HMAC Generator

hmac_generator.go

package main

import (
	"crypto/hmac"
	"crypto/sha256"
	"fmt"
	"os"
)

// GenerateHMACSignature generates an HMAC-SHA256 signature for webhook validation
// secret: the webhook secret key
// sequenceGUID: the sequence GUID from the X-Deliveroo-Sequence-Guid header
// jsonBody: the JSON request body as bytes
func GenerateHMACSignature(secret, sequenceGUID string, jsonBody []byte) string {
	h := hmac.New(sha256.New, []byte(secret))
	h.Write([]byte(sequenceGUID))
	h.Write([]byte(" "))
	h.Write(jsonBody)
	return fmt.Sprintf("%x", h.Sum(nil))
}

func main() {
	if len(os.Args) != 4 {
		fmt.Fprintf(os.Stderr, "Usage: %s <secret> <sequence-guid> <json-body>\n", os.Args[0])
		fmt.Fprintf(os.Stderr, "Example: %s my-secret-key abc-123-def '{\"test\":\"data\"}'\n", os.Args[0])
		os.Exit(1)
	}

	secret := os.Args[1]
	sequenceGUID := os.Args[2]
	jsonBody := os.Args[3]

	signature := GenerateHMACSignature(secret, sequenceGUID, []byte(jsonBody))
	fmt.Println(signature)
}