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<?php
/**
* External storage in a file backend.
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
*/
/**
* File backend accessable external objects.
*
* In this system, each store "location" maps to the name of a file backend.
* The file backends must be defined in $wgFileBackends and must be global
* and fully qualified with a global "wikiId" prefix in the configuration.
*
* @ingroup ExternalStorage
* @since 1.21
*/
class ExternalStoreMwstore extends ExternalStoreMedium {
/**
* The URL returned is of the form of the form mwstore://backend/container/wiki/id
*
* @see ExternalStoreMedium::fetchFromURL()
*/
public function fetchFromURL( $url ) {
$be = FileBackendGroup::singleton()->backendFromPath( $url );
if ( $be instanceof FileBackend ) {
// We don't need "latest" since objects are immutable and
// backends should at least have "read-after-create" consistency.
return $be->getFileContents( array( 'src' => $url ) );
}
return false;
}
/**
* Fetch data from given external store URLs.
* The URL returned is of the form of the form mwstore://backend/container/wiki/id
*
* @param array $urls An array of external store URLs
* @return array A map from url to stored content. Failed results are not represented.
*/
public function batchFetchFromURLs( array $urls ) {
$pathsByBackend = array();
foreach ( $urls as $url ) {
$be = FileBackendGroup::singleton()->backendFromPath( $url );
if ( $be instanceof FileBackend ) {
$pathsByBackend[$be->getName()][] = $url;
}
}
$blobs = array();
foreach ( $pathsByBackend as $backendName => $paths ) {
$be = FileBackendGroup::singleton()->get( $backendName );
$blobs = $blobs + $be->getFileContentsMulti( array( 'srcs' => $paths ) );
}
return $blobs;
}
/**
* @see ExternalStoreMedium::store()
*/
public function store( $backend, $data ) {
$be = FileBackendGroup::singleton()->get( $backend );
if ( $be instanceof FileBackend ) {
// Get three random base 36 characters to act as shard directories
$rand = wfBaseConvert( mt_rand( 0, 46655 ), 10, 36, 3 );
// Make sure ID is roughly lexicographically increasing for performance
$id = str_pad( UIDGenerator::newTimestampedUID128( 32 ), 26, '0', STR_PAD_LEFT );
// Segregate items by wiki ID for the sake of bookkeeping
$wiki = isset( $this->params['wiki'] ) ? $this->params['wiki'] : wfWikiID();
$url = $be->getContainerStoragePath( 'data' ) . '/' . rawurlencode( $wiki );
$url .= ( $be instanceof FSFileBackend )
? "/{$rand[0]}/{$rand[1]}/{$rand[2]}/{$id}" // keep directories small
: "/{$rand[0]}/{$rand[1]}/{$id}"; // container sharding is only 2-levels
$be->prepare( array( 'dir' => dirname( $url ), 'noAccess' => 1, 'noListing' => 1 ) );
if ( $be->create( array( 'dst' => $url, 'content' => $data ) )->isOK() ) {
return $url;
}
}
return false;
}
}
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