includes/SpecialRandomincategory.php

   1 <?php
   2
   3 /**
   4  * Special page to direct the user to a random page in specified category
   5  *
   6  * @addtogroup SpecialPage
   7  * @author VasilievVV <vasilvv@gmail.com>, based on SpecialRandompage.php code
   8  * @license GNU General Public Licence 2.0 or later
   9  */
  10
  11 /**
  12  * Main execution point
  13  * @param $par Category to select the page from
  14  */
  15 function wfSpecialRandomincategory( $par = null ) {
  16         global $wgOut, $wgRequest;
  17
  18         if( is_null( $par ) ) {
  19                 if ( $requestCategory = $wgRequest->getVal( 'category' ) ) {
  20                         $par = $requestCategory;
  21                 }
  22                 else {
  23                         $wgOut->addHTML( RandomPageInCategory::getForm() );
  24                         return;
  25                 }
  26         }
  27
  28         $rnd = new RandomPageInCategory();
  29         $rnd->setCategory( $par );
  30
  31         $title = $rnd->getRandomTitle();
  32
  33         if( is_null( $title ) ) {
  34                 $wgOut->addWikiText( wfMsg( 'randomincategory-nocategory', $par ) );
  35                 $wgOut->addHTML( RandomPageInCategory::getForm( $par ) );
  36                 return;
  37         }
  38
  39         $wgOut->reportTime();
  40         $wgOut->redirect( $title->getFullUrl() );
  41 }
  42
  43
  44 /**
  45  * Special page to direct the user to a random page in specified category
  46  *
  47  * @addtogroup SpecialPage
  48  */
  49 class RandomPageInCategory {
  50         private $category = null;
  51
  52         public function getCategory ( ) {
  53                 return $this->namespace;
  54         }
  55         public function setCategory ( $cat ) {
  56                 $category = Title::makeTitleSafe( NS_CATEGORY, $cat );
  57                 $this->category = $category->getDBKey();
  58         }
  59
  60         /**
  61          * Choose a random title. Based on Special:Random
  62          * @return Title object (or null if nothing to choose from)
  63          */
  64         public function getRandomTitle ( ) {
  65                 $randstr = wfRandom();
  66                 $row = $this->selectRandomPageFromDB( $randstr );
  67
  68                 if( !$row )
  69                         $row = $this->selectRandomPageFromDB( "0" );
  70
  71                 if( $row )
  72                         return Title::newFromText( $row->page_title, $row->page_namespace );
  73                 else
  74                         return null;
  75         }
  76
  77         private function selectRandomPageFromDB ( $randstr ) {
  78                 global $wgExtraRandompageSQL, $wgOut;
  79                 $fname = 'RandomPageInCategory::selectRandomPageFromDB';
  80
  81                 $dbr = wfGetDB( DB_SLAVE );
  82
  83                 $use_index = $dbr->useIndexClause( 'page_random' );
  84                 $page = $dbr->tableName( 'page' );
  85                 $categorylinks = $dbr->tableName( 'categorylinks' );
  86                 $category = $dbr->addQuotes( $this->category );
  87
  88                 $extra = $wgExtraRandompageSQL ? "AND ($wgExtraRandompageSQL)" : "";
  89                 $sql = "SELECT page_namespace, page_title
  90                         FROM $page $use_index JOIN $categorylinks ON page_id = cl_from
  91                         WHERE page_is_redirect = 0
  92                         AND page_random >= $randstr
  93                         AND cl_to = $category
  94                         $extra
  95                         ORDER BY page_random";
  96
  97                 $sql = $dbr->limitResult( $sql, 1, 0 );
  98                 $res = $dbr->query( $sql, $fname );
  99                 return $dbr->fetchObject( $res );
 100         }
 101
 102         public static function getForm( $par = null ) {
 103                 global $wgScript, $wgTitle, $wgRequest;
 104
 105                 if( !( $category = $par ) ) {
 106                         $category = $wgRequest->getVal( 'category' );
 107                 }
 108
 109                 $f =
 110                         Xml::openElement( 'form', array( 'method' => 'get', 'action' => $wgScript ) ) .
 111                                 Xml::openElement( 'fieldset' ) .
 112                                         Xml::element( 'legend', array(), wfMsg( 'randomincategory' ) ) .
 113                                         Xml::hidden( 'title', $wgTitle->getPrefixedText() ) .
 114                                         Xml::openElement( 'p' ) .
 115                                                 Xml::label( wfMsg( 'randomincategory-label' ), 'category' ) . ' ' .
 116                                                 Xml::input( 'category', null, $category, array( 'id' => 'category' ) ) . ' ' .
 117                                                 Xml::submitButton( wfMsg( 'randomincategory-submit' ) ) .
 118                                         Xml::closeElement( 'p' ) .
 119                                 Xml::closeElement( 'fieldset' ) .
 120                         Xml::closeElement( 'form' );
 121                 return $f;
 122         }
 123 }
 124
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