祖先宝石获取具有祖先ID的树

Question

我正在使用祖先 gem 创建一个嵌套菜单表。

当我render json: Menu.all

我明白了：

[
    {
        "id": 1,
        "label": "Menu"
        "created_at": "2018-05-14T14:28:03.883Z",
        "updated_at": "2018-05-14T14:28:03.883Z",
        "ancestry": null
    },
    {
        "id": 2,
        "label": "Menu 1-1",
        "created_at": "2018-05-14T14:28:13.982Z",
        "updated_at": "2018-05-14T14:28:13.982Z",
        "ancestry": "1"
    },
    {
        "id": 3,
        "label": "Menu 1-1-1",
        "created_at": "2018-05-14T14:28:13.982Z",
        "updated_at": "2018-05-14T14:28:13.982Z",
        "ancestry": "1/2"
    },
 etc

我想做的也是返回父母的 id（我很欣赏它是祖先字段中的最后一个数字，但我希望它分开。

所以我得到：

[
    {
        "id": 1,
        "label": "Menu"
        "created_at": "2018-05-14T14:28:03.883Z",
        "updated_at": "2018-05-14T14:28:03.883Z",
        "ancestry": null,
        "parent_id":null
    },
    {
        "id": 2,
        "label": "Menu 1-1",
        "created_at": "2018-05-14T14:28:13.982Z",
        "updated_at": "2018-05-14T14:28:13.982Z",
        "ancestry": "1",
        "parent_id":"1"
    },
    {
        "id": 3,
        "label": "Menu 1-1-1",
        "created_at": "2018-05-14T14:28:13.982Z",
        "updated_at": "2018-05-14T14:28:13.982Z",
        "ancestry": "1/2",
        "parent_id":"2"
    }, 

有人知道如何实现吗？

Answer 1

尝试覆盖 to_json (https://apidock.com/rails/ActiveRecord/Serialization/to_json) 以在模型类中包含 parent_id：

class Menu < ActiveRecord::Base
  def to_json
    super(methods: [:parent_id])
  end
end