A alternative to build in primus authentification

primus-auth.js

 var helper = require('../helper')
   , crypto = require('crypto')
   , logger = helper.logger;


/*
 * I know that primus has a authotization feature, but it not works
 *  with some transformers (like sockjs, that not support querystring)
 *
 * This auth will send userid/username and a uniq token
 *  on all packages untill user be authentificated
 *
 * Another alternative is user cookies, but it only works
 *  if your main server (that authentificate user) and awesome-im are into same domain
 */

var generateAuthToken = function(userid) {
  return crypto.createHash('sha256').update(helper.token+'&'+userid).digest('hex');
}

var validateAuthToken = function(userid, token) {
   if (!userid || generateToken(userid) !== token) {
      logger.error('invalid token "%s" for user "%s", should be "%s"', token, userid);
      return false;
   }

   return true;
}


var PrimusAuth = {};

PrimusAuth.server = function(primus, options) {
   primus.Spark.writable('auth', null);

   //
   // aiauth: {userid: <id>, username: <username>, token: <uniq token>}
   //
   primus.transform('incoming', function (p) {
      if (!this.auth && p.data.aiauth) {
         
         var aiauth = p.data.aiauth;
         this.auth  = (validateAuthToken(aiauth.userid, aiauth.token)) ?
                        p.data.aiauth : null;
      }

      if (!this.auth) {
         logger.error('invalid user token', p.data, this.address.ip);
         this.end(undefined, { reconnect: false });
         return false;
      }

      delete p.data.aiauth;

      if (p.data.aiinit) {
         primus.emit('authorized', this, this.auth, p.data);
         return false;
      }
   });

   primus.reserved.events['authorized'] = 1;
}

PrimusAuth.client = function(primus, options) {
   primus.authSent   = false;

   primus.transform('outgoing', function (p) {
      if (!primus.authSent || p.data.aiinit) {
         p.data.aiauth = options.aiauth;
      }

      if (p.data.aiinit) {
         this.authSent = true;
      }
   });

   primus.on('open', function() {
      this.authSent = false;
      this.write({aiinit: 1});
   });

   primus.on('reconnecting', function (opts) {
      this.authSent = false;
   });

   primus.on('end', function () {
      this.authSent = false;
   });
}

module.exports = PrimusAuth;