Set isajax to true in Validate3d controller to prevent Invalid form key...

Set isajax to true in Validate3d controller to prevent Invalid form key error(magento 2.3), fix for capture on shipment method

Controller/Process/Validate3d.php

@@ -22,6 +22,7 @@
  */
 
 namespace Adyen\Payment\Controller\Process;
+use Magento\Framework\App\Request\Http as HttpRequest;
 
 class Validate3d extends \Magento\Framework\App\Action\Action
 {
@@ -75,6 +76,13 @@ class Validate3d extends \Magento\Framework\App\Action\Action
         $this->_adyenHelper = $adyenHelper;
         $this->_paymentRequest = $paymentRequest;
         $this->_orderRepository = $orderRepository;
+        // Fix for Magento2.3 adding isAjax to the request params
+        if(interface_exists("\Magento\Framework\App\CsrfAwareActionInterface")) {
+            $request = $this->getRequest();
+            if ($request instanceof HttpRequest && $request->isPost()) {
+                $request->setParam('isAjax', true);
+            }
+        }
     }
 
     /**

Observer/Adminhtml/BeforeShipmentObserver.php

@@ -54,7 +54,7 @@ class BeforeShipmentObserver extends AbstractDataAssignObserver
     {
         $shipment = $observer->getEvent()->getShipment();
         $order = $shipment->getOrder();
-        $captureOnShipment = $this->_adyenHelper->getConfigData('capture_on_shipment', 'adyen_abstract', $order->getStoreId());
+        $captureOnShipment = $this->adyenHelper->getConfigData('capture_on_shipment', 'adyen_abstract', $order->getStoreId());
 
         if ($this->isPaymentMethodAdyen($order) && $captureOnShipment) {
             $payment = $order->getPayment();