刚开始学 rails，对 routing 部分有些疑惑，很多网上的资料由于不同的 rails 版本和中英文描述差异，看起来来很吃力。最后发现最我这种新手，最清晰反而是routes.rb的注释。
这是注释里routes的一些sample,我对它的理解是一些写法的分类：
- regular route
- named route
- resource route
- resource route with options
- resource route with sub-resources
- resource route with more complex sub-resources
- resource route within a namespace
- routed with "root"
他们的差别和用法我暂时没打算完全深入，先有个清晰整体的认识是现在需要的。
@lissdy 不清楚。相对与这些特殊的用法，更希望搞清楚它是怎么跑起来的。Head First Ruby on Rails 58 页中讲了个流程
Behind the scenes with routes
- When Rails receives a request from a browser, it passes the request-path to the
routes.rbto find a matching route. - If the matching route contains symbols, then the Routing system will create matching parameters in the request parameters table params[...]
- The route can also specify additional parameters that will be inserted into params[...].
:controllerand:action. - Once the
routes.rbprogram has finished, Rails will look at the value ofparams[:controller]and use it to descide which type of controller object it needs to create. - Once the controller object has been created, Rails will the use the value stored in
params[:action], to choose the method within the controller to call. - Then, when the controller method completes, Rails calls the page template that also matches the
params[:action]value. The page template then generates the response which is sent back to the browser.
我的理解是，通过 symbols 作为占位符，去匹配请求，route 里面可以配置进去:controller 和:action。Routing system 会创建一个 params[..]，这里面有请求参数和从匹配 route 中加入的:controller 和:action。顺着这个路线去找 controller 和 action