includes/api/ApiQueryBacklinks.php
<?php
/**
* Copyright © 2006 Yuri Astrakhan "<Firstname><Lastname>@gmail.com"
*
* 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
*/
use MediaWiki\Linker\LinksMigration;
use MediaWiki\Title\Title;
use Wikimedia\ParamValidator\ParamValidator;
use Wikimedia\ParamValidator\TypeDef\IntegerDef;
use Wikimedia\Rdbms\OrExpressionGroup;
/**
* This is a three-in-one module to query:
* * backlinks - links pointing to the given page,
* * embeddedin - what pages transclude the given page within themselves,
* * imageusage - what pages use the given image
*
* @ingroup API
*/
class ApiQueryBacklinks extends ApiQueryGeneratorBase {
/**
* @var Title
*/
private $rootTitle;
/**
* @var LinksMigration
*/
private $linksMigration;
private $params;
/** @var array */
private $cont;
private $redirect;
private string $bl_ns;
private string $bl_from;
private string $bl_from_ns;
private string $bl_table;
private string $bl_code;
private string $bl_title;
private bool $hasNS;
/** @var string */
private $helpUrl;
/**
* Maps ns and title to pageid
*
* @var array
*/
private $pageMap = [];
private $resultArr;
private $redirTitles = [];
private $continueStr = null;
/** @var string[][] output element name, database column field prefix, database table */
private $backlinksSettings = [
'backlinks' => [
'code' => 'bl',
'prefix' => 'pl',
'linktbl' => 'pagelinks',
'helpurl' => 'https://www.mediawiki.org/wiki/Special:MyLanguage/API:Backlinks',
],
'embeddedin' => [
'code' => 'ei',
'prefix' => 'tl',
'linktbl' => 'templatelinks',
'helpurl' => 'https://www.mediawiki.org/wiki/Special:MyLanguage/API:Embeddedin',
],
'imageusage' => [
'code' => 'iu',
'prefix' => 'il',
'linktbl' => 'imagelinks',
'helpurl' => 'https://www.mediawiki.org/wiki/Special:MyLanguage/API:Imageusage',
]
];
/**
* @param ApiQuery $query
* @param string $moduleName
* @param LinksMigration $linksMigration
*/
public function __construct( ApiQuery $query, $moduleName, LinksMigration $linksMigration ) {
$settings = $this->backlinksSettings[$moduleName];
$prefix = $settings['prefix'];
$code = $settings['code'];
$this->resultArr = [];
parent::__construct( $query, $moduleName, $code );
$this->bl_table = $settings['linktbl'];
$this->hasNS = $moduleName !== 'imageusage';
$this->linksMigration = $linksMigration;
if ( isset( $this->linksMigration::$mapping[$this->bl_table] ) ) {
[ $this->bl_ns, $this->bl_title ] = $this->linksMigration->getTitleFields( $this->bl_table );
} else {
$this->bl_ns = $prefix . '_namespace';
if ( $this->hasNS ) {
$this->bl_title = $prefix . '_title';
} else {
$this->bl_title = $prefix . '_to';
}
}
$this->bl_from = $prefix . '_from';
$this->bl_from_ns = $prefix . '_from_namespace';
$this->bl_code = $code;
$this->helpUrl = $settings['helpurl'];
}
public function execute() {
$this->run();
}
public function getCacheMode( $params ) {
return 'public';
}
public function executeGenerator( $resultPageSet ) {
$this->run( $resultPageSet );
}
/**
* @param ApiPageSet|null $resultPageSet
* @return void
*/
private function runFirstQuery( $resultPageSet = null ) {
$this->addTables( [ $this->bl_table, 'page' ] );
$this->addWhere( "{$this->bl_from}=page_id" );
if ( $resultPageSet === null ) {
$this->addFields( [ 'page_id', 'page_title', 'page_namespace' ] );
} else {
$this->addFields( $resultPageSet->getPageTableFields() );
}
$this->addFields( [ 'page_is_redirect', 'from_ns' => 'page_namespace' ] );
if ( isset( $this->linksMigration::$mapping[$this->bl_table] ) ) {
$conds = $this->linksMigration->getLinksConditions( $this->bl_table, $this->rootTitle );
$this->addWhere( $conds );
} else {
$this->addWhereFld( $this->bl_title, $this->rootTitle->getDBkey() );
if ( $this->hasNS ) {
$this->addWhereFld( $this->bl_ns, $this->rootTitle->getNamespace() );
}
}
$this->addWhereFld( $this->bl_from_ns, $this->params['namespace'] );
if ( count( $this->cont ) >= 2 ) {
$db = $this->getDB();
$op = $this->params['dir'] == 'descending' ? '<=' : '>=';
