Google breadcrumbs

google_breadcrumbs.php

<?php

/**
 * This generates breadcrumbs according to google specification
 * @link https://developers.google.com/structured-data/testing-tool/
 * Featuring:
 * - nested category trail
 * - multiple category trails
 * - starting with Home bit
 * - without the last bit (the actual product or the current category)
 */

$crumbLevels = array(
    // nested breadcrumb trail 1
    array(
        array('link' => 'url1.html', 'title' => 'URL1'),
        array('link' => 'url2.html', 'title' => 'URL2')
    ), 
    // nested breadcrumb trail 2
    array(
        array('link' => 'second-trail-url1.html', 'title' => 'Second trail URL1'),
        array('link' => 'second-trail-url2.html', 'title' => 'Second trail URL2')
    )
);

if ($crumbsLevels && is_array($crumbsLevels)) {

    $out = '<div class="breadcrumbs">'.PHP_EOL;

    foreach ($crumbsLevels as $crumbLevel => $crumbs) {
        $out .= '<ul style="clear: both">'.PHP_EOL;
        foreach ($crumbs as $crumbPosition => $_crumb) {
            $id = 'breadcrumb-'.($crumbLevel + 1).'-'.$crumbPosition;
            if (isset($crumbs[$crumbPosition+1]) && $crumbPosition + 1 < count($crumbs) - 1) {
                $childId = 'breadcrumb-' . ($crumbLevel + 1) . '-' . ($crumbPosition + 1);
            } else {
                $childId = null;
            }

            if ($crumbPosition < count($crumbs) - 1) {
                $liAttrs = array('id' => $id, 'itemscope' => '', 'itemtype' => 'http://data-vocabulary.org/Breadcrumb');
            } else {
                $liAttrs = array();
            }
            $aAttrs = array();
            $spanAttrs = array();


            if (!empty($childId)) {
                $liAttrs['itemref'] = $childId;
            }

            if ($crumbPosition > 0 && $crumbPosition < count($crumbs) - 1) {
                $liAttrs['itemprop'] = 'child';
            }

            if (!empty($_crumb['hidden'])) {
                $liAttrs['style'] = 'visibility: hidden;';
            }

            if (!empty($_crumb['link'])) {
                $aAttrs['href'] = $_crumb['link'];
                $aAttrs['title'] = $this->htmlEscape($_crumb['title']);
                $aAttrs['itemprop'] = 'url';
            }

            $spanAttrs['itemprop'] = 'title';

            $out .= '<li';
            foreach ($liAttrs as $key => $val) { $out .= " $key=\"$val\""; }
            $out .= '>';

            if (!empty($_crumb['link'])) {
                $out .= '<a ';
                foreach ($aAttrs as $key => $val) { $out .= " $key=\"$val\""; }
                $out .= '>';
            }

            $out .= '<div ';
            foreach ($spanAttrs as $key => $val) { $out .= " $key=\"$val\""; }
            $out .= '>'.$this->htmlEscape($_crumb['title']).'</div>';


            if (!empty($_crumb['link'])) {
                $out .= '</a>';
            }

            // Leave out the last crumb because it is the current page
            if ($crumbPosition < count($crumbs) - 1) {
                $out .= '<span> / </span>';
            }

            $out .= '</li>';
        }
        $out .= '</ul>'.PHP_EOL;
    }


    $out .= '</div>'.PHP_EOL; // .grid-full .breadcrumbs
    echo $out;
}