Question

遍历rails文档并遇到了针对ActiveRecord模型的creating callback classes的建议。尽管在描述它们的用法方面做得很好，但并未列出确切的位置。这样做最合适的目录是什么？

Answer 1

我建议在app/models/callbacks/中创建一个文件夹，并按如下所示组织文件：

- app
  - models
    - callbacks
      user.rb
    user.rb

然后：

class User < ApplicationRecord
  after_create ::Callbacks::User
  after_destroy ::Callbacks::User
  # we have to prepend :: here because it would try to refer to the namespace
  # ActiveModel::Validations::Callbacks otherwise
end

＆

module Callbacks
  module User
    # Warning: If you want to refer to the User model in there, you will have to
    # prepend it with `::` so it looks up from the root because this module has
    # the same name as the User model
    # ex: 
    #  ::User::SOME_CONSTANT
    # and not
    #  User::SOME_CONSTANT

    def self.after_create(user)
      ::Services::Emails::Welcome.enqueue!(user_id: user.id)
    end

    def self.after_destroy(user)
      ::Services::Emails::Goodbye.enqueue!(user_id: user.id)
    end
    # ...
  end
end

这也是使用服务对象的简单结构。

您将ActiveRecord回调类放在哪里？

1 个答案: