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 /**
  25  * Query module to get list of random pages
  26  *
  27  * @ingroup API
  28  */
  29 class ApiQueryRandom extends ApiQueryGeneratorBase {
  30         public function __construct( ApiQuery $query, $moduleName ) {
  31                 parent::__construct( $query, $moduleName, 'rn' );
  32         }
  33
  34         public function execute() {
  35                 $this->run();
  36         }
  37
  38         public function executeGenerator( $resultPageSet ) {
  39                 $this->run( $resultPageSet );
  40         }
  41
  42         /**
  43          * Actually perform the query and add pages to the result.
  44          * @param ApiPageSet|null $resultPageSet
  45          * @param int $limit Number of pages to fetch
  46          * @param string|null $start Starting page_random
  47          * @param int $startId Starting page_id
  48          * @param string|null $end Ending page_random
  49          * @return array (int, string|null) Number of pages left to query and continuation string
  50          */
  51         protected function runQuery( $resultPageSet, $limit, $start, $startId, $end ) {
  52                 $params = $this->extractRequestParams();
  53
  54                 $this->resetQueryParams();
  55                 $this->addTables( 'page' );
  56                 $this->addFields( [ 'page_id', 'page_random' ] );
  57                 if ( is_null( $resultPageSet ) ) {
  58                         $this->addFields( [ 'page_title', 'page_namespace' ] );
  59                 } else {
  60                         $this->addFields( $resultPageSet->getPageTableFields() );
  61                 }
  62                 $this->addWhereFld( 'page_namespace', $params['namespace'] );
  63                 if ( $params['redirect'] || $params['filterredir'] === 'redirects' ) {
  64                         $this->addWhereFld( 'page_is_redirect', 1 );
  65                 } elseif ( $params['filterredir'] === 'nonredirects' ) {
  66                         $this->addWhereFld( 'page_is_redirect', 0 );
  67                 } elseif ( is_null( $resultPageSet ) ) {
  68                         $this->addFields( [ 'page_is_redirect' ] );
  69                 }
  70                 $this->addOption( 'LIMIT', $limit + 1 );
  71
  72                 if ( $start !== null ) {
  73                         $start = $this->getDB()->addQuotes( $start );
  74                         if ( $startId > 0 ) {
  75                                 $startId = (int)$startId; // safety
  76                                 $this->addWhere( "page_random = $start AND page_id >= $startId OR page_random > $start" );
  77                         } else {
  78                                 $this->addWhere( "page_random >= $start" );
  79                         }
  80                 }
  81                 if ( $end !== null ) {
  82                         $this->addWhere( 'page_random < ' . $this->getDB()->addQuotes( $end ) );
  83                 }
  84                 $this->addOption( 'ORDER BY', [ 'page_random', 'page_id' ] );
  85
  86                 $result = $this->getResult();
  87                 $path = [ 'query', $this->getModuleName() ];
  88
  89                 $res = $this->select( __METHOD__ );
  90                 $count = 0;
  91                 foreach ( $res as $row ) {
  92                         if ( $count++ >= $limit ) {
  93                                 return [ 0, "{$row->page_random}|{$row->page_id}" ];
  94                         }
  95                         if ( is_null( $resultPageSet ) ) {
  96                                 $title = Title::makeTitle( $row->page_namespace, $row->page_title );
  97                                 $page = [
  98                                         'id' => (int)$row->page_id,
  99                                 ];
 100                                 ApiQueryBase::addTitleInfo( $page, $title );
 101                                 if ( isset( $row->page_is_redirect ) ) {
 102                                         $page['redirect'] = (bool)$row->page_is_redirect;
 103                                 }
 104                                 $fit = $result->addValue( $path, null, $page );
 105                                 if ( !$fit ) {
 106                                         return [ 0, "{$row->page_random}|{$row->page_id}" ];
 107                                 }
 108                         } else {
 109                                 $resultPageSet->processDbRow( $row );
 110                         }
 111                 }
 112
 113                 return [ $limit - $count, null ];
 114         }
 115
 116         /**
 117          * @param ApiPageSet|null $resultPageSet
 118          */
 119         public function run( $resultPageSet = null ) {
 120                 $params = $this->extractRequestParams();
 121
 122                 // Since 'filterredir" will always be set in $params, we have to dig
 123                 // into the WebRequest to see if it was actually passed.
