includes/api/ApiQueryRandom.php
<?php
/**
* Copyright © 2008 Brent Garber
*
* 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\Title\Title;
use Wikimedia\ParamValidator\ParamValidator;
use Wikimedia\ParamValidator\TypeDef\IntegerDef;
/**
* Query module to get list of random pages
*
* @ingroup API
*/
class ApiQueryRandom extends ApiQueryGeneratorBase {
/**
* @param ApiQuery $query
* @param string $moduleName
*/
public function __construct( ApiQuery $query, $moduleName ) {
parent::__construct( $query, $moduleName, 'rn' );
}
public function execute() {
$this->run();
}
public function executeGenerator( $resultPageSet ) {
$this->run( $resultPageSet );
}
/**
* Actually perform the query and add pages to the result.
* @param ApiPageSet|null $resultPageSet
* @param int $limit Number of pages to fetch
* @param string|null $start Starting page_random
* @param int|null $startId Starting page_id
* @param string|null $end Ending page_random
* @return array (int, string|null) Number of pages left to query and continuation string
*/
protected function runQuery( $resultPageSet, $limit, $start, $startId, $end ) {
$params = $this->extractRequestParams();
$this->resetQueryParams();
$this->addTables( 'page' );
$this->addFields( [ 'page_id', 'page_random' ] );
if ( $resultPageSet === null ) {
$this->addFields( [ 'page_title', 'page_namespace' ] );
} else {
$this->addFields( $resultPageSet->getPageTableFields() );
}
$this->addWhereFld( 'page_namespace', $params['namespace'] );
if ( $params['redirect'] || $params['filterredir'] === 'redirects' ) {
$this->addWhereFld( 'page_is_redirect', 1 );
} elseif ( $params['filterredir'] === 'nonredirects' ) {
$this->addWhereFld( 'page_is_redirect', 0 );
} elseif ( $resultPageSet === null ) {
$this->addFields( [ 'page_is_redirect' ] );
}
$this->addOption( 'LIMIT', $limit + 1 );
if ( $start !== null ) {
$db = $this->getDB();
if ( $startId > 0 ) {
$this->addWhere( $db->buildComparison( '>=', [
'page_random' => $start,
'page_id' => $startId,
] ) );
} else {
$this->addWhere( $db->buildComparison( '>=', [
'page_random' => $start,
] ) );
}
}
if ( $end !== null ) {
$this->addWhere( $this->getDB()->expr( 'page_random', '<', $end ) );
}
$this->addOption( 'ORDER BY', [ 'page_random', 'page_id' ] );
$result = $this->getResult();
$path = [ 'query', $this->getModuleName() ];
$res = $this->select( __METHOD__ );
if ( $resultPageSet === null ) {
$this->executeGenderCacheFromResultWrapper( $res, __METHOD__ );
}
$count = 0;
foreach ( $res as $row ) {
if ( $count++ >= $limit ) {
return [ 0, "{$row->page_random}|{$row->page_id}" ];
}
if ( $resultPageSet === null ) {
$title = Title::makeTitle( $row->page_namespace, $row->page_title );
$page = [
'id' => (int)$row->page_id,
];
ApiQueryBase::addTitleInfo( $page, $title );
if ( isset( $row->page_is_redirect ) ) {
$page['redirect'] = (bool)$row->page_is_redirect;
}
$fit = $result->addValue( $path, null, $page );
if ( !$fit ) {
return [ 0, "{$row->page_random}|{$row->page_id}" ];
}
} else {
$resultPageSet->processDbRow( $row );
}
}
return [ $limit - $count, null ];
}
/**
* @param ApiPageSet|null $resultPageSet
*/
public function run( $resultPageSet = null ) {
$params = $this->extractRequestParams();
// Since 'filterredir" will always be set in $params, we have to dig
// into the WebRequest to see if it was actually passed.
$request = $this->getMain()->getRequest();
if ( $request->getCheck( $this->encodeParamName( 'filterredir' ) ) ) {
$this->requireMaxOneParameter( $params, 'filterredir', 'redirect' );
}
if ( isset( $params['continue'] ) ) {
$cont = $this->parseContinueParamOrDie( $params['continue'], [ 'string', 'string', 'int', 'string' ] );
$rand = $cont[0];
$start = $cont[1];
$startId = $cont[2];
$end = $cont[3] ? $rand : null;
$this->dieContinueUsageIf( !preg_match( '/^0\.\d+$/', $rand ) );
$this->dieContinueUsageIf( !preg_match( '/^0\.\d+$/', $start ) );
$this->dieContinueUsageIf( $cont[3] !== '0' && $cont[3] !== '1' );
} else {
$rand = wfRandom();
$start = $rand;
$startId = 0;
$end = null;
}
// Set the non-continue if this is being used as a generator
// (as a list it doesn't matter because lists never non-continue)
if ( $resultPageSet !== null ) {
$endFlag = $end === null ? 0 : 1;
$this->getContinuationManager()->addGeneratorNonContinueParam(
$this, 'continue', "$rand|$start|$startId|$endFlag"
);
}
[ $left, $continue ] =
$this->runQuery( $resultPageSet, $params['limit'], $start, $startId, $end );
if ( $end === null && $continue === null ) {
// Wrap around. We do this even if $left === 0 for continuation
// (saving a DB query in this rare case probably isn't worth the
// added code complexity it would require).
$end = $rand;
[ , $continue ] = $this->runQuery( $resultPageSet, $left, null, null, $end );
}
if ( $continue !== null ) {
$endFlag = $end === null ? 0 : 1;
$this->setContinueEnumParameter( 'continue', "$rand|$continue|$endFlag" );
}
if ( $resultPageSet === null ) {
$this->getResult()->addIndexedTagName( [ 'query', $this->getModuleName() ], 'page' );
}
}
public function getCacheMode( $params ) {
return 'public';
}
public function getAllowedParams() {
return [
'namespace' => [
ParamValidator::PARAM_TYPE => 'namespace',
ParamValidator::PARAM_ISMULTI => true
],
'filterredir' => [
ParamValidator::PARAM_TYPE => [ 'all', 'redirects', 'nonredirects' ],
ParamValidator::PARAM_DEFAULT => 'nonredirects', // for BC
],
'redirect' => [
ParamValidator::PARAM_DEPRECATED => true,
ParamValidator::PARAM_DEFAULT => false,
],
'limit' => [
ParamValidator::PARAM_TYPE => 'limit',
ParamValidator::PARAM_DEFAULT => 1,
IntegerDef::PARAM_MIN => 1,
IntegerDef::PARAM_MAX => ApiBase::LIMIT_BIG1,
IntegerDef::PARAM_MAX2 => ApiBase::LIMIT_BIG2
],
'continue' => [
ApiBase::PARAM_HELP_MSG => 'api-help-param-continue'
],
];
}
protected function getExamplesMessages() {
return [
'action=query&list=random&rnnamespace=0&rnlimit=2'
=> 'apihelp-query+random-example-simple',
'action=query&generator=random&grnnamespace=0&grnlimit=2&prop=info'
=> 'apihelp-query+random-example-generator',
];
}
public function getHelpUrls() {
return 'https://www.mediawiki.org/wiki/Special:MyLanguage/API:Random';
}
}