require "active_support/callbacks" module ActionMailbox module Callbacks extend ActiveSupport::Concern include ActiveSupport::Callbacks included do define_callbacks :process end module ClassMethods def before_processing(*methods, &block) set_callback(:process, :before, *methods, &block) end def after_processing(*methods, &block) set_callback(:process, :after, *methods, &block) end def around_processing(*methods, &block) set_callback(:process, :around, *methods, &block) end end end end