inc/DAVPrincipal.php

   1 <?php
   2 /**
   3 * An object representing a DAV 'Principal'
   4 *
   5 * @package   davical
   6 * @subpackage   Principal
   7 * @author    Andrew McMillan <andrew@mcmillan.net.nz>
   8 * @copyright Catalyst .Net Ltd, Morphoss Ltd <http://www.morhposs.com/>
   9 * @license   http://gnu.org/copyleft/gpl.html GNU GPL v2 or later
  10 */
  11
  12 require_once('Principal.php');
  13
  14 /**
  15 * A class for things to do with a DAV Principal
  16 *
  17 * @package   davical
  18 */
  19 class DAVPrincipal extends Principal
  20 {
  21
  22   /**
  23   * @var RFC4791: Identifies the URL(s) of any WebDAV collections that contain
  24   * calendar collections owned by the associated principal resource.
  25   */
  26   private $calendar_home_set;
  27
  28   /**
  29   * @var CardDAV: Identifies the URL(s) of any WebDAV collections that contain
  30   * addressbook collections owned by the associated principal resource.
  31   */
  32   private $addressbook_home_set;
  33
  34   /**
  35   * @var Obsolete: Identifies the URL(s) of any calendars participating in free/busy
  36   */
  37   private $calendar_free_busy_set;
  38
  39   /**
  40   * @var RFC3744: The principals that are direct members of this group.
  41   */
  42   protected $_is_group;
  43
  44   /**
  45   * @var RFC3744: The principals that are direct members of this group.
  46   */
  47   private $group_member_set;
  48
  49   /**
  50   * @var RFC3744: The groups in which the principal is directly a member.
  51   */
  52   private $group_membership;
  53
  54   /**
  55    * @var caldav-cu-proxy-02: The principals which this one has read permissions on.
  56    */
  57   private $read_proxy_for;
  58
  59   /**
  60    * @var caldav-cu-proxy-02: The principals which this one has read-write prmissions for.
  61    */
  62   private $write_proxy_for;
  63
  64    /**
  65    * @var caldav-cu-proxy-02: The principals which have read permissions on this one.
  66    */
  67   private $read_proxy_group;
  68
  69   /**
  70    * @var caldav-cu-proxy-02: The principals which have write permissions on this one.
  71    */
  72   private $write_proxy_group;
  73
  74   /**
  75    * @var CardDAV: The URL to an addressbook entry for this principal
  76    */
  77   private $principal_address;
  78
  79   /**
  80    * A unique tag which will change if this principal changes
  81    * @var string
  82    */
  83   private $unique_tag;
  84
  85   /**
  86   * Constructor
  87   * @param mixed $parameters If null, an empty Principal is created.  If it
  88   *              is an integer then that ID is read (if possible).  If it is
  89   *              an array then the Principal matching the supplied elements
  90   *              is read.  If it is an object then it is expected to be a 'usr'
  91   *              record that was read elsewhere.
  92   *
  93   * @return boolean Whether we actually read data from the DB to initialise the record.
  94   */
  95   function __construct( $parameters = null ) {
  96     global $session, $c;
  97
  98     $this->exists = null;
  99
 100     if ( $parameters == null ) return;
 101
 102     if ( is_object($parameters) ) {
 103       dbg_error_log( 'principal', 'Principal: record for %s', $parameters->username );
 104       parent::__construct('username',$parameters->username);
 105     }
 106     else if ( is_int($parameters) ) {
 107       dbg_error_log( 'principal', 'Principal: %d', $parameters );
 108       parent::__construct('principal_id',$parameters);
 109     }
 110     else if ( is_array($parameters) ) {
 111       if ( ! isset($parameters['options']['allow_by_email']) ) $parameters['options']['allow_by_email'] = false;
 112       if ( isset($parameters['username']) ) {
 113         parent::__construct('username',$parameters['username']);
 114       }
 115       else if ( isset($parameters['user_no']) ) {
 116         parent::__construct('user_no',$parameters['user_no']);
 117       }
 118       else if ( isset($parameters['principal_id']) ) {
 119         parent::__construct('principal_id',$parameters['principal_id']);
 120       }
 121       else if ( isset($parameters['email']) ) {
 122         parent::__construct('email',$parameters['email']);
 123       }
 124       else if ( isset($parameters['path']) ) {
 125         parent::__construct('path',$parameters['path']);
 126       }
 127       else if ( isset($parameters['principal-property-search']) ) {
 128         $username = $this->PropertySearch($parameters['principal-property-search']);
 129         parent::__construct('username',$username);
 130       }
 131     }
 132
 133     if ( ! $this->exists ) return;
 134
 135     $this->InitialiseRecord();
 136
 137   }
 138
 139
 140   /**
 141   * Initialise the Principal object from a $usr record from the DB.
