Generate random hex token

token_hex.go

package random

import (
	"crypto/rand"
	"encoding/hex"
	"fmt"
)

func TokenHex(length int) (string, error) {
	// Base 16 is 2x longer than Base 256
	// 2^8 vs 2^4
	// 8bits / 4bits = 2x ratio
	buf := make([]byte, length/2)
	_, err := rand.Read(buf)
	if err != nil {
		return "", fmt.Errorf("reading rand: %w", err)
	}
	h := hex.EncodeToString(buf)
	return h, nil
}

func TestTokenHex(t *testing.T) {
	l := 16
	h, err := random.TokenHex(l)
	if err != nil {
		t.Fatalf("unexpected error: %s", err)
	}
	if len(h) != l {
		t.Errorf("expected len %d, got: %d", l, len(h))
	}
}