Sample Golang application to send HMAC authentication

post.go

package main

import (
	"bytes"
	"crypto/hmac"
	"crypto/sha256"
	"crypto/tls"
	"encoding/base64"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"net/http/httputil"
	"time"
)

func main() {

	algorithm := "hmac-sha256"
	username := "hmac-user"
	secret := "~,6a=HFaC/P]R5Zp"
	url := "https://localhost"
	path := "/ok"
	method := "POST"
	uuid := "9b83f786-5a70-11eb-ae93-0242ac130002"

	// request path
	url = url + path

	// date
	loc, _ := time.LoadLocation("GMT")
	date := time.Now().In(loc)
	layout := "Mon, 02 Jan 2006 15:04:05 GMT"
	dateFormat := date.Format(layout)

	// body
	requestBody := []byte("{\"foo\":\"bar\"}")
	digestBody := sha256.New()
	digestBody.Write([]byte(requestBody))
	digestBodyContent := base64.StdEncoding.EncodeToString(digestBody.Sum(nil))
	digestBodyHeader := "SHA-256=" + digestBodyContent

	signingString := "x-date: " + dateFormat + "\n" + method + " " + path + " HTTP/1.1" + "\n" + "x-uuid: " + uuid + "\n" + "digest: " + digestBodyHeader
	digest := hmac.New(sha256.New, []byte(secret))
	digest.Write([]byte(signingString))
	signature := base64.StdEncoding.EncodeToString(digest.Sum(nil))

	// ignore server certificate
	tr := &http.Transport{
		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
	}
	client := &http.Client{Transport: tr}
	request, err := http.NewRequest(method, url, bytes.NewBuffer(requestBody))
	if err != nil {
		log.Fatalln(err)
	}

	//header
	authorization := "hmac username=\"" + username + "\", algorithm=\"" + algorithm + "\", headers=\"x-date request-line x-uuid digest\", signature=\"" + signature + "\""

	log.Println("variables:")
	fmt.Println("url: "+ url)
	fmt.Println("username: "+ username)
	fmt.Println("secret: "+ secret)
	fmt.Println("body: "+ string(requestBody))
	fmt.Println("signingString: "+ signingString)
	fmt.Println("signature: "+ signature)
	fmt.Println("authorization: "+ authorization)

	request.Header.Set("Digest", digestBodyHeader)
	request.Header.Set("Authorization", authorization)
	request.Header.Set("X-Date", dateFormat)
	request.Header.Set("X-UUID", uuid)
	request.Header.Set("Content-Type", "application/json")

	requestDump, err := httputil.DumpRequest(request, true)

	if err == nil {
		log.Println("request:", string(requestDump))
	}

	resp, err := client.Do(request)
	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		log.Fatalln(err)
	}

	log.Println("response header:")
	for k, v := range resp.Header {
		fmt.Println(k, ":", v)
	}

	log.Println("response:", string(body))

}