package wechat

import "math/rand"

// RandomString generate random size string
func randomString(size int) (string, error) {
	// generate size string [0-9a-zA-Z]
	const chars = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
	b := make([]byte, size)
	for i := range b {
		b[i] = chars[rand.Intn(len(chars))]
	}
	return string(b), nil
}