class.ilWebAccessChecker.php

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<?php
/* Copyright (c) 1998-2010 ILIAS open source, Extended GPL, see docs/LICENSE */

// Prevent a general redirect to the login screen for anonymous users.
// The checker will show an error page with login link instead
// (see ilInitialisation::InitILIAS() for details)
$_GET["baseClass"] = "ilStartUpGUI";

// Define a pseudo module to get a correct ILIAS_HTTP_PATH 
// (needed for links on the error page).
// "data" is assumed to be the ILIAS_WEB_DIR
// (see ilInitialisation::buildHTTPPath() for details)
define("ILIAS_MODULE", substr($_SERVER['PHP_SELF'],
                                           strpos($_SERVER['PHP_SELF'], "/data/") + 6));

// Define the cookie path to prevent a different session created for web access
// (see ilInitialisation::setCookieParams() for details)
$GLOBALS['COOKIE_PATH'] = substr($_SERVER['PHP_SELF'], 0,
                                                  strpos($_SERVER['PHP_SELF'], "/data/"));

// Determine the ILIAS client from the web path
// This is needed because a session cookie may not yet exist
// (see ilINITIALISATION::determineClient() for details)
$client_start = strpos($_SERVER['PHP_SELF'], "/data/") + 6;
$client_end = strpos($_SERVER['PHP_SELF'], "/", $client_start);
$_GET['client_id'] = substr($_SERVER['PHP_SELF'], $client_start, $client_end - $client_start);

// Remember if the initial session was empty
// Then a new session record should not be written
// (see ilSession::_writeData for details)
$GLOBALS['WEB_ACCESS_WITHOUT_SESSION'] = (session_id() == "");

include_once "Services/Context/classes/class.ilContext.php";
ilContext::init(ilContext::CONTEXT_WEB_ACCESS_CHECK);

// Now the ILIAS header can be included
require_once "./include/inc.header.php";
require_once "./Services/Utilities/classes/class.ilUtil.php";
require_once "./Services/Object/classes/class.ilObject.php";
require_once "./Services/MediaObjects/classes/class.ilObjMediaObject.php";


class ilWebAccessChecker
{
        var $lng;
        var $ilAccess;

        var $subpath;

        var $file;

        var $params;


        var $disposition = "inline";

        var $check_ip = false;

        
        var $check_users = array();
        
        var $send_mimetype = true;
        

        var $mimetype = null;
        
        
        var $errorcode;

            
        var $errortext;


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

                $this->lng =& $lng;
                $this->ilAccess =& $ilAccess;
                $this->params = array();
                
                // get the requested file and its type
                $uri = parse_url($_SERVER["REQUEST_URI"]);
                parse_str($uri["query"], $this->params);

                $pattern = ILIAS_WEB_DIR . "/" . CLIENT_ID;
                $this->subpath = urldecode(substr($uri["path"], strpos($uri["path"], $pattern)));
                $this->file = realpath(ILIAS_ABSOLUTE_PATH . "/". $this->subpath);
                
                // build url path for virtual function
                $this->virtual_path = str_replace($pattern, "virtual-" . $pattern, $uri["path"]);

                
                // set the parameters provided with the checker call
                if (isset($_GET['disposition']))
                {
                        $this->setDisposition($_GET['disposition']);
                }
                if (isset($_GET['check_ip']))
                {
                        $this->setCheckIp($_GET['check_ip']);   
                }
                if (isset($_GET['send_mimetype']))
                {
                        $this->setSendMimetype($_GET['send_mimetype']);
                }               
                
                // 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 "disposition:         ". $this->disposition. "\n";
                echo "ckeck_ip:            ". $this->check_ip. "\n";
                echo "send_mimetype:       ". $this->send_mimetype. "\n";
                echo "</pre>";
                echo phpinfo();
                exit;*/
                
                
                if (!file_exists($this->file))
                {
                        $this->errorcode = 404;
                        $this->errortext = $this->lng->txt("url_not_found");
                        return false;
                }
        }

        public function determineUser()
        {
                global $ilUser;
                
            // a valid user session is found 
            if ($_SESSION["AccountId"])
            {
                $this->check_users = array($_SESSION["AccountId"]);     
                return;
            }      

            // no session cookie was delivered
            // user identification by ip address is allowed
            elseif ($GLOBALS['WEB_ACCESS_WITHOUT_SESSION'] and $this->getCheckIp())
            {
                $this->check_users = ilSession::_getUsersWithIp($_SERVER['REMOTE_ADDR']);
                
                if (count($this->check_users) == 0)
                {
                        // no user was found for the ip address
                        $this->check_users = array(ANONYMOUS_USER_ID);

