Rails 自定义渲染器

我一直在尝试基于 这篇 Yehuda Katz 的博文.

如果我调用 render :my_custom_renderer =>"index"，但它不适用于默认的 respond_with 或 format.my_custom_renderer

It works if I call render :my_custom_renderer => "index", but it doesn't work with default respond_with or format.my_custom_renderer

我创建了一个简单的例子.

I created a simple example, .

从一个空白的应用程序中，添加以下几行:

From a blank app, add the following lines:

在 config/mime_types.rb:

In config/mime_types.rb:

Mime::Type.register_alias 'text/html', :my_custom_renderer

在 config/my_custom_renderer.rb 中:

In config/my_custom_renderer.rb:

require "action_controller/metal/renderers"
ActionController.add_renderer :my_custom_renderer do |template, options|
  self.mime_type ||= Mime::HTML
  self.response_body = render_to_string(template).sub(/^/, 
                                                '\1<h1>Rendering Injection</h1>')
end

在 app/views/custom_renderer_test/index.my_custom_renderer.erb 中:

In app/views/custom_renderer_test/index.my_custom_renderer.erb:

<h1>A message "Rendering Injection" should appear above</h1>

在 app/controllers/custom_renderer_test_controller.rb 中:

In app/controllers/custom_renderer_test_controller.rb:

class CustomRenderingTestController < ApplicationController
  def index
    respond_to do |format|
      # does not go through my custom renderer!
      format.my_custom_renderer 
      # although it works if I explicitly do:
      # format.my_custom_renderer { render :my_custom_renderer => 'index' }
    end
  end
end

最后，在 config/routes.rb 中:

And, finally, in config/routes.rb:

root :to => "custom_rendering_test#index"

启动服务器并转到根页面应该会显示来自 my_custom_renderer 的消息，但它不会.我已经尝试逐步调试 Rails 源代码，但看起来我不太了解渲染架构.

Starting up a server and going to the root page should display the message from my_custom_renderer, but it does not. I've tried debugging Rails source step by step, but looks like I don't understand rendering architecture well-enough.

有人可以告诉我问题是什么吗?

Can someone please give me a hint on what the problem is?