How to get current Joomla user with external PHP script

I have a couple PHP scripts used for AJAX quer开发者_Go百科ies, but I want them to be able to operate under the umbrella of Joomla's authentication system. Is the following safe? Are there any unnecessary lines?

joomla-auth.php (located in the same directory as Joomla's index.php):

<?php

define( '_JEXEC', 1 );
define('JPATH_BASE', dirname(__FILE__));
define( 'DS', DIRECTORY_SEPARATOR );
require_once ( JPATH_BASE .DS.'includes'.DS.'defines.php' );
require_once ( JPATH_BASE .DS.'includes'.DS.'framework.php' );

/* Create the Application */
$mainframe =& JFactory::getApplication('site');

/* Make sure we are logged in at all. */
if (JFactory::getUser()->id == 0)
    die("Access denied: login required.");

?>

test.php:

<?php

include 'joomla-auth.php';

echo 'Logged in as "' . JFactory::getUser()->username . '"';

/* We then proceed to access things only the user
   of that name has access to. */
?>

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While I don't see anything in the code that's unsafe, it's best to make your AJAX/JSON calls to a standard Joomla component. There's a good article on how to do this here: http://blog.syncleon.com/2009/05/ajax-ify-your-joomla-website.html I've also written about JavaScript, Joomla, and asynchronous requests in my book http://www.packtpub.com/files/learning-joomla-1-5-extension-development-sample-chapter-8-using-javascript-effects.pdf (skip down to page 168).

Essentially, what you do is create a view for the output of your AJAX call, then create a view.xml.php (or view.json.php) file instead of a view.html.php. When you add &format=xml to the end of your request URL, it will pull from view.xml.php instead of view.html.php.

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sure does work , you need to get session data for users

jimport( 'joomla.session.session' );
$session                =& JFactory::getSession();

print the session to see what comes out