wiki.techinc.nl/includes/SpecialRandompage.php
2005-12-04 18:27:59 +00:00

60 lines
1.8 KiB
PHP

<?php
/**
* @package MediaWiki
* @subpackage SpecialPage
*/
/**
* Constructor
*
* @param string $par the namespace to get a random page from (default NS_MAIN),
* used as e.g. Special:Randompage/Category
*/
function wfSpecialRandompage( $par = NS_MAIN ) {
global $wgOut, $wgExtraRandompageSQL, $wgContLang;
$fname = 'wfSpecialRandompage';
# Determine the namespace to get a random page from.
$namespace = $wgContLang->getNsIndex($par);
if ($namespace === false || $namespace < NS_MAIN) {
$namespace = NS_MAIN;
}
# NOTE! We use a literal constant in the SQL instead of the RAND()
# function because RAND() will return a different value for every row
# in the table. That's both very slow and returns results heavily
# biased towards low values, as rows later in the table will likely
# never be reached for comparison.
#
# Using a literal constant means the whole thing gets optimized on
# the index, and the comparison is both fast and fair.
# interpolation and sprintf() can muck up with locale-specific decimal separator
$randstr = wfRandom();
$db =& wfGetDB( DB_SLAVE );
$use_index = $db->useIndexClause( 'page_random' );
$page = $db->tableName( 'page' );
$extra = $wgExtraRandompageSQL ? "AND ($wgExtraRandompageSQL)" : '';
$sql = "SELECT page_id,page_title
FROM $page $use_index
WHERE page_namespace=$namespace AND page_is_redirect=0 $extra
AND page_random>$randstr
ORDER BY page_random";
$sql = $db->limitResult($sql, 1, 0);
$res = $db->query( $sql, $fname );
$title = null;
if( $s = $db->fetchObject( $res ) ) {
$title =& Title::makeTitle( $namespace, $s->page_title );
}
if( is_null( $title ) ) {
# That's not supposed to happen :)
$title = Title::newFromText( wfMsg( 'mainpage' ) );
}
$wgOut->reportTime(); # for logfile
$wgOut->redirect( $title->getFullUrl() );
}
?>