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_LIBRARIES . '/import.legacy.php';
require_once JPATH_LIBRARIES . '/cms.php';

// Load the configuration
require_once JPATH_CONFIGURATION . '/configuration.php';

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

/**************************************************/
// Your code starts here...
/**************************************************/

if (!JFactory::getUser()->id)
{
    header("HTTP/1.0 403 access denied");

    echo "Access denied";

    exit();
}

$requestedFile = str_replace(JUri::root(), "", JUri::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;
}

Vielen Dank für die Lösung!

Klappt super und dann noch in der htaccess bei der Übergabe für den Verzeichnisschutz Parameter für die Gruppen dran hängen und schon kann man bestimmte Bereiche für bestimmte Gruppen freigeben. :)