includes/SpecialRandompage.php

   1 <?php
   2 /**
   3  * @package MediaWiki
   4  * @subpackage SpecialPage
   5  */
   6
   7 /**
   8  * Constructor
   9  */
  10 function wfSpecialRandompage() {
  11         global $wgOut, $wgTitle, $wgArticle, $wgExtraRandompageSQL;
  12         $fname = 'wfSpecialRandompage';
  13
  14         # NOTE! We use a literal constant in the SQL instead of the RAND()
  15         # function because RAND() will return a different value for every row
  16         # in the table. That's both very slow and returns results heavily
  17         # biased towards low values, as rows later in the table will likely
  18         # never be reached for comparison.
  19         #
  20         # Using a literal constant means the whole thing gets optimized on
  21         # the index, and the comparison is both fast and fair.
  22
  23         # interpolation and sprintf() can muck up with locale-specific decimal separator
  24         $randstr = wfRandom();
  25
  26         $db =& wfGetDB( DB_SLAVE );
  27         $use_index = $db->useIndexClause( 'cur_random' );
  28         $cur = $db->tableName( 'cur' );
  29
  30         if ( $wgExtraRandompageSQL ) {
  31                 $extra = "AND ($wgExtraRandompageSQL)";
  32         } else {
  33                 $extra = '';
  34         }
  35         $sqlget = "SELECT cur_id,cur_title
  36                 FROM $cur $use_index
  37                 WHERE cur_namespace=0 AND cur_is_redirect=0 $extra
  38                 AND cur_random>$randstr
  39                 ORDER BY cur_random
  40                 LIMIT 1";
  41         $res = $db->query( $sqlget, $fname );
  42
  43         $title = null;
  44         if( $s = $db->fetchObject( $res ) ) {
  45                 $title =& Title::makeTitle( NS_MAIN, $s->cur_title );
  46         }
  47         if( is_null( $title ) ) {
  48                 # That's not supposed to happen :)
  49                 $title =& Title::newFromText( wfMsg( 'mainpage' ) );
  50         }
  51         $wgOut->reportTime(); # for logfile
  52         $wgOut->redirect( $title->getFullUrl() );
  53 }
  54
  55 ?>