class.ilDAVServer.php

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<?php
// BEGIN WebDAV
/*
        +-----------------------------------------------------------------------------+
        | ILIAS open source                                                           |
        +-----------------------------------------------------------------------------+
        | Copyright (c) 1998-2005 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 'Services/WebDAV/classes/Server.php';
require_once 'Services/WebDAV/classes/class.ilDAVLocks.php';
require_once 'Services/WebDAV/classes/class.ilDAVProperties.php';
require_once 'Services/WebDAV/classes/class.ilObjectDAV.php';

require_once 'Services/User/classes/class.ilObjUser.php';
require_once 'Services/Utilities/classes/class.ilFileUtils.php';
require_once 'include/Unicode/UtfNormal.php';
require_once 'Services/Tracking/classes/class.ilChangeEvent.php';

class ilDAVServer extends HTTP_WebDAV_Server
{
        private static $instance = null;
        
        private $cachedObjectDAV;

        private $locks;
        private $properties;

        private $clientOS = 'unknown';
        private $clientOSFlavor = 'unknown';
        private $clientBrowser = 'unknown';

        private $putObjDAV = null;

        private $isHTTPS = null;

        private $isDebug = false;

        private function __construct()
        {
                $this->writelog("<constructor>");

                // Initialize the WebDAV server and create
                // locking and property support objects
                $this->locks = new ilDAVLocks();
                $this->properties = new ilDAVProperties();
                //$this->locks->createTable();
                //$this->properties->createTable();

                // Guess operating system, operating system flavor and browser of the webdav client
                //
                // - We need to know the operating system in order to properly
                // hide hidden resources in directory listings.
                //
                // - We need the operating system flavor and the browser to
                // properly support mounting of a webdav folder.
                //
                $userAgent = strtolower($_SERVER['HTTP_USER_AGENT']);
                $this->writelog('userAgent='.$userAgent);
                if (strpos($userAgent,'windows') !== false
                || strpos($userAgent,'microsoft') !== false)
                {
                        $this->clientOS = 'windows';
                        if(strpos($userAgent,'nt 5.1') !== false){
                            $this->clientOSFlavor = 'xp';
                        }else{
                            $this->clientOSFlavor = 'nichtxp';
                        }

                } else if (strpos($userAgent,'darwin') !== false
                || strpos($userAgent,'macintosh') !== false
                || strpos($userAgent,'linux') !== false
                || strpos($userAgent,'solaris') !== false
                || strpos($userAgent,'aix') !== false
                || strpos($userAgent,'unix') !== false
                || strpos($userAgent,'gvfs') !== false // nautilus browser uses this ID
                )
                {
                        $this->clientOS = 'unix';
                        if (strpos($userAgent,'linux') !== false)
                        {
                                $this->clientOSFlavor = 'linux';
                        }
                        else if (strpos($userAgent,'macintosh') !== false)
                        {
                                $this->clientOSFlavor = 'osx';
                        }
                }
                if (strpos($userAgent,'konqueror') !== false)
                {
                        $this->clientBrowser = 'konqueror';
                }
        }
        
        public static function getInstance()
        {
                if(self::$instance != NULL)
                {
                        return self::$instance;
                }
                return self::$instance = new ilDAVServer();
        }

        public function tryAuthentication()
        {
                if($GLOBALS['DIC']['ilAuthSession']->isAuthenticated())
                {
                        ilLoggerFactory::getLogger('init')->debug('User session is valid');
                        return true;
                }
                
                ilLoggerFactory::getLogger('init')->debug('Trying http (webdav) authentication.');
                
                include_once './Services/Authentication/classes/Frontend/class.ilAuthFrontendCredentialsHTTP.php';
                $credentials = new ilAuthFrontendCredentialsHTTP();
                $credentials->initFromRequest();
                
                include_once './Services/Authentication/classes/Provider/class.ilAuthProviderFactory.php';
                $provider_factory = new ilAuthProviderFactory();
                $providers = $provider_factory->getProviders($credentials);
                        
                include_once './Services/Authentication/classes/class.ilAuthStatus.php';
                $status = ilAuthStatus::getInstance();
                        
                include_once './Services/Authentication/classes/Frontend/class.ilAuthFrontendFactory.php';
                $frontend_factory = new ilAuthFrontendFactory();
                $frontend_factory->setContext(ilAuthFrontendFactory::CONTEXT_HTTP);
                $frontend = $frontend_factory->getFrontend(
                        $GLOBALS['DIC']['ilAuthSession'],
                        $status,
                        $credentials,
                        $providers
                );
                        
                $frontend->authenticate();
                        
                switch($status->getStatus())
                {
                        case ilAuthStatus::STATUS_AUTHENTICATED:
                                ilLoggerFactory::getLogger('auth')->debug('Authentication successful. Serving request');
                                ilLoggerFactory::getLogger('auth')->info('Authenticated user id: ' . $GLOBALS['DIC']['ilAuthSession']->getUserId());
                                ilLoggerFactory::getLogger('auth')->debug('Auth info authenticated: ' .$GLOBALS['DIC']['ilAuthSession']->isAuthenticated());
                                ilLoggerFactory::getLogger('auth')->debug('Auth info expired: ' .$GLOBALS['DIC']['ilAuthSession']->isExpired());
                                ilInitialisation::initUserAccount();
                                return true;
                                        
                        case ilAuthStatus::STATUS_ACCOUNT_MIGRATION_REQUIRED:
                                ilLoggerFactory::getLogger('auth')->debug('Authentication failed; Account migration required.');
                                return false;

                        case ilAuthStatus::STATUS_AUTHENTICATION_FAILED:
                                ilLoggerFactory::getLogger('auth')->debug('Authentication failed; Wrong login, password.');
                                return false;
                }
                
                return false;
        }
        

        public function serveRequest()
        {
                if(!$this->tryAuthentication())
                {
                        return false;
                }
                
                // die quickly if plugin is deactivated
                if (!self::_isActive())
                {
                        $this->writelog(__METHOD__.' WebDAV disabled. Aborting');
                        $this->http_status('403 Forbidden');
                        echo '<html><body><h1>Sorry</h1>'.
                                '<p><b>Please enable the WebDAV plugin in the ILIAS Administration panel.</b></p>'.
                                '<p>You can only access this page, if WebDAV is enabled on this server.</p>'.
                                '</body></html>';
                        return;
                }

                try {
                        $start = time();
                        $this->writelog('serveRequest():'.$_SERVER['REQUEST_METHOD'].' '.$_SERVER['PATH_INFO'].' ...');
                        parent::serveRequest();
                        $end = time();
                        $this->writelog('serveRequest():'.$_SERVER['REQUEST_METHOD'].' done status='.$this->_http_status.' elapsed='.($end - $start));
                        $this->writelog('---');
                } 
                catch (Exception $e) 
                {
            $this->writelog('serveRequest():'.$_SERVER['REQUEST_METHOD'].' caught exception: '.$e->getMessage().'\n'.$e->getTraceAsString());
                }
        }

        private function davUrlEncode($path)
        {
                // We compose the path to Unicode Normal Form NFC
                // This ensures that diaeresis and other special characters
                // are treated uniformly on Windows and on Mac OS X
                $path = UtfNormal::toNFC($path);

                $c = explode('/',$path);
                for ($i = 0; $i < count($c); $i++)
                {
                        $c[$i] = str_replace('+','%20',urlencode($c[$i]));
                }
                return implode('/',$c);
        }

        public function PROPFIND(&$options, &$files)
        {
                // Activate tree cache
                global $tree;
                //$tree->useCache(true);

                $this->writelog('PROPFIND(options:'.var_export($options, true).' files:'.var_export($files, true).'.)');
                $this->writelog('PROPFIND '.$options['path']);

                // get dav object for path
                $path =& $this->davDeslashify($options['path']);
                $objDAV =& $this->getObject($path);

                // prepare property array
                $files['files'] = array();