if ( $this->params['namespace'] !== null && count( $this->params['namespace'] ) > 1 ) {
$this->addWhere( $db->buildComparison( $op, [
$this->bl_from_ns => $this->cont[0],
$this->bl_from => $this->cont[1],
] ) );
} else {
$this->addWhere( $db->buildComparison( $op, [ $this->bl_from => $this->cont[1] ] ) );
}
}
if ( $this->params['filterredir'] == 'redirects' ) {
$this->addWhereFld( 'page_is_redirect', 1 );
} elseif ( $this->params['filterredir'] == 'nonredirects' && !$this->redirect ) {
// T24245 - Check for !redirect, as filtering nonredirects, when
// getting what links to them is contradictory
$this->addWhereFld( 'page_is_redirect', 0 );
}
$this->addOption( 'LIMIT', $this->params['limit'] + 1 );
$sort = ( $this->params['dir'] == 'descending' ? ' DESC' : '' );
$orderBy = [];
if ( $this->params['namespace'] !== null && count( $this->params['namespace'] ) > 1 ) {
$orderBy[] = $this->bl_from_ns . $sort;
}
$orderBy[] = $this->bl_from . $sort;
$this->addOption( 'ORDER BY', $orderBy );
$this->addOption( 'STRAIGHT_JOIN' );
$res = $this->select( __METHOD__ );
if ( $resultPageSet === null ) {
$this->executeGenderCacheFromResultWrapper( $res, __METHOD__ );
}
$count = 0;
foreach ( $res as $row ) {
if ( ++$count > $this->params['limit'] ) {
// We've reached the one extra which shows that there are
// additional pages to be had. Stop here...
// Continue string may be overridden at a later step
$this->continueStr = "{$row->from_ns}|{$row->page_id}";
break;
}
// Fill in continuation fields for later steps
if ( count( $this->cont ) < 2 ) {
$this->cont[] = $row->from_ns;
$this->cont[] = $row->page_id;
}
$this->pageMap[$row->page_namespace][$row->page_title] = $row->page_id;
$t = Title::makeTitle( $row->page_namespace, $row->page_title );
if ( $row->page_is_redirect ) {
$this->redirTitles[] = $t;
}
if ( $resultPageSet === null ) {
$a = [ 'pageid' => (int)$row->page_id ];
ApiQueryBase::addTitleInfo( $a, $t );
if ( $row->page_is_redirect ) {
$a['redirect'] = true;
}
// Put all the results in an array first
$this->resultArr[$a['pageid']] = $a;
} else {
$resultPageSet->processDbRow( $row );
}
}
}
/**
* @param ApiPageSet|null $resultPageSet
* @return void
*/
private function runSecondQuery( $resultPageSet = null ) {
$db = $this->getDB();
if ( isset( $this->linksMigration::$mapping[$this->bl_table] ) ) {
$queryInfo = $this->linksMigration->getQueryInfo( $this->bl_table, $this->bl_table );
$this->addTables( $queryInfo['tables'] );
$this->addJoinConds( $queryInfo['joins'] );
} else {
$this->addTables( [ $this->bl_table ] );
}
$this->addTables( [ 'page' ] );
$this->addJoinConds( [ 'page' => [ 'JOIN', "{$this->bl_from}=page_id" ] ] );
if ( $resultPageSet === null ) {
$this->addFields( [ 'page_id', 'page_title', 'page_namespace', 'page_is_redirect' ] );
} else {
$this->addFields( $resultPageSet->getPageTableFields() );
}
$this->addFields( [ $this->bl_title, 'from_ns' => 'page_namespace' ] );
if ( $this->hasNS ) {
$this->addFields( $this->bl_ns );
}
// We can't use LinkBatch here because $this->hasNS may be false
$titleWhere = [];
$allRedirNs = [];
$allRedirDBkey = [];
/** @var Title $t */
foreach ( $this->redirTitles as $t ) {
$redirNs = $t->getNamespace();
$redirDBkey = $t->getDBkey();
$expr = $db->expr( $this->bl_title, '=', $redirDBkey );
if ( $this->hasNS ) {
$expr = $expr->and( $this->bl_ns, '=', $redirNs );
}
$titleWhere[] = $expr;
$allRedirNs[$redirNs] = true;
$allRedirDBkey[$redirDBkey] = true;
}
$this->addWhere( new OrExpressionGroup( ...$titleWhere ) );
$this->addWhereFld( 'page_namespace', $this->params['namespace'] );
if ( count( $this->cont ) >= 6 ) {
$op = $this->params['dir'] == 'descending' ? '<=' : '>=';
$conds = [];
if ( $this->hasNS && count( $allRedirNs ) > 1 ) {
$conds[ $this->bl_ns ] = $this->cont[2];
}
if ( count( $allRedirDBkey ) > 1 ) {
$conds[ $this->bl_title ] = $this->cont[3];
}
// Don't bother with namespace, title, or from_namespace if it's
// otherwise constant in the where clause.
