The document discusses the modular architecture of Rails, including Railties, Engines, Applications, and Plugins. It explains how these pieces work together through configuration, initialization, generators, and other mechanisms to provide a flexible and extensible framework. Key components like Railtie, Engine, and Application are described in terms of their responsibilities and how they relate to and extend each other.

1. Plug it on!... with
Railties

2. Edgar J. Suárez
['twitter.com','github.com', 'rails.mx'].each do |host|
link_to "#{host}/edgarjs"
end
mail_to "edgar.js@gmail.com"

3. Rail-tie
Rail (HDR) @ sadi-junior / flickr.com

4. .init!
Endeavour launch @ msimdottv / flickr.com

5. rails server

6. script/server
require ‘config/application’
require ‘config/boot’

7. config/boot.rb
Bundler.setup

8. config/application.rb
require ‘rails/all’

9. rails/all.rb
require ‘rails’

10. rails.rb
require ‘pathname’
require ‘active_support’
...
require ‘rails/application’
...

11. rails/application.rb
require ‘rails/railties_path’
require ‘rails/plugin’
require ‘rails/engine’

12. rails/engine.rb
require ‘rails/railtie’

13. rails/railtie.rb
require ‘rails/initializable’
require ‘rails/configuration’

14. rails/configuration.rb
require ‘rails/paths’
require ‘rails/rack’

15. rails/all.rb
require 'rails'
%w(
active_record
action_controller
action_mailer
active_resource
rails/test_unit
).each do |framework|
begin
require "#{framework}/railtie"
rescue LoadError
end
end

16. rails new your_app -O
config/application.rb
require 'rails/all'

17. rails new your_app -O
config/application.rb
require 'rails'
# require 'active_record/railtie'
require 'action_controller/railtie'
require 'action_mailer/railtie'
require 'active_resource/railtie'
require 'rails/test_unit/railtie'

20. Modular origami : the collection so far @ fdecomite / flickr.com

21. Lego Trains @ psd / flickr.com

22. Railtie + Engine +
Application + Plugin
=
MODULAR RAILS

23. Railtie

24. Railtie
Initializers
Configuration
Rake tasks
Generators

25. Initializers
initializer "my_railtie.initialize" do |app|
app.middleware.use MyRailtie::Middleware
end

26. Configuration
config.generators.orm :my_railtie_orm
# Add a to_prepare block which is executed once in
production
# and before which request in development
config.to_prepare do
MyRailtie.setup!
end

27. Rake tasks
rake_tasks do
load "path/to/my_railtie.tasks"
end

28. Generators
generators do
require "path/to/my_railtie_generator"
end

29. Engine < Railtie
Initializers
Configuration
Paths
Rake tasks
Generators

30. Paths
paths.app = "app"
paths.app.controllers = "app/controllers"
paths.app.helpers = "app/helpers"
paths.app.models = "app/models"
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"

31. Application < Engine
Initializers
Configuration
Holds routes
Rake tasks
Builds middleware stack
Generators
Paths

32. config/application.rb
module YourRailsApp
class Application < Rails::Application
end
end

33. Plugin < Engine

34. Plugin
To be continued...
It's so damn Sexy @ picsaremine / flickr.com

35. .init!
Endeavour launch @ msimdottv / flickr.com

36. config/environment.rb
YourApp::Application.initialize!

37. YourApp::Application.initialize!
initializers.each do |initializer|
initializer.run(*args)
end
def initializers
railties.all { |r| initializers += r.initializers }
end
def all(&block)
@all ||= railties + engines + plugins
@all.each(&block) if block
@all
end

38. railties + engines +
plugins
def railties
@railties ||= ::Rails::Railtie.subclasses.map(&:new)
end
def engines
@engines ||= ::Rails::Engine.subclasses.map(&:new)
end
def plugins
@plugins ||= begin
plugin_names = (@config.plugins || [:all]).map { |p| p.to_sym }
Plugin.all(plugin_names, @config.paths.vendor.plugins)
end
end

39. Plugin.all
def self.all(list, paths)
plugins = []
paths.each do |path|
Dir["#{path}/*"].each do |plugin_path|
plugin = new(plugin_path)
next unless list.include?(plugin.name) || list.include?(:all)
plugins << plugin
end
end
plugins.sort_by do |p|
[list.index(p.name) || list.index(:all), p.name.to_s]
end
end

40. Plugin.new
def initialize(root)
@name = File.basename(root).to_sym
config.root = root
end
initializer :load_init_rb, :before => :load_application_initializers do |app|
file = Dir["#{root}/{rails/init,init}.rb"].first
config = app.config
eval(File.read(file), binding, file) if file && File.file?(file)
end

41. How to make your
Railtie

42. # railtie_name/lib/railtie_name/railtie.rb
require 'rails'
module RailtieName
class Railtie < Rails::Railtie
config.some_config = true
initializer "railtie_name.initializating" do |app|
# your initialization here
end
end
end

43. require 'railtie_name/railtie'

44. Demo

45. Thanks!
http://twitter.com/edgarjs
http://github.com/edgarjs
http://rails.mx/edgarjs
http://freshout.us
edgar.js@gmail.com