silverstripe-googlesitemaps/docs/en/index.md

# Google Sitemaps Module

SilverStripe provides support for the Google Sitemaps XML system, enabling 
Google and other search engines to see all pages on your site. This helps 
your SilverStripe website rank well in search engines, and to encourage the 
information on your site to be discovered by Google quickly.

Therefore, all Silverstripe websites contain a special controller which can be 
visited: http://yoursite.com/sitemap.xml. This is not a file directly, but 
rather a custom route which points to the GoogleSitemap controller.

See http://en.wikipedia.org/wiki/Sitemaps for info on the Google Sitemap 
format.

Whenever you publish a new or republish an existing page, SilverStripe can 
automatically inform Google of the change, encouraging a Google to take notice. 
If you install the SilverStripe Google Analytics module, you can see if Google 
has updated your page as a result.

By default, SilverStripe informs Google that the importance of a page depends 
on its position of in the sitemap. "Top level" pages are most important, and 
the deeper a page is nested, the less important it is. (For each level, 
Importance drops from 1.0, to 0.9, to 0.8, and so on, until 0.1 is reached).

In the CMS, in the Settings tab for each page, you can set the importance 
manually, including requesting to have the page excluded from the sitemap.


## Setup automatic pinging

	GoogleSitemap::enable_google_notification();

### Including DataObjects

The module provides support for including DataObject subclasses as pages in the 
SiteTree such as comments, forum posts and other pages which are stored in your
database as DataObject subclasses.

To include a DataObject instance in the Sitemap it requires that your subclass 
defines two functions:

 * AbsoluteLink() function which returns the URL for this DataObject
 * canView() function which returns a boolean value.

The following is a barebones example of a DataObject called 'MyDataObject'. It 
assumes that you have a controller called 'MyController' which has a show method 
to show the DataObject by its ID.

	<?php
	
	class MyDataObject extends DataObject {
		
		function canView() {
			return true;
		}
		
		function AbsoluteLink() {
			return Director::absoluteURL($this->Link());
		}
		
		function Link() {
			return 'MyController/show/'. $this->ID;
		}
	}


After those methods have been defined on your DataObject you now need to tell 
the Google Sitemaps module that it should be listed in the sitemap.xml file. To
do that, include the following in your _config.php file.

	GoogleSitemap::register_dataobject('MyDataObject');

If you need to change the frequency of the indexing, you can pass the change 
frequency (daily, weekly, monthly) as a second parameter to register(), So 
instead of the previous code you would write:

	GoogleSitemap::register('MyDataObject', 'daily');	
	
See the following blog post for more information:

http://www.silvercart.org/blog/dataobjects-and-googlesitemaps/

### Including other routes

If your project has routes that are not stored in the database such as custom
controllers and actions, the module provides an extension hook called 
*updateItems* which allows anyone to write extensions to alter the provided
items.

Here's an example of registering the MyController/about URL which is defined as
an action. First we create our new extension and define the links we wish to 
add to the $items list.

	<?php

	class GoogleSitemapExtension extends Extension {
		
		public function updateItems($items) {
			$base = Director::absoluteBaseUrl();
			$routes = array(
				'/MyController/',
				'/MyController/about/'
			);

			foreach($routes as $route) {
				$items->push(new ArrayData(array(
					'AbsoluteLink' => Controller::join_links($base, $route)
				)));
			}
		}
	}

Before we can see the updates we first must add this extension to our built in
class. Inside your mysite/_config.php file add the following:

	Object::add_extension('GoogleSitemap', 'GoogleSitemapExtension');