                        $_SESSION["AccountId"] = ANONYMOUS_USER_ID;
                                $ilUser->setId(ANONYMOUS_USER_ID);
                                $ilUser->read();        
                }
                elseif (count($this->check_users) == 1)
                {
                        // exactly one user is found with an active session
                        $_SESSION["AccountId"] = current($this->check_users);
                                $ilUser->setId(current($this->check_users));
                                $ilUser->read();        
                }
                else
                {
                        // more than one user found for the ip address
                        // take the anonymous user for the session
                        $_SESSION["AccountId"] = ANONYMOUS_USER_ID;
                                $ilUser->setId(ANONYMOUS_USER_ID);
                                $ilUser->read();        
                }
                return;
            }
            
            // take the anonymous user as fallback
            else
            {
                $this->check_users = array(ANONYMOUS_USER_ID);
                
                $_SESSION["AccountId"] = ANONYMOUS_USER_ID;
                        $ilUser->setId(ANONYMOUS_USER_ID);
                        $ilUser->read();        
                
                        return;
            }
        }
        
        public function checkAccess()
        {
                global $ilLog, $ilUser, $ilObjDataCache;

                // an error already occurred at class initialisation
                if ($this->errorcode)
                {
                return false;
            }

            // do this here because ip based checking may be set after construction
            $this->determineUser();
                    
                // check for type by subdirectory
                $pos1 = strpos($this->subpath, "lm_data/lm_") + 11;
                $pos2 = strpos($this->subpath, "mobs/mm_") + 8;
                $pos3 = strpos($this->subpath, "usr_images/") + 11;
                
                $obj_id = 0;
                $type = 'none';
                // trying to access data within a learning module folder
                if ($pos1 > 11)
                {
                        $type = 'lm';
                        $seperator = strpos($this->subpath, '/', $pos1);
                        $obj_id = substr($this->subpath, $pos1, ($seperator > 0 ? $seperator : strlen($this->subpath))-$pos1);
                }
                //trying to access media data
                else if ($pos2 > 8)
                {
                        $type = 'mob';
                        $seperator = strpos($this->subpath, '/', $pos2);
                        $obj_id = substr($this->subpath, $pos2, ($seperator > 0 ? $seperator : strlen($this->subpath))-$pos2);
                }
                // trying to access a user image
                elseif ($pos3 > 11)
                {
                        $type = 'user_image';
                        // user images may be: 
                        // upload_123pic, upload_123
                        // usr_123.jpg, usr_123_small.jpg, usr_123_xsmall.jpg, usr_123_xxsmall.jpg
                        $seperator = strpos($this->subpath, '_', $pos3);
                        $obj_id = (int) substr($this->subpath, $seperator + 1);
                }
                
                if (!$obj_id || $type == 'none')
                {
                        $this->errorcode = 404;
                        $this->errortext = $this->lng->txt("obj_not_found");
                        return false;
                }
                        
                switch($type)
                {
                        // SCORM or HTML learning module
                        case 'lm':
                                if ($this->checkAccessObject($obj_id))
                                {
                                        return true;
                                }
                                break;

                        // media object 
                        case 'mob':
                                if ($this->checkAccessMob($obj_id))
                                {
                                        return true;
                                }
                                break;

                        // image in user profile        
                        case 'user_image':
                                if ($this->checkAccessUserImage($obj_id))
                                {
                                        return true;
                                }
                                break;
                }

                // none of the checks above gives access
                $this->errorcode = 403;
                $this->errortext = $this->lng->txt('msg_no_perm_read');
                return false;
        }
        
        function checkAccessMob($obj_id)
        {
                $usages = ilObjMediaObject::lookupUsages($obj_id);

                foreach($usages as $usage)
                {
                        $oid = ilObjMediaObject::getParentObjectIdForUsage($usage, true);

