ruby-on-rails - 在 ActiveSupport::Concern 模块中访问模型属性

Question

我有一些模型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我的模块中的属性。

型号:

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|

我是否遗漏了什么或者我是否监督了一些重要的事情？

菲利克斯

Answer 1

我认为模块的设计还有改进的空间。但对于这个特定问题，这里是快速修复。

class Job < ActiveRecord::Base
  include ImageModel

  def image_dir
    "jobs"
  end
end