Question

我正在尝试推出自己的电子商务解决方案。扩展使用Rails的Pragmatic Web Development中解释的软件仓库应用程序。

我目前正试图找出附件。基本上我希望Product和Product_Variants使用Product_Shots来附加照片。这可能会导致product_shots表的product_variants值为空，因为并非所有产品都有prodcut_variants。有没有更好的方法来实现这个？

产品型号：

 class Product < ActiveRecord::Base

 validates :title, :description, :price, :presence=>true
 validates :title, :uniqueness => true
 validates :price, :numericality =>{:greater_than_or_equal_to => 0.01}



 has_many :line_items
 before_destroy :ensure_not_referenced_by_any_line_item

 has_and_belongs_to_many :product_categories
 has_many :product_variants

 has_many :product_shots, :dependent => :destroy
 accepts_nested_attributes_for :product_shots, :allow_destroy => true,
                            :reject_if => proc { |attributes| attributes['shot'].blank?

 }

private
def ensure_not_referenced_by_any_line_item
  if line_items.empty?
    return true
  else
  errors.add(:base, "Line items present")
end

end
end

产品变体型号

class ProductVariant < ActiveRecord::Base

  belongs_to :product
  belongs_to :product_categories

  has_many :variant_attributes
  has_many :product_shots # can I do this?
end

产品拍摄模型（由Paperclip处理）

class ProductShot < ActiveRecord::Base
  belongs_to :product, :dependent =>:destroy
  #Can I do this?
  belongs_to :product_variant, :dependent => :destroy

  has_attached_file :shot, :styles => { :medium => "637x471>", 
                :thumb => Proc.new { |instance| instance.resize }},
                :url => "/shots/:style/:basename.:extension",
                :path =>":rails_root/public/shots/:style/:basename.:extension"


  validates_attachment_content_type :shot, :content_type => ['image/png', 'image/jpg', 'image/jpeg', 'image/gif  ']                  
  validates_attachment_size :shot, :less_than => 2.megabytes


 ### End Paperclip ####

 def resize     
     geo = Paperclip::Geometry.from_file(shot.to_file(:original))

     ratio = geo.width/geo.height  

     min_width  = 142
     min_height = 119

      if ratio > 1
        # Horizontal Image
        final_height = min_height
        final_width  = final_height * ratio
        "#{final_width.round}x#{final_height.round}!"
      else
       # Vertical Image
       final_width  = min_width
       final_height = final_width * ratio
       "#{final_height.round}x#{final_width.round}!"
     end
   end 
end

Answer 1

如果我要实现这一点，我想我会把它作为一种多态关系。所以在product.rb和product_variant.rb中：

has_many :product_shots, :dependent => :destroy, :as => :pictureable

在product_shot.rb中：

belongs_to :pictureable, :polymorphic => true

现在，product和product_variant可以拥有他们想要的尽可能多（或很少）的product_shot，并且可以product.product_shots和product_variant.product_shots访问。只需确保正确设置数据库 - 您的product_shots表需要pictureable_type和pictureable_id才能使用。

Paperclip附件由2个模型共享

1 个答案: