email_validator.rb

require 'mail'

class EmailValidator < ActiveModel::EachValidator
  def valid_email?(value)
    a = Mail::Address.new(value)

    if a.domain && a.address == value
      elements = a.domain.split(/\./)
      a.domain.match(/\A\S+\Z/) && elements.none?(&:blank?) && elements.size > 1
    else
      false
    end
  rescue Mail::FieldParseError
    return false
  end

  def validate_each(record, attribute, value)
    unless valid_email?(value)
      record.errors[attribute] << (options[:message] || I18n.t('errors.messages.email.invalid'))
    end
  end
end