Helper sitemap xml

SiteMapXML.php

<?php

/**
 * SiteMapXML
 *
 * A simple helper to make simple sitemap.xml with images
 *
 * Usage:
 *   // without images
 *   $sitemap = new SiteMapXML();
 *   $sitemap->addUrl('http://example.org');
 *   $sitemap->saveXML() // returns the string xml
 * 
 *   // with images
 *   $node = $sitemap->addUrl('http://example.org');
 *   $sitemap->addImage($node, 'image url', 'image title', 'image alt');
 * 
 * @author Jeremy Perret <jerem@devster.org> 
 */
class SiteMapXML extends \DOMDocument
{
    public $root;
    
    public function __construct($charset = 'UTF-8')
    {
        parent::__construct('1.0', $charset);
        
        $this->root = $this->appendChild($this->createElement('urlset'));
        $xmlns = $this->createAttribute('xmlns');
        $xmlns->value = 'http://www.sitemaps.org/schemas/sitemap/0.9';
        $this->root->appendChild($xmlns);
        $this->createAttributeNS('http://www.google.com/schemas/sitemap-image/1.1', 'image:attr' );
    }
    
    public function addUrl($url)
    {
        $urlNode = $this->createElement('url');
        $this->root->appendChild($urlNode);

        $urlNode->appendChild($this->_createTextNode('loc', $url));
        
        return $urlNode;
    }
    
    public function addImage(\DOMElement $node, $url, $title, $catpion)
    {
        $imgNode = $this->createElement('image:image');
        $node->appendChild($imgNode);
        
        $imgNode->appendChild($this->_createTextNode('image:loc', $url));
        $imgNode->appendChild($this->_createTextNode('image:title', $title));
        $imgNode->appendChild($this->_createTextNode('image:caption', $catpion));
    }
    
    protected function _createTextNode($name, $value)
    {
        $el = $this->createElement($name);
        $el->appendChild($this->createTextNode($value));
        
        return $el;
    }
}