interactor_with_activemodel_validations.rb

# Definition of a BaseInteractor
  
class BaseInteractor
  include Interactor
  include ActiveModel::Validations
  
  # For any class that inherits this class, a `before` hook is registered, which raises ArgumentError if the reqired parameters are not passed in during invocation.
  def self.inherited(subclass)
    subclass.class_eval do
      def self.requires(*attributes)
        validates_each attributes do |record, attr_name, value| #from ActiveModel::Validations
            if value.nil?
              raise ArgumentError.new("Required attribute #{attr_name} is missing")
            end
          end
        delegate *attributes, to: :context
      end

      before do
        context.fail!(errors: errors) unless valid? # runs every validation
      end

      def read_attribute_for_validation(method_name)
        context.public_send(method_name)
      end
    end
  end
end
  
  
# Definition of the Interactor using the BaseInteractor
class MyInteractor < BaseInteractor
  requires :email, :name
  validate :email_is_internal
  
  def call
    # ...
  end
  
  private
  
  def email_is_internal
    return unless email.present?
    errors.add(:email, 'domain should be reflektive.com') unless context.email.match(/^[a-z]+.\@reflektive\.com$/i)
  end
end
  
  
# Invocation of the Interactor
result = MyInteractor.call(email: 'blah@example.com')
# => ArgumentError: Required parameter name is missing.
result = MyInteractor.call(email: 'blah@example.com', name: 'Bob')
result.success? # => false
puts result.errors # => ['email domain should be reflektive.com']