MAGETWO-92953: [2.3] Once Payflow Pro payment is Declined, customer cannot continue checkout

- allow POST request without form key on response controller

Author: viktym

app/code/Magento/Paypal/Controller/Transparent/Response.php

@@ -5,6 +5,7 @@
  */
 namespace Magento\Paypal\Controller\Transparent;
 
+use Magento\Framework\App\CsrfAwareActionInterface;
 use Magento\Framework\Registry;
 use Magento\Framework\App\Action\Context;
 use Magento\Framework\View\Result\LayoutFactory;
@@ -16,11 +17,13 @@
 use Magento\Paypal\Model\Payflow\Transparent;
 use Magento\Sales\Api\PaymentFailuresInterface;
 use Magento\Framework\Session\Generic as Session;
+use Magento\Framework\App\RequestInterface;
+use Magento\Framework\App\Request\InvalidRequestException;
 
 /**
  * Class Response
  */
-class Response extends \Magento\Framework\App\Action\Action
+class Response extends \Magento\Framework\App\Action\Action implements CsrfAwareActionInterface
 {
     /**
      * Core registry
@@ -91,6 +94,23 @@ public function __construct(
         $this->paymentFailures = $paymentFailures ?: $this->_objectManager->get(PaymentFailuresInterface::class);
     }
 
+    /**
+     * @inheritDoc
+     */
+    public function createCsrfValidationException(
+        RequestInterface $request
+    ): ?InvalidRequestException {
+        return null;
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function validateForCsrf(RequestInterface $request): ?bool
+    {
+        return true;
+    }
+
     /**
      * @return ResultInterface
      */