silverstripe-framework/core/model/RedirectorPage.php

<?php
/**
 * A redirector page redirects when the page is visited.
 * @package cms
 * @subpackage content
 */
class RedirectorPage extends Page {
	static $add_action = "Redirector to another page";
	static $icon = array("cms/images/treeicons/page-shortcut","file");
	
	static $db = array(
		"RedirectionType" => "Enum('Internal,External','Internal')",
		"ExternalURL" => "Varchar(255)",
	);
	
	static $has_one = array(
		"LinkTo" => "SiteTree",
	);
	
	static $many_many = array(
	);
	
	/**
	 * Returns this page if the redirect is external, otherwise
	 * returns the target page.
	 * @return SiteTree
	 */
	function ContentSource() {
		if($this->RedirectionType == 'Internal') {
			return $this->LinkTo();
		} else {
			return $this;
		}		
	}
	
	/**
	 * Return the the link that should be used for this redirector page, in navigation, etc.
	 * If the redirectorpage has been appropriately configured, then it will return the redirection
	 * destination, to prevent unnecessary 30x redirections.  However, if it's misconfigured, then
	 * it will return a link to itself, which will then display an error message. 
	 */
	function Link() {
		if($link = $this->redirectionLink()) return $link;
		else return $this->regularLink();
	}
	
	/**
	 * Return the normal link directly to this page.  Once you visit this link, a 30x redirection
	 * will take you to your final destination.
	 */
	function regularLink() {
		return parent::Link();
	}
	
	/**
	 * Return the link that we should redirect to.
	 * Only return a value if there is a legal redirection destination.
	 */
	function redirectionLink() {
		if($this->RedirectionType == 'External') {
			if($this->ExternalURL) {
				return Convert::raw2att($this->ExternalURL);
			}
			
		} else {
			$linkTo = $this->LinkToID ? DataObject::get_by_id("SiteTree", $this->LinkToID) : null;

			if($linkTo) {
				// We shouldn't point to ourselves - that would create an infinite loop!  Return null since we have a
				// bad configuration
				if($this->ID == $linkTo->ID) {
					return null;
			
				// If we're linking to another redirectorpage then just return the URLSegment, to prevent a cycle of redirector
				// pages from causing an infinite loop.  Instead, they will cause a 30x redirection loop in the browser, but
				// this can be handled sufficiently gracefully by the browser.
				} elseif($linkTo instanceof RedirectorPage) {
					return $linkTo->regularLink();

				// For all other pages, just return the link of the page.
				} else {
					return $linkTo->Link();
				}
			}
		}
	}
	
	function getCMSFields() {
		Requirements::javascript(SAPPHIRE_DIR . "/javascript/RedirectorPage.js");
		
    	$fields = new FieldSet(
			new TabSet("Root",
				$tabContent = new Tab("Content",
					new TextField("Title", $this->fieldLabel('Title')),
					new TextField("MenuTitle", $this->fieldLabel('MenuTitle')),
					new FieldGroup(_t('SiteTree.URL'),
						new LabelField('BaseUrlLabel',Director::absoluteBaseURL()),
						new UniqueRestrictedTextField("URLSegment",
							"URLSegment",
							"SiteTree",
							_t('SiteTree.VALIDATIONURLSEGMENT1', "Another page is using that URL. URL must be unique for each page"),
							"[^A-Za-z0-9-]+",
							"-",
							_t('SiteTree.VALIDATIONURLSEGMENT2', "URLs can only be made up of letters, digits and hyphens."),
							"",
							"",
							"",
							50
						),
						new LabelField('TrailingSlashLabel',"/")
					),
					new HeaderField('RedirectorDescHeader',_t('RedirectorPage.HEADER', "This page will redirect users to another page")),
					new OptionsetField(
						"RedirectionType", 
						_t('RedirectorPage.REDIRECTTO', "Redirect to"), 
						array(
							"Internal" => _t('RedirectorPage.REDIRECTTOPAGE', "A page on your website"),
							"External" => _t('RedirectorPage.REDIRECTTOEXTERNAL', "Another website"),
						), 
						"Internal"
					),
					new TreeDropdownField(	
						"LinkToID", 
						_t('RedirectorPage.YOURPAGE', "Page on your website"), 
						"SiteTree"
					),
					new TextField("ExternalURL", _t('RedirectorPage.OTHERURL', "Other website URL")),
					new TextareaField("MetaDescription", _t('SiteTree.METADESC'))
				),
				$tabBehaviour = new Tab("Behaviour",
					new DropdownField("ClassName",$this->fieldLabel('ClassName'), $this->getClassDropdown()),
					new CheckboxField("ShowInMenus", $this->fieldLabel('ShowInMenus')),
					new CheckboxField("ShowInSearch", $this->fieldLabel('ShowInSearch'))
				)
			)
		);
		
		$tabContent->setTitle(_t('SiteTree.TABCONTENT'));
		$tabBehaviour->setTitle(_t('SiteTree.TABBEHAVIOUR'));
		
		return $fields;
	}
}

/**
 * Controller for the {@link RedirectorPage}.
 * @package cms
 * @subpackage content
 */
class RedirectorPage_Controller extends Page_Controller {
	function init() {
		if($link = $this->redirectionLink()) {
			Director::redirect($link, 301);
		}

		parent::init();
	}
	
	/**
	 * If we ever get this far, it means that the redirection failed.
	 */
	function index() {
		return array(
			"Content" => "<p>" .
			_t('RedirectorPage.HASBEENSETUP', 'A redirector page has been set up without anywhere to redirect to.') .
			"</p>"
		);
	}
}
?>