/app/code/core/Mage/Cms/Helper/Page.php

<?php
/**
 * Magento
 *
 * NOTICE OF LICENSE
 *
 * This source file is subject to the Open Software License (OSL 3.0)
 * that is bundled with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://opensource.org/licenses/osl-3.0.php
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@magento.com so we can send you a copy immediately.
 *
 * DISCLAIMER
 *
 * Do not edit or add to this file if you wish to upgrade Magento to newer
 * versions in the future. If you wish to customize Magento for your
 * needs please refer to http://www.magento.com for more information.
 *
 * @category    Mage
 * @package     Mage_Cms
 * @copyright  Copyright (c) 2006-2018 Magento, Inc. (http://www.magento.com)
 * @license    http://opensource.org/licenses/osl-3.0.php  Open Software License (OSL 3.0)
 */


/**
 * CMS Page Helper
 *
 * @category   Mage
 * @package    Mage_Cms
 * @author     Magento Core Team <core@magentocommerce.com>
 */
class Mage_Cms_Helper_Page extends Mage_Core_Helper_Abstract
{
    const XML_PATH_NO_ROUTE_PAGE        = 'web/default/cms_no_route';
    const XML_PATH_NO_COOKIES_PAGE      = 'web/default/cms_no_cookies';
    const XML_PATH_HOME_PAGE            = 'web/default/cms_home_page';

    /**
    * Renders CMS page on front end
    *
    * Call from controller action
    *
    * @param Mage_Core_Controller_Front_Action $action
    * @param integer $pageId
    * @return boolean
    */
    public function renderPage(Mage_Core_Controller_Front_Action $action, $pageId = null)
    {
        return $this->_renderPage($action, $pageId);
    }

   /**
    * Renders CMS page
    *
    * @param Mage_Core_Controller_Front_Action $action
    * @param integer $pageId
    * @param bool $renderLayout
    * @return boolean
    */
    protected function _renderPage(Mage_Core_Controller_Varien_Action  $action, $pageId = null, $renderLayout = true)
    {

        $page = Mage::getSingleton('cms/page');
        if (!is_null($pageId) && $pageId!==$page->getId()) {
            $delimeterPosition = strrpos($pageId, '|');
            if ($delimeterPosition) {
                $pageId = substr($pageId, 0, $delimeterPosition);
            }

            $page->setStoreId(Mage::app()->getStore()->getId());
            if (!$page->load($pageId)) {
                return false;
            }
        }

        if (!$page->getId()) {
            return false;
        }

        $inRange = Mage::app()->getLocale()
            ->isStoreDateInInterval(null, $page->getCustomThemeFrom(), $page->getCustomThemeTo());

        if ($page->getCustomTheme()) {
            if ($inRange) {
                list($package, $theme) = explode('/', $page->getCustomTheme());
                Mage::getSingleton('core/design_package')
                    ->setPackageName($package)
                    ->setTheme($theme);
            }
        }

        $action->getLayout()->getUpdate()
            ->addHandle('default')
            ->addHandle('cms_page');

        $action->addActionLayoutHandles();
        if ($page->getRootTemplate()) {
            $handle = ($page->getCustomRootTemplate()
                        && $page->getCustomRootTemplate() != 'empty'
                        && $inRange) ? $page->getCustomRootTemplate() : $page->getRootTemplate();
            $action->getLayout()->helper('page/layout')->applyHandle($handle);
        }

        Mage::dispatchEvent('cms_page_render', array('page' => $page, 'controller_action' => $action));

        $action->loadLayoutUpdates();
        $layoutUpdate = ($page->getCustomLayoutUpdateXml() && $inRange)
            ? $page->getCustomLayoutUpdateXml() : $page->getLayoutUpdateXml();
        $action->getLayout()->getUpdate()->addUpdate($layoutUpdate);
        $action->generateLayoutXml()->generateLayoutBlocks();

        $contentHeadingBlock = $action->getLayout()->getBlock('page_content_heading');
        if ($contentHeadingBlock) {
            $contentHeading = $this->escapeHtml($page->getContentHeading());
            $contentHeadingBlock->setContentHeading($contentHeading);
        }

        if ($page->getRootTemplate()) {
            $action->getLayout()->helper('page/layout')
                ->applyTemplate($page->getRootTemplate());
        }

        /* @TODO: Move catalog and checkout storage types to appropriate modules */
        $messageBlock = $action->getLayout()->getMessagesBlock();
        foreach (array('catalog/session', 'checkout/session', 'customer/session') as $storageType) {
            $storage = Mage::getSingleton($storageType);
            if ($storage) {
                $messageBlock->addStorageType($storageType);
                $messageBlock->addMessages($storage->getMessages(true));
            }
        }

        if ($renderLayout) {
            $action->renderLayout();
        }

        return true;
    }

    /**
     * Renders CMS Page with more flexibility then original renderPage function.
     * Allows to use also backend action as first parameter.
     * Also takes third parameter which allows not run renderLayout method.
     *
     * @param Mage_Core_Controller_Varien_Action $action
     * @param $pageId
     * @param $renderLayout
     * @return bool
     */
    public function renderPageExtended(Mage_Core_Controller_Varien_Action $action, $pageId = null, $renderLayout = true)
    {
        return $this->_renderPage($action, $pageId, $renderLayout);
    }

    /**
     * Retrieve page direct URL
     *
     * @param string $pageId
     * @return string
     */
    public function getPageUrl($pageId = null)
    {
        $page = Mage::getModel('cms/page');
        if (!is_null($pageId) && $pageId !== $page->getId()) {
            $page->setStoreId(Mage::app()->getStore()->getId());
            if (!$page->load($pageId)) {
                return null;
            }
        }

        if (!$page->getId()) {
            return null;
        }

        return Mage::getUrl(null, array('_direct' => $page->getIdentifier()));
    }
}