How to create AJAX action for POST requests in Magento 2.3?

Question

How to create a controller action that can be requested by POST properly in own custom payment module in Magento 2.3? How to create a parent class that will be extended by classes corresponding to controller actions which can be requested by POST properly in this version of Magento? I have created such a parent class:

<?php
namespace Billon\Payment\Controller;
/**
 * Ajax source
 */
class AjaxAction extends \Magento\Framework\App\Action\Action
{
    public function __construct(\Magento\Framework\App\Action\Context $context)
    {
        return parent::__construct($context);
    }
    public function execute()
    {
        //(...)
    }
}

The classes of the controller actions looks like this:

<?php
namespace Billon\Payment\Controller\Multishipping;
/**
 * Ajax source that initiate payment in multishipping checkout
 */
class Initiation extends \Billon\Payment\Controller\AjaxAction
{
    /**
     * Initiates the payment in multishipping checkout
     */
    public function execute()
    {
        parent::execute();
        //(...)
    }
}

Such actions can be request in Magento 2.0 - 2.2 by POST (above action by '(store address)/billon/multishipping/initiation'). However I can send only GET request properly to my controller actions in Magento 2.3. After I send POST request to my action, the action redirects to the referrer with HTTP code 302. I found a ugly solution in the parent class:

<?php
namespace Billon\Payment\Controller;
/**
 * Ajax source
 */
class AjaxAction extends \Magento\Framework\App\Action\Action
{
    public function __construct()
    {
        $this->execute();
        die();
    }
    public function execute()
    {
        //(...)
    }
}

This solution disables the translation with a function '__'. How to resolve this problem? How to disable the redirection of POST requests from the controller actions to the referrers in Magento 2.3 in proper way? How should I change my action classes to receive POST request? Could you help me?

Answer 1

To create AJAX action for POST requests in Magento 2.3, Please see the code below.

namespace Billon\Payment\Controller\Multishipping;

class Initiation extends \Magento\Framework\App\Action\Action
{

    protected $resultPageFactory;
    protected $jsonHelper;

    /**
     * Constructor
     *
     * @param \Magento\Framework\App\Action\Context  $context
     * @param \Magento\Framework\Json\Helper\Data $jsonHelper
     */
    public function __construct(
        \Magento\Framework\App\Action\Context $context,
        \Magento\Framework\View\Result\PageFactory $resultPageFactory,
        \Magento\Framework\Json\Helper\Data $jsonHelper
    ) {
        $this->resultPageFactory = $resultPageFactory;
        $this->jsonHelper = $jsonHelper;
        parent::__construct($context);
    }

    /**
     * Execute view action
     *
     * @return \Magento\Framework\Controller\ResultInterface
     */
    public function execute()
    {
        try {
            return $this->jsonResponse('your response');
        } catch (\Magento\Framework\Exception\LocalizedException $e) {
            return $this->jsonResponse($e->getMessage());
        } catch (\Exception $e) {
            $this->logger->critical($e);
            return $this->jsonResponse($e->getMessage());
        }
    }

    /**
     * Create json response
     *
     * @return \Magento\Framework\Controller\ResultInterface
     */
    public function jsonResponse($response = '')
    {
        return $this->getResponse()->representJson(
            $this->jsonHelper->jsonEncode($response)
        );
    }
}

Answer 2

For future reference,

I was only able to make my request work by doing the following steps in Magento 2.3.1 otherwise I was getting a 404. I checked class vendor/magento/module-authorizenet/Controller/Directpost/Payment/BackendResponse.php for reference.

1. Add the following interfaces

    CsrfAwareActionInterface, (especially important because all post requests are using by default CSRF validation)
    HttpGetActionInterface,
    HttpPostActionInterface

2. Implement the CSRF handling functions

public function validateForCsrf(RequestInterface $request): ?bool
{
    return true;
}

public function createCsrfValidationException(
    RequestInterface $request
): ?InvalidRequestException {
    return null;
}

3. Execute

php bin/magento setup:upgrade
php cache:flush

Answer 3

In Magento 2.3, controllers must implement \Magento\Framework\App\Action\HttpPostActionInterface to be able to handle POST requests - https://devdocs.magento.com/guides/v2.3/extension-dev-guide/routing.html