Method to recursively hash a directory.

hashDir.go

package main

import (
	"crypto/md5"
	"encoding/hex"
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"
	"sort"
)

// hashByte calculates the md5 hash of a byte slice and returns it as a string.
func hashByte(contentPtr *[]byte) string {
	hasher := md5.New()
	hasher.Write(*contentPtr)
	return hex.EncodeToString(hasher.Sum(nil))
}

// hashDir hashes all files in a directory recursively.
// The function hashes the file path and content, and then hashes those hashes together.
func hashDir(dir *string) (string, error) {
	var finHash string = *dir

	var paths []string
	err := filepath.Walk(*dir, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		if !info.IsDir() {
			paths = append(paths, path)
		}
		return nil
	})
	if err != nil {
		return "", err
	}

	sort.Strings(paths)

	for _, path := range paths {
		concatBytes := hashByte(&[]byte{byte(finHash)})
		nameHash := hashByte(&[]byte(path))
		fileBytes, err := ioutil.ReadFile(path)
		if err != nil {
			return "", err
		}
		fileHash := hashByte(&fileBytes)
		finHash = concatBytes + fileHash + nameHash
	}

	return hashByte(&[]byte(finHash)), nil
}

func main() {
	dir := "Desktop"
	hash, err := hashDir(&dir)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println(hash)
}