Rails API 从嵌套值返回嵌套值

Question

我有一个应用程序，您可以在其中下载测验。每个测验都有多个问题。每个问题有五个可能的答案。这些是我的模型：

首先是测验模型：

class Quiz < ApplicationRecord

    has_many :questions
    has_many :games

    validates_presence_of :title
    validates_presence_of :abstract
    validates_presence_of :category_id

    validates_uniqueness_of :title

end

问题模型：（每个问题属于一个测验对象）

class Question < ApplicationRecord

    belongs_to :quiz

    has_many :answers
    has_many :game_questions

    validates_presence_of :quiz_id
    validates_presence_of :question

end

最后是答案模型：（每个答案都属于一个问题）

class Answer < ApplicationRecord

    belongs_to :question

    has_many :game_questions

    validates_presence_of :question_id
    validates_presence_of :answer
    validates_inclusion_of :correct_answer, :in => [true, false]
    validates_presence_of :order

end

我想通过这条路线/quiz_content/:id向我的QuizzesController发出一个get请求，然后成为具有相应id和所有问题的quiz 以及每个问题的所有相关答案

我已经设法返回一个包含所有答案的测验：

  def quiz_content
    quiz_records = Quiz.where('id = ?', params[:id]).includes(:questions)
    @quiz_records_with_associations = quiz_records.map do |record|
      record.attributes.merge('questions' => record.questions)
    end
    render json: @quiz_records_with_associations
  end

调用此控制器会返回以下 JSON 文件：

[
  {
    "id": 1,
    "title": "Testquiz",
    "abstract": "Questions for dummies",
    "category_id": 1,
    "download": 0,
    "created_at": "2017-05-20T17:16:42.511Z",
    "updated_at": "2017-05-20T17:16:42.511Z",
    "questions": [
      {
        "id": 1,
        "quiz_id": 1,
        "question": "What is 5 + 5?",
        "created_at": "2017-05-20T17:16:42.561Z",
        "updated_at": "2017-05-20T17:16:42.561Z"
      },
      {
        "id": 2,
        "quiz_id": 1,
        "question": "What's the color of the sky?",
        "created_at": "2017-05-20T17:16:42.588Z",
        "updated_at": "2017-05-20T17:16:42.588Z"
      },
      {
        "id": 3,
        "quiz_id": 1,
        "question": "How fast can a cheetah run?",
        "created_at": "2017-05-20T17:16:42.602Z",
        "updated_at": "2017-05-20T17:16:42.602Z"
      },
      {
        "id": 4,
        "quiz_id": 1,
        "question": "How many eyes does a pig have?",
        "created_at": "2017-05-20T17:16:42.620Z",
        "updated_at": "2017-05-20T17:16:42.620Z"
      },      
      {
        "id": 5,
        "quiz_id": 1,
        "question": "How would you rate this quiz?",
        "created_at": "2017-05-20T17:16:42.611Z",
        "updated_at": "2017-05-20T17:16:42.611Z"
      }
    ]
  }
]

我现在的问题是，我不知道如何返回每个问题的所有五个答案。我希望你能帮助我。 :)

Answer 1

将此添加到Quizz.rb

def as_json
  super(include: { questions: { include: :answers } })
end

和

def quiz_content
  @quiz = Quiz.includes(questions: :answers).find(params[:id])

  render json: @quiz.as_json
end

Answer 2

好的，我自己找到了解决方案：

  def quiz_content
    @quiz = Quiz.where('id = ?', params[:id])
    render json: @quiz, include: ['questions', 'questions.answers']
  end

我必须在序列化程序中添加关联：

class AnswerSerializer < ActiveModel::Serializer

    attributes(:id, :question_id, :answer, :correct_answer, :order)

    belongs_to :question

end


class QuestionSerializer < ActiveModel::Serializer

    attributes(:id, :quiz_id, :question)

    belongs_to :quiz
    has_many :answers
    has_many :game_questions

end


class QuizSerializer < ActiveModel::Serializer

    attributes(:id, :title, :abstract, :category_id, :download)

    has_many :questions

end