从Rails插件向Rails引擎模型添加方法 [英] Add methods to a Rails engine model from a Rails plugin

问题描述

我正在编写一个Rails插件来扩展Rails引擎。即 MyPlugin 具有 MyEngine 作为依赖项。

I'm writing a Rails plugin to extend a Rails engine. Namely MyPlugin has MyEngine as a dependency.

开我的Rails引擎我有一个 MyEngine :: Foo 模型。

On my Rails engine I have a MyEngine::Foo model.

我想为这个模型添加新的方法，所以我在我的插件 app / models / my_engine / foo.rb 其中包含以下代码：

I'd like to add new methods to this model so I created a file in my plugin app/models/my_engine/foo.rb which has the following code:

module MyEngine
  class Foo

        def sayhi
            puts "hi"
        end

  end
end

如果我在插件虚拟应用程序中输入Rails控制台，可以找到 MyEngine :: Foo ，但runnning MyEngine :: Foo.new.sayhi 返回

If I enter the Rails console on the plugin dummy application I can find MyEngine::Foo, but runnning MyEngine::Foo.new.sayhi returns

NoMethodError：undefined方法`sayhi'

NoMethodError: undefined method `sayhi'

为什么 MyPlugin 无法看到<$ c $的更新c> MyEngine :: Foo 模型？我在哪里错了？

Why MyPlugin cannot see the updates to MyEngine::Foo model? Where am I wrong?

推荐答案

好的，找到了。要使 MyPlugin 知道并且能够修改 MyEngine 模型，必须在插件 engine.rb 就像这样：

Ok, found out. To make MyPlugin aware and able to modify MyEngine models the engine must be required on the plugin engine.rb like so:

require "MyEngine"

module MyPlugin
  class Engine < ::Rails::Engine
    isolate_namespace MyPlugin

    # You can also inherit the ApplicationController from MyEngine
    config.parent_controller = 'MyEngine::ApplicationController'
  end
end

为了扩展 MyEngine :: Foo model然后我必须创建一个文件 lib / my_engine / foo_extension.rb ：

In order to extend MyEngine::Foo model I then had to create a file lib/my_engine/foo_extension.rb:

require 'active_support/concern'

module FooExtension
    extend ActiveSupport::Concern

    def sayhi
        puts "Hi!"
    end

    class_methods do 
        def sayhello
            puts "Hello!"
        end
    end
end

::MyEngine::Foo(:include, FooExtension)

要求它在 config / initializers / my_engine_extensions.rb

require 'my_engine/foo_extension' 

现在从 MyPlugin 我可以：

Now from MyPlugin I can:

 MyEngine::Foo.new.sayhi
 => "Hi!"
 MyEngine::Foo.sayhello
 => "Hello!"

请参阅 ActiveSupport Concern 文档了解更多详情。

See ActiveSupport Concern documentation for more details.

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