installation

1. install gems:

gem 'rotp'
gem 'active_model_otp'

2. bundle install
3. add otp_secret_key to the model:

class AddOtpSecretKeyToUsers < ActiveRecord::Migration[5.2]
  def change
    add_column :washers, :otp_secret_key, :string
  end
end

4. add has_one_time_password to model file

#User.rb

class User < ApplicationRecord
  has_one_time_password`
  .
  .
  ...
end

how to authenticate OTP (console)

When the model is created, the otp_secret_key is saved.

1. To generate a new one time password, you must run user.otp_code. This is the code you send to the user in an email or sms.
2. To authenticate the code in your controller, use user.authenticate_otp(user.otp_code, drift: 1000) the drift property specifies how much time you want the code to valid for in seconds so 7_200 for 2 hours. the default amount of time is 30 seconds

user.otp_code

user.authenticate_otp('146546')
sleep 30.seconds
user.authenticate_otp('146546')
user.authenticate_otp('146546', drift: 7_200)