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  * @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          * @param string $url
  39          * @return bool
  40          */
  41         public function fetchFromURL( $url ) {
  42                 $be = FileBackendGroup::singleton()->backendFromPath( $url );
  43                 if ( $be instanceof FileBackend ) {
  44                         // We don't need "latest" since objects are immutable and
  45                         // backends should at least have "read-after-create" consistency.
  46                         return $be->getFileContents( [ 'src' => $url ] );
  47                 }
  48
  49                 return false;
  50         }
  51
  52         /**
  53          * Fetch data from given external store URLs.
  54          * The URL returned is of the form of the form mwstore://backend/container/wiki/id
  55          *
  56          * @param array $urls An array of external store URLs
  57          * @return array A map from url to stored content. Failed results are not represented.
  58          */
  59         public function batchFetchFromURLs( array $urls ) {
  60                 $pathsByBackend = [];
  61                 foreach ( $urls as $url ) {
  62                         $be = FileBackendGroup::singleton()->backendFromPath( $url );
  63                         if ( $be instanceof FileBackend ) {
  64                                 $pathsByBackend[$be->getName()][] = $url;
  65                         }
  66                 }
  67                 $blobs = [];
  68                 foreach ( $pathsByBackend as $backendName => $paths ) {
  69                         $be = FileBackendGroup::singleton()->get( $backendName );
  70                         $blobs = $blobs + $be->getFileContentsMulti( [ 'srcs' => $paths ] );
  71                 }
  72
  73                 return $blobs;
  74         }
  75
  76         /**
  77          * @see ExternalStoreMedium::store()
  78          * @param string $backend
  79          * @param string $data
  80          * @return string|bool
  81          * @throws MWException
  82          */
  83         public function store( $backend, $data ) {
  84                 $be = FileBackendGroup::singleton()->get( $backend );
  85                 if ( $be instanceof FileBackend ) {
  86                         // Get three random base 36 characters to act as shard directories
  87                         $rand = Wikimedia\base_convert( mt_rand( 0, 46655 ), 10, 36, 3 );
  88                         // Make sure ID is roughly lexicographically increasing for performance
  89                         $id = str_pad( UIDGenerator::newTimestampedUID128( 32 ), 26, '0', STR_PAD_LEFT );
  90                         // Segregate items by wiki ID for the sake of bookkeeping
  91                         $wiki = isset( $this->params['wiki'] ) ? $this->params['wiki'] : wfWikiID();
  92
  93                         $url = $be->getContainerStoragePath( 'data' ) . '/' . rawurlencode( $wiki );
  94                         $url .= ( $be instanceof FSFileBackend )
  95                                 ? "/{$rand[0]}/{$rand[1]}/{$rand[2]}/{$id}" // keep directories small
  96                                 : "/{$rand[0]}/{$rand[1]}/{$id}"; // container sharding is only 2-levels
  97
  98                         $be->prepare( [ 'dir' => dirname( $url ), 'noAccess' => 1, 'noListing' => 1 ] );
  99                         if ( $be->create( [ 'dst' => $url, 'content' => $data ] )->isOK() ) {
 100                                 return $url;
 101                         }
 102                 }
 103
 104                 return false;
 105         }
 106 }