module AWS::Core::Signature::Version2

def string_to_sign
  host =
    case port
    when 80, 443 then self.host
    else "#{self.host}:#{port}"
    end
  [
    http_method,
    host.to_s.downcase,
    path,
    params.sort.collect { |p| p.encoded }.join('&'),
  ].join("\n")
end