 142   * @param object $usr The usr record from the DB.
 143   */
 144   function InitialiseRecord() {
 145     global $c;
 146
 147     $this->unique_tag = '"'.md5($this->username . $this->modified).'"';
 148     $this->_is_group = (isset($this->type_id) && $this->type_id == 3);
 149
 150     $this->principal_address = $this->url . 'principal.vcf';
 151
 152     $this->user_address_set = array(
 153        'mailto:'.$this->email,
 154        $this->url,
 155 //       ConstructURL( '/~'.$this->username.'/', true ),
 156 //       ConstructURL( '/__uuids__/'.$this->username.'/', true ),
 157     );
 158
 159     if ( isset ( $c->notifications_server ) ) {
 160       $this->xmpp_uri = 'xmpp:pubsub.'.$c->notifications_server['host'].'?pubsub;node=/davical-'.$this->principal_id;
 161       $this->xmpp_server = $c->notifications_server['host'];
 162     }
 163
 164     if ( $this->_is_group ) {
 165       $this->group_member_set = array();
 166       $qry = new AwlQuery('SELECT usr.username FROM group_member JOIN principal ON (principal_id=member_id) JOIN usr USING(user_no) WHERE group_id = :group_id ORDER BY principal.principal_id ', array( ':group_id' => $this->principal_id) );
 167       if ( $qry->Exec('DAVPrincipal') && $qry->rows() > 0 ) {
 168         while( $member = $qry->Fetch() ) {
 169           $this->group_member_set[] = ConstructURL( '/'. $member->username . '/', true);
 170         }
 171       }
 172     }
 173
 174     $this->group_membership = array();
 175     $qry = new AwlQuery('SELECT usr.username FROM group_member JOIN principal ON (principal_id=group_id) JOIN usr USING(user_no) WHERE member_id = :member_id UNION SELECT usr.username FROM group_member LEFT JOIN grants ON (to_principal=group_id) JOIN principal ON (principal_id=by_principal) JOIN usr USING(user_no) WHERE member_id = :member_id and by_principal != member_id ORDER BY 1', array( ':member_id' => $this->principal_id ) );
 176     if ( $qry->Exec('DAVPrincipal') && $qry->rows() > 0 ) {
 177       while( $group = $qry->Fetch() ) {
 178         $this->group_membership[] = ConstructURL( '/'. $group->username . '/', true);
 179       }
 180     }
 181
 182     $this->read_proxy_group = null;
 183     $this->write_proxy_group = null;
 184     $this->write_proxy_for = null;
 185     $this->read_proxy_for = null;
 186
 187     dbg_error_log( 'principal', ' User: %s (%d) URL: %s, By Email: %d', $this->username, $this->user_no, $this->url, $this->by_email );
 188   }
 189
 190
 191   /**
 192   * Split this out so we do it as infrequently as possible, given the cost.
 193   */
 194   function FetchProxyGroups() {
 195     global $c;
 196
 197     $this->read_proxy_group = array();
 198     $this->write_proxy_group = array();
 199     $this->write_proxy_for = array();
 200     $this->read_proxy_for = array();
 201
 202     if ( isset($c->disable_caldav_proxy) && $c->disable_caldav_proxy ) return;
 203
 204     $write_priv = privilege_to_bits(array('write'));
 205     // whom are we a proxy for? who is a proxy for us?
