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   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   * @since 1.21
  32   */
  33  class ExternalStoreMwstore extends ExternalStoreMedium {
  34      /**
  35       * The URL returned is of the form of the form mwstore://backend/container/wiki/id
  36       *
  37       * @see ExternalStoreMedium::fetchFromURL()
  38       */
  39  	public function fetchFromURL( $url ) {
  40          $be = FileBackendGroup::singleton()->backendFromPath( $url );
  41          if ( $be instanceof FileBackend ) {
  42              // We don't need "latest" since objects are immutable and
  43              // backends should at least have "read-after-create" consistency.
  44              return $be->getFileContents( array( 'src' => $url ) );
  45          }
  46  
  47          return false;
  48      }
  49  
  50      /**
  51       * Fetch data from given external store URLs.
  52       * The URL returned is of the form of the form mwstore://backend/container/wiki/id
  53       *
  54       * @param array $urls An array of external store URLs
  55       * @return array A map from url to stored content. Failed results are not represented.
  56       */
  57  	public function batchFetchFromURLs( array $urls ) {
  58          $pathsByBackend = array();
  59          foreach ( $urls as $url ) {
  60              $be = FileBackendGroup::singleton()->backendFromPath( $url );
  61              if ( $be instanceof FileBackend ) {
  62                  $pathsByBackend[$be->getName()][] = $url;
  63              }
  64          }
  65          $blobs = array();
  66          foreach ( $pathsByBackend as $backendName => $paths ) {
  67              $be = FileBackendGroup::singleton()->get( $backendName );
  68              $blobs = $blobs + $be->getFileContentsMulti( array( 'srcs' => $paths ) );
  69          }
  70  
  71          return $blobs;
  72      }
  73  
  74      /**
  75       * @see ExternalStoreMedium::store()
  76       */
  77  	public function store( $backend, $data ) {
  78          $be = FileBackendGroup::singleton()->get( $backend );
  79          if ( $be instanceof FileBackend ) {
  80              // Get three random base 36 characters to act as shard directories
  81              $rand = wfBaseConvert( mt_rand( 0, 46655 ), 10, 36, 3 );
  82              // Make sure ID is roughly lexicographically increasing for performance
  83              $id = str_pad( UIDGenerator::newTimestampedUID128( 32 ), 26, '0', STR_PAD_LEFT );
  84              // Segregate items by wiki ID for the sake of bookkeeping
  85              $wiki = isset( $this->params['wiki'] ) ? $this->params['wiki'] : wfWikiID();
  86  
  87              $url = $be->getContainerStoragePath( 'data' ) . '/' . rawurlencode( $wiki );
  88              $url .= ( $be instanceof FSFileBackend )
  89                  ? "/{$rand[0]}/{$rand[1]}/{$rand[2]}/{$id}" // keep directories small
  90                  : "/{$rand[0]}/{$rand[1]}/{$id}"; // container sharding is only 2-levels
  91  
  92              $be->prepare( array( 'dir' => dirname( $url ), 'noAccess' => 1, 'noListing' => 1 ) );
  93              if ( $be->create( array( 'dst' => $url, 'content' => $data ) )->isOK() ) {
  94                  return $url;
  95              }
  96          }
  97  
  98          return false;
  99      }
 100  }