Bootstrap Drupal multi-site for custom php script

bootstrap-drupal.php

<?php

// Needed for multisite bootstrap.
$_SERVER['HTTP_HOST'] = 'domainname.org';
// Name of this script. Include forward slash.
$_SERVER['SCRIPT_NAME'] = '/' . 'bootstrap-drupal.php';

// Set this to avoid php warnings.
$_SERVER['REMOTE_ADDR'] = '';
define('DRUPAL_ROOT', '/Absolute/path/domainname.org');
require_once DRUPAL_ROOT . '/includes/bootstrap.inc';
// Bootstrap drupal.
drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);