Update PyroCMS Core Sitemap to generate a Sitemap

sitemap.php

<?php if (!defined('BASEPATH')) exit('No direct script access allowed');
/**
 * Sitemap module public controller
 * 
 * Renders a human-readable sitemap with all public pages and blog categories
 * Also renders a machine-readable sitemap for search engines
 * 
 * @author  	Barnabas Kendall <barnabas@bkendall.biz>
 * @license 	Apache License v2.0
 * @version 	1.1
 * @package	PyroCMS\Core\Modules\Sitemap\Controllers
 */
class Sitemap extends Public_Controller {

	/**
	 * XML method - output sitemap in XML format for search engines
	 * 
	 * @return void
	 */
	public function xml()
	{
            
                $this->load->model('blog/blog_m'); 
                $this->load->model('navigation/navigation_m');  
                
		$doc = new SimpleXMLElement('<?xml version="1.0" encoding="UTF-8"?>
                    <urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
                    xmlns:image="http://www.google.com/schemas/sitemap-image/1.1"
                    xmlns:video="http://www.google.com/schemas/sitemap-video/1.1" />');
		
		// first get a list of enabled modules, use them for the listing
		$modules = $this->module_m->get_all(array('is_frontend' => 1));

		foreach ($modules as $module)
		{
			// To understand recursion, you must first understand recursion
			if ($module['slug'] == 'sitemap')
			{
				continue;
			}

			if ( ! file_exists($module['path'].'/controllers/sitemap.php'))
			{
				continue;
			}			
		}
                
                $articles = $this->blog_m->get_many_by(array('status', 'live'));
       
                foreach($articles as $article) {
                    $node = $doc->addChild('url');
                    $loc = site_url('blog/'.date('Y/m/', $article->created_on).$article->slug, $article->title);
                    $node->addChild('loc', $loc); 
                    if($article->updated_on) {
                        $node->addChild('lastmod', date(DATE_W3C, $article->updated_on));
                    }
                }
		
		$this->output
			->set_content_type('application/xml')
			->set_output($doc->asXML());
	}	
}