nextcloud/files/open_file.php

<?php
/**
* ownCloud - ajax frontend
*
* @author Robin Appelman
* @copyright 2010 Robin Appelman icewind1991@gmail.com
* 
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
* License as published by the Free Software Foundation; either 
* version 3 of the License, or any later version.
* 
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU AFFERO GENERAL PUBLIC LICENSE for more details.
*  
* You should have received a copy of the GNU Lesser General Public 
* License along with this library.  If not, see <http://www.gnu.org/licenses/>.
* 
*/

//not this file is for getting files themselves, get_files.php is for getting a list of files.

require_once('../inc/lib_base.php');

$file=$_GET['file'];
$dir=(isset($_GET['dir']))?$_GET['dir']:'';
if(strstr($file,'..') or strstr($dir,'..')){
    die();
}
$filename=$dir.'/'.$file;
$ftype=OC_FILESYSTEM::getMimeType($filename);
ob_end_clean();
header('Content-Type: '.$ftype);
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Pragma: public');
header('Content-Length: ' . OC_FILESYSTEM::filesize($filename));

OC_FILESYSTEM::readfile($filename);
?>