includes/api/ApiQueryRandom.php

   1 <?php
   2
   3 /**
   4  * Copyright © 2008 Brent Garber
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  19  * http://www.gnu.org/copyleft/gpl.html
  20  *
  21  * @file
  22  */
  23
  24 namespace MediaWiki\Api;
  25
  26 use MediaWiki\Title\Title;
  27 use Wikimedia\ParamValidator\ParamValidator;
  28 use Wikimedia\ParamValidator\TypeDef\IntegerDef;
  29
  30 /**
  31  * Query module to get list of random pages
  32  *
  33  * @ingroup API
  34  */
  35 class ApiQueryRandom extends ApiQueryGeneratorBase {
  36
  37         public function __construct( ApiQuery $query, string $moduleName ) {
  38                 parent::__construct( $query, $moduleName, 'rn' );
  39         }
  40
  41         public function execute() {
  42                 $this->run();
  43         }
  44
  45         public function executeGenerator( $resultPageSet ) {
  46                 $this->run( $resultPageSet );
  47         }
  48
  49         /**
  50          * Actually perform the query and add pages to the result.
  51          * @param ApiPageSet|null $resultPageSet
  52          * @param int $limit Number of pages to fetch
  53          * @param string|null $start Starting page_random
  54          * @param int|null $startId Starting page_id
  55          * @param string|null $end Ending page_random
  56          * @return array (int, string|null) Number of pages left to query and continuation string
  57          */
  58         protected function runQuery( $resultPageSet, $limit, $start, $startId, $end ) {
  59                 $params = $this->extractRequestParams();
  60
  61                 $this->resetQueryParams();
  62                 $this->addTables( 'page' );
  63                 $this->addFields( [ 'page_id', 'page_random' ] );
  64                 if ( $resultPageSet === null ) {
  65                         $this->addFields( [ 'page_title', 'page_namespace' ] );
  66                 } else {
  67                         $this->addFields( $resultPageSet->getPageTableFields() );
  68                 }
  69                 $this->addWhereFld( 'page_namespace', $params['namespace'] );
  70                 if ( $params['redirect'] || $params['filterredir'] === 'redirects' ) {
  71                         $this->addWhereFld( 'page_is_redirect', 1 );
  72                 } elseif ( $params['filterredir'] === 'nonredirects' ) {
  73                         $this->addWhereFld( 'page_is_redirect', 0 );
  74                 } elseif ( $resultPageSet === null ) {
  75                         $this->addFields( [ 'page_is_redirect' ] );
  76                 }
  77                 $this->addOption( 'LIMIT', $limit + 1 );
  78
  79                 if ( $start !== null ) {
  80                         $db = $this->getDB();
  81                         if ( $startId > 0 ) {
  82                                 $this->addWhere( $db->buildComparison( '>=', [
  83                                         'page_random' => $start,
  84                                         'page_id' => $startId,
  85                                 ] ) );
  86                         } else {
  87                                 $this->addWhere( $db->buildComparison( '>=', [
  88                                         'page_random' => $start,
  89                                 ] ) );
  90                         }
  91                 }
  92                 if ( $end !== null ) {
  93                         $this->addWhere( $this->getDB()->expr( 'page_random', '<', $end ) );
  94                 }
  95                 $this->addOption( 'ORDER BY', [ 'page_random', 'page_id' ] );
  96
  97                 $result = $this->getResult();
  98                 $path = [ 'query', $this->getModuleName() ];
  99
 100                 $res = $this->select( __METHOD__ );
 101
 102                 if ( $resultPageSet === null ) {
 103                         $this->executeGenderCacheFromResultWrapper( $res, __METHOD__ );
 104                 }
 105
 106                 $count = 0;
 107                 foreach ( $res as $row ) {
 108                         if ( $count++ >= $limit ) {
 109                                 return [ 0, "{$row->page_random}|{$row->page_id}" ];
 110                         }
 111                         if ( $resultPageSet === null ) {
 112                                 $title = Title::makeTitle( $row->page_namespace, $row->page_title );
 113                                 $page = [
 114                                         'id' => (int)$row->page_id,
 115                                 ];
 116                                 ApiQueryBase::addTitleInfo( $page, $title );
 117                                 if ( isset( $row->page_is_redirect ) ) {
 118                                         $page['redirect'] = (bool)$row->page_is_redirect;
 119                                 }
 120                                 $fit = $result->addValue( $path, null, $page );
 121                                 if ( !$fit ) {
 122                                         return [ 0, "{$row->page_random}|{$row->page_id}" ];
 123                                 }
 124                         } else {
 125                                 $resultPageSet->processDbRow( $row );
 126                         }
 127                 }
 128
 129                 return [ $limit - $count, null ];
 130         }
 131
 132         /**
 133          * @param ApiPageSet|null $resultPageSet
 134          */
 135         public function run( $resultPageSet = null ) {
 136                 $params = $this->extractRequestParams();
 137
 138                 // Since 'filterredir" will always be set in $params, we have to dig
 139                 // into the WebRequest to see if it was actually passed.