if ( $this->params['namespace'] !== null && count( $this->params['namespace'] ) > 1 ) {
$conds[ $this->bl_from_ns ] = $this->cont[4];
}
$conds[ $this->bl_from ] = $this->cont[5];
$this->addWhere( $db->buildComparison( $op, $conds ) );
}
if ( $this->params['filterredir'] == 'redirects' ) {
$this->addWhereFld( 'page_is_redirect', 1 );
} elseif ( $this->params['filterredir'] == 'nonredirects' ) {
$this->addWhereFld( 'page_is_redirect', 0 );
}
$this->addOption( 'LIMIT', $this->params['limit'] + 1 );
$orderBy = [];
$sort = ( $this->params['dir'] == 'descending' ? ' DESC' : '' );
// Don't order by namespace/title/from_namespace if it's constant in the WHERE clause
if ( $this->hasNS && count( $allRedirNs ) > 1 ) {
$orderBy[] = $this->bl_ns . $sort;
}
if ( count( $allRedirDBkey ) > 1 ) {
$orderBy[] = $this->bl_title . $sort;
}
if ( $this->params['namespace'] !== null && count( $this->params['namespace'] ) > 1 ) {
$orderBy[] = $this->bl_from_ns . $sort;
}
$orderBy[] = $this->bl_from . $sort;
$this->addOption( 'ORDER BY', $orderBy );
$this->addOption( 'USE INDEX', [ 'page' => 'PRIMARY' ] );
// T290379: Avoid MariaDB deciding to scan all of `page`.
$this->addOption( 'STRAIGHT_JOIN' );
$res = $this->select( __METHOD__ );
if ( $resultPageSet === null ) {
$this->executeGenderCacheFromResultWrapper( $res, __METHOD__ );
}
$count = 0;
foreach ( $res as $row ) {
$ns = $this->hasNS ? $row->{$this->bl_ns} : NS_FILE;
if ( ++$count > $this->params['limit'] ) {
// We've reached the one extra which shows that there are
// additional pages to be had. Stop here...
// Note we must keep the parameters for the first query constant
// This may be overridden at a later step
$title = $row->{$this->bl_title};
$this->continueStr = implode( '|', array_slice( $this->cont, 0, 2 ) ) .
