readmedia.php for Joomla 4 and 5

readmedia.php

<?php
/**
 * @version    1.0.0
 * @package    Readmedia
 * @copyright  Copyright (C) 2018 David Jardin - djumla GmbH
 * @license    GNU GPLv3 <http://www.gnu.org/licenses/gpl.html>
 * @link       http://www.djumla.de
 */

/* Initialize Joomla framework */
define('_JEXEC', 1);

// Load system defines
if (file_exists(dirname(__FILE__) . '/defines.php'))
{
    require_once dirname(__FILE__) . '/defines.php';
}

if (!defined('_JDEFINES'))
{
    define('JPATH_BASE', dirname(__FILE__));
    require_once JPATH_BASE . '/includes/defines.php';
}

require_once JPATH_BASE . '/includes/framework.php';

/* Create the Application */
$container = \Joomla\CMS\Factory::getContainer();

$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);

// Load the extension Namespaces
\JLoader::register('JNamespacePsr4Map', JPATH_LIBRARIES . '/namespacemap.php');
$extensionPsr4Loader = new \JNamespacePsr4Map();
$extensionPsr4Loader->load();

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

// Actual permission check starts here

if (!\Joomla\CMS\Factory::getUser()->id)
{
    header("HTTP/1.0 403 access denied");

    echo "Access denied";

    exit();
}

$requestedFile = urldecode(str_replace(\Joomla\CMS\Uri\Uri::root(), "", \Joomla\CMS\Uri\Uri::current()));
$location = dirname(__FILE__) . "/" . $requestedFile;

if (!file_exists($location))
{
    header("HTTP/1.0 404 file not found");

    echo "File not found";

    exit();
}

$size = filesize($location);
$time = date('r', filemtime($location));

$fm = @fopen($location, 'rb');

if (!$fm)
{
    header("HTTP/1.0 505 Internal server error");

    exit();
}

$begin = 0;
$end = $size;

header('HTTP/1.0 200 OK');
header("Content-Type: " . mime_content_type($location));
header('Cache-Control: public, must-revalidate, max-age=0');
header('Pragma: no-cache');
header("Content-Disposition: inline; filename=" . basename($location));
header("Content-Transfer-Encoding: binary\n");
header("Last-Modified: $time");
header('Connection: close');

$cur = $begin;
fseek($fm, $begin, 0);

while (!feof($fm) && $cur < $end && (connection_status() == 0))
{
    print fread($fm, min(1024 * 16, $end - $cur));
    $cur += 1024 * 16;
}

Ich kann da auch nur raten; eigentlich sollte die URL in einem str_replace entfernt werden, sodass nur die releative URL übrig bleiben sollte:
https://gist.github.com/SniperSister/5a31e989da962099b517bf14fb978336#file-readmedia-php-L59

Genau das passiert leider nicht. Vielleicht gibt es da einen Unterschied zwischen den PHP oder Joomla Versionen?
Ich habe die Variable umgeschrieben, sodass nun ein (für mein System) passender Pfad rauskommt - jetzt funktioniert es.

Ist abstrakt schwer zu beantworten, ggf mal den Content-Disposition Header von online zu attachment umstellen.