Multiple credentials check with Basic Auth node package

basic-auth-multiple-credentials.js

'use strict';

/**
 *  Multiple credentials check with Basic Auth node package
 * 
 *  How to use (ExpresJS example):
 *
 *  var BASIC_AUTH = [
 *    {
 *      name: process.env.BASIC_AUTH_USERNAME, 
 *      pass: process.env.BASIC_AUTH_PASSWORD
 *    },
 *    {
 *      name: process.env.BASIC_AUTH_USERNAME2, 
 *      pass: process.env.BASIC_AUTH_PASSWORD2
 *    }
 *  ];
 * 
 *  var basicAuthMultipleCredentials = require('./basic-auth-multiple-credentials');
 *  router.get('/multiple-credential-check', basicAuthMultipleCredentials(BASIC_AUTH), function(req, res) {
 *    // ... your code
 *  });
 * 
 * router.get('/single-credential-check', basicAuthMultipleCredentials(BASIC_AUTH[0]), function(req, res) {
 *    // ... your code
 *  });
 */

var auth = require('basic-auth');

module.exports = function(usersAndPasswords) {
  if (!(usersAndPasswords instanceof Array)) {
    usersAndPasswords = [usersAndPasswords];
  }

  return function(req, res, next) {
    var credentials = auth(req);
    var authenticated = function(credentials){
      return usersAndPasswords.filter(function(registeredUser) {
        return credentials.name === registeredUser.name && 
              credentials.pass === registeredUser.pass;
      }).length === 1;
    };

    if (!credentials || !authenticated(credentials)) {
      res.statusCode = 401;
      res.setHeader('WWW-Authenticate', 'Basic realm="example"');
      res.end('Access denied');
    } else {
      next();
    }
  };
};