A helpful file that shows how to generate TOTP rotating codes using Ruby

totp.md

Generating TOTP tokens from a seeds file on your machine in Ruby

This file assumes you have a file (~/.totp.yml) on your machine where you store the SERVICEs, and their secret keys:

aws: rAndOmCharaCTeRsHerE
google: rAndOmCharaCTeRsHerE

Then, you can call like this:

ruby totp.rb SERVICE

The repsonse should look like this:

$ ruby totp.rb aws

This code automatically regenerates every 30 seconds

6 seconds remaining

283646

Code copied to clipboard

totp.rb

#!/usr/bin/env ruby

# frozen_string_literal: true

require 'rotp'
require 'yaml'

SERVICE = ARGV[0]
DOT_FILE = '.totp.yml'

def services
  return @services if @services

  @services = YAML.load_file("#{Dir.home}/#{DOT_FILE}")
rescue StandardError
  raise_error( \
    "It looks like your #{DOT_FILE} file isn't set up yet." \
    ' Please complete this before proceeding.'
  )
end

def pbcopy(input)
  str = input.to_s
  IO.popen('pbcopy', 'w') { |f| f << str }
  str
end

def generate_time_remaining
  seconds = Time.now.sec
  seconds >= 30 ? 60 - seconds : 30 - seconds
end

def totp(totp_key)
  @totp ||= ROTP::TOTP.new(totp_key)
end

def raise_error(message)
  raise StandardError, message
end

def list_services
  "Here's a list of available services:\n\n  #{services.keys.join(', ')}"
end

begin
  raise_error("Please provide a service. #{list_services}") unless SERVICE

  if (totp_key = services[SERVICE])
    puts "\nThis code automatically regenerates every 30 seconds"
    puts "\n#{generate_time_remaining} seconds remaining"
    puts "\n#{pbcopy(totp(totp_key).now)}"
    puts "\nCode copied to clipboard\n\n"
  else
    raise_error( \
      "Unable to find TOTP key for '#{SERVICE}' in your #{DOT_FILE} file." \
      ' Please ensure the key is available and formatted correctly.'
    )
  end
rescue StandardError => e
  puts "\n#{e.message}\n\n"
end