silverstripe-cms/code/model/SiteTreeExtension.php

<?php

/**
 * Plug-ins for additional functionality in your SiteTree classes.
 *
 * @package cms
 * @subpackage model
 */
abstract class SiteTreeExtension extends DataExtension {

	/**
	 * Hook called before the page's {@link Versioned::publishSingle()} action is completed
	 *
	 * @param SiteTree &$original The current Live SiteTree record prior to publish
	 */
	public function onBeforePublish(&$original) {
	}

	/**
	 * Hook called after the page's {@link Versioned::publishSingle()} action is completed
	 *
	 * @param SiteTree &$original The current Live SiteTree record prior to publish
	 */
	public function onAfterPublish(&$original) {
	}

	/**
	 * Hook called before the page's {@link Versioned::doUnpublish()} action is completed
	 */
	public function onBeforeUnpublish() {
	}


	/**
	 * Hook called after the page's {@link SiteTree::doUnpublish()} action is completed
	 */
	public function onAfterUnpublish() {
	}

	/**
	 * Hook called to determine if a user may add children to this SiteTree object
	 *
	 * @see SiteTree::canAddChildren()
	 *
	 * @param Member $member The member to check permission against, or the currently
	 * logged in user
	 * @return boolean|null Return false to deny rights, or null to yield to default
	 */
	public function canAddChildren($member) {
	}

	/**
	 * Hook called to determine if a user may publish this SiteTree object
	 *
	 * @see SiteTree::canPublish()
	 *
	 * @param Member $member The member to check permission against, or the currently
	 * logged in user
	 * @return boolean|null Return false to deny rights, or null to yield to default
	 */
	public function canPublish($member) {
	}

	/**
	 * Hook called to modify the $base url of this page, with a given $action,
	 * before {@link SiteTree::RelativeLink()} calls {@link Controller::join_links()}
	 * on the $base and $action
	 *
	 * @param string &$base The URL of this page relative to siteroot, not including
	 * the action
	 * @param string|boolean &$action The action or subpage called on this page.
	 * (Legacy support) If this is true, then do not reduce the 'home' urlsegment
	 * to an empty link
	 */
	public function updateRelativeLink(&$base, &$action) {
	}

}