railtie、engine和application的confi

railtie的configuration

# frozen_string_literal: true

require "rails/configuration"

module Rails
  class Railtie
    class Configuration
      def initialize
        @@options ||= {}
      end

      # Expose the eager_load_namespaces at "module" level for convenience.
      def self.eager_load_namespaces #:nodoc:
        @@eager_load_namespaces ||= []
      end

      # All namespaces that are eager loaded
      def eager_load_namespaces
        @@eager_load_namespaces ||= []
      end

      # Add files that should be watched for change.
      def watchable_files
        @@watchable_files ||= []
      end

      # Add directories that should be watched for change.
      # The key of the hashes should be directories and the values should
      # be an array of extensions to match in each directory.
      def watchable_dirs
        @@watchable_dirs ||= {}
      end

      # This allows you to modify the application's middlewares from Engines.
      #
      # All operations you run on the app_middleware will be replayed on the
      # application once it is defined and the default_middlewares are
      # created
      def app_middleware
        @@app_middleware ||= Rails::Configuration::MiddlewareStackProxy.new
      end

      # This allows you to modify application's generators from Railties.
      #
      # Values set on app_generators will become defaults for application, unless
      # application overwrites them.
      def app_generators
        @@app_generators ||= Rails::Configuration::Generators.new
        yield(@@app_generators) if block_given?
        @@app_generators
      end

      # First configurable block to run. Called before any initializers are run.
      def before_configuration(&block)
        ActiveSupport.on_load(:before_configuration, yield: true, &block)
      end

      # Third configurable block to run. Does not run if +config.eager_load+
      # set to false.
      def before_eager_load(&block)
        ActiveSupport.on_load(:before_eager_load, yield: true, &block)
      end

      # Second configurable block to run. Called before frameworks initialize.
      def before_initialize(&block)
        ActiveSupport.on_load(:before_initialize, yield: true, &block)
      end

      # Last configurable block to run. Called after frameworks initialize.
      def after_initialize(&block)
        ActiveSupport.on_load(:after_initialize, yield: true, &block)
      end

      # Array of callbacks defined by #to_prepare.
      def to_prepare_blocks
        @@to_prepare_blocks ||= []
      end

      # Defines generic callbacks to run before #after_initialize. Useful for
      # Rails::Railtie subclasses.
      def to_prepare(&blk)
        to_prepare_blocks << blk if blk
      end

      def respond_to?(name, include_private = false)
        super || @@options.key?(name.to_sym)
      end

    private

      def method_missing(name, *args, &blk)
        if name.to_s =~ /=$/
          @@options[$`.to_sym] = args.first
        elsif @@options.key?(name)
          @@options[name]
        else
          super
        end
      end
    end
  end
end

eager_load_namespaces: 需要提前加载的命名空间
watchable_files: 需要被监听到改变的文件
watchable_dirs: 需要被监听到改变的文件夹
app_middleware: 中间件的proxy类
app_generators: app的生成器
before_configuration: 在所有initializers前被执行的block
before_eager_load: 在所有需要被提前加载之前执行的block
before_initialize: 在框架initialize之前被执行的block
after_initialize: 在框架initialize加载后被执行的block
to_prepare_blocks: 需要被执行to_prepare的块
to_prepare: 通用的callbacks再after_initialize之前

engine的configuration

主要都是rails app的应用目录

# frozen_string_literal: true

require "rails/railtie/configuration"

module Rails
  class Engine
    class Configuration < ::Rails::Railtie::Configuration
      attr_reader :root
      attr_accessor :middleware
      attr_writer :eager_load_paths, :autoload_once_paths, :autoload_paths

      def initialize(root = nil)
        super()
        @root = root
        @generators = app_generators.dup
        @middleware = Rails::Configuration::MiddlewareStackProxy.new
      end

      # Holds generators configuration:
      #
      #   config.generators do |g|
      #     g.orm             :data_mapper, migration: true
      #     g.template_engine :haml
      #     g.test_framework  :rspec
      #   end
      #
      # If you want to disable color in console, do:
      #
      #   config.generators.colorize_logging = false
      #
      def generators
        @generators ||= Rails::Configuration::Generators.new
        yield(@generators) if block_given?
        @generators
      end

      def paths
        @paths ||= begin
          paths = Rails::Paths::Root.new(@root)

          paths.add "app",                 eager_load: true, glob: "{*,*/concerns}"
          paths.add "app/assets",          glob: "*"
          paths.add "app/controllers",     eager_load: true
          paths.add "app/channels",        eager_load: true, glob: "**/*_channel.rb"
          paths.add "app/helpers",         eager_load: true
          paths.add "app/models",          eager_load: true
          paths.add "app/mailers",         eager_load: true
          paths.add "app/views"

