Question

我有三个模型（这里简化）：

class Child < ActiveRecord::Base
  has_many    :childviews, :dependent => :nullify
  has_many    :observations, :through => :childviews  
end
class Childview < ActiveRecord::Base
  belongs_to  :observation
  belongs_to  :child
end
class Observation < ActiveRecord::Base
  has_many    :childviews, :dependent => :nullify
  has_many    :children, :through => :childviews
end

我正在使用Rails的to_json方法将这个发送给一些JavaScript：

render :layout => false , :json => @child.to_json(
  :include => {
    :observations => {
      :include => :photos, 
      :methods => [:key, :title, :subtitle]
    }
  },
  :except => [:password]
)

这完美无缺。通过连接表（子视图）可以很好地检索观察结果。

然而，我还想获取位于childviews连接表中的数据;特别是'needs_edit'的值。

我无法弄清楚如何在to_json调用中获取此数据。

任何人都可以帮助我吗？非常感谢提前。

qryss

Answer 1

不确定，但不应该这样做吗？

@child.to_json(
  :include => {
    :observations => {
      :include => :photos, 
      :methods => [:key, :title, :subtitle]
    },
    :childviews => { :only => :needs_edit }
  }, 
  :except => [:password]
)

编辑：这可能也有效，因为childviews属于overvation：

@child.to_json(
  :include => {
    :observations => {
      :include => { :photos, :childviews => { :only => :needs_edit } } 
      :methods => [:key, :title, :subtitle]
    }
  }, 
  :except => [:password]
)

Answer 2

感谢Rock的指点 - 我现在已经开始工作了！

此代码：

@child.to_json(:include => 
  {
    :observations => {
      :include => {
        :photos => {},
        :childviews => {:only => :needs_edit}
      }, 
      :methods => [:S3_key, :title, :subtitle]
    }     
  },
  :except => [:password]
)

给我这个输出（缩写为清晰）：

{
    "child":
    {
        "foo":"bar",
        "observations":
        [
            {
                "foo2":"bar2",
                "photos":
                [
                    {
                        "foo3":"bar3",
                    }
                ],
                "childviews":
                [
                    {
                        "needs_edit":true
                    }
                ]
            }
        ]
    }
}

谢谢你，摇滚！那是我的头脑。

：）

qryss

使用to_json时如何访问'：has_many：through'连接表数据？

2 个答案: