開場白

鼬～～哩賀，我是寫程式的山姆老弟，昨天跟大家一起看了 Rails 的 Command Line 有哪些特殊指令，今天來看看 Rails 的各種設定，像是你們在 config/application.rb 或是 config/environments/development.rb 之中會看到的各種 config.xxxx = true 一樣，夠夠～

ps. 這一篇超級無敵長，我就挑我自己覺得有用的、很驚艷的來介紹XD

ps. 本篇使用的「設定檔」字眼，將會等於

• config/application.rb 或
• config/environments/development.rb 或
• config/environments/test.rb 或
• config/environments/production.rb 或
• 其他環境設定檔(config/environments/*.rb)

ps. 以下設定後面接的括號，將會是這個設定所需要輸入的格式，例如 config.beginning_of_week (Symbol)，這個設定的使用方式就是 config.beginning_of_week = :sunday

General (就是我不知道怎麼分類的都會在這裡 XD)

• config.beginning_of_week (Symbol), default: :monday
• config.after_initialize (Block), default: nil
• config.console (Class), default: nil
• config.disable_sandbox (Boolean), default: false
• config.encoding (String), default: UTF-8
• config.force_ssl (Boolean), default: false
• config.middleware (Instance), default: ActionDispatch::MiddlewareStack
• config.credentials.content_path (Instance), default: Pathname('config/credentials.yml.enc')
• config.credentials.key_path (Instance), default: Pathname('config/master.key')
• config.secret_key_base (?), default: nil
• config.require_master_key (Boolean), default: false
• config.ssl_options (Hash), default: {:hsts=>{:subdomains=>true}} (從 Rails 5.0 以後都是這個預設值)
• config.time_zone (String), default: 'UTC'

Assets

• config.asset_host (String), default: nil
• config.javascript_path (String), default: 'javascript'
• config.public_file_server.enabled (Boolean), default: true in development,false in production
• config.assets.css_compressor (Symbol), default: sass-rails
• config.assets.js_compressor (Symbol), default: ?
• config.assets.gzip (Boolean), default: true
• config.assets.paths (Array), default: [.../javascript, .../images, .../stylesheets]
• config.assets.precompile (Array), default: ["manifest.js", "turbo.js", "turbo.min.js", "turbo.min.js.map", "actiontext.js", "trix.js", "trix.css", "es-module-shims.js", "es-module-shims.min.js", "es-module-shims.js.map", "stimulus.js", "stimulus.min.js", "stimulus.min.js.map", "activestorage", "activestorage.esm", "actioncable.js", "actioncable.esm.js"]
• config.assets.unknown_asset_fallback (Boolean), default: false (從 Rails 5.1 以後都是這個預設值)
• config.assets.prefix (String), default: '/assets'
• config.assets.manifest (String), default: ?
• config.assets.digest (Boolean), default: true
• config.assets.debug (Boolean), default: true in development, false in production
• config.assets.version (String), default: 1.0
• config.assets.compile (Boolean), default: true in development, false in production
• config.assets.logger (Class/Boolean), default: Logger
• config.assets.quiet (Boolean), default: true in development, false in production

Loading

• config.autoload_once_paths (Array), default: []
• config.autoload_paths (Array), default: []
• config.add_autoload_paths_to_load_path(Boolean), default: true
• config.eager_load (Boolean), default: false in development, true in production
• config.eager_load_namespaces (Array), default: [I18n, ActiveSupport, ActionDispatch, ActiveModel, ActionView::Railtie, ActionView, ActionController, ActiveRecord, GlobalID, ActiveStorage::Engine, ActiveStorage, ActionMailer, ActionCable::Engine, ActionCable, ActionMailbox::Engine, ActionMailbox, ActionText::Engine, ActionText, Importmap::Engine, Turbo::Engine, Turbo, Stimulus::Engine, Rails7Minitest::Application]
• config.eager_load_paths (Array), default: ["app/channels", "app/controllers", "app/controllers/concerns", "app/helpers", "app/jobs", "app/mailers", "app/models", "app/models/concerns]
• config.enable_dependency_loading (Boolean), default: false
• config.rake_eager_load (Boolean), default: false
• config.reload_classes_only_on_change (Boolean), default: true

Caching

• config.cache_store (Symbol), default: :file_store
• config.cache_classes (Array), default: false in development, true in production
• config.session_store (Symbol), default: :cookie_store，還有 :mem_cache_store, :your_custom_store, :disabled 可以選填

Debugging

• config.consider_all_requests_local (Boolean), default: true in development, false in production

• config.colorize_logging (Boolean), default: true

• config.exceptions_app (Class), default: nil

• config.debug_exception_response_format (Symbol), default: :default,:api for API only apps

• config.file_watcher (Class), default: ActiveSupport::FileUpdateChecker

• config.filter_parameters (Array), default: []，但 Rails 預設會建立 config/initializers/filter_parameter_logging.rb

  # config/initializers/filter_parameter_logging.rb
  Rails.application.config.filter_parameters += [
    :passw, :secret, :token, :_key, :crypt, :salt, :certificate, :otp, :ssn
  ]
  

• config.log_formatter (Instance), default: ActiveSupport::Logger::SimpleFormatter

• config.log_level (Symbol), default: :debug in development & test, :info in production，可帶入的有 :debug, :info, :warn, :error, :fatal, :unknown

• config.log_tags (Array), default: []

• config.logger (Instance), default: ActiveSupport::TaggedLogging

值得注意的點

• 可以在設定檔使用 console block，這個 block 只有在 $ rails console 才會執行

  # config/application.rb
  module YourApplicationName
    class Application < Rails::Application
  		console do
  			puts("Only called when using '$ rails console'. This is cool!")
  		end
    end
  end
  

• 在設定檔中可以使用的 initialization event，不只有 after_initialize block，還有 before_configuration, before_initialize, to_prepare, before_eager_load

• 可以透過 config.x(這邊一定要用 x)，把自己的設定放在 Rails 的設定中

  # config/application.rb
  module MyApp
    class Application < Rails::Application
  		...
      config.x.payment = { 
        environment: 'sandbox',
        merchant_id: 'development_merchant_id',
        public_key:  'development_public_key',
        private_key: 'development_private_key'
      }
    end
  end
  
  # $ rails console
  # [1] pry(main)> Rails.configuration.x.payment[:environment] # sandbox
  

總結

Rails 提供的細節設定有 超級無敵多，強烈推薦大家去「逛逛」 ，我這篇文章裡面寫的，大概只佔 RailsGuide 的 1/20 而已吧，其他還有關於 middleware, i18n, active_record, action_controller, action_dispatch, action_view, action_mailbox, action_mailer, active_support, active_job, action_cable, active_storage, action_text, database 各種的設定，去看看 Rails 還有哪些奇葩的設定，是一種劉姥姥進大觀園的概念XD，不需要把這些設定記下來、也不需要全部的設定都去理解，大部分的開發者沒事不會需要調這些設定，但當有需求的時候，就會用到這些設定，所以在有需求之前，還是先去了解有哪些設定可以調整，等到了有需求的時候，就知道可以怎麼調、去哪裡找文件來調整

這一篇 RailsGuide 還有另一種用途，就是當作工具書來使用，當有需求要做一些客製化的設定，就來這篇搜尋關鍵字，看有沒有現成的設定可以直接調，不過比較麻煩的是各個設定之間，可能會打架，所以調整設定之前，要仔細看一下說明

那今天就先這樣囉，我們明天見～