Question

我正在使用Rails 4.2.1和active_model_serializers 0.10.0.rc2

我是API的新手，并选择了active_model_serializers，因为它似乎正在成为rails的标准（尽管我并不反对使用RABL或其他串行器）

我遇到的问题是，我似乎无法在多层次关系中包含各种属性。比如我有：

项目

class ProjectSerializer < ActiveModel::Serializer
  attributes                      :id, 
                                  :name,
                                  :updated_at

  has_many                        :estimates, include_nested_associations: true

end

和估算

class EstimateSerializer < ActiveModel::Serializer
  attributes                      :id, 
                                  :name, 
                                  :release_version, 
                                  :exchange_rate, 
                                  :updated_at,

                                  :project_id, 
                                  :project_code_id, 
                                  :tax_type_id 

  belongs_to                      :project
  belongs_to                      :project_code
  belongs_to                      :tax_type

  has_many                        :proposals

end

提案

class ProposalSerializer < ActiveModel::Serializer
  attributes                      :id, 
                                  :name, 
                                  :updated_at,

                                  :estimate_id

  belongs_to                      :estimate
end

当我点击上面/projects/1时产生：

{
  "id": 1,
  "name": "123 Park Ave.",
  "updated_at": "2015-08-09T02:36:23.950Z",
  "estimates": [
    {
      "id": 1,
      "name": "E1",
      "release_version": "v1.0",
      "exchange_rate": "0.0",
      "updated_at": "2015-08-12T04:23:38.183Z",
      "project_id": 1,
      "project_code_id": 8,
      "tax_type_id": 1
    }
  ]
}

然而，我想要制作的是：

{
  "id": 1,
  "name": "123 Park Ave.",
  "updated_at": "2015-08-09T02:36:23.950Z",
  "estimates": [
    {
      "id": 1,
      "name": "E1",
      "release_version": "v1.0",
      "exchange_rate": "0.0",
      "updated_at": "2015-08-12T04:23:38.183Z",
      "project": { 
        "id": 1,
        "name": "123 Park Ave."
      },
      "project_code": {
        "id": 8,
        "valuation": 30
      },
      "tax_type": {
        "id": 1,
        "name": "no-tax"
      },
      "proposals": [
        {
          "id": 1,
          "name": "P1",
          "updated_at": "2015-08-12T04:23:38.183Z"
        },
        {
          "id": 2,
          "name": "P2",
          "updated_at": "2015-10-12T04:23:38.183Z"
        }
      ]
    }
  ]
}

理想情况下，我还希望能够指定每个序列化程序中包含的那些关联的属性，关联和属性。

我一直在查看AMS问题，似乎有一些关于应该如何处理（或者如果这种功能甚至实际上得到支持）的来回，但我有难以弄清楚目前的状态究竟是什么。

建议的解决方案之一是使用调用嵌套属性的方法覆盖属性，但这似乎被视为黑客，所以我想尽可能避免它。

无论如何，非常感谢如何处理此API或一般API建议的示例。

Answer 1

每次提交1426：https://github.com/rails-api/active_model_serializers/pull/1426 - 以及相关讨论，您可以看到json和attributes序列化的默认嵌套是一个级别。

如果您希望默认深度嵌套，可以在active_model_serializer初始值设定项中设置配置属性：

ActiveModelSerializers.config.default_includes = '**'

有关 v0.10.6 ：https://github.com/rails-api/active_model_serializers/blob/v0.10.6/docs/general/adapters.md#include-option

的详细参考

Answer 2

所以这不是最好的，甚至不是一个好的答案，但这是我需要的方式。

虽然在使用带有AMS的json_api适配器时似乎支持包含嵌套和侧载属性，但我需要支持flat json。此外，这种方法运行良好，因为每个序列化器都专门生成我需要它独立于任何其他序列化器而不需要在控制器中执行任何操作。

欢迎提供评论/替代方法。

项目模型

class Project < ActiveRecord::Base      
  has_many  :estimates, autosave: true, dependent: :destroy
end

<强> ProjectsController

def index
  @projects = Project.all
  render json: @projects
end

<强> ProjectSerializer

class ProjectSerializer < ActiveModel::Serializer
  attributes  :id, 
              :name,
              :updated_at,

              # has_many
              :estimates



  def estimates
    customized_estimates = []

    object.estimates.each do |estimate|
      # Assign object attributes (returns a hash)
      # ===========================================================
      custom_estimate = estimate.attributes


      # Custom nested and side-loaded attributes
      # ===========================================================
      # belongs_to
      custom_estimate[:project] = estimate.project.slice(:id, :name) # get only :id and :name for the project
      custom_estimate[:project_code] = estimate.project_code
      custom_estimate[:tax_type] = estimate.tax_type

      # has_many w/only specified attributes
      custom_estimate[:proposals] = estimate.proposals.collect{|proposal| proposal.slice(:id, :name, :updated_at)}

      # ===========================================================
      customized_estimates.push(custom_estimate)
    end

    return customized_estimates
  end
end

<强>结果

[
  {
    "id": 1,
    "name": "123 Park Ave.",
    "updated_at": "2015-08-09T02:36:23.950Z",
    "estimates": [
      {
        "id": 1,
        "name": "E1",
        "release_version": "v1.0",
        "exchange_rate": "0.0",
        "created_at": "2015-08-12T04:23:38.183Z",
        "updated_at": "2015-08-12T04:23:38.183Z",
        "project": {
          "id": 1,
          "name": "123 Park Ave."
        },
        "project_code": {
          "id": 8,
          "valuation": 30,
          "created_at": "2015-08-09T18:02:42.079Z",
          "updated_at": "2015-08-09T18:02:42.079Z"
        },
        "tax_type": {
          "id": 1,
          "name": "No Tax",
          "created_at": "2015-08-09T18:02:42.079Z",
          "updated_at": "2015-08-09T18:02:42.079Z"
        },
        "proposals": [
          {
            "id": 1,
            "name": "P1",
            "updated_at": "2015-08-12T04:23:38.183Z"
          },
          {
            "id": 2,
            "name": "P2",
            "updated_at": "2015-10-12T04:23:38.183Z"
          }
        ]
      }
    ]
  }
]

