commerce-8.x-2.8/modules/payment/src/Plugin/Commerce/PaymentGateway/OffsitePaymentGatewayBase.php

<?php

namespace Drupal\commerce_payment\Plugin\Commerce\PaymentGateway;

use Drupal\commerce_order\Entity\OrderInterface;
use Drupal\Core\Url;
use Symfony\Component\HttpFoundation\Request;

/**
 * Provides the base class for off-site payment gateways.
 */
abstract class OffsitePaymentGatewayBase extends PaymentGatewayBase implements OffsitePaymentGatewayInterface {

  /**
   * {@inheritdoc}
   */
  public function getNotifyUrl() {
    return Url::fromRoute('commerce_payment.notify', [
      'commerce_payment_gateway' => $this->entityId,
    ], ['absolute' => TRUE]);
  }

  /**
   * {@inheritdoc}
   */
  public function onReturn(OrderInterface $order, Request $request) {}

  /**
   * {@inheritdoc}
   */
  public function onCancel(OrderInterface $order, Request $request) {
    drupal_set_message($this->t('You have canceled checkout at @gateway but may resume the checkout process here when you are ready.', [
      '@gateway' => $this->getDisplayLabel(),
    ]));
  }

  /**
   * {@inheritdoc}
   */
  public function onNotify(Request $request) {}

}