Magento Checkout, Check if the user is logged-in

Question

I have to redirect the user to our SSO login page ifhe is not logged-in during the checkout.

As suggested here, I added this check into my phtml file that overrides this vendor/magento/module-checkout/view/frontend/templates/onepage.phtml.

if(!$this->customerSession->isLoggedIn()) 

Debugging the code seems that this->customerSession is not present. So, how can I check if the user is logged-in into this phtml file?

Answer 1

Direct answer to your question : You dont, you should not check in phtml file.

customerSession is not available in block and this is normal, you can see which methods are available in here : https://github.com/magento/magento2/blob/2.4-develop/app/code/Magento/Checkout/Block/Onepage.php

Important Advice: do not include any logic in templates, it is a very bad practice

Proper solution : for that purpose you can use a plugin to change the result of redirection to cart to force login page :

etc/frontend/di.xml

<?xml version="1.0" ?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <type name="Magento\Checkout\Controller\Index\Index">
        <plugin name="redirect_to_login_sso_instead_of_cart"
                type="Project\Sso\Plugin\Frontend\Checkout\Controller\Index\IndexPlugin" sortOrder="10"
                disabled="false"/>
    </type>
</config>

and then in Project\Sso\Plugin\Frontend\Checkout\Controller\Index\IndexPlugin :

<?php

declare(strict_types=1);

namespace Project\Sso\Plugin\Frontend\Checkout\Controller\Index;

use Magento\Checkout\Controller\Index\Index;
use Magento\Customer\Model\Session;
use Magento\Framework\Exception\SessionException;

class IndexPlugin
{

    /** @var Session */
    private $customerSession;

    public function __construct(
        Session $customerSession
    ) {
        $this->customerSession = $customerSession;
    }

    /**
     * @throws SessionException
     */
    public function afterExecute(
        Index $subject,
        $result
    ) {
        if (!$this->customerSession->isLoggedIn()) {
            $this->customerSession->authenticate();
        }
        return $result;
    }

}

Tested 100% works.