function randomString(length) {
  let seed = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
  let result = ''
  for (var i = length; i > 0; --i) result += seed[Math.floor(Math.random() * seed.length)]
  return result
}
let rString = randomString(32)