Extension:RDFa Breadcrumbs

The RDFa Breadcrumbs extension allows users to include breadcrumbs on pages which will get RDFa markup. It does not depend on categories but allows the definition on the individual pages.

Usage

{{#breadcrumbs:
   [[Main Page]]
   | {{ll|Manual:Extensions|Extensions}}
   | [[Extension:RDFa Breadcrumbs|RDFa Breadcrumbs]]
   | ... }}

This will look like this:

Main Page > Extensions > RDFa Breadcrumbs

In addition it will include RDFa markup so that Google will recognize it as Breadcrumb.

Installation

• Copy the code into a file and place the file(s) in a directory called Rdfabreadcrumbs in your extensions/ folder.
• Add the following code at the bottom of your LocalSettings.php :

  require_once "$IP/extensions/Rdfabreadcrumbs/Rdfabreadcrumbs.php";
  

• Edit [[MediaWiki:common.css]] and add the following section at the end:

.breadcrumbs {
   clear: both;
   border:1px solid #AAAAAA;
   background-color:#F9F9F9;
   padding:5px;
}

•  Done – Navigate to Special:Version on your wiki to verify that the extension is successfully installed.

Code

Rdfabreadcrumbs.php

<?php

// License: CC BY 2010 Hendrik Brummermann <nhb_web@nexgo.de>

if ( !defined( 'MEDIAWIKI' ) ) {
        die( 'This file is an extension to MediaWiki and thus not a valid entry point.' );
}

$wgHooks['ParserFirstCallInit'][] = 'efRDFaBreadcrumbs_Setup';
$wgHooks['LanguageGetMagic'][]       = 'efRDFaBreadcrumbs_Magic';

$wgExtensionCredits['parserhook'][] = array(
	'path' => __FILE__,
	'name' => 'RDFa_Breadcrumbs',
	'version' => '1.0',
	'url' => 'https://www.mediawiki.org/wiki/Extension:RDFa_Breadcrumbs',
	'author' => 'Hendrik Brummermann',
	'description' => 'Allows for breadcrumbs with RDFa markup',
);

function efRDFaBreadcrumbs_Setup( &$parser ) {
	$parser->setFunctionHook('breadcrumbs', 'RDFaBreadcrumbs_Render' );
	return true;
}

function efRDFaBreadcrumbs_Magic( &$magicWords, $langCode ) {
	$magicWords['breadcrumbs'] = array( 0, 'breadcrumbs' );
	return true;
}

function RDFaBreadcrumbs_Render($parser) {
	$output = '<div class="breadcrumbs" xmlns:v="http://rdf.data-vocabulary.org/#">';
	for ($i = 1; $i < func_num_args(); $i++) {
		if ($i > 1) {
			$output .= ' &gt; ';
		}
		$output .= '<span typeof="v:Breadcrumb">';
		$item = trim(func_get_arg($i));
		$output .= '<a href="'.htmlspecialchars(getURLFromLink($item))
			.'" rel="v:url" property="v:title">';
		$output .= htmlspecialchars(getTextFromLink($item));
		$output .= '</a></span>';
	}
	$output = $output . '</div>';
	return array($output, 'noparse' => true, 'isHTML' => true);
}

function getURLFromLink($link) {
	global $wgArticlePath;
	if (strpos($link, '[[') === 0) {
		// internal link
		$delimiter = '|';
		$start = 2;
		$pos2 = strpos($link, $delimiter);
		if ($pos2 === FALSE) {
			$pos2 = strlen($link) - 2;
		}
		$url = substr($link, $start, $pos2 - $start);
		return trim(preg_replace('/\$1/', urlencode(preg_replace('/[ +]/', '_', trim($url))), $wgArticlePath));
	} else if (strpos($link, '[') === 0) {
		// external link
		$delimiter = ' ';
		$start = 1;
		$pos2 = strpos($link, $delimiter);
		if ($pos2 === FALSE) {
			$pos2 = strlen($link) - 1;
		}
		$url = substr($link, $start, $pos2 - $start);
		return trim($url);
	} else {
		return trim(preg_replace('/\$1/', urlencode(preg_replace('/[ +]/', '_', trim($link))), $wgArticlePath));
	}
}

function getTextFromLink($link) {
	if (strpos($link, '[[') === 0) {
		// internal link
		$delimiter = '|';
		$start = 1;
	} else if (strpos($link, '[') === 0) {
		// external link
		$delimiter = ' ';
		$start = 0;
	} else {
		return trim($link);
	}
	$pos1 = strpos($link, $delimiter);
	if ($pos1 === FALSE) {
		$pos1 = $start;
	}
	$pos2 = strpos($link, ']');
	return trim(substr($link, $pos1 + 1, $pos2 - $pos1 - 1));
}