rails 路由学习1

rails config/routes.rb 指定路由的代码如下

Rails4demo::Application.routes.draw do
  root 'users#index'
  resources :users
  get 'photos/:id' => 'photos#show', :defaults => { :format => 'jpg' }
  get '/logout' => 'sessions#destroy', :as => :logout
  get "/stories" => redirect("/photos")
end

上面的代码定义了5种风格的路由，rails在启动时会读取routes.rb，生成标准状态的格式，以此来匹配url，指定controller和action。

带defaults的get调用

Rails4demo::Application.routes.draw do
  get '/logout' => 'sessions#destroy', :as => :logout
end

会生成以下变量

app: #<ActionDispatch::Routing::RouteSet::Dispatcher:0x007fd05e0cf7e8
           @defaults={:format=>"jpg", :controller=>"photos", :action=>"show"},
           @glob_param=nil,
           @controller_class_names=#<ThreadSafe::Cache:0x007fd05e0cf7c0
           @backend={},
           @default_proc=nil>>
conditions: {:path_info=>"/photos/:id(.:format)", :required_defaults=>[:controller, :action], :request_method=>["GET"]}
requirements: {}
defaults: {:format=>"jpg", :controller=>"photos", :action=>"show"}
as: nil
anchor: true

指定了controller和action；如果url符合conditions的要求，app会执行。requirements 是一些其他限制。

带 as的get调用

Rails4demo::Application.routes.draw do
  get '/logout' => 'sessions#destroy', :as => :logout
end

会生成以下变量

app: #<ActionDispatch::Routing::RouteSet::Dispatcher:0x007f8ded87e740
           @defaults={:controller=>"sessions", :action=>"destroy"},
           @glob_param=nil,
           @controller_class_names=#<ThreadSafe::Cache:0x007f8ded87e718 @backend={},
           @default_proc=nil>>
conditions: {:path_info=>"/logout(.:format)", :required_defaults=>[:controller, :action], :request_method=>["GET"]}
requirements: {}
defaults: {:controller=>"sessions", :action=>"destroy"}
as: "logout"
anchor: true

resources 会生成类似的8种app。
ActionDispatch::Routing::Mapper定义了 用于定义route的方法

module ActionDispatch
  module Routing
    class Mapper
      include Base
      include HttpHelpers
      include Redirection
      include Scoping
      include Concerns
      include Resources
    end
  end
end

• Base定义了 root, match 和 mount
• HttpHelper定义了get、put、patch、post、delete
• Scoping定了 scope、namespace、constraints
• Resources定义了resource、resources、collection、member、shallow
  由url匹配到app是由journey执行的，这个gem主要是通过正则匹配，我们随后继续研究.