                // sanity check
                if (is_null($objDAV)) {
                        return false;
                }
                if (! $objDAV->isPermitted('visible,read')) {
                        return '403 Forbidden';
                }

                // store information for the requested path itself
                // FIXME : create display name for object.
                $encodedPath = $this->davUrlEncode($path);
                
                $GLOBALS['ilLog']->write(print_r($encodedPath,true));

                $files['files'][] =& $this->fileinfo($encodedPath, $encodedPath, $objDAV);

                // information for contained resources requested?
                if (!empty($options['depth']))  {
                        // The breadthFirst list holds the collections which we have not
                        // processed yet. If depth is infinity we append unprocessed collections
                        // to the end of this list, and remove processed collections from
                        // the beginning of this list.
                        $breadthFirst = array($objDAV);
                        $objDAV->encodedPath = $encodedPath;

                        while (count($breadthFirst) > 0) {
                                // remove a collection from the beginning of the breadthFirst list
                                $collectionDAV = array_shift($breadthFirst);
                                $childrenDAV =& $collectionDAV->childrenWithPermission('visible,read');
                                foreach ($childrenDAV as $childDAV)
                                {
                                        // On duplicate names, work with the older object (the one with the
                                        // smaller object id).
                                        foreach ($childrenDAV as $duplChildDAV)
                                        {
                                                if ($duplChildDAV->getObjectId() < $childDAV->getObjectId() &&
                                                                $duplChildDAV->getResourceName() == $childDAV->getResourceName())
                                                {
                                                        continue 2;
                                                }
                                        }

                                        // only add visible objects to the file list
                                        if (!$this->isFileHidden($childDAV))
                                        {
                                                $this->writelog('PROPFIND() child ref_id='.$childDAV->getRefId());
                                                $files['files'][] =& $this->fileinfo(
                                                        $collectionDAV->encodedPath.'/'.$this->davUrlEncode($childDAV->getResourceName()),
                                                        $collectionDAV->encodedPath.'/'.$this->davUrlEncode($childDAV->getDisplayName()),
                                                        $childDAV
                                                );
                                                if ($options['depth']=='infinity' && $childDAV->isCollection()) {
                                                        // add a collection to the end of the breadthFirst list
                                                        $breadthFirst[] = $childDAV;
                                                        $childDAV->encodedPath = $collectionDAV->encodedPath.'/'.$this->davUrlEncode($childDAV->getResourceName());
                                                }
                                        }
                                }
                        }
                }

                // Record read event but don't catch up with write events, because
                // with WebDAV, a user can not see all objects contained in a folder.
                global $ilUser;
                ilChangeEvent::_recordReadEvent($objDAV->getILIASType(), $objDAV->getRefId(),
                        $objDAV->getObjectId(), $ilUser->getId(), false);
                
                // ok, all done
                $this->writelog('PROPFIND():true options='.var_export($options, true).' files='.var_export($files,true));
                return true;
        }

        private function isFileHidden(&$objDAV)
        {
                // Hide null resources which haven't got an active lock
                if ($objDAV->isNullResource()) {
                        if (count($this->locks->getLocksOnObjectDAV($objDAV)) == 0) {
                                return;
                        }
                }

                $name = $objDAV->getResourceName();
                $isFileHidden = false;
                switch ($this->clientOS)
                {
                case 'unix' :
                        // Hide Windows thumbnail files, and files which start with '~$'.
                        $isFileHidden =
                                $name == 'Thumbs.db'
                                || substr($name, 0, 2) == '~$';
                        // Hide files which contain /
                        $isFileHidden |= preg_match('/\\//', $name);
                        break;
                case 'windows' :
                        // Hide files that start with '.'.
                        $isFileHidden = substr($name, 0, 1) == '.';
                        // Hide files which contain \ / : * ? " < > |
                        $isFileHidden |= preg_match('/\\\\|\\/|:|\\*|\\?|"|<|>|\\|/', $name);
                        break;
                default :
                        // Hide files which contain /
                        $isFileHidden |= preg_match('/\\//', $name);
                        break;
                }
                $this->writelog($this->clientOS.' '.$name.' isHidden:'.$isFileHidden.' clientOS:'.$this->clientOS);
                return $isFileHidden;
        }

        private function fileinfo($resourcePath, $displayPath, &$objDAV)
        {
                global $ilias;

                $this->writelog('fileinfo('.$resourcePath.')');
                // create result array
                $info = array();
                /* Some clients, for example WebDAV-Sync, need a trailing slash at the
                 * end of a resource path to a collection.
                 * However Mac OS X does not like this!
                 */
                if ($objDAV->isCollection() && $this->clientOSFlavor != 'osx') {
                        $info['path'] = $resourcePath.'/';
                } else {
                        $info['path'] = $resourcePath;
                }

                $info['props'] = array();

                // no special beautified displayname here ...
                $info["props"][] =& $this->mkprop("displayname", $displayPath);

                // creation and modification time
                $info["props"][] =& $this->mkprop("creationdate", $objDAV->getCreationTimestamp());
                $info["props"][] =& $this->mkprop("getlastmodified", $objDAV->getModificationTimestamp());

                // directory (WebDAV collection)
                $info["props"][] =& $this->mkprop("resourcetype", $objDAV->getResourceType());
                $info["props"][] =& $this->mkprop("getcontenttype", $objDAV->getContentType());
                $info["props"][] =& $this->mkprop("getcontentlength", $objDAV->getContentLength());

                // Only show supported locks for users who have write permission
                if ($objDAV->isPermitted('write'))
                {
                        $info["props"][] =& $this->mkprop("supportedlock",
                                '<D:lockentry>'
                                        .'<D:lockscope><D:exclusive/></D:lockscope>'
                                        .'<D:locktype><D:write/></D:locktype>'
                                .'</D:lockentry>'
                                .'<D:lockentry>'
                                        .'<D:lockscope><D:shared/></D:lockscope>'
                                        .'<D:locktype><D:write/></D:locktype>'
                                .'</D:lockentry>'
                        );
                }

                // Maybe we should only show locks on objects for users who have write permission.
                // But if we don't show these locks, users who have write permission in an object
                // further down in a hierarchy can't see who is locking their object.
                $locks = $this->locks->getLocksOnObjectDAV($objDAV);
                $lockdiscovery = '';
                foreach ($locks as $lock)
                {
                        // DAV Clients expects to see their own owner name in
                        // the locks. Since these names are not unique (they may
                        // just be the name of the local user running the DAV client)
                        // we return the ILIAS user name in all other cases.
                        if ($lock['ilias_owner'] == $ilias->account->getId())
                        {
                                $owner = $lock['dav_owner'];
                        } else {
                                $owner = '<D:href>'.$this->getLogin($lock['ilias_owner']).'</D:href>';
                        }
                        $this->writelog('lockowner='.$owner.' ibi:'.$lock['ilias_owner'].' davi:'.$lock['dav_owner']);

                        $lockdiscovery .=
                        '<D:activelock>'
                                .'<D:lockscope><D:'.$lock['scope'].'/></D:lockscope>'
                                //.'<D:locktype><D:'.$lock['type'].'/></D:locktype>'
                                .'<D:locktype><D:write/></D:locktype>'
                                .'<D:depth>'.$lock['depth'].'</D:depth>'
                                .'<D:owner>'.$owner.'</D:owner>'

                                // more than a million is considered an absolute timestamp
                                // less is more likely a relative value
                                .'<D:timeout>Second-'.(($lock['expires'] > 1000000) ? $lock['expires']-time():$lock['expires']).'</D:timeout>'
                                .'<D:locktoken><D:href>'.$lock['token'].'</D:href></D:locktoken>'
                        .'</D:activelock>'
                        ;
                }
                if (strlen($lockdiscovery) > 0)
                {
                        $info["props"][] =& $this->mkprop("lockdiscovery", $lockdiscovery);
                }