"|$ns|$title|{$row->from_ns}|{$row->page_id}";
break;
}
// Fill in continuation fields for later steps
if ( count( $this->cont ) < 6 ) {
$this->cont[] = $ns;
$this->cont[] = $row->{$this->bl_title};
$this->cont[] = $row->from_ns;
$this->cont[] = $row->page_id;
}
if ( $resultPageSet === null ) {
$a = [ 'pageid' => (int)$row->page_id ];
ApiQueryBase::addTitleInfo( $a, Title::makeTitle( $row->page_namespace, $row->page_title ) );
if ( $row->page_is_redirect ) {
$a['redirect'] = true;
}
$parentID = $this->pageMap[$ns][$row->{$this->bl_title}];
// Put all the results in an array first
$this->resultArr[$parentID]['redirlinks'][$row->page_id] = $a;
} else {
$resultPageSet->processDbRow( $row );
}
}
}
/**
* @param ApiPageSet|null $resultPageSet
* @return void
*/
private function run( $resultPageSet = null ) {
$this->params = $this->extractRequestParams( false );
$this->redirect = isset( $this->params['redirect'] ) && $this->params['redirect'];
$userMax = ( $this->redirect ? ApiBase::LIMIT_BIG1 / 2 : ApiBase::LIMIT_BIG1 );
$botMax = ( $this->redirect ? ApiBase::LIMIT_BIG2 / 2 : ApiBase::LIMIT_BIG2 );
$result = $this->getResult();
if ( $this->params['limit'] == 'max' ) {
$this->params['limit'] = $this->getMain()->canApiHighLimits() ? $botMax : $userMax;
$result->addParsedLimit( $this->getModuleName(), $this->params['limit'] );
} else {
$this->params['limit'] = $this->getMain()->getParamValidator()->validateValue(
$this, 'limit', (int)$this->params['limit'], [
ParamValidator::PARAM_TYPE => 'limit',
IntegerDef::PARAM_MIN => 1,
IntegerDef::PARAM_MAX => $userMax,
IntegerDef::PARAM_MAX2 => $botMax,
IntegerDef::PARAM_IGNORE_RANGE => true,
]
);
}
$this->rootTitle = $this->getTitleFromTitleOrPageId( $this->params );
// only image titles are allowed for the root in imageinfo mode
if ( !$this->hasNS && $this->rootTitle->getNamespace() !== NS_FILE ) {
$this->dieWithError(
[ 'apierror-imageusage-badtitle', $this->getModuleName() ],
'bad_image_title'
);
}
// Parse and validate continuation parameter
// (Can't use parseContinueParamOrDie(), because the length is variable)
$this->cont = [];
if ( $this->params['continue'] !== null ) {
$cont = explode( '|', $this->params['continue'] );
switch ( count( $cont ) ) {
case 8:
// redirect page ID for result adding
$this->cont[7] = (int)$cont[7];
$this->dieContinueUsageIf( $cont[7] !== (string)$this->cont[7] );
/* Fall through */
case 7:
// top-level page ID for result adding
$this->cont[6] = (int)$cont[6];
$this->dieContinueUsageIf( $cont[6] !== (string)$this->cont[6] );
/* Fall through */
case 6:
// ns for 2nd query (even for imageusage)
$this->cont[2] = (int)$cont[2];
$this->dieContinueUsageIf( $cont[2] !== (string)$this->cont[2] );
// title for 2nd query
$this->cont[3] = $cont[3];
// from_ns for 2nd query
$this->cont[4] = (int)$cont[4];
$this->dieContinueUsageIf( $cont[4] !== (string)$this->cont[4] );
// from_id for 1st query
$this->cont[5] = (int)$cont[5];
$this->dieContinueUsageIf( $cont[5] !== (string)$this->cont[5] );
/* Fall through */
case 2:
// from_ns for 1st query
$this->cont[0] = (int)$cont[0];
$this->dieContinueUsageIf( $cont[0] !== (string)$this->cont[0] );
// from_id for 1st query
$this->cont[1] = (int)$cont[1];
$this->dieContinueUsageIf( $cont[1] !== (string)$this->cont[1] );
break;
default:
// @phan-suppress-next-line PhanImpossibleCondition
$this->dieContinueUsageIf( true );
}
ksort( $this->cont );
}
$this->runFirstQuery( $resultPageSet );
if ( $this->redirect && count( $this->redirTitles ) ) {
$this->resetQueryParams();
$this->runSecondQuery( $resultPageSet );
}
// Fill in any missing fields in case it's needed below
$this->cont += [ 0, 0, 0, '', 0, 0, 0 ];
if ( $resultPageSet === null ) {
// Try to add the result data in one go and pray that it fits
$code = $this->bl_code;
$data = array_map( static function ( $arr ) use ( $code ) {
if ( isset( $arr['redirlinks'] ) ) {
$arr['redirlinks'] = array_values( $arr['redirlinks'] );
ApiResult::setIndexedTagName( $arr['redirlinks'], $code );
}
return $arr;
}, array_values( $this->resultArr ) );
$fit = $result->addValue( 'query', $this->getModuleName(), $data );
if ( !$fit ) {
// It didn't fit. Add elements one by one until the
// result is full.
ksort( $this->resultArr );
// @phan-suppress-next-line PhanSuspiciousValueComparison
if ( count( $this->cont ) >= 7 ) {
$startAt = $this->cont[6];
} else {
$startAt = array_key_first( $this->resultArr );
}
$idx = 0;
foreach ( $this->resultArr as $pageID => $arr ) {
if ( $pageID < $startAt ) {
continue;
}
// Add the basic entry without redirlinks first
$fit = $result->addValue(
[ 'query', $this->getModuleName() ],
$idx, array_diff_key( $arr, [ 'redirlinks' => '' ] ) );
if ( !$fit ) {
$this->continueStr = implode( '|', array_slice( $this->cont, 0, 6 ) ) .
