在ActiveAdmin中编辑has_one关联-在属性为空时销毁 [英] Editing a has_one association in ActiveAdmin - destroying when attribute is blanked

问题描述

我有一个模型，其中很小比例的对象将具有相当大的描述性文本。为了使数据库保持某种标准化，我想将此描述性文本提取到一个单独的模型中，但在ActiveAdmin中创建合理的工作流时遇到了麻烦。

I've got a model in which a very small percentage of the objects will have a rather large descriptive text. Trying to keep my database somewhat normalized, I wanted to extract this descriptive text to a separate model, but I'm having trouble creating a sensible workflow in ActiveAdmin.

我的模型如下：

class Person < ActiveRecord::Base
  has_one :long_description

  accepts_nested_attributes_for :long_description, reject_if: proc { |attrs| attrs['text'].blank? }
end

class LongDescription < ActiveRecord::Base
  attr_accessible :text, :person_id
  belongs_to :person

  validates :text, presence: true
end

当前，我已经创建了一个用于编辑Person模型的表单，看起来有点像这样：

Currently I've created a form for editing the Person model, looking somewhat like this:

  form do |f|
    ...
    f.inputs :for => [
                      :long_description,
                      f.object.long_description || LongDescription.new
                     ] do |ld_f|
      ld_f.input :text
    end

    f.actions
  end

这可用于添加/编辑LongDescription对象，并且如果没有输入任何文本，它会自动验证/创建LongDescription对象。

This works for adding/editing the LongDescription object, and it avdois validating/creating the LongDescription object if no text is entered.

我想实现的是还能够删除LongDescription对象，例如，如果 text 属性再次设置为空字符串/nil。

What I'd like to achieve is to also be able to remove the LongDescription object, for example if the text attribute is ever set to an empty string/nil again.

具有比我更好的Rails或ActiveAdmin技能的人都知道如何实现此目标？

Anyone with better Rails or ActiveAdmin skills than me know how to achieve this?

推荐答案

这似乎是一个非常不寻常的体系结构决定，但实现起来却很简单：

That seems like an awfully unusual architecture decision, but the implementation is pretty simple:

class LongDescription < ActiveRecord::Base

  validates_presence_of :text, on: :create

  after_save do
    destroy if text.blank?
  end
end

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