Extension:RandomSelection

MediaWiki extensions manual - list

RandomSelection Release status: stable
Implementation	Tag
Description	Displays a random option from the given set.
Author(s)	Ross McClure
Last version	2.1.5 (2010-01-17)
MediaWiki	1.12+
License	No license specified
Download	see below Changelog
Example	Example
Hooks used ParserFirstCallInit
Check usage (experimental)

The RandomSelection extension allows for randomly-generated content inside your wiki; e.g. rotating images, random greetings, etc.

Usage

To choose between one or more options, simply place each option inside an <option> tag, like so:

<choose>
<option>This is the first choice.</option>
<option>This is the second choice.</option>
<option>And so on...</option>
</choose>

From each set of <choose> tags, precisely one <option> tag will be selected at random, and its contents shown.

If you'd like some options to be shown more often than others, you can add weight to the option tags, like so:

<choose>

<option weight="2">This option will be shown twice as often as a normal option.</option>

<option>By default, options have a weight of 1.</option>

<option weight="1.5">This option also has a weight of 1.  Fractional portions are ignored.</option>

</choose>

Anything can be placed inside of option tags: links, images, even templates. Note, however, that template arguments will not be expanded due to bugzilla:2257.

Installation

1. Save the souce code into a file called RandomSelection.php
2. Create a folder called RandomSelection in the extensions directory of your installation (.../extensions/) and move the file RandomSelection.php into it
3. Add following line in LocalSettings.php:

   require_once( "{$IP}/extensions/RandomSelection/RandomSelection.php" );
   

4. Installation may now be verified at Special:Version

Source Code

The code in this page will only work in MediaWiki 1.12 and above. (Alternate version for 1.5 and above).

<?php
/**
 * RandomSelection -- randomly displays one of the given options.
 * Usage: <choose><option>A</option><option>B</option></choose>
 * Optional parameter: <option weight="3"> == 3x weight given
 *
 * @file RandomSelection.php
 * @ingroup Extensions
 * @version 2.1.5
 * @date 17 January 2010
 * @author Ross McClure <http://www.mediawiki.org/wiki/User:Algorithm>
 * @link http://www.mediawiki.org/wiki/Extension:RandomSelection Documentation
 */
 
if( !defined( 'MEDIAWIKI' ) ) {
        die( "This is not a valid entry point to MediaWiki.\n" );
}
 
$wgHooks['ParserFirstCallInit'][] = 'wfRandomSelection';
 
$wgExtensionCredits['parserhook'][] = array(
        'name' => 'RandomSelection',
        'version' => '2.1.5',
        'author' => 'Ross McClure',
        'description' => 'Displays a random option from the given set.',
        'url' => 'http://www.mediawiki.org/wiki/Extension:RandomSelection',
);
 
function wfRandomSelection( &$parser ) {
        $parser->setHook( 'choose', 'renderChosen' );
        return true;
}
 
function renderChosen( $input, $argv, $parser ) {
        # Prevent caching
 $parser->disableCache();
 
        # Parse the options and calculate total weight
 $len = preg_match_all(
                "/<option(?:(?:\\s[^>]*?)?\\sweight=[\"']?([^\\s>]+))?"
                        . "(?:\\s[^>]*)?>([\\s\\S]*?)<\\/option>/",
                $input,
                $out
        );
        $r = 0;
        for( $i = 0; $i < $len; $i++ ) {
                if( strlen( $out[1][$i] ) == 0 ) {
                        $out[1][$i] = 1;
                } else {
                        $out[1][$i] = intval( $out[1][$i] );
                }
                $r += $out[1][$i];
        }
 
        # Choose an option at random
 if( $r <= 0 ) {
                return '';
        }
        $r = mt_rand( 1, $r );
        for( $i = 0; $i < $len; $i++ ) {
                $r -= $out[1][$i];
                if( $r <= 0 ) {
                        $input = $out[2][$i];
                        break;
                }
        }
 
        # Parse tags and return
 return $parser->recursiveTagParse( $input );
}

Changelog

• Dec 10 07 -- Updated for compatibility with MW 1.12's new parser model
• Feb 23 08 -- Minor bugfix
• May 8 08 -- Bugfix
• July 08 -- Use ParserFirstCallInit hook if it's available
• 30 September 2009 -- Doxygen comments added + minor tweaks
• 17 January 2010 -- dropped backwards compatibility with old MediaWikis as per r55838 and made the extension work under PHP 5.3+