token='
  };

  var httpcallback = function(response) {
    var str = '';

    //another chunk of data has been recieved, so append it to `str`
    response.on('data', function (chunk) {
      str += chunk;
    });

    //the whole response has been recieved, so we just print it out here
    response.on('end', function () {
      open(this.req.res.headers.location);
    });
  }

  var svr = http.createServer(function(request, response) {
    var url_parts = url.parse(request.url, true);
    var query = url_parts.query;
    if(query != undefined) { 
      token.oauth_token = query.oauth_token;
      token.oauth_verifier = query.oauth_verifier;
      getAccessToken();
    }
    response.writeHead(200, {'Content-Type': 'text/plain'});
    response.write('Request Complete');
    response.end();
  }).listen(8888);

  function auth(consumerKey, consumerSecret) {
    twitter =  new twitterAPI({
      consumerKey    : consumerKey,
      consumerSecret : consumerSecret,
      callback       : 'http://127.0.0.1:8888/auth'
    });

    twitter.getRequestToken(function(error, requestToken, requestTokenSecret, results){
      if (error) {
        console.log('auth',"Error getting OAuth request token : " + error);
        deferred.reject(new Error("Status code was " + error));
      } else {
        //store token and tokenSecret somewhere, you'll need them later; redirect user
        token.requestToken = requestToken;
        token.requestTokenSecret = requestTokenSecret;
        token.stepOneResults = results;
        deferred.notify("Request Tokens successful. Awaiting callback.");  
        options.path += requestToken;    
        http.request(options, httpcallback).end();
      }
    });
  }

  var reqcount = 3;

  function getAccessToken() {
    twitter.getAccessToken(token.requestToken, token.requestTokenSecret, token.oauth_verifier, function(error, accessToken, accessTokenSecret, results) {
      if (error) {
        //3 bad requests and kick out
        deferred.notify('Bad request.' +  reqcount-- + ' tries left.' ); 
        if(reqcount == 0) {
          svr.timeout = 10;
          svr.close();
          deferred.reject(new Error('Too many bad requests.'));
        }
      } else {
        //store accessToken and accessTokenSecret somewhere (associated to the user)
        //Step 4: Verify Credentials belongs here
        token.accessToken = accessToken;
        token.accessTokenSecret = accessTokenSecret;
        svr.timeout = 10;
        svr.close();
        deferred.resolve(token,this);
      }
    });
  }

  return {
    twitter        : twitter,
    token          : token,
    options        : options,
    httpcallback   : httpcallback,
    svr            : svr,
    auth           : auth,
    getAccessToken : getAccessToken,
    deferred       : deferred
  }
}
)();

exports.deferred = authObject.deferred;
exports.token = authObject.token;
exports.auth = function (consumerKey, consumerSecret) {
  authObject.auth(consumerKey, consumerSecret);
  return authObject.deferred.promise;
}

I used this as a quick way to get the Twitter Auth token but have it bounce back to my local machine.
When you set up your app in Twitter set your call back url to http://127.0.0.1:8888/auth.

//example
var twAuth = require('./tw-auth');
    twAuth.auth('Your Consumer Key Here','Your Customer Secret Here').then(function(token) {
    console.log('Got token', token);
}, function (error) {
      // If there's an error 
      console.error(error);
}, function (progress) {
      // Log the progress as it comes in.
      console.log(progress);
});

If you would like to extract the params from the query string, you can use the require('querystring').parse function, or pass true as the second argument to require('url').parse. Example:

node> require('url').parse('/status?name=ryan', true)
{ href: '/status?name=ryan',
search: '?name=ryan',
query: { name: 'ryan' },
pathname: '/status' }

If(query.xyz && query.zyx){...}