                        // for content snippets we must get their usages and check them
                        if ($usage["type"] == "mep:pg")
                        {
                                include_once("./Modules/MediaPool/classes/class.ilMediaPoolPage.php");
                                $usages2 = ilMediaPoolPage::lookupUsages($usage["id"]);
                                foreach($usages2 as $usage2)
                                {
                                        $oid2 = ilObjMediaObject::getParentObjectIdForUsage($usage2, true);
                                        if ($this->checkAccessMobUsage($usage2, $oid2))
                                        {
                                                return true;
                                        }
                                }
                        }
                        else // none content snippets just go the usual way
                        {
                                if ($this->checkAccessMobUsage($usage, $oid))
                                {
                                        return true;
                                }
                        }
                }
                
                return false;
        }
                
        function checkAccessMobUsage($usage, $oid)
        {
                global $ilObjDataCache;
                
                switch($usage['type'])
                {
                        case 'lm:pg':
                                if ($this->checkAccessObject($oid, 'lm'))
                                {
                                        return true;
                                }
                                /* as $usage['id'] (== page) is not processed anymore, we can use standard
                                if ($oid > 0)
                                {
                                        if ($this->checkAccessLM($oid, 'lm', $usage['id']))
                                        {
                                                return true;
                                        }
                                }                                
                                */
                                break;
                        
                        case 'news':
                                // media objects in news (media casts)
                                include_once("./Modules/MediaCast/classes/class.ilObjMediaCastAccess.php");
                                include_once("./Services/News/classes/class.ilNewsItem.php");
                        
                                if ($this->checkAccessObject($oid, 'mcst'))
                                {
                                        return true;
                                }
                                elseif (ilObjMediaCastAccess::_lookupPublicFiles($oid) && ilNewsItem::_lookupVisibility($usage["id"]) == NEWS_PUBLIC)
                                {
                                        return true;
                                }
                                break;

                        /* see default
            case 'dcl:html':
                include_once("./Modules/DataCollection/classes/class.ilObjDataCollectionAccess.php");
                include_once("./Services/Object/classes/class.ilObject2.php");
                $ref_ids = ilObject2::_getAllReferences($oid);
                foreach($ref_ids as $ref_id)
                    if(ilObjDataCollectionAccess::_checkAccess("view", "read", $ref_id, $oid))
                        return true;
                break;
                        */
                                
                        case 'frm~:html':
                        case 'exca~:html':
                                // $oid = userid
                                foreach ($this->check_users as $user_id)
                                {
                                        if ($ilObjDataCache->lookupType($oid) == 'usr' && $oid == $user_id)
                                        {
                                                return true;
                                        }
                                }
                                break;

                        case 'qpl:pg':
                        case 'qpl:html':
                                // test questions
                                if ($this->checkAccessTestQuestion($oid, $usage['id']))
                                {
                                        return true;
                                }
                                break;

                        case 'gdf:pg':
                                // special check for glossary terms
                                if ($this->checkAccessGlossaryTerm($oid, $usage['id']))
                                {
                                        return true;
                                }
                                break;
                                
                        case 'sahs:pg':
                                // check for scorm pages
                                if ($this->checkAccessObject($oid, 'sahs'))
                                {
                                        return true;
                                }
                                break;
                                
                        case 'prtf:pg':
                                // special check for portfolio pages
                                if ($this->checkAccessPortfolioPage($oid, $usage['id']))
                                {
                                        return true;
                                }                               
                                break;
                                
                        case 'blp:pg':                          
                                // special check for blog pages
                                if ($this->checkAccessBlogPage($oid, $usage['id']))
                                {
                                        return true;
                                }               
                                break;
                                
                        case 'impr:pg':
                                // #13237
                                include_once 'Services/Imprint/classes/class.ilImprint.php';
                                return (ilImprint::isActive() || $this->checkAccessObject(SYSTEM_FOLDER_ID, 'adm'));

                        default:                                
                                // standard object check
                                if ($this->checkAccessObject($oid))
                                {
                                        return true;
                                }
                                break;
                }
                
                return false;
        }
        
        
        private function checkAccessLM($obj_id, $obj_type, $page = 0)
        {
            global $lng;
                
                // OBSOLETE (see above)
        