                // get additional properties from database
                $properties = $this->properties->getAll($objDAV);
                foreach ($properties as $prop)
                {
                        $info["props"][] = $this->mkprop($prop['namespace'], $prop['name'], $prop['value']);
                }

                //$this->writelog('fileinfo():'.var_export($info, true));
                return $info;
        }

        public function GET(&$options)
        {
                global $ilUser;

                $this->writelog('GET('.var_export($options, true).')');
                $this->writelog('GET('.$options['path'].')');

                // get dav object for path
                $path = $this->davDeslashify($options['path']);
                $objDAV =& $this->getObject($path);
                
                // sanity check
                if (is_null($objDAV) || $objDAV->isNullResource())
                {
                        return false;
                }

                if (! $objDAV->isPermitted('visible,read'))
                {
                        return '403 Forbidden';
                }

                //  is this a collection?
                if ($objDAV->isCollection())
                {
                        if (isset($_GET['mount']))
                        {
                                return $this->mountDir($objDAV, $options);
                        } 
                        else if (isset($_GET['mount-instructions']))
                        {
                                return $this->showMountInstructions($objDAV, $options);
                        } 
                        else 
                        {
                                return $this->getDir($objDAV, $options);
                        }
                }
                // detect content type
                $options['mimetype'] =& $objDAV->getContentType();
                // detect modification time
                // see rfc2518, section 13.7
                // some clients seem to treat this as a reverse rule
                // requiring a Last-Modified header if the getlastmodified header was set
                $options['mtime'] =& $objDAV->getModificationTimestamp();

                // detect content length
                $options['size'] =& $objDAV->getContentLength();

                // get content as stream or as data array
                $options['stream'] =& $objDAV->getContentStream();
                if (is_null($options['stream']))
                {
                        $options['data'] =& $objDAV->getContentData();
                }

                // Record read event and catch up write events
                ilChangeEvent::_recordReadEvent($objDAV->getILIASType(), $objDAV->getRefId(),
                        $objDAV->getObjectId(), $ilUser->getId());
                
                $this->writelog('GET:'.var_export($options, true));

                return true;
        }
        private function mountDir(&$objDAV, &$options)
        {
                $path = $this->davDeslashify($options['path']);

                header('Content-Type: application/davmount+xml');

                echo "<dm:mount xmlns:dm=\"http://purl.org/NET/webdav/mount\">\n";
                echo "  </dm:url>".$this->base_uri."</dm:url>\n";

                $xmlPath = str_replace('&','&amp;',$path);
                $xmlPath = str_replace('<','&lt;',$xmlPath);
                $xmlPath = str_replace('>','&gt;',$xmlPath);

                echo "  </dm:open>$xmlPath</dm:open>\n";
                echo "</dm:mount>\n";

                exit;

        }
        private function showMountInstructions(&$objDAV, &$options)
        {
                global $lng,$ilUser;

                $path = $this->davDeslashify($options['path']);

                // The $path variable may contain a full or a shortened DAV path.
                // We convert it into an object path, which we can then use to 
                // construct a new full DAV path.
                $objectPath = $this->toObjectPath($path);

                // Construct a (possibly) full DAV path from the object path.
                $fullPath = '';
                foreach ($objectPath as $object)
                {
                        if ($object->getRefId() == 1 && $this->isFileHidden($object))
                        {
                                // If the repository root object is hidden, we can not
                                // create a full path, because nothing would appear in the
                                // webfolder. We resort to a shortened path instead.
                                $fullPath .= '/ref_1';
                        }
                        else
                        {
                                $fullPath .= '/'.$this->davUrlEncode($object->getResourceName());
                        }
                }

                // Construct a shortened DAV path from the object path.
                $shortenedPath = '/ref_'.
                                $objectPath[count($objectPath) - 1]->getRefId();

                if ($objDAV->isCollection())
                {
                        $shortenedPath .= '/';
                        $fullPath .= '/';
                }

                // Prepend client id to path
                $shortenedPath = '/'.CLIENT_ID.$shortenedPath;
                $fullPath = '/'.CLIENT_ID.$fullPath;

                // Construct webfolder URI's. The URI's are used for mounting the
                // webfolder. Since mounting using URI's is not standardized, we have
                // to create different URI's for different browsers.
                $webfolderURI = $this->base_uri.$shortenedPath;
                $webfolderURI_Konqueror = ($this->isWebDAVoverHTTPS() ? "webdavs" : "webdav").
                                substr($this->base_uri, strrpos($this->base_uri,':')).
                                $shortenedPath;
                                ;
                $webfolderURI_Nautilus = ($this->isWebDAVoverHTTPS() ? "davs" : "dav").
                                substr($this->base_uri, strrpos($this->base_uri,':')).
                                $shortenedPath
                                ;
                $webfolderURI_IE = $this->base_uri.$shortenedPath;

                $webfolderTitle = $objectPath[count($objectPath) - 1]->getResourceName();

                header('Content-Type: text/html; charset=UTF-8');
                echo "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";
                echo "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.1 plus MathML 2.0 plus SVG 1.1//EN\"\n";
                echo "  \"http://www.w3.org/2002/04/xhtml-math-svg/xhtml-math-svg.dtd\">\n";
                echo "<html xmlns=\"http://www.w3.org/1999/xhtml\">\n";
                echo "  <head>\n";
                echo "  <title>".sprintf($lng->txt('webfolder_instructions_titletext'), $webfolderTitle)."</title>\n";
                echo "  </head>\n";
                echo "  <body>\n";

                echo ilDAVServer::_getWebfolderInstructionsFor($webfolderTitle,
                        $webfolderURI, $webfolderURI_IE, $webfolderURI_Konqueror, $webfolderURI_Nautilus,
                        $this->clientOS,$this->clientOSFlavor);

                echo "  </body>\n";
                echo "</html>\n";
                
                // Logout anonymous user to force authentication after calling mount uri
                if($ilUser->getId() == ANONYMOUS_USER_ID)
                {
                        $GOBALS['DIC']['ilAuthSession']->logout();
                }
                
                exit;
        }
        private function getDir(&$objDAV, &$options)
        {
                global $ilias, $lng;

                // Activate tree cache
                global $tree;
                //$tree->useCache(true);

                $path = $this->davDeslashify($options['path']);

                // The URL of a directory must end with a slash.
                // If it does not we are redirecting the browser.
                // The slash is required, because we are using relative links in the
                // HTML code we are generating below.
                if ($path.'/' != $options['path'])
                {
                        header('Location: '.$this->base_uri.$path.'/');
                        exit;
                }

                header('Content-Type: text/html; charset=UTF-8');

                // fixed width directory column format
                $format = "%15s  %-19s  %-s\n";

                echo "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";
                echo "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.1 plus MathML 2.0 plus SVG 1.1//EN\"\n";
                echo "  \"http://www.w3.org/2002/04/xhtml-math-svg/xhtml-math-svg.dtd\">\n";
                echo "<html xmlns=\"http://www.w3.org/1999/xhtml\">\n";
                echo "<head>\n";
                echo "<title>".sprintf($lng->txt('webfolder_index_of'), $path)."</title>\n";

                // Create "anchorClick" behavior for for Internet Explorer
                // This allows to create a link to a webfolder
                echo "<style type=\"text/css\">\n";
                echo "<!--\n";
                echo "a {\n";
                echo "  behavior:url(#default#AnchorClick);\n";
                echo "}\n";
                echo "-->\n";
                echo "</style>\n";

                echo "</head><body>\n";

