def signature_info
      @signature_info ||= begin
        match = x_mws_authentication && x_mws_authentication.match(/\A([^ ]+) *([^:]+):([^:]+)\z/)
        match ? { token: match[1], app_uuid: match[2], signature: match[3] } : {}
      end
    end
def signature_info
      @signature_info ||= begin
        match = x_mws_authentication && x_mws_authentication.match(/\A([^ ]+) *([^:]+):([^:]+)\z/)
        match ? { token: match[1], app_uuid: match[2], signature: match[3] } : {}
      end
    end
returns a hash with keys :token, :app_uuid, and :signature parsed from the X-MWS-Authentication header