Decrypt session cookie content in Rails

decrypt_session_cookie.rb

def decrypt_cookie cookie_value, secret_key_base = nil
  key_generator = if secret_key_base
                    ActiveSupport::KeyGenerator.new secret_key_base, iterations: 1000
                  else
                    Rails.application.key_generator
                  end
  secret = key_generator.generate_key Rails.application.config.action_dispatch.encrypted_cookie_salt
  salt = key_generator.generate_key Rails.application.config.action_dispatch.encrypted_signed_cookie_salt
  encryptor = ActiveSupport::MessageEncryptor.new secret.first(32), salt, serializer: JSON
  
  encryptor.decrypt_and_verify URI.unescape(cookie_value)
end