Ruby on rails Rails中全局共享数据结构的存储位置

我的一个模型中有这样的数据结构：

def image_size_limits
    {
        "web" => {"maxheight" => 480, "maxwidth" => 680, "minheight" => 400, "minwidth" => 600}, 
        "phone" => {"height" => 345, "width" => 230, "minheight" => 300, "minwidth" => 200},
        "tablet" => {"height" => 680, "width" => 480, "minheight" => 600, "minwidth" => 400},
        "other" => {"height" => 680, "width" => 480, "minheight" => 600, "minwidth" => 400}
    }
end

我在自定义验证器中使用它，我必须验证上传图像的大小。我希望能够不仅在这个模型中使用这个数据结构，而且在任何地方都可以使用。在我的所有模型、视图和控制器中

---

我该怎么做，把它放在哪里？

我会使用一个模块

将其粘贴到

lib

目录中。（您可能需要将Rails 3配置为从

lib

文件夹自动加载类和模块。请参阅。）

然后在模型或控制器中：

class MyModel < ActiveRecord::Base
  include ImageSizes
  # ...
end


class MyController < ApplicationController
  include ImageSizes
  # ...
end

classmymodel

---

现在，包括

ImageSizes

模块的每个型号或控制器都可以访问该模块的方法，即

imagesize\u limits

另一个选项是创建初始值设定项文件并在其中声明常量

# config/initializers/image_size_limits.rb

IMAGE_SIZE_LIMITS = {
  "web" => {"maxheight" => 480, "maxwidth" => 680, "minheight" => 400, "minwidth" => 600}, 
  "phone" => {"height" => 345, "width" => 230, "minheight" => 300, "minwidth" => 200},
  "tablet" => {"height" => 680, "width" => 480, "minheight" => 600, "minwidth" => 400},
  "other" => {"height" => 680, "width" => 480, "minheight" => 600, "minwidth" => 400}
}

---

然后，在您的模型或控制器中，只需使用

IMAGE\u SIZE\u LIMITS['web']['maxheight']

即可获得Rails 4中的

480

，这也会引起关注。看看这个：

# config/initializers/image_size_limits.rb

IMAGE_SIZE_LIMITS = {
  "web" => {"maxheight" => 480, "maxwidth" => 680, "minheight" => 400, "minwidth" => 600}, 
  "phone" => {"height" => 345, "width" => 230, "minheight" => 300, "minwidth" => 200},
  "tablet" => {"height" => 680, "width" => 480, "minheight" => 600, "minwidth" => 400},
  "other" => {"height" => 680, "width" => 480, "minheight" => 600, "minwidth" => 400}
}