          paths.add "lib",                 load_path: true
          paths.add "lib/assets",          glob: "*"
          paths.add "lib/tasks",           glob: "**/*.rake"

          paths.add "config"
          paths.add "config/environments", glob: "#{Rails.env}.rb"
          paths.add "config/initializers", glob: "**/*.rb"
          paths.add "config/locales",      glob: "*.{rb,yml}"
          paths.add "config/routes.rb"

          paths.add "db"
          paths.add "db/migrate"
          paths.add "db/seeds.rb"

          paths.add "vendor",              load_path: true
          paths.add "vendor/assets",       glob: "*"

          paths
        end
      end

      def root=(value)
        @root = paths.path = Pathname.new(value).expand_path
      end

      def eager_load_paths
        @eager_load_paths ||= paths.eager_load
      end

      def autoload_once_paths
        @autoload_once_paths ||= paths.autoload_once
      end

      def autoload_paths
        @autoload_paths ||= paths.autoload_paths
      end
    end
  end
end

application的configuration

# frozen_string_literal: true

require "active_support/core_ext/kernel/reporting"
require "active_support/file_update_checker"
require "rails/engine/configuration"
require "rails/source_annotation_extractor"

module Rails
  class Application
    class Configuration < ::Rails::Engine::Configuration
      attr_accessor :allow_concurrency, :asset_host, :autoflush_log,
                    :cache_classes, :cache_store, :consider_all_requests_local, :console,
                    :eager_load, :exceptions_app, :file_watcher, :filter_parameters,
                    :force_ssl, :helpers_paths, :logger, :log_formatter, :log_tags,
                    :railties_order, :relative_url_root, :secret_key_base, :secret_token,
                    :ssl_options, :public_file_server,
                    :session_options, :time_zone, :reload_classes_only_on_change,
                    :beginning_of_week, :filter_redirect, :x, :enable_dependency_loading,
                    :read_encrypted_secrets, :log_level, :content_security_policy_report_only,
                    :content_security_policy_nonce_generator, :require_master_key

      attr_reader :encoding, :api_only, :loaded_config_version

      def initialize(*)
        super
        self.encoding                            = Encoding::UTF_8
        @allow_concurrency                       = nil
        @consider_all_requests_local             = false
        @filter_parameters                       = []
        @filter_redirect                         = []
        @helpers_paths                           = []
        @public_file_server                      = ActiveSupport::OrderedOptions.new
        @public_file_server.enabled              = true
        @public_file_server.index_name           = "index"
        @force_ssl                               = false
        @ssl_options                             = {}
        @session_store                           = nil
        @time_zone                               = "UTC"
        @beginning_of_week                       = :monday
        @log_level                               = :debug
        @generators                              = app_generators
        @cache_store                             = [ :file_store, "#{root}/tmp/cache/" ]
        @railties_order                          = [:all]
        @relative_url_root                       = ENV["RAILS_RELATIVE_URL_ROOT"]
        @reload_classes_only_on_change           = true
        @file_watcher                            = ActiveSupport::FileUpdateChecker
        @exceptions_app                          = nil
        @autoflush_log                           = true
        @log_formatter                           = ActiveSupport::Logger::SimpleFormatter.new
        @eager_load                              = nil
        @secret_token                            = nil
        @secret_key_base                         = nil
        @api_only                                = false
        @debug_exception_response_format         = nil
        @x                                       = Custom.new
        @enable_dependency_loading               = false
        @read_encrypted_secrets                  = false
        @content_security_policy                 = nil
        @content_security_policy_report_only     = false
        @content_security_policy_nonce_generator = nil
        @require_master_key                      = false
        @loaded_config_version                   = nil
      end

      def load_defaults(target_version)
        case target_version.to_s
        when "5.0"
          if respond_to?(:action_controller)
            action_controller.per_form_csrf_tokens = true
            action_controller.forgery_protection_origin_check = true
          end

          ActiveSupport.to_time_preserves_timezone = true

          if respond_to?(:active_record)
            active_record.belongs_to_required_by_default = true
          end

          self.ssl_options = { hsts: { subdomains: true } }
        when "5.1"
          load_defaults "5.0"

          if respond_to?(:assets)
            assets.unknown_asset_fallback = false
          end

          if respond_to?(:action_view)
            action_view.form_with_generates_remote_forms = true
          end
        when "5.2"
          load_defaults "5.1"

          if respond_to?(:active_record)
            active_record.cache_versioning = true
            # Remove the temporary load hook from SQLite3Adapter when this is removed
            ActiveSupport.on_load(:active_record_sqlite3adapter) do
              ActiveRecord::ConnectionAdapters::SQLite3Adapter.represent_boolean_as_integer = true
            end
          end

          if respond_to?(:action_dispatch)
            action_dispatch.use_authenticated_cookie_encryption = true
          end

          if respond_to?(:active_support)
            active_support.use_authenticated_message_encryption = true
            active_support.use_sha1_digests = true
          end

          if respond_to?(:action_controller)
            action_controller.default_protect_from_forgery = true
          end

          if respond_to?(:action_view)
            action_view.form_with_generates_ids = true
          end
        else
          raise "Unknown version #{target_version.to_s.inspect}"
        end