 206     // (as per Caldav Proxy section 5.1 Paragraph 7 and 5)
 207     $sql = 'SELECT principal_id, username, pprivs(:request_principal::int8,principal_id,:scan_depth::int) FROM principal JOIN usr USING(user_no) WHERE principal_id IN (SELECT * from p_has_proxy_access_to(:request_principal,:scan_depth))';
 208     $params = array( ':request_principal' => $this->principal_id, ':scan_depth' => $c->permission_scan_depth );
 209     $qry = new AwlQuery($sql, $params);
 210     if ( $qry->Exec('DAVPrincipal') && $qry->rows() > 0 ) {
 211       while( $relationship = $qry->Fetch() ) {
 212         if ( (bindec($relationship->pprivs) & $write_priv) != 0 ) {
 213           $this->write_proxy_for[] = ConstructURL( '/'. $relationship->username . '/', true);
 214           $this->group_membership[] = ConstructURL( '/'. $relationship->username . '/calendar-proxy-write/', true);
 215         }
 216         else {
 217           $this->read_proxy_for[] = ConstructURL( '/'. $relationship->username . '/', true);
 218           $this->group_membership[] = ConstructURL( '/'. $relationship->username . '/calendar-proxy-read/', true);
 219         }
 220       }
 221     }
 222
 223     $sql = 'SELECT principal_id, username, pprivs(:request_principal::int8,principal_id,:scan_depth::int) FROM principal JOIN usr USING(user_no) WHERE principal_id IN (SELECT * from grants_proxy_access_from_p(:request_principal,:scan_depth))';
 224     $qry = new AwlQuery($sql, $params ); // reuse $params assigned for earlier query
 225     if ( $qry->Exec('DAVPrincipal') && $qry->rows() > 0 ) {
 226       while( $relationship = $qry->Fetch() ) {
 227         if ( bindec($relationship->pprivs) & $write_priv ) {
 228           $this->write_proxy_group[] = ConstructURL( '/'. $relationship->username . '/', true);
 229         }
 230         else {
 231           $this->read_proxy_group[] = ConstructURL( '/'. $relationship->username . '/', true);
 232         }
 233       }
 234     }
 235 //      @dbg_error_log( 'principal', 'Read-proxy-for:    %s', implode(',',$this->read_proxy_for) );
 236 //      @dbg_error_log( 'principal', 'Write-proxy-for:   %s', implode(',',$this->write_proxy_for) );
 237 //      @dbg_error_log( 'principal', 'Read-proxy-group:  %s', implode(',',$this->read_proxy_group) );
 238 //      @dbg_error_log( 'principal', 'Write-proxy-group: %s', implode(',',$this->write_proxy_group) );
 239   }
 240
 241
 242   /**
 243   * Accessor for the read proxy group
 244   */
 245   function ReadProxyGroup() {
 246     if ( !isset($this->read_proxy_group) ) $this->FetchProxyGroups();
 247     return $this->read_proxy_group;
 248   }
 249
 250
 251   /**
 252   * Accessor for the write proxy group
 253   */
 254   function WriteProxyGroup() {
 255     if ( !isset($this->write_proxy_group) ) $this->FetchProxyGroups();
 256     return $this->write_proxy_group;
 257   }
 258
 259
 260   /**
 261   * Accessor for read or write proxy
 262   * @param string read/write - which sort of proxy list is requested.
 263   */
 264   function ProxyFor( $type ) {
 265     if ( !isset($this->read_proxy_for) ) $this->FetchProxyGroups();
 266     if ( $type == 'write' ) return $this->write_proxy_for;
 267     return $this->read_proxy_for;
 268   }
 269
 270
 271   /**
 272   * Accessor for the group membership - the groups this principal is a member of
 273   */
 274   function GroupMembership() {
 275     if ( !isset($this->read_proxy_group) ) $this->FetchProxyGroups();
 276     return $this->group_membership;
 277   }
 278
 279
 280   /**
 281   * Accessor for the group member set - the members of this group
 282   */
 283   function GroupMemberSet() {
 284     if ( ! $this->_is_group ) return null;
 285     return $this->group_member_set;
 286   }
 287
 288
 289   /**
 290   * Is this a group principal?
