content/classes/class.ilWebAccessChecker.php

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<?php
/*
        +-----------------------------------------------------------------------------+
        | ILIAS open source                                                           |
        +-----------------------------------------------------------------------------+
        | Copyright (c) 1998-2001 ILIAS open source, University of Cologne            |
        |                                                                             |
        | This program is free software; you can redistribute it and/or               |
        | modify it under the terms of the GNU General Public License                 |
        | as published by the Free Software Foundation; either version 2              |
        | of the License, or (at your option) any later version.                      |
        |                                                                             |
        | This program 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 General Public License for more details.                                |
        |                                                                             |
        | You should have received a copy of the GNU General Public License           |
        | along with this program; if not, write to the Free Software                 |
        | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA. |
        +-----------------------------------------------------------------------------+
*/

require_once "./include/inc.header.php";
require_once "./classes/class.ilUtil.php";
require_once "./classes/class.ilObject.php";
require_once "./content/classes/Media/class.ilObjMediaObject.php";

class ilWebAccessChecker
{
        var $lng;
        var $ilAccess;
        var $checked_list;
        
        var $subpath;

        var $file;


        var $mimetype;      

        var $errorcode;

            
        var $errortext;


        function ilWebAccessChecker()
        {
                global $ilAccess, $lng;

                $this->lng =& $lng;
                $this->ilAccess =& $ilAccess;
                $this->checked_list = & $_SESSION["WebAccessChecked"];

                // get the requested file and its type
                $uri = parse_url($_SERVER["REQUEST_URI"]);

                $pattern = ILIAS_WEB_DIR . "/" . CLIENT_ID;
                $this->subpath = substr($uri["path"], strpos($uri["path"], $pattern));
                $this->file = realpath(ILIAS_ABSOLUTE_PATH . "/". $this->subpath);
                
                /* debugging
                echo "<pre>";
                echo "REQUEST_URI:         ". $_SERVER["REQUEST_URI"]. "\n";
                echo "Parsed URI:          ". $uri["path"]. "\n";
                echo "DOCUMENT_ROOT:       ". $_SERVER["DOCUMENT_ROOT"]. "\n";
                echo "PHP_SELF:            ". $_SERVER["PHP_SELF"]. "\n";
                echo "SCRIPT_NAME:         ". $_SERVER["SCRIPT_NAME"]. "\n";
                echo "SCRIPT_FILENAME:     ". $_SERVER["SCRIPT_FILENAME"]. "\n";
                echo "PATH_TRANSLATED:     ". $_SERVER["PATH_TRANSLATED"]. "\n";
                echo "ILIAS_WEB_DIR:       ". ILIAS_WEB_DIR. "\n";
                echo "ILIAS_HTTP_PATH:     ". ILIAS_HTTP_PATH. "\n";
                echo "ILIAS_ABSOLUTE_PATH: ". ILIAS_ABSOLUTE_PATH. "\n";
                echo "CLIENT_ID:           ". CLIENT_ID. "\n";
                echo "CLIENT_WEB_DIR:      ". CLIENT_WEB_DIR. "\n";
                echo "subpath:             ". $this->subpath. "\n";
                echo "file:                ". $this->file. "\n";
                echo "</pre>";
                exit;
                */

                if (file_exists($this->file))
                {
                        $this->mimetype = ilObjMediaObject::getMimeType($this->file);
                }
                else
                {
                        $this->errorcode = 404;
                        $this->errortext = $this->lng->txt("url_not_found");
                        return false;
                }
        }

        function checkAccess()
        {
                // extract the object id (currently only for learning modules)
                $pos1 = strpos($this->subpath, "lm_data/lm_") + 11;
                $pos2 = strpos($this->subpath, "/", $pos1);
                if ($pos1 === false or $pos2 === false)
                {
                        $this->errorcode = 404;
                        $this->errortext = $this->lng->txt("url_not_found");
                        return false;
                }
                $obj_id = substr($this->subpath, $pos1, $pos2-$pos1);
                if (!is_numeric($obj_id))
                {
                        $this->errorcode = 404;
                        $this->errortext = $this->lng->txt("obj_not_found");
                        return false;
                }

                // look in cache, if already checked
                if (is_array($this->checked_list))
                {
                        if (in_array($obj_id, $this->checked_list))
                        {
                                return true;
                        }
                }

                // find the object references
                $obj_type = ilObject::_lookupType($obj_id);
                $ref_ids  = ilObject::_getAllReferences($obj_id);
                if (!$ref_ids)
                {
                        $this->errorcode = 403;
                        $this->errortext = $this->lng->txt("permission_denied");
                        return false;
                }

                // check, if one of the references is readable
                $readable = false;
                foreach($ref_ids as $ref_id)
                {
                        if ($this->ilAccess->checkAccess("read", "view", $ref_id, $obj_type, $obj_id))
                        {
                                $readable = true;
                                break;
                        }
                }
                if ($readable)
                {
                        //add object to cache
                        $this->checked_list[] = $obj_id;
                        return true;
                }
                else
                {
                        $this->errorcode = 403;
                        $this->errortext = $this->lng->txt("permission_denied");
                        return false;
                }
        }
        
        function sendFile()
        {
                if (isset($_SERVER["HTTPS"]))
                {
                        header("Pragma: ");
                        header("Cache-Control: ");
                        header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
                        header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
                        header("Cache-Control: no-store, no-cache, must-revalidate"); // HTTP/1.1
                        header("Cache-Control: post-check=0, pre-check=0", false);
                }
                else
                {
                        header("Cache-Control: no-cache, must-revalidate");
                        header("Pragma: no-cache");
                }
                header("Content-Type: " . $this->mimetype);
                header("Content-Length: ".(string)(filesize($this->file)));
                header("Connection: close");

                ilUtil::readFile( $this->file );
                exit;
        }
        
        function sendError()
        {
                switch ($this->errorcode)
                {
                        case 403:
                                header("HTTP/1.0: 403 Forbidden");
                                break;
                        case 404:
                                header("HTTP/1.0: 404 Not Found");
                                break;
                }
                exit($this->errortext);
        }
}
?>