        @loaded_config_version = target_version
      end

      def encoding=(value)
        @encoding = value
        silence_warnings do
          Encoding.default_external = value
          Encoding.default_internal = value
        end
      end

      def api_only=(value)
        @api_only = value
        generators.api_only = value

        @debug_exception_response_format ||= :api
      end

      def debug_exception_response_format
        @debug_exception_response_format || :default
      end

      def debug_exception_response_format=(value)
        @debug_exception_response_format = value
      end

      def paths
        @paths ||= begin
          paths = super
          paths.add "config/database",    with: "config/database.yml"
          paths.add "config/secrets",     with: "config", glob: "secrets.yml{,.enc}"
          paths.add "config/environment", with: "config/environment.rb"
          paths.add "lib/templates"
          paths.add "log",                with: "log/#{Rails.env}.log"
          paths.add "public"
          paths.add "public/javascripts"
          paths.add "public/stylesheets"
          paths.add "tmp"
          paths
        end
      end

      # Loads and returns the entire raw configuration of database from
      # values stored in <tt>config/database.yml</tt>.
      def database_configuration
        path = paths["config/database"].existent.first
        yaml = Pathname.new(path) if path

        config = if yaml && yaml.exist?
          require "yaml"
          require "erb"
          loaded_yaml = YAML.load(ERB.new(yaml.read).result) || {}
          shared = loaded_yaml.delete("shared")
          if shared
            loaded_yaml.each do |_k, values|
              values.reverse_merge!(shared)
            end
          end
          Hash.new(shared).merge(loaded_yaml)
        elsif ENV["DATABASE_URL"]
          # Value from ENV['DATABASE_URL'] is set to default database connection
          # by Active Record.
          {}
        else
          raise "Could not load database configuration. No such file - #{paths["config/database"].instance_variable_get(:@paths)}"
        end

        config
      rescue Psych::SyntaxError => e
        raise "YAML syntax error occurred while parsing #{paths["config/database"].first}. " \
              "Please note that YAML must be consistently indented using spaces. Tabs are not allowed. " \
              "Error: #{e.message}"
      rescue => e
        raise e, "Cannot load `Rails.application.database_configuration`:\n#{e.message}", e.backtrace
      end

      def colorize_logging
        ActiveSupport::LogSubscriber.colorize_logging
      end

      def colorize_logging=(val)
        ActiveSupport::LogSubscriber.colorize_logging = val
        generators.colorize_logging = val
      end

      def session_store(new_session_store = nil, **options)
        if new_session_store
          if new_session_store == :active_record_store
            begin
              ActionDispatch::Session::ActiveRecordStore
            rescue NameError
              raise "`ActiveRecord::SessionStore` is extracted out of Rails into a gem. " \
                "Please add `activerecord-session_store` to your Gemfile to use it."
            end
          end

          @session_store = new_session_store
          @session_options = options || {}
        else
          case @session_store
          when :disabled
            nil
          when :active_record_store
            ActionDispatch::Session::ActiveRecordStore
          when Symbol
            ActionDispatch::Session.const_get(@session_store.to_s.camelize)
          else
            @session_store
          end
        end
      end

      def session_store? #:nodoc:
        @session_store
      end

      def annotations
        SourceAnnotationExtractor::Annotation
      end

      def content_security_policy(&block)
        if block_given?
          @content_security_policy = ActionDispatch::ContentSecurityPolicy.new(&block)
        else
          @content_security_policy
        end
      end

      class Custom #:nodoc:
        def initialize
          @configurations = Hash.new
        end

        def method_missing(method, *args)
          if method =~ /=$/
            @configurations[$`.to_sym] = args.first
          else
            @configurations.fetch(method) {
              @configurations[method] = ActiveSupport::OrderedOptions.new
            }
          end
        end

        def respond_to_missing?(symbol, *)
          true
        end
      end
    end
  end
end

load_defaults: 根据rails的目标版本做一些配置
api_only=: 设置api_only
debug_exception_response_format、debug_exception_response_format=：异常相应格式
database_configuration: 加载数据库的原始配置 database.yml
colorize_logging: 日志设置colorize
session_store session_store?: session的存储 是否设置了session_store
content_security_policy: 内容加密协议