                //if (!$page)
                //{
                        $ref_ids  = ilObject::_getAllReferences($obj_id);
                        foreach($ref_ids as $ref_id)
                        {
                                foreach ($this->check_users as $user_id)
                                {
                                        if ($this->ilAccess->checkAccessOfUser($user_id, "read", "view", $ref_id, $obj_type, $obj_id))
                                        {
                                                return true;
                                        }
                                }
                        }
                        return false;
                //}     
                //else
                //{
                //      $ref_ids  = ilObject::_getAllReferences($obj_id);
                //      foreach($ref_ids as $ref_id)
                //      {
                //              if ($this->ilAccess->checkAccess("read", "", $ref_id))
                //              {
                //                      require_once 'Modules/LearningModule/classes/class.ilObjLearningModule.php'; 
                //                      $lm = new ilObjLearningModule($obj_id,false);
                //                      if ($lm->_checkPreconditionsOfPage($ref_id, $obj_id, $page))
                //                              return true;
                //              }
                //      }
                //      return false;
                //}
        }
        
        private function checkAccessObject($obj_id, $obj_type = '')
        {
            global $ilAccess;

                if (!$obj_type)
                {
                        $obj_type = ilObject::_lookupType($obj_id);
                }
                $ref_ids  = ilObject::_getAllReferences($obj_id);

                foreach($ref_ids as $ref_id)
                {
                        foreach ($this->check_users as $user_id)
                        {                               
                                if ($ilAccess->checkAccessOfUser($user_id, "read", "view", $ref_id, $obj_type, $obj_id))
                                {
                                        return true;
                                }
                        }
                }
                return false;
        }

        
        private function checkAccessTestQuestion($obj_id, $usage_id = 0)
        {
            global $ilAccess;

                // give access if direct usage is readable
            if ($this->checkAccessObject($obj_id))
                {
                return true;
            }

                $obj_type = ilObject::_lookupType($obj_id);
                if ($obj_type == 'qpl')
                {
                        // give access if question pool is used by readable test
                        // for random selection of questions
                        include_once('./Modules/Test/classes/class.ilObjTestAccess.php');
                        $tests = ilObjTestAccess::_getRandomTestsForQuestionPool($obj_id);
                        foreach ($tests as $test_id)
                        {
                    if ($this->checkAccessObject($test_id, 'tst'))
                                {
                        return true;
                    }
                        }
                }
                return false;
        }


        private function checkAccessGlossaryTerm($obj_id, $page_id)
        {
        // give access if glossary is readable
            if ($this->checkAccessObject($obj_id))
                {
                        return true;
                }

                include_once("./Modules/Glossary/classes/class.ilGlossaryDefinition.php");
                include_once("./Modules/Glossary/classes/class.ilGlossaryTerm.php");
                $term_id = ilGlossaryDefinition::_lookupTermId($page_id);

                include_once('./Services/COPage/classes/class.ilInternalLink.php');
                $sources = ilInternalLink::_getSourcesOfTarget('git',$term_id, 0);

                if ($sources)
                {
                        foreach ($sources as $src)
                        {
                                switch ($src['type'])
                                {
                                        // Give access if term is linked by a learning module with read access.
                                        // The term including media is shown by the learning module presentation!
                                        case 'lm:pg':
                                                include_once("./Modules/LearningModule/classes/class.ilLMObject.php");
                                                $src_obj_id = ilLMObject::_lookupContObjID($src['id']);
                                                if ($this->checkAccessObject($src_obj_id, 'lm'))
                                                {
                                                        return true;
                                                }
                                                break;

                                        // Don't yet give access if the term is linked by another glossary
                                        // The link will lead to the origin glossary which is already checked
                                        /*
                                        case 'gdf:pg':
                                                $src_term_id = ilGlossaryDefinition::_lookupTermId($src['id']);
                                                $src_obj_id = ilGlossaryTerm::_lookGlossaryID($src_term_id);
                                                if ($this->checkAccessObject($src_obj_id, 'glo'))
                                                {
                                                        return true;
                                                }
                                                break;
                                        */
                                }
                        }
                }
        }
        
        private function checkAccessPortfolioPage($obj_id, $page_id)
        {               
                include_once "Modules/Portfolio/classes/class.ilPortfolioAccessHandler.php";
                $access_handler = new ilPortfolioAccessHandler();               
                foreach ($this->check_users as $user_id)
                {                               
                        if ($access_handler->checkAccessOfUser($user_id, "read", "view", $obj_id, "prtf"))
                        {
                                return true;
                        }
                }               
                return false;                                   
        }       
        
        private function checkAccessBlogPage($obj_id, $page_id)
        {                                       
                include_once "Services/PersonalWorkspace/classes/class.ilWorkspaceTree.php";
                $tree = new ilWorkspaceTree(0);         
                $node_id = $tree->lookupNodeId($obj_id);
                
