silverstripe-cms/code/Model/RedirectorPageController.php

<?php
namespace SilverStripe\CMS\Model;

use PageController;

/**
 * Controller for the {@link RedirectorPage}.
 */
class RedirectorPageController extends PageController
{

	protected function init()
	{
		parent::init();

		// Check we don't already have a redirect code set
		/** @var RedirectorPage $page */
		$page = $this->data();
		if (!$this->getResponse()->isFinished() && $link = $page->redirectionLink()) {
			$this->redirect($link, 301);
		}
	}

	/**
	 * If we ever get this far, it means that the redirection failed.
	 */
	public function Content()
	{
		return "<p class=\"message-setupWithoutRedirect\">" .
		_t('RedirectorPage.HASBEENSETUP', 'A redirector page has been set up without anywhere to redirect to.') .
		"</p>";
	}
}