Get current article id Joomla! 2.5 - php

Question

I'm trying to retrieve the "current" article id from an external script in Joomla! 2.5
Firstly, I included Joomla core files:
define( '_JEXEC', 1 );
defined('_JEXEC') or die('Restricted access');
define( 'JPATH_BASE', realpath(dirname(__FILE__).'/..' ));
define( 'DS', DIRECTORY_SEPARATOR );
require_once ( JPATH_BASE .DS.'includes'.DS.'defines.php' );
require_once ( JPATH_BASE .DS.'includes'.DS.'framework.php' );
Then, initialized the session:
$mainframe =& JFactory::getApplication('site');
$mainframe->initialise();
Now, I know that for Joomla 2.5 I have to use Jinput instead of JRequest (deprecated), so:
$jAp = JFactory::getApplication();
$jInput = $jAp->input;
As already told, I'm trying to retrieve the article id.
I tried many instances but nothing seems to work.
$id = $jInput->get('id', 0); // doesn't work
$idInt = $jInput->getInt('id',0); //doesn't work
Also with JRequest... I can't get current article id.
This works only if I would request data for logged in users, example:
$user = JFactory::getUser();
echo $user->username; // this works...
What I am missing?
Where is my fault?
Thanks a lot to all!

Answer 1

Debugging AJAX can be complex. I often find adding some logging in my handler helps a lot, for example adding the following to the start of your code...
# logging of all hits
$log_file = realpath(dirname(__FILE__)) . '/ajax_debug.log';
$fh = fopen($log_file, 'a') or die();
$log_string = "Backend Hit \n" . date("Y-m-d H:i:s") . "\n";
$log_string .= "POST: " . print_r($_POST, true) . "\n";
$log_string .= "GET: " . print_r($_GET, true) . "\n";
$log_string .= "Hit by: " . $_SERVER['REMOTE_ADDR'] . "\n";
$log_string .= "\n\n\n";
fwrite($fh, $log_string);
fclose($fh);
You didn't mention how/where your AJAX code was implemented. It sounds like it might be an implementation outwith Joomla. I would tend to put this in a plug-in if it is quite stand-alone, though module or component AJAX handlers also work well in Joomla. There are some good docs and code at https://docs.joomla.org/Using_Joomla_Ajax_Interface