includes/externalstore/ExternalStoreMwstore.php

   1 <?php
   2 /**
   3  * External storage in a file backend.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  */
  22
  23 /**
  24  * File backend accessable external objects.
  25  *
  26  * In this system, each store "location" maps to the name of a file backend.
  27  * The file backends must be defined in $wgFileBackends and must be global
  28  * and fully qualified with a global "wikiId" prefix in the configuration.
  29  *
  30  * @ingroup ExternalStorage
  31  */
  32 class ExternalStoreMwstore extends ExternalStoreMedium {
  33         /**
  34          * The URL returned is of the form of the form mwstore://backend/container/wiki/id
  35          *
  36          * @see ExternalStoreMedium::fetchFromURL()
  37          */
  38         public function fetchFromURL( $url ) {
  39                 $be = FileBackendGroup::singleton()->backendFromPath( $url );
  40                 if ( $be instanceof FileBackend ) {
  41                         // We don't need "latest" since objects are immutable and
  42                         // backends should at least have "read-after-create" consistency.
  43                         return $be->getFileContents( array( 'src' => $url ) );
  44                 }
  45                 return false;
  46         }
  47
  48         /**
  49          * @see ExternalStoreMedium::store()
  50          */
  51         public function store( $backend, $data ) {
  52                 $be = FileBackendGroup::singleton()->get( $backend );
  53                 if ( $be instanceof FileBackend ) {
  54                         // Get three random base 36 characters to act as shard directories
  55                         $rand = wfBaseConvert( mt_rand( 0, 46655 ), 10, 36, 3 );
  56                         // Make sure ID is roughly lexicographically increasing for performance
  57                         $id = str_pad( UIDGenerator::getTimestampedID128( 32 ), 26, '0', STR_PAD_LEFT );
  58                         // Segregate items by wiki ID for the sake of book keeping
  59                         $wiki = isset( $this->params['wiki'] ) ? $this->params['wiki'] : wfWikiID();
  60
  61                         $url = $be->getContainerStoragePath( 'data' ) . '/' .
  62                                 rawurlencode( $wiki ) . "/{$rand[0]}/{$rand[1]}/{$rand[2]}/{$id}";
  63
  64                         $be->prepare( array( 'dir' => dirname( $url ) ) );
  65                         if ( $be->create( array( 'dst' => $url, 'content' => $data ) )->isOK() ) {
  66                                 return $url;
  67                         }
  68                 }
  69                 return false;
  70         }
  71 }