我基本上忽略了尝试在序列化程序中实现任何has_many或belongs_to关联，并且只是自定义了行为。我使用slice来选择特定属性。希望更优雅的解决方案即将推出。

Answer 3

如果您使用的是JSONAPI适配器，则可以执行以下操作来呈现嵌套关系：

render json: @project, include: ['estimates', 'estimates.project_code', 'estimates.tax_type', 'estimates.proposals']

您可以从jsonapi文档中了解更多信息：http://jsonapi.org/format/#fetching-includes

Answer 4

您可以更改ActiveModel::Serializer的<{1}}：

# config/initializers/active_model_serializer.rb
ActiveModel::Serializer.config.default_includes = '**' # (default '*')

另外，为了避免无限递归，可以控制嵌套序列化如下：

class UserSerializer < ActiveModel::Serializer
  include Rails.application.routes.url_helpers

  attributes :id, :phone_number, :links, :current_team_id

  # Using serializer from app/serializers/profile_serializer.rb
  has_one :profile
  # Using serializer described below:
  # UserSerializer::TeamSerializer
  has_many :teams

  def links
    {
      self: user_path(object.id),
      api: api_v1_user_path(id: object.id, format: :json)
    }
  end

  def current_team_id
    object.teams&.first&.id
  end

  class TeamSerializer < ActiveModel::Serializer
    attributes :id, :name, :image_url, :user_id

    # Using serializer described below:
    # UserSerializer::TeamSerializer::GameSerializer
    has_many :games

    class GameSerializer < ActiveModel::Serializer
      attributes :id, :kind, :address, :date_at

      # Using serializer from app/serializers/gamers_serializer.rb
      has_many :gamers
    end
  end
end

结果：

{
   "user":{
      "id":1,
      "phone_number":"79202700000",
      "links":{
         "self":"/users/1",
         "api":"/api/v1/users/1.json"
      },
      "current_team_id":1,
      "profile":{
         "id":1,
         "name":"Alexander Kalinichev",
         "username":"Blackchestnut",
         "birthday_on":"1982-11-19",
         "avatar_url":null
      },
      "teams":[
         {
            "id":1,
            "name":"Agile Season",
            "image_url":null,
            "user_id":1,
            "games":[
               {
                  "id":13,
                  "kind":"training",
                  "address":"",
                  "date_at":"2016-12-21T10:05:00.000Z",
                  "gamers":[
                     {
                        "id":17,
                        "user_id":1,
                        "game_id":13,
                        "line":1,
                        "created_at":"2016-11-21T10:05:54.653Z",
                        "updated_at":"2016-11-21T10:05:54.653Z"
                     }
                  ]
               }
            ]
         }
      ]
   }
}

Answer 5

在我的情况下，我创建了一个名为＆＃39; active_model_serializer.rb＆＃39;放置在＆＃39; MyApp / config / initializers＆＃39;具有以下内容：

ActiveModelSerializers.config.default_includes = '**'

不要忘记重启服务器：

$ rails s

Answer 6

这应该做你想要的。

@project.to_json( include: { estimates: { include: {:project, :project_code, :tax_type, :proposals } } } )

顶级嵌套将自动包含在内，但任何比这更深的嵌套都需要包含在您的节目操作中或您调用此处的任何位置。

Answer 7

为了强调 Eric Norcross' answer，我添加了以下答案。

我在 Rails 应用程序中使用 jsonapi-serializer gem 进行序列化。我没有发现包含嵌套在控制器和侧载属性中对我来说很方便。我只是想要更好地分离关注点。所以任何与序列化有关的东西都应该只在序列化文件中，它们应该与控制器文件无关。

所以就我而言，我有以下关联：

学校模式

module Baserecord
  class School < ApplicationRecord
    has_many :programs, class_name: Baserecord.program_class, dependent: :destroy
    has_many :faculties, class_name: Baserecord.faculty_class, through: :programs, dependent: :destroy
end

程序模型

module Baserecord
  class Faculty < ApplicationRecord
    belongs_to :program, class_name: Baserecord.program_class
    has_many :departments, class_name: Baserecord.department_class, dependent: :destroy
    has_many :program_of_studies, class_name: Baserecord.program_of_study_class, through: :departments,
                                  dependent: :destroy
  end
end

这是我构建序列化程序文件的方式：

学校连载

module Baserecord
  class SchoolSerializer
    include JSONAPI::Serializer
    attributes :id, :name, :code, :description, :school_logo, :motto, :address

    attribute :programs do |object|

      # Create an empty array
      customized_programs = []

      object.programs.each do |program|

        # Assign object attributes (returns a hash)
        custom_program = program.attributes

        # Create custom nested and side-loaded attributes
        custom_program[:faculties] = program.faculties

        # Push the created custom nested and side-loaded attributes into the empty array
        customized_programs.push(custom_program)
      end

      # Return the new array
      customized_programs
    end

    cache_options store: Rails.cache, namespace: 'jsonapi-serializer', expires_in: 1.hour
  end
end

仅此而已。

我希望这会有所帮助

使用active_model_serializers序列化深层嵌套关联

7 个答案: