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 {
                $this->clientOSFlavor = 'nichtxp';
            }
        } elseif (strpos($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) {
                $this->clientOSFlavor = 'linux';
            } elseif (strpos($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, $options);
            } elseif (isset($_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', $parentDAV->getObjectId());
        } elseif ($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->getVersion()) . '/' . $this->putObjDAV->obj->getFileName(), $this->putObjDAV->obj->getFileName());
            if ($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->getVersion()) . '/' . $objDAV->obj->getFileName()));
            }
            $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);
            }
        }
    }

    public function getMountURI($refId, $nodeId = 0, $ressourceName = null, $parentRefId = null, $genericURI = false)
    {
        if ($genericURI) {
            $baseUri = ($this->isWebDAVoverHTTPS() ? "https:" : "http:");
            $query = null;
        } elseif ($this->clientOS == 'windows') {
            $baseUri = ($this->isWebDAVoverHTTPS() ? "https:" : "http:");
            $query = 'mount-instructions';
        } elseif ($this->clientBrowser == 'konqueror') {
            $baseUri = ($this->isWebDAVoverHTTPS() ? "webdavs:" : "webdav:");
            $query = null;
        } elseif ($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 $uri;
    }
    public function getFolderURI($refId, $nodeId = 0, $ressourceName = null, $parentRefId = null)
    {
        if ($this->clientOS == 'windows') {
            $baseUri = ($this->isWebDAVoverHTTPS() ? "https:" : "http:");
            $query = null;
        } elseif ($this->clientBrowser == 'konqueror') {
            $baseUri = ($this->isWebDAVoverHTTPS() ? "webdavs:" : "webdav:");
            $query = null;
        } elseif ($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;
                // no break
            case 'm':
                $val *= 1024;
                // no break
            case 'k':
                $val *= 1024;
        }

        return $val;
    }
}
// END WebDAV