module ActionDispatch::Http::MimeNegotiation

def formats
  @env["action_dispatch.request.formats"] ||= begin
    params_readable = begin
                        parameters[:format]
                      rescue ActionController::BadRequest
                        false
                      end
    if params_readable
      Array(Mime[parameters[:format]])
    elsif use_accept_header && valid_accept_header
      accepts
    elsif xhr?
      [Mime::JS]
    else
      [Mime::HTML]
    end
  end
end