Question

我正在使用Rails 4.2.3。我在课堂上定义一个静态变量时遇到了麻烦。我有

class MainService < Abstractmy_objectFinderService

  # class variables 
  @@my_object_desc_link_template = "https://results.Main.com/mobile/results/my_objects?_dc=1467745366092&eventID=21476"

…

          event_link = MainService.my_object_data_link_template.sub( %r{intervalID=[^&]+}, "intervalID=#{interval_id}" )
                                          .sub( %r{eventID=[^&]+}, "eventID=#{event_id}" )
                                          .sub( %r{my_objectID=[^&]+}, "my_objectID=#{my_object_id}" )

但是当我运行我的代码时，我收到了错误

undefined method `my_object_desc_link_template' for MainService:Class

我还需要做什么才能成功定义静态变量？

Answer 1

在Ruby中，您不会在方法块之外初始化变量。那就是说我会猜测你的代码示例做了什么并完全重写：

class MainService
  BASE_URL =  "https://results.Main.com/mobile/results/my_objects"
  DEFAULT_PARAMS = {_dc: 1467745366092}

  def self.event_link(interval_id, my_object_id, event_id)
    params = {intervalID: interval_id,
              eventID: event_id,
              my_object_ID: my_object_id}

    "#{BASE_URL}?#{DEFAULT_PARAMS.merge(params).to_query}"
  end
end

然后使用event_link类方法从任何地方调用它：

MainService.event_link(1, 2, 3)
=> https://results.Main.com/mobile/results/my_objects?_dc=1467745366092&eventID=3&intervalID=1&my_object_ID=2"

如果您真的想要使用类变量，请告诉我。

获得＆＃34;未定义的方法＆＃34;当试图在Rails中访问我的静态变量时

1 个答案: