How to restrict access to a specific CMS page in Magento 2 based on customer login status?

To restrict access to a specific CMS page in Magento 2 based on whether the customer is logged in or not, you can implement an observer that listens to the controller_action_predispatch_cms_page_view event. Here’s how you can achieve this:

Create an Observer Class (RestrictPage.php): This observer checks if the accessed CMS page matches a specific identifier (hot-sale) and redirects non-logged-in customers to the login page.

<?php
namespace JJRestrictPageObserver;


use MagentoFrameworkEventObserverInterface;
use MagentoFrameworkEventObserver;
use MagentoCustomerModelSession as CustomerSession;
use MagentoFrameworkAppActionFlag;
use MagentoFrameworkAppResponseRedirectInterface;
use MagentoCmsApiPageRepositoryInterface;
use MagentoFrameworkAppRequestHttp;
use MagentoFrameworkAppResponseHttp as Response;


class RestrictPage implements ObserverInterface
{
    protected $customerSession;
    protected $actionFlag;
    protected $redirect;
    protected $pageRepository;
    protected $request;
    protected $response;


    public function __construct(
        CustomerSession $customerSession,
        ActionFlag $actionFlag,
        RedirectInterface $redirect,
        PageRepositoryInterface $pageRepository,
        Http $request,
        Response $response
    ) {
        $this->customerSession = $customerSession;
        $this->actionFlag = $actionFlag;
        $this->redirect = $redirect;
        $this->pageRepository = $pageRepository;
        $this->request = $request;
        $this->response = $response;
    }


    public function execute(Observer $observer)
    {
        $pageId = $this->request->getParam('page_id', $this->request->getParam('id', false));
        if ($pageId) {
            try {
                $page = $this->pageRepository->getById($pageId);
                if ($page->getIdentifier() == 'hot-sale' && !$this->customerSession->isLoggedIn()) {
                    $this->actionFlag->set('', MagentoFrameworkAppActionAction::FLAG_NO_DISPATCH, true);
                    if (!$this->customerSession->getBeforeUrl()) {
                        $this->customerSession->setBeforeUrl($this->request->getUriString());
                    }
                    $this->redirect->redirect($this->response, 'customer/account/login');
                }
            } catch (Exception $e) {
                // Handle the exception if the page does not exist or other errors
            }
        }
        return $this;
    }
}

Configure the Observer: Declare your observer in the events.xml file of your module to listen to the controller_action_predispatch_cms_page_view event.

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:framework:Event/etc/events.xsd">
    <event name="controller_action_predispatch_cms_page_view">
        <observer name="restrict_page_observer"
                  instance="JJRestrictPageObserverRestrictPage"/>
    </event>
</config>