通過關聯在has_many中嵌套json模型

Question

使用Rails 3.2。我有以下代碼：

# month.rb       
class Month < ActiveRecord::Base 
    has_many :days 

    def map_markers 
    days.as_json(
     :only => :position, 
     :include => { 
     :day_shops => { 
      :only => :position, 
      :include => { 
      :shops => { 
       :only => [ :name ] 
      } 
      } 
     } 
     } 
    ) 
    end 
end 

# day.rb 
class Day < ActiveRecord::Base 
    belongs_to :month 
    has_many :day_shops 
    has_many :shops, :through => :day_shops 
end 

# day_shop.rb 
class DayShop < ActiveRecord::Base 
    belongs_to :day 
    belongs_to :shop 
end 

# shop.rb 
class Shop < ActiveRecord::Base 
end 

我所試圖實現的是包裹在day_shop模型shop模型（這是一個through表），但是當我把它包起來的JSON像上面，我得到：

undefined method 'shops' for #<DayShop id: 87, day_id: 26, shop_id: 1, position: 1> 

我預期的JSON是：

- position: 1 
    :day_shops: 
    - position: 1 
    :shops: 
    - name: Company A 
    - position: 2 
    :shops: 
    - name: Company B 
- position: 2 
    :day_shops: 
    - position: 1 
    :shops: 
    - name: Company A 
    - position: 2 
    :shops: 
    - name: Company C 

如何更改我的方法是什麼？謝謝。

Answer 1

DayShop belongs to a Shop，而你是其​​中shops到day_shop在map_marker方法。修改map_marker到：

def map_markers 
    days.as_json(
    :only => :position, 
    :include => { 
     :day_shops => { 
     :only => :position, 
     :include => { 
      :shop => { 
      :only => [ :name ] 
      } 
     } 
     } 
    } 
) 
end