Question

鉴于以下内容：

module RESTable
  BASE_URL  = "http://url.domain/api/rest"
  LOGIN_URL = "#{BASE_URL}/login"
  LOGOUT_URL = "#{BASE_URL}/logout"

  def request_url
    "#{BASE_URL}/mbo/#{@@object_resource}/_format=json"
  rescue NameError
    p "@@object_resource was not defined"
  end
end

class ServiceRequests
  include RESTable
  @@object_resource = "sr"

  def initialize
    binding.pry
  end
end

在pry会话中，调用request_url会产生：

"@@object_resource was not defined"

但@@ object_resource设置为“sr”。

我的想法是，对于每个类，我只需要包含RESTable模块，并且调用request_url将根据我所包含的类的@@ object_resource给出正确的URL。

更一般地说，如何从模块中调用类变量？

Answer 1

我通过在模块上声明@@ object_resource然后在@@ object_resource未更改（即空白）时引发错误来解决此问题。

这是更新的模块：

module RESTable
  BASE_URL  = "http://url.domain/api/rest"
  LOGIN_URL = "#{BASE_URL}/login"
  LOGOUT_URL = "#{BASE_URL}/logout"
  @@object_resource = ""

  def request_url
    raise StandardError, "@@object_resource can't be blank" if @@object_resource == ""
    "#{BASE_URL}/mbo/#{@@object_resource}/_format=json"
  rescue NameError
    p "@@object_resource was not defined"
  end
end

访问Module方法中的类变量

1 个答案: