Rails application の起動と実行メモ

rails コマンド

• bin/rails
• require "rails/cli"
• rails/cli: require 'rails/app_rails_loader'
• Rails::AppRailsLoader.exec_app_rails:
  • bundler のチェック
  • APP_PATH = Dir.pwd + config/application.rb
  • require File.expand_path('../boot', APP_PATH)
  • require 'rails/commands'
• rails/commands: ARGVの操作と alias の設定
• require 'rails/commands/commands_tasks'
  • help message の定義
  • command の dispatch
  • require APP_PATH: gem の require, Rails.application
• Rails::CommandsTasks.new(ARGV).run_command!(command): runner とかの実体を呼んで実行する
• exec_app_rails: 正常に command が終了したら rails/cli まで戻る
• if ARGV.first == 'plugin': require 'rails/commands/plugin' - plugin generate
• else: require 'rails/commands/application' - application generate

Rails.application#call は実際にどうやってなにが呼ばれるのか

ActionController::Base#action(action).call(env) が呼ばれるまでを追ってみた。

雑にまとめると、通常の routing では

• Rails::Application#call
• ActionDispatch::MiddlewareStack#call
• ActionDispatch::Routing::RouteSet#cal
• ActionDispatch::Journey::Router#call
• ActionDispatch::Jouney::Route#app.call
• Routing::RouteSet::Dispatcher#call
• SomeController.action(action).call

となる。以下乱雑なメモ

• Rails::Application#call: super
• Rails::Engine#call: #app.call(env)
• Rails::Engine#app:
  • config.middleware = config.middleware.merge_into(default_middleware_stack)
  • config.middleware.build(endpoint)
• #config: Application::Configuration.new(find_root_with_flag("config.ru", Dir.pwd)) & config= もある
• Rails::Application#config: #app_middleware
• Rails:::Railtie#app_middleware: @@app_middleware ||= Rails::Configuration::MiddlewareStackProxy.new
• MiddlewareStackProxy#merge_into: #default_middleware_stack
• Rails::Application#default_middleware_stack: DefaultMiddlewareStack.new, #buidl_stack
  • #build_stack: ActionDispatch::MiddlewareStack.new.tap {}
• ActionDispatch::MiddlewareStack#build(endpoint):
  • Rails::Engine#endpoint: self.class.endpoint || routes
  • Rails::Engine#routes: ActionDispatch::Routing::RouteSet.new
  • #build(app = ActionDispatch::Routing::RouteSet.new) no block: middlewares.freeze.reverse.inject(app) { |a, e| e.build(a) }
  • ActionDispatch::MiddlewareStack::Middleware#build: klass.new(app, *args, &block)
  • Middleware#klass: 各 middleware で .new(app, *args, &block) する。args, block は use or insert とかの args, block が来る。
  • 返り値は全ての rack middleware をチェーンした ActionDispatch::Routing::RouteSet (= Rails::Application.endpoint)。endpoint を任意の rack interface 互換のものにどこかで差し替えれば Raisl の routing を差し替えれるかもしれない。
• ActionDispatch::Routing::RouteSet#call: @router.call(env)
  • @router: Journey::Router.new(Journey::Routes.new)
• Journey::Router#call: find_routes(env).each {|route| status, headers, body = route.app.call(env) }
  • route: filter_routes
  • Journey::Router#filter_routes: routes#simulator
  • Journey::Routes#simulator: GTG::Simulator.new(GTG::Builder.new(ast).transition_table)
  • Simulater.new(string):
    • string: Gtg#transition_table
  • Simulater#simulate: state
    • state: TODO
• ActionDispatch::Jouney::Route#app.call(env):
  • #app: Set by Mapper
    • Mapper#app: Constraints.new(endpoint, blocks, @set.request_class)
    • endpoint: (:to option (get '/', to: 'users#index') which responsd_to? :call) or (dispatcher)
    • Mapping#dispatcher: Routing::RouteSet::Dispatcher.new(:defaults => defaults)
      • defaults: defaults: { format: 'jpg' } otion
• Routing::RouteSet::Dispatcher#call(env): rack app とかが指定されない場合これが呼ばれる
  • params: env['action_dispatch.request.path_parameters']
  • params['controller], params['action']: すでにセットされている
• Dispatcher#dispatch(controller):
  • controller: controller_reference(controller_params)
    • const_name: @controller_class_names[controller_param] ||= "#{controller_param.camelize}Controller"
    • ActiveSupport::Dependencies.constantize(const_name)
• controller#action(action).call(env)

---

journey、やらなきゃいけないことが複雑でコードも複雑でめっちゃ疲れた追い切れない... JourneyHackingGuides ほしい...

次は named routes がどこの routes がどう呼ばれてるのか調べたい...