                $hrefPath = '';
                $pathComponents = explode('/',$path);
                $uriComponents = array();
                foreach ($pathComponents as $component)
                {
                        $uriComponents[] = $this->davUrlEncode($component);
                }
                for ($i = 0; $i < count($pathComponents); $i++)
                {
                        $displayName = htmlspecialchars($pathComponents[$i]);
                        if ($i != 0) {
                                $hrefPath .= '/';
                        }
                        $uriPath = implode('/', array_slice($uriComponents,0,$i + 1));
                        if ($i < 2)
                        {
                                // The first two path elements consist of the webdav.php script
                                // and the client id. These elements are not part of the
                                // directory structure and thus are not represented as links.
                                $hrefPath .= $displayName;
                        }
                        else
                        {
                                $hrefPath .= '<a href="'.$this->base_uri.$uriPath.'/">'.$displayName.'</a>';
                        }
                }
                echo "<h3>".sprintf($lng->txt('webfolder_index_of'), $hrefPath)."</h3>\n";

                // Display user id
                if ($ilias->account->getLogin() == 'anonymous')
                {
                        echo "<p><font size=\"-1\">".$lng->txt('not_logged_in')."</font><br>\n";
                } else {
                        echo "<p><font size=\"-1\">".$lng->txt('login_as')." <i>"
                                .$ilias->account->getFirstname().' '
                                .$ilias->account->getLastname().' '
                                .' '.$ilias->account->getLogin().'</i> '
                                .', '.$lng->txt('client').' <i>'.$ilias->getClientId().'</i>.'
                                ."</font><p>\n";
                }

                // Create "open as webfolder" link
                $href = $this->base_uri.$uriPath;
                // IE can not mount long paths. If the path has more than one element, we
                // create a relative path with a ref-id.
                if (count($pathComponents) > 2)
                {
                        $hrefIE = $this->base_uri.'/'.CLIENT_ID.'/ref_'.$objDAV->getRefId();
                } else {
                        $hrefIE = $href;
                }
                echo "<p><font size=\"-1\">".
                                sprintf($lng->txt('webfolder_dir_info'), "$href?mount-instructions").
                                "</font></p>\n";
                echo "<p><font size=\"-1\">".
                                sprintf($lng->txt('webfolder_mount_dir_with'),
                                        "$hrefIE\" folder=\"$hrefIE", // Internet Explorer
                                        'webdav'.substr($href,4), // Konqueror
                                        'dav'.substr($href,4), // Nautilus
                                        $href.'?mount' // RFC 4709
                                )
                        ."</font></p>\n";

                echo "<pre>";
                printf($format, $lng->txt('size'), $lng->txt('last_change'), $lng->txt('filename'));
                echo "<hr>";

                $collectionCount = 0;
                $fileCount = 0;
                $children =& $objDAV->childrenWithPermission('visible,read');
                foreach ($children as $childDAV) {
                        if ($childDAV->isCollection() && !$this->isFileHidden($childDAV))
                        {
                                $collectionCount++;
                                $name = $this->davUrlEncode($childDAV->getResourceName());
                                printf($format,
                                        '-',
                                        strftime("%Y-%m-%d %H:%M:%S", $childDAV->getModificationTimestamp()),
                                        '<a href="'.$name.'/'.'">'.$childDAV->getDisplayName()."</a>");
                        }
                }
                foreach ($children as $childDAV) {
                        if ($childDAV->isFile() && !$this->isFileHidden($childDAV))
                        {
                                $fileCount++;
                                $name = $this->davUrlEncode($childDAV->getResourceName());
                                printf($format,
                                        number_format($childDAV->getContentLength()),
                                        strftime("%Y-%m-%d %H:%M:%S", $childDAV->getModificationTimestamp()),
                                        '<a href="'.$name.'">'.$childDAV->getDisplayName()."</a>");
                        }
                }
                foreach ($children as $childDAV) {
                        if ($childDAV->isNullResource() && !$this->isFileHidden($childDAV))
                        {
                                $name = $this->davUrlEncode($childDAV->getResourceName());
                                printf($format,
                                        'Lock',
                                        strftime("%Y-%m-%d %H:%M:%S", $childDAV->getModificationTimestamp()),
                                        '<a href="'.$name.'">'.$childDAV->getDisplayName()."</a>");
                        }
                }
                echo "<hr>";
                echo $collectionCount.' '.$lng->txt(($collectionCount == 1) ? 'folder' : 'folders').', ';
                echo $fileCount.' '.$lng->txt(($fileCount == 1) ? 'file' : 'files').'.';
                echo "</pre>";
                echo "</body></html>\n";

                exit;
        }


        public function PUT(&$options)
        {
                global $ilUser;

                $this->writelog('PUT('.var_export($options, true).')');

                $path = $this->davDeslashify($options['path']);
                $parent = dirname($path);
                $name = $this->davBasename($path);
                
                //Check if FileType is allowed          
                if ($name != ilFileUtils::getValidFilename($name)) {
                        return false;
                }

                // get dav object for path
                $parentDAV =& $this->getObject($parent);

                // sanity check
                if (is_null($parentDAV) || ! $parentDAV->isCollection()) {
                        return '409 Conflict';
                }

        // Prevent putting of files which exceed upload limit
        // FIXME: since this is an optional parameter, we should to do the
        // same check again in function PUTfinished.
                if ($options['content_length'] != null &&
                $options['content_length'] > $this->getUploadMaxFilesize()) {

            $this->writelog('PUT is forbidden, because content length='.
                        $options['content_length'].' is larger than upload_max_filesize='.
                        $this->getUploadMaxFilesize().'in php.ini');

            return '403 Forbidden';
        }
        
                // determine mime type
                include_once("./Services/Utilities/classes/class.ilMimeTypeUtil.php");
                $mime = ilMimeTypeUtil::lookupMimeType($name);

                $objDAV =& $this->getObject($path);
                if (is_null($objDAV))
                {
                        $ttype = $parentDAV->getILIASFileType();
                        $isperm = $parentDAV->isPermitted('create', $ttype);
                        if (! $isperm)
                        {
                $this->writelog('PUT is forbidden, because user has no create permission');

                                return '403 Forbidden';
                        }
                        $options["new"] = true;
                        $objDAV =& $parentDAV->createFile($name);
                        $this->writelog('PUT obj='.$objDAV.' name='.$name.' content_type='.$options['content_type']);
                        //$objDAV->setContentType($options['content_type']);
                        $objDAV->setContentType($mime);
                        if ($options['content_length'] != null)
                        {
                                $objDAV->setContentLength($options['content_length']);
                        }
                        $objDAV->write();
                        // Record write event
                        ilChangeEvent::_recordWriteEvent($objDAV->getObjectId(), $ilUser->getId(), 'create', $parentDAV->getObjectId());
                }
                else if ($objDAV->isNullResource())
                {
                        if (! $parentDAV->isPermitted('create', $parentDAV->getILIASFileType()))
                        {
                $this->writelog('PUT is forbidden, because user has no create permission');
                                return '403 Forbidden';
                        }
                        $options["new"] = false;
                        $objDAV =& $parentDAV->createFileFromNull($name, $objDAV);
                        $this->writelog('PUT obj='.$objDAV.' name='.$name.' content_type='.$options['content_type']);
                        //$objDAV->setContentType($options['content_type']);
                        $objDAV->setContentType($mime);
                        if ($options['content_length'] != null)
                        {
                                $objDAV->setContentLength($options['content_length']);
                        }
                        $objDAV->write();

                        // Record write event
                        ilChangeEvent::_recordWriteEvent($objDAV->getObjectId(), $ilUser->getId(), 'create', $parentDAV->getObjectId());
                }
                else
                {
                        if (! $objDAV->isPermitted('write'))
                        {
                $this->writelog('PUT is forbidden, because user has no write permission');
                                return '403 Forbidden';
                        }
                        $options["new"] = false;
                        $this->writelog('PUT obj='.$objDAV.' name='.$name.' content_type='.$options['content_type'].' content_length='.$options['content_length']);

                        // Create a new version if the previous version is not empty
                        if ($objDAV->getContentLength() != 0) {
                                $objDAV->createNewVersion();
                        }

                        //$objDAV->setContentType($options['content_type']);
                        $objDAV->setContentType($mime);
                        if ($options['content_length'] != null)
                        {
                        $objDAV->setContentLength($options['content_length']);
                        }
                        $objDAV->write();

