class ActionDispatch::Request

Content-Type header is provided and the request_method is POST.
A request body is not assumed to contain form-data when no

+FORM_DATA_MEDIA_TYPES+ array.
list of form-data media types can be modified through the
"application/x-www-form-urlencoded" or "multipart/form-data". The
the request Content-Type for one of the media-types:
Determine whether the request body contains form-data by checking

def form_data?
  FORM_DATA_MEDIA_TYPES.include?(media_type)
end