 140                 $request = $this->getMain()->getRequest();
 141                 if ( $request->getCheck( $this->encodeParamName( 'filterredir' ) ) ) {
 142                         $this->requireMaxOneParameter( $params, 'filterredir', 'redirect' );
 143                 }
 144
 145                 if ( isset( $params['continue'] ) ) {
 146                         $cont = $this->parseContinueParamOrDie( $params['continue'], [ 'string', 'string', 'int', 'string' ] );
 147                         $rand = $cont[0];
 148                         $start = $cont[1];
 149                         $startId = $cont[2];
 150                         $end = $cont[3] ? $rand : null;
 151                         $this->dieContinueUsageIf( !preg_match( '/^0\.\d+$/', $rand ) );
 152                         $this->dieContinueUsageIf( !preg_match( '/^0\.\d+$/', $start ) );
 153                         $this->dieContinueUsageIf( $cont[3] !== '0' && $cont[3] !== '1' );
 154                 } else {
 155                         $rand = wfRandom();
 156                         $start = $rand;
 157                         $startId = 0;
 158                         $end = null;
 159                 }
 160
 161                 // Set the non-continue if this is being used as a generator
 162                 // (as a list it doesn't matter because lists never non-continue)
 163                 if ( $resultPageSet !== null ) {
 164                         $endFlag = $end === null ? 0 : 1;
 165                         $this->getContinuationManager()->addGeneratorNonContinueParam(
 166                                 $this, 'continue', "$rand|$start|$startId|$endFlag"
 167                         );
 168                 }
 169
 170                 [ $left, $continue ] =
 171                         $this->runQuery( $resultPageSet, $params['limit'], $start, $startId, $end );
 172                 if ( $end === null && $continue === null ) {
 173                         // Wrap around. We do this even if $left === 0 for continuation
 174                         // (saving a DB query in this rare case probably isn't worth the
 175                         // added code complexity it would require).
 176                         $end = $rand;
 177                         [ , $continue ] = $this->runQuery( $resultPageSet, $left, null, null, $end );
 178                 }
 179
 180                 if ( $continue !== null ) {
 181                         $endFlag = $end === null ? 0 : 1;
 182                         $this->setContinueEnumParameter( 'continue', "$rand|$continue|$endFlag" );
 183                 }
 184
 185                 if ( $resultPageSet === null ) {
 186                         $this->getResult()->addIndexedTagName( [ 'query', $this->getModuleName() ], 'page' );
 187                 }
 188         }
 189
 190         public function getCacheMode( $params ) {
 191                 return 'public';
 192         }
 193
 194         public function getAllowedParams() {
 195                 return [
 196                         'namespace' => [
 197                                 ParamValidator::PARAM_TYPE => 'namespace',
 198                                 ParamValidator::PARAM_ISMULTI => true
 199                         ],
 200                         'filterredir' => [
 201                                 ParamValidator::PARAM_TYPE => [ 'all', 'redirects', 'nonredirects' ],
 202                                 ParamValidator::PARAM_DEFAULT => 'nonredirects', // for BC
 203                         ],
 204                         'redirect' => [
 205                                 ParamValidator::PARAM_DEPRECATED => true,
 206                                 ParamValidator::PARAM_DEFAULT => false,
 207                         ],
 208                         'limit' => [
 209                                 ParamValidator::PARAM_TYPE => 'limit',
 210                                 ParamValidator::PARAM_DEFAULT => 1,
 211                                 IntegerDef::PARAM_MIN => 1,
 212                                 IntegerDef::PARAM_MAX => ApiBase::LIMIT_BIG1,
 213                                 IntegerDef::PARAM_MAX2 => ApiBase::LIMIT_BIG2
 214                         ],
 215                         'continue' => [
 216                                 ApiBase::PARAM_HELP_MSG => 'api-help-param-continue'
 217                         ],
 218                 ];
 219         }
 220
 221         protected function getExamplesMessages() {
 222                 return [
 223                         'action=query&list=random&rnnamespace=0&rnlimit=2'
 224                                 => 'apihelp-query+random-example-simple',
 225                         'action=query&generator=random&grnnamespace=0&grnlimit=2&prop=info'
 226                                 => 'apihelp-query+random-example-generator',
 227                 ];
 228         }
 229
 230         public function getHelpUrls() {
 231                 return 'https://www.mediawiki.org/wiki/Special:MyLanguage/API:Random';
 232         }
 233 }
 234
 235 /** @deprecated class alias since 1.43 */
 236 class_alias( ApiQueryRandom::class, 'ApiQueryRandom' );