 124                 $request = $this->getMain()->getRequest();
 125                 if ( $request->getCheck( $this->encodeParamName( 'filterredir' ) ) ) {
 126                         $this->requireMaxOneParameter( $params, 'filterredir', 'redirect' );
 127                 }
 128
 129                 if ( isset( $params['continue'] ) ) {
 130                         $cont = explode( '|', $params['continue'] );
 131                         $this->dieContinueUsageIf( count( $cont ) != 4 );
 132                         $rand = $cont[0];
 133                         $start = $cont[1];
 134                         $startId = (int)$cont[2];
 135                         $end = $cont[3] ? $rand : null;
 136                         $this->dieContinueUsageIf( !preg_match( '/^0\.\d+$/', $rand ) );
 137                         $this->dieContinueUsageIf( !preg_match( '/^0\.\d+$/', $start ) );
 138                         $this->dieContinueUsageIf( $cont[2] !== (string)$startId );
 139                         $this->dieContinueUsageIf( $cont[3] !== '0' && $cont[3] !== '1' );
 140                 } else {
 141                         $rand = wfRandom();
 142                         $start = $rand;
 143                         $startId = 0;
 144                         $end = null;
 145                 }
 146
 147                 // Set the non-continue if this is being used as a generator
 148                 // (as a list it doesn't matter because lists never non-continue)
 149                 if ( $resultPageSet !== null ) {
 150                         $endFlag = $end === null ? 0 : 1;
 151                         $this->getContinuationManager()->addGeneratorNonContinueParam(
 152                                 $this, 'continue', "$rand|$start|$startId|$endFlag"
 153                         );
 154                 }
 155
 156                 list( $left, $continue ) =
 157                         $this->runQuery( $resultPageSet, $params['limit'], $start, $startId, $end );
 158                 if ( $end === null && $continue === null ) {
 159                         // Wrap around. We do this even if $left === 0 for continuation
 160                         // (saving a DB query in this rare case probably isn't worth the
 161                         // added code complexity it would require).
 162                         $end = $rand;
 163                         list( $left, $continue ) = $this->runQuery( $resultPageSet, $left, null, null, $end );
 164                 }
 165
 166                 if ( $continue !== null ) {
 167                         $endFlag = $end === null ? 0 : 1;
 168                         $this->setContinueEnumParameter( 'continue', "$rand|$continue|$endFlag" );
 169                 }
 170
 171                 if ( is_null( $resultPageSet ) ) {
 172                         $this->getResult()->addIndexedTagName( [ 'query', $this->getModuleName() ], 'page' );
 173                 }
 174         }
 175
 176         public function getCacheMode( $params ) {
 177                 return 'public';
 178         }
 179
 180         public function getAllowedParams() {
 181                 return [
 182                         'namespace' => [
 183                                 ApiBase::PARAM_TYPE => 'namespace',
 184                                 ApiBase::PARAM_ISMULTI => true
 185                         ],
 186                         'filterredir' => [
 187                                 ApiBase::PARAM_TYPE => [ 'all', 'redirects', 'nonredirects' ],
 188                                 ApiBase::PARAM_DFLT => 'nonredirects', // for BC
 189                         ],
 190                         'redirect' => [
 191                                 ApiBase::PARAM_DEPRECATED => true,
 192                                 ApiBase::PARAM_DFLT => false,
 193                         ],
 194                         'limit' => [
 195                                 ApiBase::PARAM_TYPE => 'limit',
 196                                 ApiBase::PARAM_DFLT => 1,
 197                                 ApiBase::PARAM_MIN => 1,
 198                                 ApiBase::PARAM_MAX => ApiBase::LIMIT_BIG1,
 199                                 ApiBase::PARAM_MAX2 => ApiBase::LIMIT_BIG2
 200                         ],
 201                         'continue' => [
 202                                 ApiBase::PARAM_HELP_MSG => 'api-help-param-continue'
 203                         ],
 204                 ];
 205         }
 206
 207         protected function getExamplesMessages() {
 208                 return [
 209                         'action=query&list=random&rnnamespace=0&rnlimit=2'
 210                                 => 'apihelp-query+random-example-simple',
 211                         'action=query&generator=random&grnnamespace=0&grnlimit=2&prop=info'
 212                                 => 'apihelp-query+random-example-generator',
 213                 ];
 214         }
 215
 216         public function getHelpUrls() {
 217                 return 'https://www.mediawiki.org/wiki/Special:MyLanguage/API:Random';
 218         }
 219 }