includes/interwiki/ClassicInterwikiLookup.php
<?php
/**
* 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
*/
namespace MediaWiki\Interwiki;
use Interwiki;
use MapCacheLRU;
use MediaWiki\Config\ServiceOptions;
use MediaWiki\HookContainer\HookContainer;
use MediaWiki\HookContainer\HookRunner;
use MediaWiki\Language\Language;
use MediaWiki\MainConfigNames;
use MediaWiki\WikiMap\WikiMap;
use WANObjectCache;
use Wikimedia\Rdbms\IConnectionProvider;
/**
* InterwikiLookup backed by the `interwiki` database table or $wgInterwikiCache.
*
* By default this uses the SQL backend (`interwiki` database table) and includes
* two levels of caching. When parsing a wiki page, many interwiki lookups may
* be required and thus there is in-class caching for repeat lookups. To reduce
* database pressure, there is also WANObjectCache for each prefix.
*
* Optionally, a pregenerated dataset can be statically set via $wgInterwikiCache,
* in which case there are no calls to either database or WANObjectCache.
*
* @since 1.28
*/
class ClassicInterwikiLookup implements InterwikiLookup {
/**
* @internal For use by ServiceWiring
* @var string[]
*/
public const CONSTRUCTOR_OPTIONS = [
MainConfigNames::InterwikiExpiry,
MainConfigNames::InterwikiCache,
MainConfigNames::InterwikiScopes,
MainConfigNames::InterwikiFallbackSite,
'wikiId',
];
private ServiceOptions $options;
/** @var Language */
private $contLang;
/** @var WANObjectCache */
private $wanCache;
/** @var HookRunner */
private $hookRunner;
/** @var IConnectionProvider */
private $dbProvider;
/** @var MapCacheLRU<Interwiki|false> */
private $instances;
/**
* Specify number of domains to check for messages:
* - 1: Just local wiki level
* - 2: wiki and global levels
* - 3: site level as well as wiki and global levels
* @var int
*/
private $interwikiScopes;
/** @var array|null Complete pregenerated data if available */
private $data;
/** @var string */
private $wikiId;
/** @var string|null */
private $thisSite = null;
/**
* @param ServiceOptions $options
* @param Language $contLang Language object used to convert prefixes to lower case
* @param WANObjectCache $wanCache Cache for interwiki info retrieved from the database
* @param HookContainer $hookContainer
* @param IConnectionProvider $dbProvider
*/
public function __construct(
ServiceOptions $options,
Language $contLang,
WANObjectCache $wanCache,
HookContainer $hookContainer,
IConnectionProvider $dbProvider
) {
$options->assertRequiredOptions( self::CONSTRUCTOR_OPTIONS );
$this->options = $options;
$this->contLang = $contLang;
$this->wanCache = $wanCache;
$this->hookRunner = new HookRunner( $hookContainer );
$this->dbProvider = $dbProvider;
$this->instances = new MapCacheLRU( 1000 );
$this->interwikiScopes = $options->get( MainConfigNames::InterwikiScopes );
$interwikiData = $options->get( MainConfigNames::InterwikiCache );
$this->data = is_array( $interwikiData ) ? $interwikiData : null;
$this->wikiId = $options->get( 'wikiId' );
}
/**
* @inheritDoc
* @param string $prefix
* @return bool
*/
public function isValidInterwiki( $prefix ) {
$iw = $this->fetch( $prefix );
return (bool)$iw;
}
/**
* @inheritDoc
* @param string|null $prefix
* @return Interwiki|null|false
*/
public function fetch( $prefix ) {
if ( $prefix === null || $prefix === '' ) {
return null;
}
$prefix = $this->contLang->lc( $prefix );
return $this->instances->getWithSetCallback(
$prefix,
function () use ( $prefix ) {
return $this->load( $prefix );
}
);
}
/**
* Purge the instance cache and memcached for an interwiki prefix
*
* Note that memcached is not used when $wgInterwikiCache
* is enabled, as the pregenerated data will be used statically
* without need for memcached.
*
* @param string $prefix
*/
public function invalidateCache( $prefix ) {
$this->instances->clear( $prefix );
$key = $this->wanCache->makeKey( 'interwiki', $prefix );
$this->wanCache->delete( $key );
}
/**
* Get value from pregenerated data
*
* @param string $prefix
* @return string|false The pregen value or false if prefix is not known
*/
private function getPregenValue( string $prefix ) {
// Lazily resolve site name
if ( $this->interwikiScopes >= 3 && !$this->thisSite ) {
$this->thisSite = $this->data['__sites:' . $this->wikiId]
?? $this->options->get( MainConfigNames::InterwikiFallbackSite );
}
$value = $this->data[$this->wikiId . ':' . $prefix] ?? false;
// Site level
if ( $value === false && $this->interwikiScopes >= 3 ) {
$value = $this->data["_{$this->thisSite}:{$prefix}"] ?? false;
}
// Global level
if ( $value === false && $this->interwikiScopes >= 2 ) {
$value = $this->data["__global:{$prefix}"] ?? false;
}
return $value;
}
/**
* Fetch interwiki data and create an Interwiki object.
*
* Use pregenerated data if enabled. Otherwise try memcached first
* and fallback to a DB query.
