3439542: Handle Guzzle ConnectException

Closes #3439542

src/Plugin/WebformHandler/WebformAPIHandler.php

@@ -22,6 +22,7 @@ use Drupal\webform\WebformTokenManagerInterface;
 use Drupal\webform_api_handler\Plugin\RequestManager;
 use Drupal\webform_api_handler\Plugin\ResponseManager;
 use GuzzleHttp\ClientInterface;
+use GuzzleHttp\Exception\ConnectException;
 use GuzzleHttp\Exception\RequestException;
 use Psr\Http\Message\ResponseInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
@@ -295,6 +296,14 @@ class WebformAPIHandler extends RemotePostWebformHandler {
       $this->handleError($state, $message, $request_url, $request_method, $request_type, $request_options, $response);
       return;
     }
+    catch (ConnectException $connect_exception) {
+      // Encode HTML entities to prevent broken markup from breaking the page.
+      $message = $connect_exception->getMessage();
+      $message = nl2br(htmlentities($message));
+
+      $this->handleError($state, $message, $request_url, $request_method, $request_type, $request_options, NULL);
+      return;
+    }
 
     // Display submission exception if response code is not 2xx.
     $status_code = $response->getStatusCode();