The Power of Rails 2.3
Engines & Templates
Tse-Ching Ho
2009/03/10

Rails app used to be
rails engines_demo
cd engines_demo
script/generate scaffold product serial_number:string price:float
discount:float quantity:integer name:string remark:string
rake db:migrate
sudo gem install png
script/plugin install git://github.com/toretore/barby.git
script/server

Use Template
rails <app> -m ~/template.rb
rails <app> -m http://gist.github.com/12345.txt
rake rails:template LOCATION=~/template.rb

Commands for Template
plugin(name, options) capify!
gem(name, options = {}) freeze!
rake(command, options = {}) initializer(filename, data = nil, &block)
generate(what, *args) lib(filename, data = nil, &block)
route(routing_code) rakefile(filename, data = nil, &block)
run(command, log_action = true) vendor(filename, data = nil, &block)
git(command = {}) file(filename, data = nil, log_action =
true, &block)
inside(dir = '', &block)
load_template(template)
ask(question)
environment(data = nil, &block)
yes?(question)
gsub_file(relative_destination, regexp,
no?(question) *args, &block)
rails-2.3.0/lib/rails_generator/generators/applications/app/
template_runner.rb

Lessons for Template
hooks related commands of one gem or plugin
groups hooked commands into functional sets
files one set in one template
writes scaffold generation template for
project
combines templates for each project

Start the Engine
script/generate plugin <your-plugin>
cd vendor/plugins/<your-plugin>
mkdir app config db
move codes to your plugin

Issues in Rails 2.3 Gem
App routes.rb not loaded when both engine
and inflections present
Allow ActionMailer to use view_paths from
plugins
Improve view performance in development
and reinstate template reloading in
production
rake rails:freeze:edge
Rake tasks for run engine migrations

Demo

Authlogic_Bundle
http://github.com/
tsechingho/
authlogic_bundle
Engines + template
i18n + authlogic +
open_id_authentication +
declarative_authorization

barcode creator : barby
http://github.com/toretore/barby
created from template
make into engines

Q&A

References
http://guides.rubyonrails.org/2_3_release_notes.html
http://m.onkey.org/2008/12/4/rails-templates
http://railscasts.com/episodes/148-app-templates-in-rails-2-3
http://railscasts.com/episodes/149-rails-engines
http://github.com/pixels-and-bits/strappy/
http://github.com/tsechingho/authlogic_bundle/
http://github.com/jeremymcanally/rails-templates/tree/master
http://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets?
q=engines