                        // Record write event
                        ilChangeEvent::_recordWriteEvent($objDAV->getObjectId(), $ilUser->getId(), 'update');
                        ilChangeEvent::_catchupWriteEvents($objDAV->getObjectId(), $ilUser->getId(), 'update');
                }
                // store this object, we reuse it in method PUTfinished
                $this->putObjDAV = $objDAV;

                $out =& $objDAV->getContentOutputStream();
                $this->writelog('PUT outputstream='.$out);

                return $out;
        }

        public function PUTfinished(&$options)
        {
                $this->writelog('PUTfinished('.var_export($options, true).')');

                if($this->putObjDAV->getResourceType()==""){
                        $vir = ilUtil::virusHandling($this->putObjDAV->obj->getDirectory($this->putObjDAV->obj->version).'/'.$this->putObjDAV->obj->filename, $this->putObjDAV->obj->filename);
                        if ($vir[0] == false)
                        {
                                $this->writelog('PUTfinished Virus found: '.$vir[1]);
                                //delete file
                                ilDAVServer::DELETE($options);
                                return false;
                        }
                }

                // Update the content length in the file object, if the
                // the client did not specify a content_length
                if ($options['content_length'] == null || $this->putObjDAV->getContentLength() == 0)
                {
                        $objDAV = $this->putObjDAV;
                        if ($objDAV->getContentOutputStreamLength() != null) {
                                $objDAV->setContentLength($objDAV->getContentOutputStreamLength());
                        } else {
                                $objDAV->write();
                                $objDAV->setContentLength(filesize($objDAV->obj->getDirectory($objDAV->obj->version).'/'.$objDAV->obj->filename));
                        }
                        $objDAV->write();
                        $this->putObjDAV = null;
                }
                return true;
        }


        public function MKCOL($options)
        {
                global $ilUser;

                $this->writelog('MKCOL('.var_export($options, true).')');
                $this->writelog('MKCOL '.$options['path']);

                $path =& $this->davDeslashify($options['path']);
                $parent =& dirname($path);
                $name =& $this->davBasename($path);

                // No body parsing yet
                if(!empty($_SERVER["CONTENT_LENGTH"])) {
                        return "415 Unsupported media type";
                }

                // Check if an object with the path already exists.
                $objDAV =& $this->getObject($path);
                if (! is_null($objDAV))
                {
                        return '405 Method not allowed';
                }

                // get parent dav object for path
                $parentDAV =& $this->getObject($parent);

                // sanity check
                if (is_null($parentDAV) || ! $parentDAV->isCollection())
                {
                        return '409 Conflict';
                }

                if (! $parentDAV->isPermitted('create',$parentDAV->getILIASCollectionType()))
                {
                        return '403 Forbidden';
                }

                // XXX Implement code that Handles null resource here

                $objDAV = $parentDAV->createCollection($name);

                if ($objDAV != null)
                {
                        // Record write event
                        ilChangeEvent::_recordWriteEvent((int) $objDAV->getObjectId(), $ilUser->getId(), 'create', $parentDAV->getObjectId());
                }

                $result = ($objDAV != null) ? "201 Created" : "409 Conflict";
                return $result;
        }


        public function DELETE($options)
        {
                global $ilUser;

                $this->writelog('DELETE('.var_export($options, true).')');
                $this->writelog('DELETE '.$options['path']);

                // get dav object for path
                $path =& $this->davDeslashify($options['path']);
                $parentDAV =& $this->getObject(dirname($path));
                $objDAV =& $this->getObject($path);

                // sanity check
                if (is_null($objDAV) || $objDAV->isNullResource())
                {
                        return '404 Not Found';
                }
                if (! $objDAV->isPermitted('delete'))
                {
                        return '403 Forbidden';
                }

                $parentDAV->remove($objDAV);

                // Record write event
                ilChangeEvent::_recordWriteEvent($objDAV->getObjectId(), $ilUser->getId(), 'delete', $parentDAV->getObjectId());

                return '204 No Content';
        }

        public function MOVE($options)
        {
                global $ilUser;

                $this->writelog('MOVE('.var_export($options, true).')');
                $this->writelog('MOVE '.$options['path'].' '.$options['dest']);

                // Get path names
                $src = $this->davDeslashify($options['path']);
                $srcParent = dirname($src);
                $srcName = $this->davBasename($src);
                $dst = $this->davDeslashify($options['dest']);

                $dstParent = dirname($dst);
                $dstName = $this->davBasename($dst);
                $this->writelog('move '.$dst.'   dstname='.$dstName);
                // Source and destination must not be the same
                if ($src == $dst)
                {
                                return '409 Conflict (source and destination are the same)';
                }

                // Destination must not be in a subtree of source
                if (substr($dst,strlen($src)+1) == $src.'/')
                {
                                return '409 Conflict (destination is in subtree of source)';
                }

                // Get dav objects for path
                $srcDAV =& $this->getObject($src);
                $dstDAV =& $this->getObject($dst);
                $srcParentDAV =& $this->getObject($srcParent);
                $dstParentDAV =& $this->getObject($dstParent);

                // Source must exist
                if ($srcDAV == null)
                {
                                return '409 Conflict (source does not exist)';
                }

                // Overwriting is only allowed, if overwrite option is set to 'T'
                $isOverwritten = false;
                if ($dstDAV != null)
                {
                                if ($options['overwrite'] == 'T')
                                {
                                                // Delete the overwritten destination
                                                if ($dstDAV->isPermitted('delete'))
                                                {
                                                                $dstParentDAV->remove($dstDAV);
                                                                $dstDAV = null;
                                                                $isOverwritten = true;
                                                } else {
                                                                return '403 Not Permitted';
                                                }
                                } else {
                                                return '412 Precondition Failed';
                                }
                }

                // Parents of destination must exist
                if ($dstParentDAV == null)
                {
                                return '409 Conflict (parent of destination does not exist)';
                }

                if ($srcParent == $dstParent)
                {
                                // Rename source, if source and dest are in same parent

                                // Check permission
                                if (! $srcDAV->isPermitted('write'))
                                {
                                                return '403 Forbidden';
                                }
        $this->writelog('rename dstName='.$dstName);
                                $srcDAV->setResourceName($dstName);
                                $srcDAV->write();
                } else {
                                // Move source, if source and dest are in same parent


                                if (! $srcDAV->isPermitted('delete'))
                                {
                                                return '403 Forbidden';
                                }

                                if (! $dstParentDAV->isPermitted('create', $srcDAV->getILIASType()))
                                {
                                                return '403 Forbidden';
                                }
                                $dstParentDAV->addMove($srcDAV, $dstName);
                }

                // Record write event
                if ($isOverwritten)
                {
                        ilChangeEvent::_recordWriteEvent($srcDAV->getObjectId(), $ilUser->getId(), 'rename');
                }
                else
                {
                        ilChangeEvent::_recordWriteEvent($srcDAV->getObjectId(), $ilUser->getId(), 'remove', $srcParentDAV->getObjectId());
                        ilChangeEvent::_recordWriteEvent($srcDAV->getObjectId(), $ilUser->getId(), 'add', $dstParentDAV->getObjectId());
                }               

                return ($isOverwritten) ? '204 No Content' : '201 Created';
        }

        public function COPY($options, $del=false)
        {
                global $ilUser;
                $this->writelog('COPY('.var_export($options, true).' ,del='.$del.')');
                $this->writelog('COPY '.$options['path'].' '.$options['dest']);

                // no copying to different WebDAV Servers
                if (isset($options["dest_url"])) {
                        return "502 bad gateway";
                }

                $src = $this->davDeslashify($options['path']);
                $srcParent = dirname($src);
                $srcName = $this->davBasename($src);
                $dst = $this->davDeslashify($options['dest']);
                $dstParent = dirname($dst);
                $dstName = $this->davBasename($dst);

