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201 lines
6 KiB
Ruby
201 lines
6 KiB
Ruby
require 'rails/initializable'
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require 'rails/configuration'
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require 'active_support/inflector'
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require 'active_support/core_ext/module/introspection'
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module Rails
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# Railtie is the core of the Rails framework and provides several hooks to extend
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# Rails and/or modify the initialization process.
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#
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# Every major component of Rails (Action Mailer, Action Controller,
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# Action View, Active Record and Active Resource) is a Railtie. Each of
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# them is responsible for their own initialization. This makes Rails itself
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# absent of any component hooks, allowing other components to be used in
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# place of any of the Rails defaults.
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#
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# Developing a Rails extension does _not_ require any implementation of
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# Railtie, but if you need to interact with the Rails framework during
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# or after boot, then Railtie is needed.
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#
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# For example, an extension doing any of the following would require Railtie:
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#
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# * creating initializers
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# * configuring a Rails framework for the application, like setting a generator
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# * adding config.* keys to the environment
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# * setting up a subscriber with ActiveSupport::Notifications
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# * adding rake tasks
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#
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# == Creating your Railtie
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#
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# To extend Rails using Railtie, create a Railtie class which inherits
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# from Rails::Railtie within your extension's namespace. This class must be
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# loaded during the Rails boot process.
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#
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# The following example demonstrates an extension which can be used with or without Rails.
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#
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# # lib/my_gem/railtie.rb
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# module MyGem
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# class Railtie < Rails::Railtie
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# end
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# end
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#
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# # lib/my_gem.rb
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# require 'my_gem/railtie' if defined?(Rails)
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#
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# == Initializers
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#
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# To add an initialization step from your Railtie to Rails boot process, you just need
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# to create an initializer block:
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#
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# class MyRailtie < Rails::Railtie
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# initializer "my_railtie.configure_rails_initialization" do
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# # some initialization behavior
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# end
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# end
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#
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# If specified, the block can also receive the application object, in case you
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# need to access some application specific configuration, like middleware:
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#
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# class MyRailtie < Rails::Railtie
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# initializer "my_railtie.configure_rails_initialization" do |app|
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# app.middleware.use MyRailtie::Middleware
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# end
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# end
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#
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# Finally, you can also pass :before and :after as option to initializer, in case
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# you want to couple it with a specific step in the initialization process.
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#
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# == Configuration
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#
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# Inside the Railtie class, you can access a config object which contains configuration
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# shared by all railties and the application:
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#
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# class MyRailtie < Rails::Railtie
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# # Customize the ORM
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# config.app_generators.orm :my_railtie_orm
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#
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# # Add a to_prepare block which is executed once in production
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# # and before each request in development
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# config.to_prepare do
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# MyRailtie.setup!
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# end
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# end
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#
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# == Loading rake tasks and generators
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#
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# If your railtie has rake tasks, you can tell Rails to load them through the method
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# rake_tasks:
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#
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# class MyRailtie < Rails::Railtie
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# rake_tasks do
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# load "path/to/my_railtie.tasks"
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# end
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# end
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#
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# By default, Rails load generators from your load path. However, if you want to place
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# your generators at a different location, you can specify in your Railtie a block which
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# will load them during normal generators lookup:
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#
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# class MyRailtie < Rails::Railtie
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# generators do
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# require "path/to/my_railtie_generator"
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# end
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# end
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#
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# == Application, Plugin and Engine
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#
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# A Rails::Engine is nothing more than a Railtie with some initializers already set.
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# And since Rails::Application and Rails::Plugin are engines, the same configuration
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# described here can be used in all three.
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#
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# Be sure to look at the documentation of those specific classes for more information.
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#
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class Railtie
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autoload :Configurable, "rails/railtie/configurable"
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autoload :Configuration, "rails/railtie/configuration"
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include Initializable
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ABSTRACT_RAILTIES = %w(Rails::Railtie Rails::Plugin Rails::Engine Rails::Application)
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class << self
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private :new
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def subclasses
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@subclasses ||= []
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end
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def inherited(base)
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unless base.abstract_railtie?
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base.send(:include, Railtie::Configurable)
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subclasses << base
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end
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end
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def rake_tasks(&blk)
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@rake_tasks ||= []
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@rake_tasks << blk if blk
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@rake_tasks
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end
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def console(&blk)
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@load_console ||= []
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@load_console << blk if blk
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@load_console
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end
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def generators(&blk)
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@generators ||= []
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@generators << blk if blk
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@generators
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end
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def abstract_railtie?
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ABSTRACT_RAILTIES.include?(name)
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end
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def railtie_name(name = nil)
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@railtie_name = name.to_s if name
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@railtie_name ||= generate_railtie_name(self.name)
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end
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protected
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def generate_railtie_name(class_or_module)
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ActiveSupport::Inflector.underscore(class_or_module).gsub("/", "_")
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end
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end
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delegate :railtie_name, :to => "self.class"
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def config
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@config ||= Railtie::Configuration.new
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end
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def eager_load!
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end
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def load_console(app)
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self.class.console.each { |block| block.call(app) }
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end
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def load_tasks(app)
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extend Rake::DSL if defined? Rake::DSL
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self.class.rake_tasks.each { |block| block.call(app) }
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# load also tasks from all superclasses
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klass = self.class.superclass
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while klass.respond_to?(:rake_tasks)
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klass.rake_tasks.each { |t| self.instance_exec(app, &t) }
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klass = klass.superclass
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end
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end
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def load_generators(app)
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self.class.generators.each { |block| block.call(app) }
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end
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def railtie_namespace
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@railtie_namespace ||= self.class.parents.detect { |n| n.respond_to?(:_railtie) }
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end
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end
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end
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