"|$pageID";
break;
}
$hasRedirs = false;
$redirLinks = isset( $arr['redirlinks'] ) ? (array)$arr['redirlinks'] : [];
ksort( $redirLinks );
// @phan-suppress-next-line PhanSuspiciousValueComparisonInLoop
if ( count( $this->cont ) >= 8 && $pageID == $startAt ) {
$redirStartAt = $this->cont[7];
} else {
$redirStartAt = array_key_first( $redirLinks );
}
foreach ( $redirLinks as $key => $redir ) {
if ( $key < $redirStartAt ) {
continue;
}
$fit = $result->addValue(
[ 'query', $this->getModuleName(), $idx, 'redirlinks' ],
null, $redir );
if ( !$fit ) {
$this->continueStr = implode( '|', array_slice( $this->cont, 0, 6 ) ) .
"|$pageID|$key";
break;
}
$hasRedirs = true;
}
if ( $hasRedirs ) {
$result->addIndexedTagName(
[ 'query', $this->getModuleName(), $idx, 'redirlinks' ],
$this->bl_code );
}
if ( !$fit ) {
break;
}
$idx++;
}
}
$result->addIndexedTagName(
[ 'query', $this->getModuleName() ],
$this->bl_code
);
}
if ( $this->continueStr !== null ) {
$this->setContinueEnumParameter( 'continue', $this->continueStr );
}
}
public function getAllowedParams() {
$retval = [
'title' => [
ParamValidator::PARAM_TYPE => 'string',
],
'pageid' => [
ParamValidator::PARAM_TYPE => 'integer',
],
'continue' => [
ApiBase::PARAM_HELP_MSG => 'api-help-param-continue',
],
'namespace' => [
ParamValidator::PARAM_ISMULTI => true,
ParamValidator::PARAM_TYPE => 'namespace'
],
'dir' => [
ParamValidator::PARAM_DEFAULT => 'ascending',
ParamValidator::PARAM_TYPE => [
'ascending',
'descending'
]
],
'filterredir' => [
ParamValidator::PARAM_DEFAULT => 'all',
ParamValidator::PARAM_TYPE => [
'all',
'redirects',
'nonredirects'
]
],
'limit' => [
ParamValidator::PARAM_DEFAULT => 10,
ParamValidator::PARAM_TYPE => 'limit',
IntegerDef::PARAM_MIN => 1,
IntegerDef::PARAM_MAX => ApiBase::LIMIT_BIG1,
IntegerDef::PARAM_MAX2 => ApiBase::LIMIT_BIG2
]
];
if ( $this->getModuleName() !== 'embeddedin' ) {
$retval['redirect'] = false;
}
return $retval;
}
protected function getExamplesMessages() {
$title = Title::newMainPage()->getPrefixedText();
$mp = rawurlencode( $title );
$examples = [
'backlinks' => [
"action=query&list=backlinks&bltitle={$mp}"
=> 'apihelp-query+backlinks-example-simple',
"action=query&generator=backlinks&gbltitle={$mp}&prop=info"
=> 'apihelp-query+backlinks-example-generator',
],
'embeddedin' => [
'action=query&list=embeddedin&eititle=Template:Stub'
=> 'apihelp-query+embeddedin-example-simple',
'action=query&generator=embeddedin&geititle=Template:Stub&prop=info'
=> 'apihelp-query+embeddedin-example-generator',
],
'imageusage' => [
'action=query&list=imageusage&iutitle=File:Albert%20Einstein%20Head.jpg'
=> 'apihelp-query+imageusage-example-simple',
'action=query&generator=imageusage&giutitle=File:Albert%20Einstein%20Head.jpg&prop=info'
=> 'apihelp-query+imageusage-example-generator',
]
];
return $examples[$this->getModuleName()];
}
public function getHelpUrls() {
return $this->helpUrl;
}
}