                // sanity check
                if ($src == $dst)
                {
                        return '409 Conflict'; // src and dst are the same
                }

                if (substr($dst,strlen($src)+1) == $src.'/')
                {
                        return '409 Conflict'; // dst is in subtree of src
                }

                $this->writelog('COPY src='.$src.' dst='.$dst);
                // get dav object for path
                $srcDAV =& $this->getObject($src);
                $dstDAV =& $this->getObject($dst);
                $dstParentDAV =& $this->getObject($dstParent);

                if (is_null($srcDAV) || $srcDAV->isNullResource())
                {
                        return '409 Conflict'; // src does not exist
                }
                if (is_null($dstParentDAV) || $dstParentDAV->isNullResource())
                {
                        return '409 Conflict'; // parent of dst does not exist
                }
                $isOverwritten = false;

                // XXX Handle nulltype for dstDAV
                if (! is_null($dstDAV))
                {
                        if ($options['overwrite'] == 'T')
                        {
                                if ($dstDAV->isPermitted('delete'))
                                {
                                        $dstParentDAV->remove($dstDAV);
                                        ilChangeEvent::_recordWriteEvent($dstDAV->getObjectId(), $ilUser->getId(), 'delete', $dstParentDAV->getObjectId());

                                        $dstDAV = null;
                                        $isOverwritten = true;
                                } else {
                                        return '403 Forbidden';
                                }
                        } else {
                                        return '412 Precondition Failed';
                        }
                }

                if (! $dstParentDAV->isPermitted('create', $srcDAV->getILIASType()))
                {
                        return '403 Forbidden';
                }
                $dstDAV = $dstParentDAV->addCopy($srcDAV, $dstName);

                // Record write event
                ilChangeEvent::_recordReadEvent($srcDAV->getILIASType(), $srcDAV->getRefId(),
                        $srcDAV->getObjectId(), $ilUser->getId());
                ilChangeEvent::_recordWriteEvent($dstDAV->getObjectId(), $ilUser->getId(), 'create', $dstParentDAV->getObjectId());             

                return ($isOverwritten) ? '204 No Content' : '201 Created';
        }

        public function PROPPATCH(&$options)
        {
                $this->writelog('PROPPATCH(options='.var_export($options, true).')');
                $this->writelog('PROPPATCH '.$options['path']);

                // get dav object for path
                $path =& $this->davDeslashify($options['path']);
                $objDAV =& $this->getObject($path);

                // sanity check
                if (is_null($objDAV) || $objDAV->isNullResource()) return false;

                $isPermitted = $objDAV->isPermitted('write');
                foreach($options['props'] as $key => $prop) {
                        if (!$isPermitted || $prop['ns'] == 'DAV:')
                        {
                                $options['props'][$key]['status'] = '403 Forbidden';
                        } else {
                                $this->properties->put($objDAV, $prop['ns'],$prop['name'],$prop['val']);
                        }
                }

                return "";
        }


        public function LOCK(&$options)
        {
                global $ilias;
                $this->writelog('LOCK('.var_export($options, true).')');
                $this->writelog('LOCK '.$options['path']);

                // Check if an object with the path exists.
                $path =& $this->davDeslashify($options['path']);
                $objDAV =& $this->getObject($path);
                // Handle null-object locking
                // --------------------------
                if (is_null($objDAV))
                {
                        $this->writelog('LOCK handling null-object locking...');

                        // If the name does not exist, we create a null-object for it
                        if (isset($options["update"]))
                        {
                                $this->writelog('LOCK lock-update failed on non-existing null-object.');
                                return '412 Precondition Failed';
                        }

                        $parent = dirname($path);
                        $parentDAV =& $this->getObject($parent);
                        if (is_null($parentDAV))
                        {
                                $this->writelog('LOCK lock failed on non-existing path to null-object.');
                                return '404 Not Found';
                        }
                        if (! $parentDAV->isPermitted('create', $parentDAV->getILIASFileType()) &&
                                ! $parentDAV->isPermitted('create', $parentDAV->getILIASCollectionType()))
                        {
                                $this->writelog('LOCK lock failed - creation of null object not permitted.');
                                return '403 Forbidden';
                        }

                        $objDAV =& $parentDAV->createNull($this->davBasename($path));
                        $this->writelog('created null resource for '.$path);
                }

                // ---------------------
                if (! $objDAV->isNullResource() && ! $objDAV->isPermitted('write'))
                {
                        $this->writelog('LOCK lock failed - user has no write permission.');
                        return '403 Forbidden';
                }

                // XXX - Check if there are other locks on the resource
                if (!isset($options['timeout']) || is_array($options['timeout']))
                {
                        $options["timeout"] = time()+360; // 6min.
                }

                if(isset($options["update"])) { // Lock Update
                        $this->writelog('LOCK update token='.var_export($options,true));
                        $success = $this->locks->updateLockWithoutCheckingDAV(
                                $objDAV,
                                $options['update'],
                                $options['timeout']
                        );
                        if ($success)
                        {
                                $data = $this->locks->getLockDAV($objDAV, $options['update']);
                                if ($data['ilias_owner'] == $ilias->account->getId())
                                {
                                        $owner = $data['dav_owner'];
                                } else {
                                        $owner = '<D:href>'.$this->getLogin($data['ilias_owner']).'</D:href>';
                                }
                                $options['owner'] = $owner;
                                $options['locktoken'] = $data['token'];
                                $options['timeout'] = $data['expires'];
                                $options['depth'] = $data['depth'];
                                $options['scope'] = $data['scope'];
                                $options['type'] = $data['scope'];
                        }

                } else {
                        $this->writelog('LOCK create new lock');

                        // XXX - Attempting to create a recursive exclusive lock
                        // on a collection must fail, if any of nodes in the subtree
                        // of the collection already has a lock.
                        // XXX - Attempting to create a recursive shared lock
                        // on a collection must fail, if any of nodes in the subtree
                        // of the collection already has an exclusive lock.
                        //$owner = (strlen(trim($options['owner'])) == 0) ? $ilias->account->getLogin() : $options['owner'];
                        $this->writelog('lock owner='.$owner);
                        $success = $this->locks->lockWithoutCheckingDAV(
                                $objDAV,
                                $ilias->account->getId(),
                                trim($options['owner']),
                                $options['locktoken'],
                                $options['timeout'],
                                $options['depth'],
                                $options['scope']
                        );
                }

                // Note: As a workaround for the Microsoft WebDAV Client, we return
                //       true/false here (resulting in the status '200 OK') instead of
                //       '204 No Content').
                //return ($success) ? '204 No Content' : false;
                return $success;
        }

        public function UNLOCK(&$options)
        {
                global $log, $ilias;
                $this->writelog('UNLOCK(options='.var_export($options, true).')');
                $this->writelog('UNLOCK '.$options['path']);

                // Check if an object with the path exists.
                $path =& $this->davDeslashify($options['path']);
                $objDAV =& $this->getObject($path);
                if (is_null($objDAV)) {
                        return '404 Not Found';
                }
                if (! $objDAV->isPermitted('write')) {
                        return '403 Forbidden';
                }

                $success = $this->locks->unlockWithoutCheckingDAV(
                        $objDAV,
                        $options['token']
                );

                // Delete null resource object if there are no locks associated to
                // it anymore
                if ($objDAV->isNullResource()
                && count($this->locks->getLocksOnObjectDAV($objDAV)) == 0)
                {
                        $parent = dirname($this->davDeslashify($options['path']));
                        $parentDAV =& $this->getObject($parent);
                        $parentDAV->remove($objDAV);
                }

                // Workaround for Mac OS X: We must return 200 here instead of
                // 204.
                //return ($success) ? '204 No Content' : '412 Precondition Failed';
                return ($success) ? '200 OK' : '412 Precondition Failed';
        }

        protected function checkLock($path)
        {
                global $ilias;

                $this->writelog('checkLock('.$path.')');
                $result = null;

