在 Rails 中具有完整层次结构的 JSON

Question

我的应用中有一个层次结构：

• 环境有容器
• 容器有物品
• 项目有表情

所以我的模型代码如下所示：

class Environment < ActiveRecord::Base
  has_many :containers, :dependent => :destroy

  def as_json(options = {})
    super(options.merge(include: :containers))
  end

end

class Container < ActiveRecord::Base
  has_many :items, :dependent => :destroy
  belongs_to :environment

  def as_json(options = {})
    super(options.merge(include: :items))
  end

end

class Item < ActiveRecord::Base
  has_many :expressions, :dependent => :destroy
  belongs_to :container

  def as_json(options = {})
    super(options.merge(include: :expressions))
  end

end

class Expression < ActiveRecord::Base
  belongs_to :item

def as_json(options = {})
  super()
end

end

在定期获取记录我通常只需要低于所需记录的一个层次结构，这就是为什么在as_json 中我只向下合并一个层次结构（获取环境将返回一组容器但那些容器不会有物品）

我的问题：

现在我需要向控制器添加一个方法，以允许完整的层次结构响应，即GET /environment/getFullHierarchy/3 将返回：id=3 的环境及其所有容器和每个容器all it's Items & for each Item all it's expressions. 不破坏当前的 as_json

我对 Rails 有点陌生，正在使用 Rails 4.2.6 并且不知道从哪里开始 - 谁能帮忙？

Answer 1

当然是这样的，希望你能明白。

EnvironmentSerializer.new(environment) 获取层次结构 json。

假设环境表有列 environment_attr1 ， environment_attr2

class EnvironmentSerializer < ActiveModel::Serializer
  attributes :environment_attr1, :environment_attr2 , :containers

  # This method is called if you have defined a 
  # attribute above which is not a direct value like for
  # a rectancle serializer will have attributes length and width
  # but you can add a attribute area as a symbol and define a method
  # area which returns object.length * object.width
  def containers
     ActiveModel::ArraySerializer.new(object.containers,
           each_serializer: ContainerSerializer)
  end
end

class ContainerSerializer < ActiveModel::Serializer
   attributes :container_attr1, :container_attr2 , :items
   def items
     ActiveModel::ArraySerializer.new(object.items,
        each_serializer: ItemSerializer)
   end
end



   class ItemSerializer < ActiveModel::Serializer
   ... 
   end

   class ExpressionSerializer < ActiveModel::Serializer
   ... 
   end