 291   * @return boolean Whether this is a group principal
 292   */
 293   function IsGroup() {
 294     return $this->_is_group;
 295   }
 296
 297
 298   /**
 299   * Return an arbitrary property
 300   * @return string The name of the arbitrary property
 301   */
 302   function GetProperty( $property_id ) {
 303
 304     switch( $property_id ) {
 305       case 'DAV::resource-id':
 306         if ( $this->exists && $this->principal_id > 0 )
 307           ConstructURL('/.resources/'.$this->principal_id);
 308         else
 309           return null;
 310         break;
 311     }
 312
 313     if ( isset($this->{$property_id}) ) {
 314       if ( ! is_object($this->{$property_id}) ) return $this->{$property_id};
 315       return clone($this->{$property_id});
 316     }
 317     return null;
 318   }
 319
 320   /**
 321   * Returns the unique_tag (ETag or getctag) for this resource
 322   */
 323   public function unique_tag() {
 324     if ( isset($this->unique_tag) ) return $this->unique_tag;
 325
 326     if ( $this->exists !== true ) $this->unique_tag = '"-1"';
 327
 328     return $this->unique_tag;
 329   }
 330
 331
 332   /**
 333   * Get the calendar_home_set, as lazily as possible
 334   */
 335   function calendar_home_set() {
 336     if ( !isset($this->calendar_home_set) ) {
 337       $this->calendar_home_set = array();
 338       $qry = new AwlQuery('SELECT DISTINCT parent_container FROM collection WHERE is_calendar AND dav_name ~ :dav_name_start',
 339                              array( ':dav_name_start' => '^'.$this->dav_name));
 340       if ( $qry->Exec('principal',__LINE__,__FILE__) ) {
 341         if ( $qry->rows() > 0 ) {
 342           while( $calendar = $qry->Fetch() ) {
 343             $this->calendar_home_set[] = ConstructURL($calendar->parent_container, true);
 344           }
 345         }
 346         else {
 347           $this->calendar_home_set[] = $this->url;
 348         }
 349       }
 350     }
 351     return $this->calendar_home_set;
 352   }
 353
 354
 355   /**
 356   * Get the addressbook_home_set, as lazily as possible
 357   */
 358   function addressbook_home_set() {
 359     if ( !isset($this->addressbook_home_set) ) {
 360       $this->addressbook_home_set = array();
 361       $qry = new AwlQuery('SELECT DISTINCT parent_container FROM collection WHERE is_addressbook AND dav_name ~ :dav_name_start',
 362                              array( ':dav_name_start' => '^'.$this->dav_name));
 363       if ( $qry->Exec('principal',__LINE__,__FILE__) ) {
 364         if ( $qry->rows() > 0 ) {
 365           while( $addressbook = $qry->Fetch() ) {
 366             $this->addressbook_home_set[] = ConstructURL($addressbook->parent_container, true);
 367           }
 368         }
 369         else {
 370           $this->addressbook_home_set[] = $this->url;
 371         }
 372       }
 373     }
 374     return $this->addressbook_home_set;
 375   }
 376
 377
 378   /**
 379   * Get the calendar_free_busy_set, as lazily as possible
 380   */
 381   function calendar_free_busy_set() {
 382     if ( !isset($this->calendar_free_busy_set) ) {
 383       /**
 384       * calendar-free-busy-set has been dropped from draft 5 of the scheduling extensions for CalDAV
 385       * in favour of ???
 386       */
 387       $this->calendar_free_busy_set = array();
 388       $qry = new AwlQuery('SELECT dav_name FROM collection WHERE is_calendar AND (schedule_transp = \'opaque\' OR schedule_transp IS NULL) AND dav_name ~ :dav_name_start ORDER BY user_no, collection_id',
 389                              array( ':dav_name_start' => '^'.$this->dav_name));
 390       if ( $qry->Exec('principal',__LINE__,__FILE__) ) {
 391         while( $calendar = $qry->Fetch() ) {
 392           $this->calendar_free_busy_set[] = ConstructURL($calendar->dav_name, true);
 393         }
 394       }
 395     }
 396     return $this->calendar_free_busy_set;
 397   }
 398
 399
 400   /**
 401   * Return the privileges bits for the current session user to this resource
 402   */
 403   function Privileges() {
 404     global $session;
 405     if ( !isset($this->privileges) ) $this->privileges = 0;
 406     if ( is_string($this->privileges) ) $this->privileges = bindec( $this->privileges );
 407     if ( $this->_is_group ) {
 408       if ( isset($session->principal) && in_array($session->principal->url(), $this->GroupMemberSet()) ) {
 409         $this->privileges |=  privilege_to_bits( array('DAV::read', 'DAV::read-current-user-privilege-set') );