                // get dav object for path
                //$objDAV = $this->getObject($path);

                // convert DAV path into ilObjectDAV path
                $objPath = $this->toObjectPath($path);
                if (! is_null($objPath))
                {
                        $objDAV = $objPath[count($objPath) - 1];
                        $locks = $this->locks->getLocksOnPathDAV($objPath);
                        foreach ($locks as $lock)
                        {
                                $isLastPathComponent = $lock['obj_id'] == $objDAV->getObjectId()
                                && $lock['node_id'] == $objDAV->getNodeId();

                                // Check all locks on last object in path,
                                // but only locks with depth infinity on parent objects.
                                if ($isLastPathComponent || $lock['depth'] == 'infinity')
                                {
                                        // DAV Clients expects to see their own owner name in
                                        // the locks. Since these names are not unique (they may
                                        // just be the name of the local user running the DAV client)
                                        // we return the ILIAS user name in all other cases.
                                        if ($lock['ilias_owner'] == $ilias->account->getId())
                                        {
                                                $owner = $lock['dav_owner'];
                                        } else {
                                                $owner = $this->getLogin($lock['ilias_owner']);
                                        }

                                        // FIXME - Shouldn't we collect all locks instead of
                                        //         using an arbitrary one?
                                        $result = array(
                                                "type"    => "write",
                                                "obj_id"   => $lock['obj_id'],
                                                "node_id"   => $lock['node_id'],
                                                "scope"   => $lock['scope'],
                                                "depth"   => $lock['depth'],
                                                "owner"   => $owner,
                                                "token"   => $lock['token'],
                                                "expires" => $lock['expires']
                                        );
                                        if ($lock['scope'] == 'exclusive')
                                        {
                                                // If there is an exclusive lock in the path, it
                                                // takes precedence over all non-exclusive locks in
                                                // parent nodes. Therefore we can can finish collecting
                                                // locks.
                                                break;
                                        }
                                }
                        }
                }
                $this->writelog('checkLock('.$path.'):'.var_export($result,true));

                return $result;
        }

        protected function getLogin($userId)
        {
                $login = ilObjUser::_lookupLogin($userId);
                $this->writelog('getLogin('.$userId.'):'.var_export($login,true));
                return $login;
        }


        private function getObject($davPath)
        {
                global $tree;

                // If the second path elements starts with 'file_', the following
                // characters of the path element directly identify the ref_id of
                // a file object.
                $davPathComponents = explode('/',substr($davPath,1));

                if (count($davPathComponents) > 1 &&
                        substr($davPathComponents[1],0,5) == 'file_')
                {
                        $ref_id = substr($davPathComponents[1],5);
                        $nodePath = $tree->getNodePath($ref_id, $tree->root_id);

                        // Poor IE needs this, in order to successfully display
                        // PDF documents
                        header('Pragma: private');
                }
                else
                {
                        $nodePath = $this->toNodePath($davPath);
                        if ($nodePath == null && count($davPathComponents) == 1)
                        {
                                return ilObjectDAV::createObject(-1,'mountPoint');
                        }
                }
                if (is_null($nodePath))
                {
                        return null;
                } else {
                        $top = $nodePath[count($nodePath)  - 1];
                        return ilObjectDAV::createObject($top['child'],$top['type']);
                }
        }
        private function toObjectPath($davPath)
        {
                $this->writelog('toObjectPath('.$davPath);
                global $tree;

                $nodePath = $this->toNodePath($davPath);

                if (is_null($nodePath))
                {
                        return null;
                } else {
                        $objectPath = array();
                        foreach ($nodePath as $node)
                        {
                                $pathElement = ilObjectDAV::createObject($node['child'],$node['type']);
                                if (is_null($pathElement))
                                {
                                        break;
                                }
                                $objectPath[] = $pathElement;
                        }
                        return $objectPath;
                }
        }

        public function toNodePath($davPath)
        {
                global $tree;
                $this->writelog('toNodePath('.$davPath.')...');

                // Split the davPath into path titles
                $titlePath = explode('/',substr($davPath,1));

                // Remove the client id from the beginning of the title path
                if (count($titlePath) > 0)
                {
                        array_shift($titlePath);
                }

                // If the last path title is empty, remove it
                if (count($titlePath) > 0 && $titlePath[count($titlePath) - 1] == '')
                {
                        array_pop($titlePath);
                }

                // If the path is empty, return null
                if (count($titlePath) == 0)
                {
                        $this->writelog('toNodePath('.$davPath.'):null, because path is empty.');
                        return null;
                }

                // If the path is an absolute path, ref_id is null.
                $ref_id = null;

                // If the path is a relative folder path, convert it into an absolute path
                if (count($titlePath) > 0 && substr($titlePath[0],0,4) == 'ref_')
                {
                        $ref_id = substr($titlePath[0],4);
                        array_shift($titlePath);
                }

                $nodePath = $tree->getNodePathForTitlePath($titlePath, $ref_id);

                $this->writelog('toNodePath():'.var_export($nodePath,true));
                return $nodePath;
        }

        private function davDeslashify($path)
        {
                $path = UtfNormal::toNFC($path);

                if ($path[strlen($path)-1] == '/') {
                        $path = substr($path,0, strlen($path) - 1);
                }
                $this->writelog('davDeslashify:'.$path);
                return $path;
        }

        private function davBasename($path)
        {
                $components = explode('/',$path);
                return count($components) == 0 ? '' : $components[count($components) - 1];
        }

        protected function writelog($message)
        {
                // Only write log message, if we are in debug mode
                if ($this->isDebug)
                {
                        global $ilLog, $ilias;
                        if ($ilLog)
                        {
                                if ($message == '---')
                                {
                                                $ilLog->write('');
                                } else {
                                                $ilLog->write(
                                                                $ilias->account->getLogin()
                                                .' '.$_SERVER['REMOTE_ADDR'].':'.$_SERVER['REMOTE_PORT']
                                                .' ilDAVServer.'.str_replace("\n",";",$message)
                                                        );
                                }
                        }
                        else
                        {
                                $fh = fopen('/opt/ilias/log/ilias.log', 'a');
                                fwrite($fh, date('Y-m-d H:i:s '));
                                fwrite($fh, str_replace("\n",";",$message));
                                fwrite($fh, "\n\n");
                                fclose($fh);
                        }
                }
        }

        function getMountURI($refId, $nodeId = 0, $ressourceName = null, $parentRefId = null, $genericURI = false)
        {
                if ($genericURI) {
                        $baseUri = ($this->isWebDAVoverHTTPS() ? "https:" : "http:");
                        $query = null;
                } else if ($this->clientOS == 'windows') {
                        $baseUri = ($this->isWebDAVoverHTTPS() ? "https:" : "http:");
                        $query = 'mount-instructions';
                } else if ($this->clientBrowser == 'konqueror') {
                        $baseUri = ($this->isWebDAVoverHTTPS() ? "webdavs:" : "webdav:");
                        $query = null;
                } else if ($this->clientBrowser == 'nautilus') {
                        $baseUri = ($this->isWebDAVoverHTTPS() ? "davs:" : "dav:");
                        $query = null;
                } else {
                        $baseUri = ($this->isWebDAVoverHTTPS() ? "https:" : "http:");
                        $query = 'mount-instructions';
                }
                $baseUri.= "//$_SERVER[HTTP_HOST]$_SERVER[SCRIPT_NAME]";
                $baseUri = substr($baseUri,0,strrpos($baseUri,'/')).'/webdav.php/'.CLIENT_ID;

