script based phpBB user add

For a customer I had to implement a script based user management for phpBB (add/delete) called from within a Java web app using existing login data. After evaluating and merging a lot of non-working suggestions/examples I managed to build a working script (tested with phpBB 3.0.4). Maybe it saves you some time.

<?php
if (isset($_REQUEST['forum_username']) && isset($_REQUEST['forum_password']) && isset($_REQUEST['forum_email'])) {
 
 define('IN_PHPBB', true);
 
 $phpbb_root_path = (defined('PHPBB_ROOT_PATH')) ? PHPBB_ROOT_PATH : '../forum/';     
 $phpEx = substr(strrchr(__FILE__, '.'), 1);

 include($phpbb_root_path . 'common.' . $phpEx);
 include($phpbb_root_path . 'includes/ucp/ucp_register.php');
 include($phpbb_root_path . 'includes/functions_user.' . $phpEx);
 
 $username = $_REQUEST['forum_username'];
 $username_clean = strtolower($username_clean);
 $password = $_REQUEST['forum_password'];
 $email = $_REQUEST['forum_email'];
 
 $user_row = array(
  'username' => $username,
  'username_clean' => $username_clean,
  'user_password' => phpbb_hash($password),
  'user_pass_convert' => 0,
  'user_email' => $email,
  'user_email_hash' => crc32(strtolower($email)) . strlen($email),
  'group_id' => 7,
  'user_type' => 0,
 );
 
 user_add($user_row);
}
?>