从YAML创建嵌套对象以通过Ruby中的方法调用访问属性 [英] Create nested object from YAML to access attributes via method calls in Ruby

问题描述

我对红宝石完全陌生. 我必须解析一个YAML文件来构造一个对象

I am completely new to ruby. I have to parse a YAML file to construct an object

YAML文件

projects:
  - name: Project1
    developers:
      - name: Dev1
        certifications:
          - name: cert1
      - name: Dev2
        certifications:
          - name: cert2
  - name: Project2
    developers:
      - name: Dev1
        certifications:
          - name: cert3
      - name: Dev2
        certifications:
          - name: cert4

我想从此YAML创建一个对象，为此我在Ruby中编写了以下代码

I want to create an object from this YAML for which I wrote the following code in Ruby

require 'yaml'
object = YAML.load(File.read('./file.yaml'))

我可以使用[]成功访问该对象的属性 例如

I can successfully access the attributes of this object with [] For e.g.

puts object[projects].first[developers].last[certifications].first[name]
# prints ABC

但是，我想通过方法调用来访问属性

However, I want to access the attributes via method calls

例如

puts object.projects.first.developers.last.certifications.first.name
# should print ABC

有什么方法可以构造这样的对象，该对象的属性可以通过上述(点)方式进行访问? 我已经阅读了 OpenStruct 和 hashugar . 我也想避免使用第三方宝石

Is there any way to construct such an object whose attributes can be accessed in the (dots) way mentioned above? I have read about OpenStruct and hashugar. I also want to avoid usage of third party gems

推荐答案

如果您只是在进行实验，则有一种快速而肮脏的方法:

If you are just experimenting, there is a quick and dirty way to do this:

class Hash
  def method_missing(name, *args)
    send(:[], name.to_s, *args)
  end
end

我不会在生产代码中使用它，因为method_missing和猴子补丁通常都是解决问题的方法.

I wouldn't use that in production code though, since both method_missing and monkey-patching are usually recipes for trouble down the road.

更好的解决方案是递归遍历数据结构，并用openstruct代替散列.

A better solution is to recursively traverse the data-structure and replace hashes with openstructs.

require 'ostruct'
def to_ostruct(object)
  case object
  when Hash
    OpenStruct.new(Hash[object.map {|k, v| [k, to_ostruct(v)] }])
  when Array
    object.map {|x| to_ostruct(x) }
  else
    object
  end
end

puts to_ostruct(object).projects.first.developers.last.certifications.first.name

请注意，如果您经常做这两种方法，那么这两种方法都可能存在性能问题-如果您的应用程序对时间敏感，请确保对其进行基准测试！不过，这可能与您无关.

Note that there are potentially performance issues with either approach if you are doing them a lot - if your application is time-sensitive make sure you benchmark them! This probably isn't relevant to you though.

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