                $uri = $baseUri.'/ref_'.$refId.'/';
                if ($query != null)
                {
                        $uri .= '?'.$query;
                }

                return $uri;
        }
        function getFolderURI($refId, $nodeId = 0, $ressourceName = null, $parentRefId = null)
        {
                if ($this->clientOS == 'windows') {
                        $baseUri = ($this->isWebDAVoverHTTPS() ? "https:" : "http:");
                        $query = null;
                } else if ($this->clientBrowser == 'konqueror') {
                        $baseUri = ($this->isWebDAVoverHTTPS() ? "webdavs:" : "webdav:");
                        $query = null;
                } else if ($this->clientBrowser == 'nautilus') {
                        $baseUri = ($this->isWebDAVoverHTTPS() ? "davs:" : "dav:");
                        $query = null;
                } else {
                        $baseUri = ($this->isWebDAVoverHTTPS() ? "https:" : "http:");
                        $query = null;
                }
                $baseUri.= "//$_SERVER[HTTP_HOST]$_SERVER[SCRIPT_NAME]";
                $baseUri = substr($baseUri,0,strrpos($baseUri,'/')).'/webdav.php/'.CLIENT_ID;

                $uri = $baseUri.'/ref_'.$refId.'/';
                if ($query != null)
                {
                        $uri .= '?'.$query;
                }

                return $uri;
        }
        public function getObjectURI($refId, $ressourceName = null, $parentRefId = null)
        {
                $nodeId = 0;
                $baseUri = ($this->isWebDAVoverHTTPS() ? "https:" : "http:").
                                "//$_SERVER[HTTP_HOST]$_SERVER[SCRIPT_NAME]";
                $baseUri = substr($baseUri,0,strrpos($baseUri,'/')).'/webdav.php/'.CLIENT_ID;

                if (! is_null($ressourceName) && ! is_null($parentRefId))
                {
                        // Quickly create URI from the known data without needing SQL queries
                        $uri = $baseUri.'/ref_'.$parentRefId.'/'.$this->davUrlEncode($ressourceName);
                } else {
                        // Create URI and use some SQL queries to get the missing data
                        global $tree;
                        $nodePath = $tree->getNodePath($refId);

                        if (is_null($nodePath) || count($nodePath) < 2)
                        {
                                // No object path? Return null - file is not in repository.
                                $uri = null;
                        } else {
                                $uri = $baseUri.'/ref_'.$nodePath[count($nodePath) - 2]['child'].'/'.
                                                $this->davUrlEncode($nodePath[count($nodePath) - 1]['title']);
                        }
                }
                return $uri;
        }

        public function getFileURI($refId, $ressourceName = null, $parentRefId = null)
        {
                $nodeId = 0;
                $baseUri = ($this->isWebDAVoverHTTPS() ? "https:" : "http:").
                                "//$_SERVER[HTTP_HOST]$_SERVER[SCRIPT_NAME]";
                $baseUri = substr($baseUri,0,strrpos($baseUri,'/')).'/webdav.php/'.CLIENT_ID;

                if (! is_null($ressourceName) && ! is_null($parentRefId))
                {
                        // Quickly create URI from the known data without needing SQL queries
                        $uri = $baseUri.'/file_'.$refId.'/'.$this->davUrlEncode($ressourceName);
                } else {
                        // Create URI and use some SQL queries to get the missing data
                        global $tree;
                        $nodePath = $tree->getNodePath($refId);

                        if (is_null($nodePath) || count($nodePath) < 2)
                        {
                                // No object path? Return null - file is not in repository.
                                $uri = null;
                        } else {
                                $uri = $baseUri.'/file_'.$nodePath[count($nodePath) - 1]['child'].'/'.
                                                $this->davUrlEncode($nodePath[count($nodePath) - 1]['title']);
                        }
                }
                return $uri;
        }

        public function isWebDAVoverHTTPS() {
                if ($this->isHTTPS == null) {
                        global $ilSetting;
                        require_once './Services/Http/classes/class.ilHTTPS.php';
                        $https = new ilHTTPS();
                        $this->isHTTPS = $https->isDetected() || $ilSetting->get('https');
                }
                return $this->isHTTPS;
        }

        public static function _isActive()
        {
                global $ilClientIniFile;
                return $ilClientIniFile->readVariable('file_access','webdav_enabled') == '1';
        }
        public static function _isActionsVisible()
        {
                global $ilClientIniFile;
                return $ilClientIniFile->readVariable('file_access','webdav_actions_visible') == '1';
        }

        public static function _getDefaultWebfolderInstructions()
        {
                global $lng;
                return $lng->txt('webfolder_instructions_text');
        }

        public static function _getWebfolderInstructionsFor($webfolderTitle,
                        $webfolderURI, $webfolderURI_IE, $webfolderURI_Konqueror, $webfolderURI_Nautilus,
                        $os = 'unknown', $osFlavor = 'unknown')
        {
                global $ilSetting;

                $settings = new ilSetting('file_access');
                $str = $settings->get('custom_webfolder_instructions', '');
                if (strlen($str) == 0 || ! $settings->get('custom_webfolder_instructions_enabled'))
                {
                        $str = ilDAVServer::_getDefaultWebfolderInstructions();
                }
                if(is_file('Customizing/clients/'.CLIENT_ID.'/webdavtemplate.htm')){
                        $str = fread(fopen('Customizing/clients/'.CLIENT_ID.'/webdavtemplate.htm', "rb"),filesize('Customizing/clients/'.CLIENT_ID.'/webdavtemplate.htm'));
                }
                $str=utf8_encode($str);

                preg_match_all('/(\\d+)/', $webfolderURI, $matches);
                $refID=end($matches[0]);
                
                $str = str_replace("[WEBFOLDER_ID]", $refID, $str);
                $str = str_replace("[WEBFOLDER_TITLE]", $webfolderTitle, $str);
                $str = str_replace("[WEBFOLDER_URI]", $webfolderURI, $str);
                $str = str_replace("[WEBFOLDER_URI_IE]", $webfolderURI_IE, $str);
                $str = str_replace("[WEBFOLDER_URI_KONQUEROR]", $webfolderURI_Konqueror, $str);
                $str = str_replace("[WEBFOLDER_URI_NAUTILUS]", $webfolderURI_Nautilus, $str);
                $str = str_replace("[ADMIN_MAIL]", $ilSetting->get("admin_email"), $str);

                if(strpos($_SERVER['HTTP_USER_AGENT'],'MSIE')!==false){
                        $str = preg_replace('/\[IF_IEXPLORE\](?:(.*))\[\/IF_IEXPLORE\]/s','\1', $str);
                }else{
                        $str = preg_replace('/\[IF_NOTIEXPLORE\](?:(.*))\[\/IF_NOTIEXPLORE\]/s','\1', $str);
                }
                
                switch ($os)
                {
                        case 'windows' :
                                $operatingSystem = 'WINDOWS';
                                break;
                        case 'unix' :
                                switch ($osFlavor)
                                {
                                        case 'osx' :
                                                $operatingSystem = 'MAC';
                                                break;
                                        case 'linux' :
                                                $operatingSystem = 'LINUX';
                                                break;
                                        default :
                                                $operatingSystem = 'LINUX';
                                                break;
                                }
                                break;
                        default :
                                $operatingSystem = 'UNKNOWN';
                                break;
                }

                if ($operatingSystem != 'UNKNOWN')
                {
                        $str = preg_replace('/\[IF_'.$operatingSystem.'\](?:(.*))\[\/IF_'.$operatingSystem.'\]/s','\1', $str);
                        $str = preg_replace('/\[IF_([A-Z_]+)\](?:(.*))\[\/IF_\1\]/s','', $str);
                }
                else
                {
                        $str = preg_replace('/\[IF_([A-Z_]+)\](?:(.*))\[\/IF_\1\]/s','\2', $str);
                }
                return $str;
        }

    private function getUploadMaxFilesize() {
        $val = ini_get('upload_max_filesize');

        $val = trim($val);
        $last = strtolower($val[strlen($val)-1]);
        switch($last) {
            // The 'G' modifier is available since PHP 5.1.0
            case 'g':
                $val *= 1024;
            case 'm':
                $val *= 1024;
            case 'k':
                $val *= 1024;
        }

        return $val;
    }
}
// END WebDAV
?>