func getSignedStr()

in util/golang/service/service.go [128:160]
22 lines of code
4 McCabe index (conditional complexity)

func getSignedStr(req *tea.Request, canonicalizedResource, accessKeySecret string) string {
	// Find out the "x-oss-"'s address in header of the request
	temp := make(map[string]string)

	for k, v := range req.Headers {
		if strings.HasPrefix(strings.ToLower(k), "x-opensearch-") {
			temp[strings.ToLower(k)] = tea.StringValue(v)
		}
	}
	hs := newSorter(temp)

	// Sort the temp by the ascending order
	hs.Sort()

	// Get the canonicalizedOSSHeaders
	canonicalizedOSSHeaders := ""
	for i := range hs.Keys {
		canonicalizedOSSHeaders += hs.Keys[i] + ":" + hs.Vals[i] + "\n"
	}

	// Give other parameters values
	// when sign URL, date is expires
	date := tea.StringValue(req.Headers["Date"])
	contentType := tea.StringValue(req.Headers["Content-Type"])
	contentMd5 := tea.StringValue(req.Headers["Content-MD5"])

	signStr := tea.StringValue(req.Method) + "\n" + contentMd5 + "\n" + contentType + "\n" + date + "\n" + canonicalizedOSSHeaders + canonicalizedResource
	h := hmac.New(func() hash.Hash { return sha1.New() }, []byte(accessKeySecret))
	io.WriteString(h, signStr)
	signedStr := base64.StdEncoding.EncodeToString(h.Sum(nil))

	return signedStr
}