webform_rest_submission.patch

diff --git a/src/Event/WebformSubmissionDataEvent.php b/src/Event/WebformSubmissionDataEvent.php
new file mode 100644
index 0000000..c378f45
--- /dev/null
+++ b/src/Event/WebformSubmissionDataEvent.php
@@ -0,0 +1,52 @@
+<?php
+
+namespace Drupal\webform_rest\Event;
+
+use Drupal\Component\EventDispatcher\Event;
+use Drupal\webform\WebformSubmissionInterface;
+
+/**
+ * Class WebformSubmissionDataEvent, an event to modify the data part of the response sent from calling GET webform submission.
+ */
+class WebformSubmissionDataEvent extends Event
+{
+  /**
+   * @var WebformSubmissionInterface
+   */
+  private WebformSubmissionInterface $webformSubmission;
+
+  /**
+   * @var array
+   */
+  private array $data;
+
+  /**
+   * Construct for injection dependency.
+   *
+   * @param array $data
+   * @param WebformSubmissionInterface $webformSubmission
+   */
+  public function __construct(WebformSubmissionInterface $webformSubmission, array $data) {
+    $this->webformSubmission = $webformSubmission;
+    $this->setData($data);
+  }
+
+  /**
+   * @return WebformSubmissionInterface
+   */
+  public function getWebformSubmission(): WebformSubmissionInterface
+  {
+        return $this->webformSubmission;
+  }
+
+  public function getData(): array
+  {
+          return $this->data;
+  }
+
+  public function setData(array $data)
+  {
+        $this->data = $data;
+        return $this;
+  }
+}
diff --git a/src/Plugin/rest/resource/WebformSubmissionResource.php b/src/Plugin/rest/resource/WebformSubmissionResource.php
index ebe22aa..4102129 100644
--- a/src/Plugin/rest/resource/WebformSubmissionResource.php
+++ b/src/Plugin/rest/resource/WebformSubmissionResource.php
@@ -5,6 +5,7 @@ namespace Drupal\webform_rest\Plugin\rest\resource;
 use Drupal\webform\WebformSubmissionForm;
 use Drupal\rest\Plugin\ResourceBase;
 use Drupal\rest\ModifiedResourceResponse;
+use Drupal\webform_rest\Event\WebformSubmissionDataEvent;
 use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
 use Symfony\Component\DependencyInjection\ContainerInterface;

@@ -43,6 +44,13 @@ class WebformSubmissionResource extends ResourceBase {

   protected $currentUser;

+  /**
+   * An event dispatcher instance to use for dispatching events.
+   *
+   * @var \Symfony\Contracts\EventDispatcher\EventDispatcherInterface
+   */
+  protected $eventDispatcher;
+
   /**
    * {@inheritdoc}
    */
@@ -51,6 +59,7 @@ class WebformSubmissionResource extends ResourceBase {
     $instance->entityTypeManager = $container->get('entity_type.manager');
     $instance->request = $container->get('request_stack');
     $instance->currentUser = $container->get('current_user');
+    $instance->eventDispatcher = $container->get('event_dispatcher');
     return $instance;
   }

@@ -110,9 +119,13 @@ class WebformSubmissionResource extends ResourceBase {
         // Grab submission data.
         $data = $webform_submission->getData();

+        // Dispatch WebformSubmissionDataEvent to allow modification of data.
+        $event = new WebformSubmissionDataEvent($webform_submission, $data);
+        $this->eventDispatcher->dispatch($event);
+
         $response = [
           'entity' => $webform_submission,
-          'data' => $data,
+          'data' => $event->getData(),
         ];

         // Return the submission.