                // repository
                if(!$node_id)
                {
                        return $this->checkAccessObject($obj_id);
                }
                // workspace
                else
                {                       
                        include_once "Services/PersonalWorkspace/classes/class.ilWorkspaceAccessHandler.php";                                           
                        foreach ($this->check_users as $user_id)
                        {                                                               
                                $access_handler = new ilWorkspaceAccessHandler($tree);
                                if ($access_handler->checkAccessOfUser($tree, $user_id, "read", "view", $node_id, "blog"))
                                {
                                        return true;
                                }
                        }               
                }
                return false;                                   
        }       

        private function checkAccessUserImage($usr_id)
        {
                global $ilUser, $ilSetting;
                
                // check if own image is viewed
                if ($usr_id == $ilUser->getId())
                {
                        return true;                    
                }

                // check if image is in the public profile
                $public_upload = ilObjUser::_lookupPref($usr_id, 'public_upload');
                if ($public_upload != 'y')
                {
                        return false;
                }
                
                // check the publication status of the profile
                $public_profile = ilObjUser::_lookupPref($usr_id, 'public_profile');

                if ($public_profile == 'g' 
                        and $ilSetting->get('enable_global_profiles')
                        and $ilSetting->get('pub_section'))
                {
                        // globally public
                        return true;
                }
                elseif (($public_profile == 'y' or $public_profile == 'g')
                        and $ilUser->getId() != ANONYMOUS_USER_ID)
                {
                        // public for logged in users
                        return true;
                }
                else
                {
                        // not public
                        return false;
                }
        }


        public function setDisposition($a_disposition)
        {
                if (in_array(strtolower($a_disposition), array('inline','attachment','virtual')))
                {
                        $this->disposition = strtolower($a_disposition);
                }
                else
                {
                        $this->disposition = 'inline';
                }
        }

        public function getDisposition()
        {
                return $this->disposition;
        }

        public function setSendMimetype($a_send_mimetype)
        {
                if (in_array(strtolower($a_send_mimetype), array('','0','off','false')))
                {
                        $this->mimetype = null;
                        $this->send_mimetype = false;
                }
                elseif (in_array(strtolower($a_send_mimetype), array('1','on','true')))
                {
                        $this->mimetype = null;
                        $this->send_mimetype = true;
                }
                else
                {
                        $this->mimetype = $a_send_mimetype;
                        $this->send_mimetype = true;
                }
        }
        
        public function getSendMimetype()
        {
                return $this->send_mimetype;
        }

        
        public function setCheckIp($a_check_ip)
        {
                if (in_array(strtolower($a_check_ip), array('','0','off','false')))
                {
                        $this->check_ip = false;
                }
                elseif (in_array(strtolower($a_check_ip), array('1','on','true')))
                {
                        $this->check_ip = true;
                }
        }
        
        public function getCheckIp()
        {
                return $this->check_ip;
        }
        
        
        public function sendFile()
        {
                //$system_use_xsendfile = true;
                //$xsendfile_available = (boolean) $_GET["xsendfile"];
                $xsendfile_available = false;
                //if (function_exists('apache_get_modules'))
                //{
                //      $modules = apache_get_modules();
                //      $xsendfile_available = in_array('mod_xsendfile', $modules);
                //}
                
                //$xsendfile_available = $system_use_xsendfile & $xsendfile_available;
                
                // delivery via apache virtual function
                if ($this->getDisposition() == "virtual")
                {
                        $this->sendFileVirtual();
                        exit;
                }
                // delivery for download dialogue
                elseif ($this->getDisposition() == "attachment")
                {
                        if ($xsendfile_available)
                        {
                                header('x-sendfile: ' . $this->file);
                                header("Content-Type: application/octet-stream");
                        }
                        else
                                ilUtil::deliverFile($this->file, basename($this->file));
                        exit;
                }
                // inline delivery
                else
                {
                        if (!isset($_SERVER["HTTPS"]))
                        {
                                header("Cache-Control: no-cache, must-revalidate");
                                header("Pragma: no-cache");
                        }

                        if ($this->getSendMimetype())
                        {
                                header("Content-Type: " . $this->getMimeType());
                        }

                        // see bug 12622 and 12124
                        if (isset($_SERVER['HTTP_RANGE']))  { // do it for any device that supports byte-ranges not only iPhone
                                ilUtil::rangeDownload($this->file);
                                exit;
                        }

                        header("Content-Length: ".(string)(filesize($this->file)));
                        
                        if (isset($_SERVER["HTTPS"]))
                        {
                                header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
                                header('Pragma: public');
                        }

                        header("Connection: close");

