How to get user session info from external php script with Joomla-4.x?

Question

How we can get the logged in user information and session information from external php script with Joomla-4.x?

The below code working with Joomla 3.x and doesn't working with Joomla-4.x

define( '_JEXEC', 1 );
define( 'JPATH_BASE', realpath(dirname(__FILE__).'/../..' ));
require_once ( JPATH_BASE .'/includes/defines.php' );
require_once ( JPATH_BASE .'/includes/framework.php' );
$mainframe = JFactory::getApplication('site');
$mainframe->initialise();
$session = JFactory::getSession();
jimport( 'joomla.application.module.helper' );
 
$session = $session->getId();
$db = JFactory::getDbo();
$user =& JFactory::getUser();
$userid= $user->id;

Answer 1

The below code is mostly from Joomla's /includes/app.php but without the last line. The last few lines then get information about the user and the user session.

<?php
define('_JEXEC', 1);
define('JPATH_BASE', __DIR__);
require_once JPATH_BASE . '/includes/defines.php';
require_once JPATH_BASE . '/includes/framework.php';

// Boot the DI container
$container = \Joomla\CMS\Factory::getContainer();

/*
 * Alias the session service keys to the web session service as that is the primary session backend for this application
 *
 * In addition to aliasing "common" service keys, we also create aliases for the PHP classes to ensure autowiring objects
 * is supported.  This includes aliases for aliased class names, and the keys for aliased class names should be considered
 * deprecated to be removed when the class name alias is removed as well.
 */
$container->alias('session.web', 'session.web.site')
    ->alias('session', 'session.web.site')
    ->alias('JSession', 'session.web.site')
    ->alias(\Joomla\CMS\Session\Session::class, 'session.web.site')
    ->alias(\Joomla\Session\Session::class, 'session.web.site')
    ->alias(\Joomla\Session\SessionInterface::class, 'session.web.site');

// Instantiate the application.
$app = $container->get(\Joomla\CMS\Application\SiteApplication::class);

// Set the application as global app
\Joomla\CMS\Factory::$application = $app;

$userInfo = \Joomla\CMS\Factory::getApplication()->getSession()->get('user');
$userSession = \Joomla\CMS\Factory::getApplication()->getSession();

Disclaimer: Most of the information in this post was derived from https://gist.github.com/PhilETaylor/0c36d87da0f2ad231b378b47c54cfb9b