require 'rails/railtie' require 'active_support/core_ext/module/delegation' require 'pathname' module Rails # Rails::Engine allows you to wrap a specific Rails application and share it accross # different applications. Since Rails 3.0, every Rails::Application is nothing # more than an Engine, allowing you to share it very easily. # # Any Rails::Engine is also a Rails::Railtie, so the same methods (like rake_tasks and # generators) and configuration available in the latter can also be used in the former. # # == Creating an Engine # # In Rails versions before to 3.0, your gems automatically behaved as Engine, however # this coupled Rails to Rubygems. Since Rails 3.0, if you want a gem to automatically # behave as Engine, you have to specify an Engine for it somewhere inside your plugin # lib folder (similar with how we spceify a Railtie): # # # lib/my_engine.rb # module MyEngine # class Engine < Rails::Engine # engine_name :my_engine # end # end # # Then ensure that this file is loaded at the top of your config/application.rb (or in # your Gemfile) and it will automatically load models, controllers, helpers and metals # inside app, load routes at "config/routes.rb", load locales at "config/locales/*", # load tasks at "lib/tasks/*". # # == Configuration # # Besides the Railtie configuration which is shared across the application, in a # Rails::Engine you can access load_paths, eager_load_paths and load_once_paths, # which differently from a Railtie, are scoped to the current Engine. # # Example: # # class MyEngine < Rails::Engine # # config.middleware is shared configururation # config.middleware.use MyEngine::Middleware # # # Add a load path for this specific Engine # config.load_paths << File.expand_path("../lib/some/path", __FILE__) # end # # == Paths # # Since Rails 3.0, both your Application and Engines do not have hardcoded paths. # This means that you are not required to place your controllers at "app/controllers", # but in any place which you find convenient. # # For example, let's suppose you want to lay your controllers at lib/controllers, all # you need to do is: # # class MyEngine < Rails::Engine # paths.app.controllers = "lib/controllers" # end # # You can also have your controllers being loaded from both "app/controllers" and # "lib/controllers": # # class MyEngine < Rails::Engine # paths.app.controllers << "lib/controllers" # end # # The available paths in an Engine are: # # class MyEngine < Rails::Engine # paths.app = "app" # paths.app.controllers = "app/controllers" # paths.app.helpers = "app/helpers" # paths.app.models = "app/models" # paths.app.metals = "app/metal" # paths.app.views = "app/views" # paths.lib = "lib" # paths.lib.tasks = "lib/tasks" # paths.config = "config" # paths.config.initializers = "config/initializers" # paths.config.locales = "config/locales" # paths.config.routes = "config/routes.rb" # end # # Your Application class adds a couple more paths to this set. And as in your Application, # all folders under "app" are automatically added to the load path. So if you have # "app/observers", it's added by default. # class Engine < Railtie autoload :Configurable, "rails/engine/configurable" autoload :Configuration, "rails/engine/configuration" class << self attr_accessor :called_from # TODO Remove this. It's deprecated. alias :engine_name :railtie_name def inherited(base) unless base.abstract_railtie? base.called_from = begin # Remove the line number from backtraces making sure we don't leave anything behind call_stack = caller.map { |p| p.split(':')[0..-2].join(':') } File.dirname(call_stack.detect { |p| p !~ %r[railties[\w\-\.]*/lib/rails|rack[\w\-\.]*/lib/rack] }) end end super end def find_root_with_flag(flag, default=nil) root_path = self.called_from while root_path && File.directory?(root_path) && !File.exist?("#{root_path}/#{flag}") parent = File.dirname(root_path) root_path = parent != root_path && parent end root = File.exist?("#{root_path}/#{flag}") ? root_path : default raise "Could not find root path for #{self}" unless root RUBY_PLATFORM =~ /(:?mswin|mingw)/ ? Pathname.new(root).expand_path : Pathname.new(root).realpath end end delegate :middleware, :paths, :root, :to => :config def load_tasks super config.paths.lib.tasks.to_a.sort.each { |ext| load(ext) } end # Add configured load paths to ruby load paths and remove duplicates. initializer :set_load_path, :before => :bootstrap_load_path do config.load_paths.reverse_each do |path| $LOAD_PATH.unshift(path) if File.directory?(path) end $LOAD_PATH.uniq! end # Set the paths from which Rails will automatically load source files, # and the load_once paths. initializer :set_autoload_paths, :before => :bootstrap_load_path do |app| ActiveSupport::Dependencies.load_paths.unshift(*config.load_paths) if reloadable?(app) ActiveSupport::Dependencies.load_once_paths.unshift(*config.load_once_paths) else ActiveSupport::Dependencies.load_once_paths.unshift(*config.load_paths) end # Freeze so future modifications will fail rather than do nothing mysteriously config.load_paths.freeze config.load_once_paths.freeze end initializer :add_routing_paths do |app| paths.config.routes.to_a.each do |route| app.routes_reloader.paths.unshift(route) if File.exists?(route) end end # DEPRECATED: Remove in 3.1 initializer :add_routing_namespaces do |app| paths.app.controllers.to_a.each do |load_path| load_path = File.expand_path(load_path) Dir["#{load_path}/*/**/*_controller.rb"].collect do |path| namespace = File.dirname(path).sub(/#{load_path}\/?/, '') app.routes.controller_namespaces << namespace unless namespace.empty? end end end # I18n load paths are a special case since the ones added # later have higher priority. initializer :add_locales do config.i18n.railties_load_path.concat(paths.config.locales.to_a) end initializer :add_view_paths do views = paths.app.views.to_a ActionController.base_hook { prepend_view_path(views) } if defined?(ActionController) ActionMailer.base_hook { prepend_view_path(views) } if defined?(ActionMailer) end initializer :add_metals do |app| app.metal_loader.paths.unshift(*paths.app.metals.to_a) end initializer :add_generator_templates do |app| config.generators.templates.unshift(*paths.lib.templates.to_a) end initializer :load_application_initializers do paths.config.initializers.to_a.sort.each do |initializer| load(initializer) end end initializer :load_application_classes do |app| next if $rails_rake_task if app.config.cache_classes config.eager_load_paths.each do |load_path| matcher = /\A#{Regexp.escape(load_path)}\/(.*)\.rb\Z/ Dir.glob("#{load_path}/**/*.rb").sort.each do |file| require_dependency file.sub(matcher, '\1') end end end end protected def reloadable?(app) app.config.reload_engines end end end