gem 回形针插值

Question

美好的一天。
我有导轨 3.1。和宝石回形针
在我管理公司合同的应用程序中：

MODEL    
    model/contract.rb
      has_many :contract_files

    model/contract_file.rb
      has_attached_file :data

CONSOLE
Loading development environment (Rails 3.1.0)

1.9.2p290 :001 > cont = Contract.first

  Contract Load (0.1ms)  SELECT "contracts".* FROM "contracts" LIMIT 1    
         => #Contract id: 1, organization: "Com.org", and etc ....

1.9.2p290 :002 > cont.contract_files

  ContractFile Load (0.2ms)  SELECT "contract_files".* FROM "contract_files"
     WHERE "contract_files"."contract_id" = 1     
         => #[ContractFile id: 88, caption: "asdf", and etc ...]

问题
好心，请告诉我，我怎样才能提取 Contract id: 1 in

model/contract_files.rb    
      has_attached_file :data,
      :url => "/assets/paperclip/:contract_id/:filename"

我想获得的示例
在 http//localhost:3000/contracts/1 上获取此类文件路径： http://localhost:3000/contracts/1/assets/paperclip/1/XXX.pdf http//localhost:3000/contracts/1/assets/paperclip/1/XXY.pdf http://localhost:3000/contracts/1/assets/paperclip/1/XXZ.pdf

非常感谢您的帮助。

Answer 1

如果我明白了，你可以这样做：

Contract.find( params[:id] ).contract_files.map { |cf| cf.data.url }
# Dont't forget to handle nonexistent id

更新

要将 contract_id 放在 url 中，您应该以这种方式恢复默认的回形针 :url 和 :path 参数：

#model/contract_file.rb
has_attached_file :data, :path => "public/contracts/:parent_id/assets/paperclip/:id.:extension", :url => "/contracts/:parent_id/assets/paperclip/:id.:extension"

Paperclip.interpolates :parent_id do |a, s|
    a.instance.contract.id
end