 410       }
 411     }
 412     return $this->privileges;
 413   }
 414
 415
 416   /**
 417   * Returns a representation of the principal as a collection
 418   */
 419   function AsCollection() {
 420     $dav_name = (isset($this->original_request_url) ? DeconstructURL($this->original_request_url) : $this->dav_name());
 421     $collection = (object) array(
 422                             'collection_id' => ($this->principal_id() ? $this->principal_id() : 0),
 423                             'is_calendar' => false,
 424                             'is_addressbook' => false,
 425                             'is_principal' => true,
 426                             'type'     => 'principal' . (isset($this->original_request_url) ? '_link' : ''),
 427                             'user_no'  => ($this->user_no() ? $this->user_no() : 0),
 428                             'username' => $this->username(),
 429                             'dav_name' => $dav_name,
 430                             'parent_container' => '/',
 431                             'email'    => ($this->email()? $this->email() : ''),
 432                             'created'  => $this->created,
 433                             'updated'  => $this->modified,
 434                             'dav_etag' => substr($this->unique_tag(),1,-1),
 435                             'resourcetypes' => $this->resourcetypes
 436                   );
 437     $collection->dav_displayname =  (isset($this->dav_displayname) ? $this->dav_displayname : (isset($this->fullname) ? $this->fullname : $collection->username));
 438
 439     return $collection;
 440   }
 441
 442
 443   function PropertySearch( $parameters ) {
 444     throw new Exception("Unimplemented!");
 445   }
 446
 447   /**
 448   * Returns properties which are specific to this principal
 449   */
 450   function PrincipalProperty( $tag, $prop, &$reply, &$denied ) {
 451
 452     dbg_error_log('principal',': RenderAsXML: Principal Property "%s"', $tag );
 453     switch( $tag ) {
 454       case 'DAV::getcontenttype':
 455         $reply->DAVElement( $prop, 'getcontenttype', 'httpd/unix-directory' );
 456         break;
 457
 458       case 'DAV::resourcetype':
 459         $reply->DAVElement( $prop, 'resourcetype', array( new XMLElement('principal'), new XMLElement('collection')) );
 460         break;
 461
 462       case 'DAV::displayname':
 463         $reply->DAVElement( $prop, 'displayname', $this->fullname );
 464         break;
 465
 466       case 'DAV::principal-URL':
 467         $reply->DAVElement( $prop, 'principal-URL', $reply->href($this->url()) );
 468         break;
 469
 470       case 'DAV::getlastmodified':
 471         $reply->DAVElement( $prop, 'getlastmodified', ISODateToHTTPDate($this->modified) );
 472         break;
 473
 474       case 'DAV::creationdate':
 475         $reply->DAVElement( $prop, 'creationdate', DateToISODate($this->created) );
 476         break;
 477
 478       case 'DAV::getcontentlanguage':
 479         /** Use the principal's locale by preference, otherwise system default */
 480         $locale = (isset($c->current_locale) ? $c->current_locale : '');
 481         if ( isset($this->locale) && $this->locale != '' ) $locale = $this->locale;
 482         $reply->DAVElement( $prop, 'getcontentlanguage', $locale );
 483         break;
 484
 485       case 'http://calendarserver.org/ns/:group-member-set':
 486       case 'DAV::group-member-set':
 487         if ( ! $this->_is_group ) return false;
 488         $reply->DAVElement( $prop, 'group-member-set', $reply->href($this->group_member_set) );
 489         break;
 490
 491       case 'http://calendarserver.org/ns/:group-membership':
 492       case 'DAV::group-membership':
 493         $reply->DAVElement( $prop, 'group-membership', $reply->href($this->GroupMembership()) );
 494         break;
 495
 496       case 'urn:ietf:params:xml:ns:caldav:schedule-inbox-URL':
 497         $reply->CalDAVElement($prop, 'schedule-inbox-URL', $reply->href($this->url('schedule-inbox')) );
 498         break;
 499
 500       case 'urn:ietf:params:xml:ns:caldav:schedule-outbox-URL':
 501         $reply->CalDAVElement($prop, 'schedule-outbox-URL', $reply->href($this->url('schedule-outbox')) );
 502         break;
 503
 504       case 'urn:ietf:params:xml:ns:caldav:schedule-default-calendar-URL':
 505         $reply->CalDAVElement($prop, 'schedule-default-calendar-URL', $reply->href($this->url('schedule-default-calendar')) );
