This plugin displays a list of keywords with links to categories the current page belongs to. Those links are marked as Technorati tags and point to the page with the tag name in your wiki. For example for this page I could define “wiki:DokuWiki”, “wiki:plugins”, “plugin:category”, “tag” and “person:Esther_Brunner” as categories:

??wiki:DokuWiki wiki:plugins category :tag person:Esther_Brunner??

This would produce a list that looks like this:¹⁾

DokuWiki, plugins, category, tag, Esther Brunner

You can see the plugin in action here. <!– seems to be offline –>

To install, put the following PHP file in /lib/plugins/category/syntax.php.

<?php
/**
 * Category Plugin: displays list of keywords with links to categories this page
 * belongs to. The links are marked as tags for Technorati and other services
 * using tagging.
 *
 * Usage: ??category tags separated through spaces??
 *
 * @license    GPL 2 (http://www.gnu.org/licenses/gpl.html)
 * @author     Esther Brunner <esther [at] kaffeehaus [dot] ch>
 */
 
if(!defined('DOKU_INC')) define('DOKU_INC',realpath(dirname(__FILE__).'/../../').'/');
if(!defined('DOKU_PLUGIN')) define('DOKU_PLUGIN',DOKU_INC.'lib/plugins/');
require_once(DOKU_PLUGIN.'syntax.php');
 
/**
 * All DokuWiki plugins to extend the parser/rendering mechanism
 * need to inherit from this class
 */
class syntax_plugin_category extends DokuWiki_Syntax_Plugin {
 
    /**
     * return some info
     */
    function getInfo(){
        return array(
            'author' => 'Esther Brunner',
            'email'  => 'esther@kaffeehaus.ch',
            'date'   => '2005-07-12',
            'name'   => 'Category Plugin',
            'desc'   => 'Displays a list of keywords with links to categories this page belongs to. '.
                        'The links are marked as tags for Technorati and other services using tagging.',
            'url'    => 'http://www.dokuwiki.org/plugin:category',
        );
    }
 
    /**
     * What kind of syntax are we?
     */
    function getType(){
        return 'substition';
    }
 
    /**
     * Where to sort in?
     */
    function getSort(){
        return 305;
    }
 
    /**
     * Paragraph Type
     */
    function getPType(){
        return 'block';
    }
 
    /**
     * Connect pattern to lexer
     */
    function connectTo($mode) {
        $this->Lexer->addSpecialPattern("\?\?.+?\?\?",$mode,'plugin_category');
    }
 
    /**
     * Handle the match
     */
    function handle($match, $state, $pos, &$handler){
        $match = substr($match,2,-2);  // strip markup
        $match = explode(' ',$match);  // split tags
        return $match;
    }            
 
    /**
     * Create output
     */
    function render($mode, &$renderer, $data) {
        global $ID;
        global $conf;
 
        if($mode == 'xhtml'){
 
            $renderer->doc .= '<div class="category">';
            $c = count($data);
            for ($i = 0; $i < $c; $i++) {
                $tag = $data[$i];
                $title = str_replace('_', ' ' ,noNS($tag));
                resolve_pageid(getNS($ID),$tag,$exists); // resolve shortcuts
                if ($exists){
                    $class = 'wikilink1';
                    if ($conf['useheading']) {
                        $oldtitle = $title;
                        $title = trim(p_get_first_heading($tag));
                        if (!$title) $title = $oldtitle;
                    }
                } else {
                    $class = 'wikilink2';
                }
                $renderer->doc .= '<a href="'.wl($tag).'" class="'.$class.'" rel="tag" '.
                                  'onclick="return svchk()" onkeypress="return svchk()">'.$title.'</a>';
                if ($i !== ($c - 1)) $renderer->doc .= ', ';
            }
            $renderer->doc .= '</div>';
            return true;
        }
        return false;
    }
 
}
 
//Setup VIM: ex: et ts=4 enc=utf-8 :
?>

You can customize the look of the category <div> in lib/tpl/default/design.css, for example with this style:

.category {
    padding-top: 3px;
    border-top: 2px dotted #dee7ec;
    text-align: right;
}

• 2005-07-01: style changed from table to right aligned keyword list after a horizontal rule.
• 2005-07-12:
  • now allows subnamespaces – thanks to Geoffrey Roberts for this suggestion!
  • if $conf['useheading'] is on the first heading is used instead of the ID
  • style changed again to customizable div .category
• 2005-09-13:
  • if $conf['useheading'] is enabled display the pagename if there is no heading

Note that the JavaScript function “svchk()” no longer exists (and is now unnecessary) in Dokuwiki, and does cause JavaScript errors, so references should be removed.
– todd [at] rollerorgans [dot] com 2007-02-26