The Rails Engine That Could

A lightning talk delivered at BostonRB outlining our experiences with developing a Rails engine.

Transcript

1. The Rails Engine That Could? Saturday, April 28, 2012
2. Hi! dpickett on Twitter www.launchware.com on the InterTubes Hiring Saturday, April 28, 2012
3. • A Brief History • A Rails Engine In Rails 3.1 • Implementation Gotchas • Deployment Gotchas With Heroku • Conclusions What I Can Tell You About Rails Engines Saturday, April 28, 2012
4. • Components in Rails Beta and Rails 1 • Components removed in Rails 2 Out With The Old... Saturday, April 28, 2012
5. ...In With the New • Engines in Rails 3 • Enginex as part of Rails 3.1 Saturday, April 28, 2012
6. Generating rails generate plugin thomas --mountable Saturday, April 28, 2012
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9. Manage Dependencies In Your Gemspec Shift Your Perspective Saturday, April 28, 2012
10. Shifting Perspectives • Think like an API designer • Favor composition over inheritance • Obey SOLID principles for more maintainable code Saturday, April 28, 2012
11. Maintain Perspective • Do as you would normally: • Write migrations • Seed data • Run rake tasks • Run generators Saturday, April 28, 2012
12. Gotchas Saturday, April 28, 2012
13. Routes • Routes are loaded where you mount them • Only one opportunity for placement • No flexibility to divide up routes for fine tuning priorities Saturday, April 28, 2012
14. Namespacing • Namespace Your Engine - it will save you lots of pain. • If you must in your consuming application, use ActiveSupport’s require_dependency to override: require_dependency Thomas::Engine.root.join(“app/models/user”).to_s class User < ActiveRecord::Base #override the engine here end Saturday, April 28, 2012
15. Routes • Routes are loaded where you mount them • Only one opportunity for placement • No flexibility to divide up routes for fine tuning priorities Saturday, April 28, 2012
16. Consumer::Application do Thomas::Routes::UserRoutes.draw(self) #custom routes here Thomas::Routes::ScheduleRoutes.draw(self) end module Thomas module Routes module UserRoutes def self.draw(map) map.instance_eval do resources :user... end end end end end Saturday, April 28, 2012
17. Named Routes Helpers • If you don’t namespace, I found these to be incredibly problematic • You must include helpers in your application controller and in your request specs/tests Saturday, April 28, 2012
18. class ApplicationController < ActionController::Base include Thomas::Engine.routes.url_helpers include ActionDispatch::Routing::PolymorphicRoutes end You’ll use these two lines a lot. Apply when you get an undefined *_path or *_url method Saturday, April 28, 2012
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20. Devise • Wiring I18n load paths is deferred until the app comes up, disallowing override ability Saturday, April 28, 2012
21. class Thomas::Engine < Rails::Engine config.after_initialize do Rails.application.config.after_initialize do paths = I18n.load_path.delete_if do |p| p =~ /devise\-/ end #put devise’s default locales in its place I18n.load_path = paths + I18n.load_path I18n.reload! end end Saturday, April 28, 2012
22. Inherited Resources And Responders Doesn’t Work Drops Your Responder Saturday, April 28, 2012
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24. Wrong Thomas... ...Go B’s Saturday, April 28, 2012
25. class ApplicationController < ActionController::Base def self.engine_inherit_resources inherit_resources self.responder = MobileResponder end end end Saturday, April 28, 2012
26. Deploying Private Gems To Heroku • Bundle with your github credentials in plaintext • Maintain your own gem server • Write a rake task to vendor the gem and commit when deploying • NEW: http://www.gemfury.com/ Saturday, April 28, 2012
27. Overall, Engines Are Great • There’s still room for improvement, but they’re awesome once you get going • They will challenge you as a developer and as a Rails Framework user Saturday, April 28, 2012
28. Thanks! • I’ll post slides @ www.launchware.com • Chat me up on Twitter: @dpickett • Chat me up on IRC: dpickett in #boston.rb • We’re hiring! Saturday, April 28, 2012