includes/api/ApiQueryRandom.php

   1 <?php
   2
   3 /**
   4  *
   5  *
   6  * Created on Monday, January 28, 2008
   7  *
   8  * Copyright © 2008 Brent Garber
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License along
  21  * with this program; if not, write to the Free Software Foundation, Inc.,
  22  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  23  * http://www.gnu.org/copyleft/gpl.html
  24  *
  25  * @file
  26  */
  27
  28 /**
  29  * Query module to get list of random pages
  30  *
  31  * @ingroup API
  32  */
  33 class ApiQueryRandom extends ApiQueryGeneratorBase {
  34         private $pageIDs;
  35
  36         public function __construct( ApiQuery $query, $moduleName ) {
  37                 parent::__construct( $query, $moduleName, 'rn' );
  38         }
  39
  40         public function execute() {
  41                 $this->run();
  42         }
  43
  44         public function executeGenerator( $resultPageSet ) {
  45                 $this->run( $resultPageSet );
  46         }
  47
  48         /**
  49          * @param string $randstr
  50          * @param int $limit
  51          * @param int $namespace
  52          * @param ApiPageSet $resultPageSet
  53          * @param bool $redirect
  54          * @return void
  55          */
  56         protected function prepareQuery( $randstr, $limit, $namespace, &$resultPageSet, $redirect ) {
  57                 $this->resetQueryParams();
  58                 $this->addTables( 'page' );
  59                 $this->addOption( 'LIMIT', $limit );
  60                 $this->addWhereFld( 'page_namespace', $namespace );
  61                 $this->addWhereRange( 'page_random', 'newer', $randstr, null );
  62                 $this->addWhereFld( 'page_is_redirect', $redirect );
  63                 if ( is_null( $resultPageSet ) ) {
  64                         $this->addFields( array( 'page_id', 'page_title', 'page_namespace' ) );
  65                 } else {
  66                         $this->addFields( $resultPageSet->getPageTableFields() );
  67                 }
  68         }
  69
  70         /**
  71          * @param ApiPageSet $resultPageSet
  72          * @return int
  73          */
  74         protected function runQuery( $resultPageSet = null ) {
  75                 $res = $this->select( __METHOD__ );
  76                 $count = 0;
  77                 foreach ( $res as $row ) {
  78                         $count++;
  79                         if ( is_null( $resultPageSet ) ) {
  80                                 // Prevent duplicates
  81                                 if ( !in_array( $row->page_id, $this->pageIDs ) ) {
  82                                         $fit = $this->getResult()->addValue(
  83                                                 array( 'query', $this->getModuleName() ),
  84                                                 null, $this->extractRowInfo( $row ) );
  85                                         if ( !$fit ) {
  86                                                 // We can't really query-continue a random list.
  87                                                 // Return an insanely high value so
  88                                                 // $count < $limit is false
  89                                                 return 1E9;
  90                                         }
  91                                         $this->pageIDs[] = $row->page_id;
  92                                 }
  93                         } else {
  94                                 $resultPageSet->processDbRow( $row );
  95                         }
  96                 }
  97
  98                 return $count;
  99         }
 100
 101         /**
 102          * @param ApiPageSet $resultPageSet
 103          * @return void
 104          */
 105         public function run( $resultPageSet = null ) {
 106                 $params = $this->extractRequestParams();
 107                 $result = $this->getResult();
 108                 $this->pageIDs = array();
 109
 110                 $this->prepareQuery(
 111                         wfRandom(),
 112                         $params['limit'],
 113                         $params['namespace'],
 114                         $resultPageSet,
 115                         $params['redirect']
 116                 );
 117                 $count = $this->runQuery( $resultPageSet );
 118                 if ( $count < $params['limit'] ) {
 119                         /* We got too few pages, we probably picked a high value
 120                          * for page_random. We'll just take the lowest ones, see
 121                          * also the comment in Title::getRandomTitle()
 122                          */
 123                         $this->prepareQuery(
 124                                 0,
 125                                 $params['limit'] - $count,
 126                                 $params['namespace'],
 127                                 $resultPageSet,
 128                                 $params['redirect']
 129                         );
 130                         $this->runQuery( $resultPageSet );
 131                 }
 132
 133                 if ( is_null( $resultPageSet ) ) {
 134                         $result->setIndexedTagName_internal( array( 'query', $this->getModuleName() ), 'page' );
 135                 }
 136         }
 137
 138         private function extractRowInfo( $row ) {
 139                 $title = Title::makeTitle( $row->page_namespace, $row->page_title );
 140                 $vals = array();
 141                 $vals['id'] = intval( $row->page_id );
 142                 ApiQueryBase::addTitleInfo( $vals, $title );
 143
 144                 return $vals;
 145         }
 146
 147         public function getCacheMode( $params ) {
 148                 return 'public';
 149         }
 150
 151         public function getAllowedParams() {
 152                 return array(
 153                         'namespace' => array(
 154                                 ApiBase::PARAM_TYPE => 'namespace',
 155                                 ApiBase::PARAM_ISMULTI => true
 156                         ),
 157                         'limit' => array(
 158                                 ApiBase::PARAM_TYPE => 'limit',
 159                                 ApiBase::PARAM_DFLT => 1,
 160                                 ApiBase::PARAM_MIN => 1,
 161                                 ApiBase::PARAM_MAX => 10,
 162                                 ApiBase::PARAM_MAX2 => 20
 163                         ),
 164                         'redirect' => false,
 165                 );
 166         }
 167
 168         public function getParamDescription() {
 169                 return array(
 170                         'namespace' => 'Return pages in these namespaces only',
 171                         'limit' => 'Limit how many random pages will be returned',
 172                         'redirect' => 'Load a random redirect instead of a random page'
 173                 );
 174         }
 175
 176         public function getResultProperties() {
 177                 return array(
 178                         '' => array(
 179                                 'id' => 'integer',
 180                                 'ns' => 'namespace',
 181                                 'title' => 'string'
 182                         )
 183                 );
 184         }
 185
 186         public function getDescription() {
 187                 return array(
 188                         'Get a set of random pages.',
 189                         'NOTE: Pages are listed in a fixed sequence, only the starting point is random.',
 190                         '      This means that if, for example, "Main Page" is the first random page on',
 191                         '      your list, "List of fictional monkeys" will *always* be second, "List of',
 192                         '      people on stamps of Vanuatu" third, etc.',
 193                         'NOTE: If the number of pages in the namespace is lower than rnlimit, you will',
 194                         '      get fewer pages. You will not get the same page twice.'
 195                 );
 196         }
 197
 198         public function getExamples() {
 199                 return 'api.php?action=query&list=random&rnnamespace=0&rnlimit=2';
 200         }
 201
 202         public function getHelpUrls() {
 203                 return 'https://www.mediawiki.org/wiki/API:Random';
 204         }
 205 }