*
* @param string $prefix The interwiki prefix
* @return Interwiki|false False is prefix is invalid
*/
private function load( $prefix ) {
if ( $this->data !== null ) {
$value = $this->getPregenValue( $prefix );
return $value ? $this->makeFromPregen( $prefix, $value ) : false;
}
$iwData = [];
$abort = !$this->hookRunner->onInterwikiLoadPrefix( $prefix, $iwData );
if ( isset( $iwData['iw_url'] ) ) {
// Hook provided data
return $this->makeFromRow( $iwData );
}
if ( $abort ) {
// Hook indicated no other source may be considered
return false;
}
$fname = __METHOD__;
$iwData = $this->wanCache->getWithSetCallback(
$this->wanCache->makeKey( 'interwiki', $prefix ),
$this->options->get( MainConfigNames::InterwikiExpiry ),
function ( $oldValue, &$ttl, array &$setOpts ) use ( $prefix, $fname ) {
$dbr = $this->dbProvider->getReplicaDatabase();
$row = $dbr->newSelectQueryBuilder()
->select( self::selectFields() )
->from( 'interwiki' )
->where( [ 'iw_prefix' => $prefix ] )
->caller( $fname )->fetchRow();
return $row ? (array)$row : '!NONEXISTENT';
}
);
// Handle non-existent case
return is_array( $iwData ) ? $this->makeFromRow( $iwData ) : false;
}
/**
* @param array $row Row from the interwiki table, possibly via memcached
* @return Interwiki
*/
private function makeFromRow( array $row ) {
$url = $row['iw_url'];
$local = $row['iw_local'] ?? 0;
$trans = $row['iw_trans'] ?? 0;
$api = $row['iw_api'] ?? '';
$wikiId = $row['iw_wikiid'] ?? '';
return new Interwiki( null, $url, $api, $wikiId, $local, $trans );
}
/**
* @param string $prefix
* @param string $value
* @return Interwiki
*/
private function makeFromPregen( string $prefix, string $value ) {
// Split values
[ $local, $url ] = explode( ' ', $value, 2 );
return new Interwiki( $prefix, $url, '', '', (int)$local );
}
/**
* Fetch all interwiki prefixes from pregenerated data
*
* @param null|string $local
* @return array Database-like rows
*/
private function getAllPrefixesPregenerated( $local ) {
// Lazily resolve site name
if ( $this->interwikiScopes >= 3 && !$this->thisSite ) {
$this->thisSite = $this->data['__sites:' . $this->wikiId]
?? $this->options->get( MainConfigNames::InterwikiFallbackSite );
}
// List of interwiki sources
$sources = [];
// Global level
if ( $this->interwikiScopes >= 2 ) {
$sources[] = '__global';
}
// Site level
if ( $this->interwikiScopes >= 3 ) {
$sources[] = '_' . $this->thisSite;
}
$sources[] = $this->wikiId;
$data = [];
foreach ( $sources as $source ) {
$list = $this->data['__list:' . $source] ?? '';
foreach ( explode( ' ', $list ) as $iw_prefix ) {
$row = $this->data["{$source}:{$iw_prefix}"] ?? null;
if ( !$row ) {
continue;
}
[ $iw_local, $iw_url ] = explode( ' ', $row );
if ( $local !== null && $local != $iw_local ) {
continue;
}
$data[$iw_prefix] = [
'iw_prefix' => $iw_prefix,
'iw_url' => $iw_url,
'iw_local' => $iw_local,
];
}
}
return array_values( $data );
}
/**
* Build an array in the format accepted by $wgInterwikiCache.
*
* Given the array returned by getAllPrefixes(), build a PHP array which
* can be given to self::__construct() as $interwikiData, i.e. as the
* value of $wgInterwikiCache. This is used to construct mock
* interwiki lookup services for testing (in particular, parsertests).
*
* @param array $allPrefixes An array of interwiki information such as
* would be returned by ::getAllPrefixes()
* @param int $scope The scope at which to insert interwiki prefixes.
* See the $interwikiScopes parameter to ::__construct().
* @param ?string $thisSite The value of $thisSite, if $scope is 3.
* @return array
*/
public static function buildCdbHash(
array $allPrefixes, int $scope = 1, ?string $thisSite = null
): array {
$result = [];
$wikiId = WikiMap::getCurrentWikiId();
$keyPrefix = ( $scope >= 2 ) ? '__global' : $wikiId;
if ( $scope >= 3 && $thisSite ) {
$result[ "__sites:$wikiId" ] = $thisSite;
$keyPrefix = "_$thisSite";
}
$list = [];
foreach ( $allPrefixes as $iwInfo ) {
$prefix = $iwInfo['iw_prefix'];
$result["$keyPrefix:$prefix"] = implode( ' ', [
$iwInfo['iw_local'] ?? 0, $iwInfo['iw_url']
] );
$list[] = $prefix;
}
$result["__list:$keyPrefix"] = implode( ' ', $list );
$result["__list:__sites"] = $wikiId;
return $result;
}
/**
* Fetch all interwiki prefixes from DB
*
* @param bool|null $local
* @return array[] Database rows
*/
private function getAllPrefixesDB( $local ) {
$where = [];
if ( $local !== null ) {
$where['iw_local'] = (int)$local;
}
$dbr = $this->dbProvider->getReplicaDatabase();
$res = $dbr->newSelectQueryBuilder()
->select( self::selectFields() )
->from( 'interwiki' )
->where( $where )
->orderBy( 'iw_prefix' )
->caller( __METHOD__ )->fetchResultSet();
$retval = [];
foreach ( $res as $row ) {
$retval[] = (array)$row;
}
return $retval;
}
/**
* Fetch all interwiki data
*
* @param string|null $local If set, limit returned data to local or non-local interwikis
* @return array[] Database-like interwiki rows
*/
public function getAllPrefixes( $local = null ) {
if ( $this->data !== null ) {
return $this->getAllPrefixesPregenerated( $local );
} else {
return $this->getAllPrefixesDB( $local );
}
}
/**
* List of interwiki table fields to select.
*
* @return string[]
*/
private static function selectFields() {
return [
'iw_prefix',
'iw_url',
'iw_api',
'iw_wikiid',
'iw_local',
'iw_trans'
];
}
}