getNormalizedRequestMethod example

  protected function deserialize(RouteMatchInterface $route_match, Request $request, ResourceInterface $resource) {
    // Deserialize incoming data if available.     $received = $request->getContent();
    $unserialized = NULL;
    if (!empty($received)) {
      $method = static::getNormalizedRequestMethod($route_match);
      $format = $request->getContentTypeFormat();

      $definition = $resource->getPluginDefinition();

      // First decode the request data. We can then determine if the       // serialized data was malformed.       try {
        $unserialized = $this->serializer->decode($received, $format, ['request_method' => $method]);
      }
      catch (UnexpectedValueException $e) {
        // If an exception was thrown at this stage, there was a problem