silverstripe-framework/core/control/Sitemap.php

<?php
/**
 * Initial implementation of Sitemap support.
 * SitemapController should handle requests to 'sitemap.xml'
 * the other two classes are used to render the sitemap
 */

class Sitemap extends Controller {
	protected $Pages;
	function __construct()
	{
		$this->Pages=DataObject::get('SiteTree');
	}

	public function Items()
	{
		foreach($this->Pages as $page)
		{
			// If the page has been set to 0 priority, we set a flag so it won't be included
			if(isset($page->Priority) && $page->Priority <= 0)
				$page->Include = false;
			else
				$page->Include = true;
			
			// The one field that isn't easy to deal with in the template is
			// Change frequency, so we set that here.
			$properties = $page->toMap();
			$created = new Datetime($properties['Created']);
			$now = new Datetime();
			$versions = $properties['Version'];
			$timediff = $now->format('U') - $created->format('U');
			
			// Check how many revisions have been made over the lifetime of the
			// Page for a rough estimate of it's changing frequency.
			
			$period = $timediff / ($versions + 1);
			
			if($period > 60*60*24*365) // > 1 year
			{
				$page->ChangeFreq='yearly';
			}
			else if($period > 60*60*24*30) // > ~1 month
			{
				$page->ChangeFreq='monthly';
			}
			else if($period > 60*60*24*7) // > 1 week
			{
				$page->ChangeFreq='weekly';
			}
			else if($period > 60*60*24) // > 1 day
			{
				$page->ChangeFreq='daily';
			}
			else if($period > 60*60) // > 1 hour
			{
				$page->ChangeFreq='hourly';
			}
			else // < 1 hour
			{
				$page->ChangeFreq='always';
			}
		}
		return $this->Pages;
	}
	
	static function Ping()
	{
		//Don't ping if the site has disabled it
		if(!Sitemap::$pings)
			return;
			
		$location = urlencode(Director::absoluteBaseURL() . '/sitemap.xml');
		
		$response = HTTP::sendRequest("www.google.com", "/webmasters/sitemaps/ping",
			"sitemap=" . $location);
			
		return $response;
	}
	
	protected static $pings = true;
	
	/**
	 * Disables pings to google when the sitemap changes
	 * To use this, in your _config.php file simply include the line
	 * Sitemap::DisableGoogleNotification();
	 */
	static function DisableGoogleNotification()
	{
		self::$pings = false;
	}
	
	
	function index($url)
	{
		// We need to override the default content-type
		ContentNegotiator::disable();
		header('Content-type: application/xml; charset="utf-8"');
		
		// But we want to still render.
		return array();
	}
}
?>