扩展 ActiveRecord::Base 的正确方法
我通过以下方式扩展了 ActiveRecord::Base 类：
- 我在
lib下创建了一个目录，我们现在调用它foo - 编写了模块提供了额外的方法
has_many_bidirection，以在 lib/foo/active_record.rb的ActiveRecord::Base类中 建立双向has_many关系>：
模块 Foo 活动记录模块 自动加载：关联，'active_record/associations' 自动加载：基础，'active_record/base' 结尾 结尾在
lib/foo/active_record/base.rb中：模块 Foo 活动记录模块 模块底座 def self.included(基础) base.class_eval 做 包括协会 结尾 结尾 结尾 结尾 结尾当然还有
lib/foo/active_record/associations.rb<中的真实代码< /代码>：模块 Foo 活动记录模块 模块关联 def self.included(基础) base.extend(类方法) 结尾 模块类方法 def has_many_bi Direction(...) # ... 结尾 结尾 结尾 结尾 结尾扩展了
ActiveRecord::Base类在配置文件末尾包含以下代码的config/environment.rb：ActiveRecord::Base.class_eval 做 包括 Foo::ActiveRecord::Base 结尾通过这种方式，Rails 正确地包含在我的模块中，我可以毫无问题地使用它
- 直到我想要观察< /strong> 扩展类，因为在
config/environment.rb中，config.active_record.observers部分位于扩展部分之前，并且此时可观察类对新方法一无所知。
产生以下错误：
/Library/Ruby/Gems/1.8/gems/activerecord-2.3.10/lib/active_record/base.rb:1998:in `method_missing': undefined method `has_many_bidirectional' for #<Class:0x1032f2fc0> (NoMethodError)
from .../app/models/user.rb:27
我的问题是，扩展 ActiveRecord::Base 类的正确方法是什么？ （我不想在我的 User 类中使用回调方法。）
我真的必须在 lib 下创建一个 gem 而不是模块吗code> 目录有这个功能吗？
谢谢！
I have extended the ActiveRecord::Base class in the following way:
- I made a directory under the
lib, let's call it nowfoo - wrote the module which provides the extra method
has_many_bidirectionalto have bidirectional has_many relationships inActiveRecord::Baseclasses in the
lib/foo/active_record.rb:module Foo module ActiveRecord autoload :Associations, 'active_record/associations' autoload :Base, 'active_record/base' end endin the
lib/foo/active_record/base.rb:module Foo module ActiveRecord module Base def self.included(base) base.class_eval do include Associations end end end end endand of course the real code in
lib/foo/active_record/associations.rb:module Foo module ActiveRecord module Associations def self.included(base) base.extend(ClassMethods) end module ClassMethods def has_many_bidirectional(...) # ... end end end end endextended the
ActiveRecord::Baseclass in theconfig/environment.rbwith the following code at the end of the configuration file:ActiveRecord::Base.class_eval do include Foo::ActiveRecord::Base endwith this way Rails was properly included my module, and I could use it without any problem
- until I wanted to observe an extended class, because in the
config/environment.rbtheconfig.active_record.observerspart is before the extending part, and the observable class does not know anything about the new method at that point.
The following error produced:
/Library/Ruby/Gems/1.8/gems/activerecord-2.3.10/lib/active_record/base.rb:1998:in `method_missing': undefined method `has_many_bidirectional' for #<Class:0x1032f2fc0> (NoMethodError)
from .../app/models/user.rb:27
My question is, which is the correct way to extend the ActiveRecord::Base class? (I don't want to use callback methods in my User class.)
Do I really have to create a gem instead of a module under the lib directory to have this functionality?
Thanks!
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正如我所发现的，最好的方法是使用生成器创建一个插件：
通过这种方式，Rails 会将其包含在观察者部分之前。可以在此处找到一个很好的教程。
我以前的所有代码都可以轻松地采用这种方式。
As I digged it out, the best way is to create a plugin with the generator:
And with this way Rails will include it before the observer part. A good tutorial can be found here.
All of my previous code can be easily adopted to this way.