COWBOYS & ENGINES

Fernand Galiana

Tuesday, September 17, 13

HISTORY

0.14.2 ~ 2005

2.3 ~ 2009 -- Engine support

3.0 ~ 2010 -- Yehuda and crew

Tuesday, September 17, 13

SURPRISE?

> rails c> Rails::Application.ancestors=> [Rails::Application, Rails::Engine,...]

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IMPETUS?

Mini rails apps [MVC|Assets|lib]

Divide conquer

Reusable components

Decoupling

Performance

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ENGINE TYPES

full

mountable

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CREATE!

> rails plugin new engines/blee [opts]

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NOTABLES...

--full

--mountable

-T

-B

-d [mysql|pg|sqlite3|etc...]

-j [jquery|coffeescript]

-dummy_path

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CREATE!

> rails plugin new engines/cowboy \ --mountable -T -B\ --dummy-path=spec/dummy \ -j coffeescript -d mysql

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TEH BROG!

You rock, bro!

Tuesday, September 17, 13

LAB I

git clone https://github.com/derailed/ng_training

git checkout -b lab_1

follow the README!

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ANATOMY

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STRUCTURE

cowboy_engine o app o bin o config o lib o spec

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STRUCTURE

cowboy_engine o app

o assetso controllerso helperso modelso views

o bin o ...

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STRUCTURE

cowboy_engine o app

o controllerso cowboy_engine

o cowboys_controller.rbo ...

o bin o ...

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ENGINE GEMSPEC

Gem::Specification.new do |s| s.name = "pilgrim" s.version = Pilgrim::VERSION s.authors = ["Fernand"] s.email = ["fernand.galiana@gmail.com"] s.homepage = "http://pilgrim" s.summary = "Pilgrim’s engine" s.description = "Pilgrim’s engine"

s.files = Dir["{app,config,db,lib}/**/*", "MIT-LICENSE", "Rakefile", "README.rdoc"]

s.add_dependency 'rails' , '~> 4.0.0' s.add_dependency 'bootstrap-sass' , '~> 2.3.2.2' s.add_dependency 'font-awesome-sass-rails', '~> 3.0.2.2' s.add_development_dependency "mysql2" , '~> 0.3.13' s.add_development_dependency 'rspec-rails' , '~> 2.14.0' end

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THE ENGINE

module Cowboy class Engine < ::Rails::Engine isolate_namespace config.autoload_paths += [File.join( self.root, %w[lib blee] )] endend

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BUSINESS AS USUAL

rails g [model|controller|migration]

custom generators

engine initializers

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GEMFILE

gem ‘cowboy’, path: ‘engines/cowboy’

my_app/Gemfile

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CONVENIENCE

Cowboy::Engine.root

Cowboy::Engine.helpers

Cowboy::Engine.routes.url_helpers

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MIGRATIONS

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MIGRATIONS

> rake cowboy:install:migrations

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MIGRATIONS

rake db:migrate SCOPE=Cowboy

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MONKEYMIGS!

module Cowboy class Engine < ::Rails::Engine isolate_namespace Cowboy initializer :append_migrations do |app| next if app.root.to_s.match self.root.to_s config.paths["db/migrate"].expanded.each do |expanded_path| app.config.paths["db/migrate"] << expanded_path end end endend

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ISOLATED MODELS

table names expects engine_name_table_name

self.table_name = :guns

or

table_name_prefix = “”

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ROUTING

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engines/cowboy/config/routes.rb

ENGINE ROUTES

Cowboy::Engine.routes.draw do resources :guns, only: [:create] resources :belt do resources :ammos endend

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APP ROUTES

Rango::Application.routes.draw do root 'welcome#index'

mount Cowboy::Engine => '/pilgrim', as: :cowboy_ng resources :jenkins do resources :bullets, controller: 'cowboy/bullets' endend

rango/config/routes.rb

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CONTEXT MATTERS!

Cowboy engine contextguns_path => /gunsmain_app.welcome_path => /welcome

Main Application contextcowboy_ng.guns_path => /pilgrims/gunswelcome_path => /welcome

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my_app/controllers/guns_controller.rb

HELPERS

class GunsController < ApplicationController helper Cowboy::BulletsHelper

...end

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ENGINE ASSETS

stylesheet_link_tag cowboy/guns.css

javascript_include_tag cowboy/guns.js

or

*=require cowboy/guns

//=require cowboy/guns

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PARTIALS

render gun => render partial: ‘cowboy/...’, object: gun

render :partial ‘fred’ => render :partial ‘cowboy/fred’

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LOADING ORDER

config.railties_order = [Cowboy::Engine, :main_app, :all]

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TESTING

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TESTING (RSPEC)

spec/dummy

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TESTING (RSPEC)

config.include Dummy::Application.routes.url_helpers

use_route :cowboy

Tuesday, September 17, 13

LAB II

Scenario: Other models in the system need to be commentable. Spin out this functionality as a new ‘social’ engine

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CHEAT

> rails plugin new engines/social -T --mountable \ -j coffeescript -B -d mysql \ --dummy-path=spec/dummy

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LAB III

Scenario: PM wants a reporting admin ui to track comments. In light of this new feature commenting behavior needs to be shared across several engines.

Refactor social engine to depend on the new common engine

Tuesday, September 17, 13

Q&A

Get a rope?

Tuesday, September 17, 13