 506         break;
 507
 508       case 'http://calendarserver.org/ns/:dropbox-home-URL':
 509         $reply->CalendarserverElement($prop, 'dropbox-home-URL', $reply->href($this->url('dropbox')) );
 510         break;
 511
 512       case 'http://calendarserver.org/ns/:xmpp-server':
 513         if ( ! isset( $this->xmpp_uri ) ) return false;
 514         $reply->CalendarserverElement($prop, 'xmpp-server', $this->xmpp_server );
 515         break;
 516
 517       case 'http://calendarserver.org/ns/:xmpp-uri':
 518         if ( ! isset( $this->xmpp_uri ) ) return false;
 519         $reply->CalendarserverElement($prop, 'xmpp-uri', $this->xmpp_uri );
 520         break;
 521
 522       case 'urn:ietf:params:xml:ns:carddav:addressbook-home-set':
 523         $reply->CardDAVElement($prop, $tag, $reply->href( $this->addressbook_home_set() ) );
 524         break;
 525
 526       case 'urn:ietf:params:xml:ns:caldav:calendar-home-set':
 527         $reply->CalDAVElement($prop, $tag, $reply->href( $this->calendar_home_set() ) );
 528         break;
 529
 530       case 'urn:ietf:params:xml:ns:caldav:calendar-free-busy-set':
 531         $reply->CalDAVElement( $prop, 'calendar-free-busy-set', $reply->href( $this->calendar_free_busy_set() ) );
 532         break;
 533
 534       case 'urn:ietf:params:xml:ns:caldav:calendar-user-address-set':
 535         $reply->CalDAVElement($prop, 'calendar-user-address-set', $reply->href($this->user_address_set) );
 536         break;
 537
 538       case 'DAV::owner':
 539         // After a careful reading of RFC3744 we see that this must be the principal-URL of the owner
 540         $reply->DAVElement( $prop, 'owner', $reply->href( $this->url ) );
 541         break;
 542
 543       // Empty tag responses.
 544       case 'DAV::alternate-URI-set':
 545         $reply->DAVElement( $prop, $reply->Tag($tag));
 546         break;
 547
 548       case 'SOME-DENIED-PROPERTY':  /** @todo indicating the style for future expansion */
 549         $denied[] = $reply->Tag($tag);
 550         break;
 551
 552       default:
 553         return false;
 554         break;
 555     }
 556
 557     return true;
 558   }
 559
 560
 561   /**
 562   * Render XML for a single Principal (user) from the DB
 563   *
 564   * @param array $properties The requested properties for this principal
 565   * @param reference $reply A reference to the XMLDocument being used for the reply
 566   * @param boolean $props_only Default false.  If true will only return the fragment with the properties, not a full response fragment.
 567   *
 568   * @return string An XML fragment with the requested properties for this principal
 569   */
 570   function RenderAsXML( $properties, &$reply, $props_only = false ) {
 571     global $request;
 572
 573     dbg_error_log('principal',': RenderAsXML: Principal "%s"', $this->username );
 574
 575     $prop = new XMLElement('prop');
 576     $denied = array();
 577     $not_found = array();
 578     foreach( $properties AS $k => $tag ) {
 579       if ( ! $this->PrincipalProperty( $tag, $prop, $reply, $denied ) ) {
 580         dbg_error_log( 'principal', 'Request for unsupported property "%s" of principal "%s".', $tag, $this->username );
 581         $not_found[] = $reply->Tag($tag);
 582       }
 583     }
 584
 585     if ( $props_only ) return $prop;
 586
 587     $status = new XMLElement('status', 'HTTP/1.1 200 OK' );
 588
 589     $propstat = new XMLElement( 'propstat', array( $prop, $status) );
 590     $href = $reply->href($this->url );
 591
 592     $elements = array($href,$propstat);
 593
 594     if ( count($denied) > 0 ) {
 595       $status = new XMLElement('status', 'HTTP/1.1 403 Forbidden' );
 596       $noprop = new XMLElement('prop');
 597       foreach( $denied AS $k => $v ) {
 598         $noprop->NewElement( $v );
 599       }
 600       $elements[] = new XMLElement( 'propstat', array( $noprop, $status) );
 601     }
 602
 603     if ( count($not_found) > 0 ) {
 604       $status = new XMLElement('status', 'HTTP/1.1 404 Not Found' );
 605       $noprop = new XMLElement('prop');
 606       foreach( $not_found AS $k => $v ) {
 607         $noprop->NewElement( $v );
 608       }
 609       $elements[] = new XMLElement( 'propstat', array( $noprop, $status) );
 610     }
 611
 612     $response = new XMLElement( 'response', $elements );
 613
 614     return $response;
 615   }
 616
 617 }