访问ActiveSupport :: Concern模块中的模型属性

时间:2013-09-18 10:09:20

标签: ruby-on-rails activerecord ruby-on-rails-4

我有一些模型只在其他路径上共享相同的功能。所以我决定将这些方法放在一个模块中并在模型中设置路径。我的问题是我无法访问模块中的属性。

模型:

class Job < ActiveRecord::Base
  include ImageModel

  image_dir = "jobs"
end

模块:

module ImageModel
  extend ActiveSupport::Concern

  def delete_image
      unless pic_link == "" || pic_link == nil
        begin
          if File.delete(Rails.root.join("public", "images", image_dir, pic_link))
            return true
          else
            return false
          end
        rescue
          return true #an error occured but when the image does not exist we still return true
        end
      end

      return true
    end

    def replace_image(new_image)
      File.open(Rails.root.join("public", "images", image_dir, new_image.original_filename), "wb") do |f|
        if f.write new_image.read
          delete_image
          pic_link = new_image.original_filename
          return true #everything went fine
        else
          return false #return false if new image could not be written
        end
      end
    end
end

我得到的错误:

undefined local variable or method `image_dir' for #<Job:0x007f8a93b9e8d8>

在这一行:

File.open(Rails.root.join("public", "images", image_dir, new_image.original_filename), "wb") do |f|

我是否遗漏了某些东西,或者我是否监督过重要的事情?

菲利克斯

2 个答案:

答案 0 :(得分:1)

我认为模块的设计仍有改进的余地。但对于这个具体问题,这里是quickfix。

class Job < ActiveRecord::Base
  include ImageModel

  def image_dir
    "jobs"
  end
end

答案 1 :(得分:0)

您应该在模块中定义image_dir = "jobs"。因为你将模块包含在你的模型中,而你的模块无法获得声明,你已经在模型中完成了。

或者您可以更改delete_image方法以获取参数:

def delete_image(image_dir)
      unless pic_link == "" || pic_link == nil
        begin
          if File.delete(Rails.root.join("public", "images", image_dir, pic_link))
            return true
          else
            return false
          end
        rescue
          return true #an error occured but when the image does not exist we still return true
        end
      end

      return true
    end

并且在那里调用该方法,传递这样的参数:

 delete_image("jobs")

replace_image方法的情况下相同:

 def replace_image(new_image, image_dir)
      File.open(Rails.root.join("public", "images", image_dir, new_image.original_filename), "wb") do |f|
        if f.write new_image.read
          delete_image
          pic_link = new_image.original_filename
          return true #everything went fine
        else
          return false #return false if new image could not be written
        end
      end
    end

希望它会有所帮助。感谢