Ruby - 动态添加属性到类（在运行时） [英] Ruby - dynamically add property to class (at runtime)

问题描述

我正在寻找一种方法来在运行时为我已经定义的类添加属性，或更好：

  
 attr_accessor：login，：password 
 def initialize args = {} 
 self.login = args [：login] 
 self.password = args [：password] 
结束
 end 
  

但是，我有这个散列

  {：swift_bic =>XXXX，：account_name =>XXXX，：id =>123，：iban => XXXX} 
  

，我希望此哈希成为我的客户端实例

  client = Client.new：login => 'user'，：password => 'xxxxx'
  

然后用神奇的魔法

  client @@％$％PLIM！ {：swift_bic =>XXXX，：account_name =>XXXX，：id =>123，：iban =>XXXX} 
  pre> 
 
 
我可以访问
  client.swift_bic = > 'XXXX'
 client.account_name => 'XXXX'
 client.id => 123 
  
，我也想保持一个合适的对象结构，如：
  Client.new（：login =>'user'，：password =>'xxxxx'）inspect 
＃ 0x1033c4818 @ password ='xxxxx'，@ login ='user'>  
 $ b            client.inspect 
＃< Client：0x1033c4818 @ password ='xxxxx'，@ login ='user'，@ swift_bic ='XXXX'，@ account_name ='XXXX'@id => ; '123'，@iban => 'XXXX'> 
 
这将给我一个非常漂亮和格式良好的json之后
 
 
 
这是可能的吗？
 
 
 
我从一个web服务得到这个哈希，所以我不知道是否一个新的属性在那里，然后我将不得不更新我的应用程序，每当他们对他们的服务执行升级。 
所以，我想避免这种情况：/ 
 
 
 
谢谢你们。
 
 
 
 ：       在添加它们后很多地使用访问器，你可以将它们添加为真正的方法，例如：
  class客户端
 def add_attrs（attrs）
 attrs.each do | var，value | 
 class_eval {attr_accessor var} 
 instance_variable_set@＃{var}，value 
 end 
 end 
 end 
  
这将使它们像普通的实例变量一样工作，但只限于一个 client 。
 
I'm looking for a way to add properties to my already defined class at runtime, or better:
class Client
    attr_accessor :login, :password
    def initialize args = {}
        self.login    = args[:login]
        self.password = args[:password]
    end
end
But then, I have this hash
{:swift_bic=>"XXXX", :account_name=>"XXXX", :id=>"123", :iban=>"XXXX"} 
and I want this hash to become part of my client instance like
client = Client.new :login => 'user', :password => 'xxxxx'
then with a miraculous magic
client @@%$%PLIM!!! {:swift_bic=>"XXXX", :account_name=>"XXXX", :id=>"123", :iban=>"XXXX"} 
I would be able to access
client.swift_bic => 'XXXX'
client.account_name => 'XXXX'
client.id => 123
and I also would like to maintain a proper object structure like:
Client.new(:login => 'user', :password => 'xxxxx').inspect
#<Client:0x1033c4818 @password='xxxxx', @login='user'>
after the magic
client.inspect
#<Client:0x1033c4818 @password='xxxxx', @login='user', @swift_bic='XXXX', @account_name='XXXX' @id => '123', @iban => 'XXXX'>
which would give me a very nice and well formatted json after that

Is it possible at all?

I'm getting this hash from a webservice, so I wouldn't know if theres a new property in there, and then I would have to update my app each time they perform an upgrade on their service.
So, I'm sort of trying to avoid this :/

Thanks chaps.

:)
解决方案
The method_missing approach would work, but if you're going to use the accessors a lot after adding them, you might as well add them as real methods, like this:
class Client
  def add_attrs(attrs)
    attrs.each do |var, value|
      class_eval { attr_accessor var }
      instance_variable_set "@#{var}", value
    end
  end
end
This will make them work like normal instance variables, but restricted to just one client.

                        
这篇关于Ruby  - 动态添加属性到类（在运行时）的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！