Question

我无法弄清楚如何检索具有深层嵌套关联的ActiveRecord对象。下面是我尝试实现的一个表示为JSON对象的示例。

目前，我的项目模型有：

has_many :groups
has_many :users, through: :groups
has_many :members, through: :groups, source: :users

预期结果（JSON）：

{
  "id": 7,
  "name": "Test Project",
  "description": "Project description",
  "groups": [
    {
      "id": 1,
      "name": "Test Group 1",
      "description": "First test group",
      "members": [
        {
          "id": 1,
          "name": "Admin",
          "email": "admin@exmaple.com"
        },
        {
          "id": 2,
          "name": "Test User",
          "email": "test@exmaple.com"
        }
      ]
    }
  ]
}

示例代码：

class Project < ActiveRecord::Base
  has_many :groups
  has_many :users, through: :groups
  has_many :members, through: :groups, source: :users
end

我最接近期望的结果是通过向项目模型添加groups方法来获取所有成员：

最近的结果（JSON）：

{
  "id": 7,
  "name": "Test Project",
  "description": "Project description",
  "groups": [
    {
      "id": 1,
      "name": "Admin",
      "email": "admin@exmaple.com"
    },
    {
      "id": 2,
      "name": "Test User",
      "email": "test@exmaple.com"
    }
  ]
}

示例代码：

class Project < ActiveRecord::Base
  has_many :groups
  has_many :users, through: :groups
  has_many :members, through: :groups, source: :users

  def groups
    members.all
  end
end

Answer 1

您可以尝试使用activemodel序列化程序来包含关联的记录。

class ProjectSerializer < ActiveModel::Serializer
  attributes :id
  has_many :groups 
end

class GroupSerializer < ActiveModel::Serializer
  attributes :id
  has_many :members
end

您可以在以下位置查看：https://github.com/rails-api/active_model_serializers

has_many，has_one和belongs_to声明描述资源之间的关系。默认情况下，当您序列化帖子时，您也将获得其评论。

Answer 2

你可以这样做：

class Project < ActiveRecord::Base
  has_many :groups
  has_many :users, through: :groups
  has_many :members, through: :groups, source: :users
end

Project.find(7).to_json(include: {groups: {include: :users}})

检索深层嵌套的ActiveRecord关联

2 个答案: