req.Header.Set("Expires", expiresStr)
	}

	// url.RawPath will be valid if path has any encoded characters, if not it will
	// be empty - in which case we need to consider url.Path (bug in net/http?)
	encodedResource := req.URL.RawPath
	encodedQuery := req.URL.RawQuery
	if encodedResource == "" {
		splits := strings.SplitN(req.URL.Path, "?", 2)
		encodedResource = splits[0]
		if len(splits) == 2 {