gistfile1.txt

diff --git a/src/Plugin/rest/resource/WebformAutocompleteOptions.php b/src/Plugin/rest/resource/WebformAutocompleteOptions.php
new file mode 100644
index 0000000..09a7cb8
--- /dev/null
+++ b/src/Plugin/rest/resource/WebformAutocompleteOptions.php
@@ -0,0 +1,76 @@
+<?php
+
+namespace Drupal\webform_rest\Plugin\rest\resource;
+
+use Drupal\rest\Plugin\ResourceBase;
+use Drupal\rest\ModifiedResourceResponse;
+use Drupal\webform\Entity\Webform;
+use Drupal\webform\Entity\WebformOptions;
+use Drupal\webform\Utility\WebformOptionsHelper;
+use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
+use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
+
+/**
+ * Creates a resource for retrieving webform elements.
+ *
+ * @RestResource(
+ *   id = "webform_rest_autocomplete_options",
+ *   label = @Translation("Webform Autocomplete Options"),
+ *   uri_paths = {
+ *     "canonical" = "/webform_rest/{webform_id}/autocomplete_options/{options_id}"
+ *   }
+ * )
+ */
+class WebformAutocompleteOptions extends ResourceBase {
+
+  /**
+   * Responds to GET requests, returns webform autocomplete options.
+   *
+   * @param string $webform_id
+   *   Webform ID.
+   * @param string $options_id
+   *   Webform options ID.
+   *
+   * @return \Drupal\rest\ResourceResponse
+   *   HTTP response object containing webform autocomplete options.
+   *
+   * @throws \Symfony\Component\HttpKernel\Exception\HttpException
+   *   Throws HttpException in case of error.
+   */
+  public function get($webform_id, $options_id) {
+    if (empty($webform_id)) {
+      throw new BadRequestHttpException(t("Webform ID wasn't provided"));
+    }
+    if (!$options_id) {
+      throw new BadRequestHttpException(t("Options ID wasn't provided"));
+    }
+
+    $webform = Webform::load($webform_id);
+    $elements = $webform->getElementsInitializedAndFlattened();
+
+    // Ensure that webform contains an autocomplete element using requested
+    // options.
+    $has_access = FALSE;
+    foreach ($elements as $element) {
+      if (isset($element['#autocomplete_items']) && $element['#autocomplete_items'] === $options_id) {
+        $has_access = TRUE;
+        break;
+      }
+    }
+
+    $options_entity = WebformOptions::load($options_id);
+
+    if (!$options_entity || !$has_access) {
+      throw new NotFoundHttpException(t("Can't load autocomplete options."));
+    }
+
+    $options = $options_entity->getOptions();
+    if (empty($options)) {
+      $element = ['#options' => $options_entity->id()];
+      $options = WebformOptions::getElementOptions($element);
+    }
+
+    return new ModifiedResourceResponse(WebformOptionsHelper::convertOptionsToString($options));
+  }
+
+}