                        if ($xsendfile_available)
                        {
                                header('x-sendfile: ' . $this->file);
                                if ($this->getSendMimetype())
                                {
                                        header("Content-Type: " . $this->getMimeType());
                                }
                        }
                        else
                        {
                                ilUtil::readFile( $this->file);
                        }
                        
                        exit;
                }
        }
        
        public function sendFileVirtual()
        {
                global $ilLog;

                header('Last-Modified: '. date ("D, j M Y H:i:s", filemtime($this->file)). " GMT");
                header('ETag: "'. md5(filemtime($this->file).filesize($this->file)).'"');
                header('Accept-Ranges: bytes');
                header("Content-Length: ".(string)(filesize($this->file)));
                if ($this->getSendMimetype())
                {
                        header("Content-Type: " . $this->getMimeType());
                }
                if(!apache_setenv('ILIAS_CHECKED','1'))
                {
                        $ilLog->write(__METHOD__.' '.__LINE__.': Could not set the environment variable ILIAS_CHECKED.');
                }

                if(!virtual($this->virtual_path))
                {
                        $ilLog->write(__METHOD__.' '.__LINE__.': Could not perform the required sub-request to deliver the file: '.$this->virtual_path);
                }

                exit;
        }
        
        
        public function sendError()
        {
                global $ilSetting, $ilUser, $tpl, $lng, $tree;

                switch ($this->errorcode)
                {
                        case 404:
                                header("HTTP/1.0 404 Not Found");
                                break;
                        case 403:
                        default:
                                header("HTTP/1.0 403 Forbidden");
                                break;
                }
                
                // set the page base to the ILIAS directory
                // to get correct references for images and css files
                $tpl->setCurrentBlock("HeadBaseTag");
                $tpl->setVariable('BASE', ILIAS_HTTP_PATH . '/error.php');
                $tpl->parseCurrentBlock();
        $tpl->addBlockFile("CONTENT", "content", "tpl.error.html");

                // Check if user is logged in
                $anonymous = ($ilUser->getId() == ANONYMOUS_USER_ID);

                if ($anonymous)
                {
                        // Provide a link to the login screen for anonymous users

                        $tpl->SetCurrentBlock("ErrorLink");
                        $tpl->SetVariable("TXT_LINK", $lng->txt('login_to_ilias'));
                        $tpl->SetVariable("LINK", ILIAS_HTTP_PATH. '/login.php?cmd=force_login&client_id='.CLIENT_ID);
                        $tpl->ParseCurrentBlock();
                }
                else
                {
                        // Provide a link to the repository for authentified users

                        $nd = $tree->getNodeData(ROOT_FOLDER_ID);
                        $txt = $nd['title'] == 'ILIAS' ? $lng->txt('repository') : $nd['title'];

                        $tpl->SetCurrentBlock("ErrorLink");
                        $tpl->SetVariable("TXT_LINK", $txt);
                        $tpl->SetVariable("LINK", ILIAS_HTTP_PATH. '/ilias.php?baseClass=ilRepositoryGUI&amp;client_id='.CLIENT_ID);
                        $tpl->ParseCurrentBlock();
                }

                $tpl->setCurrentBlock("content");
                $tpl->setVariable("ERROR_MESSAGE",($this->errortext));
                $tpl->setVariable("SRC_IMAGE", ilUtil::getImagePath("mess_failure.png"));
                $tpl->parseCurrentBlock();

                $tpl->show();
                exit;
        }
        
        public function getMimeType($default = 'application/octet-stream')
        {
                // take a previously set mimetype
                if (isset($this->mimetype))
                {
                        return $this->mimetype;
                }
                
                $mime = '';
                // alex: changed due to bug http://www.ilias.de/mantis/view.php?id=9332
/*              if (extension_loaded('Fileinfo'))
                {
                        $finfo = finfo_open(FILEINFO_MIME);
                        $mime = finfo_file($finfo, $this->file);
                        finfo_close($finfo);
                        if ($pos = strpos($mime, ' '))
                        {
                                $mime = substr($mime, 0, $pos);
                        }
                }
                else
                {*/
                include_once("./Services/Utilities/classes/class.ilMimeTypeUtil.php");
                $mime = ilMimeTypeUtil::getMimeType($this->file);
                //$mime = ilObjMediaObject::getMimeType($this->file);
//              }
                
                // set and return the mime type
                $this->mimetype = $mime ? $mime : $default;
                return $this->mimetype;
        }
}
?>