Engines

COWBOYS & ENGINES

Fernand Galiana

Tuesday, September 17, 13

HISTORY

0.14.2 ~ 2005

2.3 ~ 2009 -- Engine support

3.0 ~ 2010 -- Yehuda and crew


SURPRISE?

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


IMPETUS?

Mini rails apps [MVC|Assets|lib]

Divide conquer

Reusable components

Decoupling

Performance


ENGINE TYPES

full

mountable


CREATE!

> rails plugin new engines/blee [opts]


NOTABLES...

--full

--mountable

-T

-B

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

-j [jquery|coffeescript]

-dummy_path


CREATE!

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


TEH BROG!

You rock, bro!


LAB I

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

git checkout -b lab_1

follow the README!


https://github.com/derailed/ng_training

https://github.com/derailed/ng_training

ANATOMY


STRUCTURE

cowboy_engine o app o bin o config o lib o spec


STRUCTURE

cowboy_engine o app

o assetso controllerso helperso modelso views

o bin o ...


STRUCTURE

cowboy_engine o app

o controllerso cowboy_engine

o cowboys_controller.rbo ...

o bin o ...


ENGINE GEMSPEC

Gem::Specification.new do |s| s.name = "pilgrim" s.version = Pilgrim::VERSION s.authors = ["Fernand"] s.email = ["[email protected]"] 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


THE ENGINE

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


BUSINESS AS USUAL

rails g [model|controller|migration]

custom generators

engine initializers


GEMFILE

gem ‘cowboy’, path: ‘engines/cowboy’

my_app/Gemfile


CONVENIENCE

Cowboy::Engine.root

Cowboy::Engine.helpers

Cowboy::Engine.routes.url_helpers


MIGRATIONS


MIGRATIONS

> rake cowboy:install:migrations


MIGRATIONS

rake db:migrate SCOPE=Cowboy


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


ISOLATED MODELS

table names expects engine_name_table_name

self.table_name = :guns

or

table_name_prefix = “”


ROUTING


engines/cowboy/config/routes.rb

ENGINE ROUTES

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


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


CONTEXT MATTERS!

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

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


my_app/controllers/guns_controller.rb

HELPERS

class GunsController < ApplicationController helper Cowboy::BulletsHelper

...end


ENGINE ASSETS

stylesheet_link_tag cowboy/guns.css

javascript_include_tag cowboy/guns.js

or

*=require cowboy/guns

//=require cowboy/guns


PARTIALS

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

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


LOADING ORDER

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


TESTING


TESTING (RSPEC)

spec/dummy


TESTING (RSPEC)

config.include Dummy::Application.routes.url_helpers

use_route :cowboy


LAB II

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


CHEAT

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


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


Q&A

Get a rope?


Engines

Technology

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