Rails Mountable Engine*
*plus some cat crazyness
Bartłomiej Skwira
I work in Amberbit
..and we make... oh.... that's the old logo ;)
*sth didn't work out
..again... I work in Amberbit
..and we make internetZ using: Ruby, Rails, Angular, CoffeeScript, HAML/Slim, SCSS etc...
Find us @ http://www.amberbit.com
Agenda:
- Waaaaat is it?
- How we can do that?
- Some innards
- ????????
- PROFIT
What is it?
- A mini app that enhances a host app
- ..so a plugin? => yeap
- Examples: Devise, Rails (Engine on steroids!)
- Requirements: Rails >= 3.1.0rc5
- *Can be distributed as a gem
What can we do in the engine?
- create controllers/models/views/helpers/mailers etc (namespace!)
- generators work and namespace by default
- customize engine's routes in config/routes.rb
- add gem dependencies, assets, initializers, locales, rake tasks etc
- TEST IT !
- use rails console (in the dummy app :P) => namespace!
New feature in Rails 3.2.36 - judo cat
How
$ rails plugin new brug --mountable
create
create README.rdoc
create Rakefile
create brug.gemspec
create MIT-LICENSE
create .gitignore
create Gemfile
create app
create app/controllers/brug/application_controller.rb
create app/helpers/brug/application_helper.rb
create app/mailers
create app/models
create app/views/layouts/brug/application.html.erb
create app/assets/images/brug
create app/assets/images/brug/.keep
create config/routes.rb
create lib/brug.rb
create lib/tasks/brug_tasks.rake
create lib/brug/version.rb
create lib/brug/engine.rb
create app/assets/stylesheets/brug/application.css
create app/assets/javascripts/brug/application.js
create bin
create bin/rails
create test/test_helper.rb
create test/brug_test.rb
append Rakefile
create test/integration/navigation_test.rb
vendor_app test/dummy
run bundle install
What did we get?
Namespaces, namespaces everywhere !!!1
module Brug
class ApplicationController < ActionController::Base
end
end
#also assets
engine.rb - add configs here
module Brug
class Engine < ::Rails::Engine
isolate_namespace Brug
end
end
Testing?
A dummy Rails App
*Inception FTW!
RSpec + FactoryGirl
$ rails plugin new brug -T --mountable --full --dummy-path=spec/test_app
#T - skip Test::Unit
#--full tells the generator that you want app and config directories
#Gemfile
source "http://rubygems.org"
gemspec
gem "rspec-rails", "~> 2.12.2"
gem "factory_girl_rails", "~> 4.0"
#engine.rb
module Brug
class Engine < ::Rails::Engine
isolate_namespace GemName
config.generators do |g|
g.test_framework :rspec
g.fixture_replacement :factory_girl, :dir => 'spec/factories'
end
end
end
$rails generate rspec:install
Mounting the engine in routes.rb
#brug/test/dummy/config/routes.rb
Rails.application.routes.draw do
mount Brug::Engine => "/brug" #any path here
#add this line to README of your engine/gem
end
Migrations
In the engine:
$ rake db:migrate
In the mounting app:
#migrations are copied to the app
$ rake brug:install:migrations
Load seed data
Brug::Engine.load_seed
Routing....
...The Cat Way
Routing....
...The Mountable Engine Way
In the Engine
#engine path
root_url
#mounting app path
main_app.root_url
In the mounting app:
#config/routes.rb
mount Brug::Engine => "/brug", as: 'brug_engine'
brug_engine.root_url
Hooking the engine in the app....
...The Cat Way
Hooking the engine in the app....
...The Mountable Engine Way
Locally
#Gemfile
gem 'brug', path: "/workspace/.../hidden_porn_dir/.../brug
#run bundle install
#routes.rb
mount Brug::Engine => "/brug"
Other goodnes we can do?
- use a model/controller provided by the app
- make the used model configurable => use mattr_acessor
- override models, views and controllers
- add gem dependencies via .gemspec
Haml? sure!
#engine.rb
config.generators.do |g|
g.template_engine :haml
end
Middleware stack
module MyEngine
class Engine < Rails::Engine
middleware.use SomeMiddleware
end
end
Engine helpers in the app
class ApplicationController < ActionController::Base
#1 selected
helper MyEngine::SharedEngineHelper
#all of them
helper MyEngine::Engine.helpers
end
Resources
Questions?
