如何检索类名？ [英] How to retrieve a class name?

问题描述

我使用Ruby on Rails 3.0.7，我想检索类名，如果它是命名空间。例如，如果我有一个名为 User :: Profile :: Manager 的类，我将从中检索 Manager 使用某些未知的Ruby或Ruby on Rails方法和安全方式。

I am using Ruby on Rails 3.0.7 and I would like to retrieve the class name, also if it is namespaced. For example, if I have a class named User::Profile::Manager I would retrieve the Manager string from that using some unknown to me Ruby or Ruby on Rails method and in a secure way.

BTW ：什么其他

推荐答案

一些有用的简单元编程调用：

Some useful simple metaprogramming calls:

user = User::Profile::Manager.new(some_params)
user.class # => User::Profile::Manager
user.class.class # => Class
user.class.name # => "User::Profile::Manager"
user.class.name.class # => String

# respond_to? lets you know if you can call a method on an object or if the method you specify is undefined
user.respond_to?(:class) # => true
user.respond_to?(:authenticate!) # => Might be true depending on your authentication solution
user.respond_to?(:herpderp) # => false (unless you're the best programmer ever)

# class.ancestors is an array of the class names of the inheritance chain for an object
# In rails 3.1 it yields this for strings:
"string".class.ancestors.each{|anc| puts anc}

String
JSON::Ext::Generator::GeneratorMethods::String
Comparable
Object
PP::ObjectMixin
JSON::Ext::Generator::GeneratorMethods::Object
ActiveSupport::Dependencies::Loadable
Kernel
BasicObject

如果你想要 User :: Profile :: Manager 的最低级别的类， [使用正则表达式对我来说似乎有点过分;]]：

If you want the lowest-level class from User::Profile::Manager I'd probably do the following [using a regex for this seems like overkill to me ;)]:

user = User::Profile::Manager.new
class_as_string = user.class.name.split('::').last # => "Manager"
class_as_class = class_name.constantize # => Manager

编辑：

如果你真的想看看一些更多的元编程调用，请检查文档对象和模块类，并查看google结果Ruby Metaprogramming。

If you actually want to look through some more metaprogramming calls, check the docs for the Object and Module classes, and check out the google results for "Ruby Metaprogramming".

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