rails_engines_talk

controller_to_be_included.rb

# example take from 
# https://github.com/schneems/wicked/blob/40443aea2aba0fe506b9c878fb677f08f2114200/lib/wicked/wizard.rb

require 'active_support/concerns'

module FooBar::Concerns::Controllers::OneController
	extend ActiveSupport::Concerns

	# controller level methods associated with a Rails-route and View
	# IE, the controller structure
	def add
	end

	def subtract
	end

	def mutliply
	end

	def divide
	end

	# Non Rails-route methods used in the controller methods
	# for route actions, EG: rendering, redirecting, paths, etc.
	# IE, the controller guts
	# 
	# NOTE - these files are not included since it's simple to see
	#        how they would fit into the file/code structure.
	# 
	include FooBar::Concerns::Controllers::OneController::Render
	include FooBar::Concerns::Controllers::OneController::Redirect
	include FooBar::Concerns::Controllers::OneController::Path

	# First check out this link,
	# http://www.ruby-doc.org/core-1.9.3/Module.html#method-i-included
	# 
	# The 'included do' uses the methods within it's block any time
	# the 'included do' methods are callled within the MyApp Rails
	# application. In other words, 'included do' links method calls in the
	# Rails application to the method definitions within the Rails Egnine.
	include do
		helper_method :foo_bar_render, :foo_bar_redirect, :foo_bar_path
		before_filter :foo_bar_setup
	end

	private
	def foo_bar_setup
	end

	public
end

draft_outline.md

Transforming rails plugins into rails engines

introduction

briefly cover reasons why plugins and engines are useful

models - active_record relationships models+controllers - authentications - devise views

what are plugins? rails 2.3 style plugins

probably seen this message,

You have Rails 2.3-style plugins in vendor/plugins! Support for these plugins will be removed in Rails 4.0. Move them out and bundle them in your Gemfile, or fold them in to your app as lib/myplugin/* and config/initializers/myplugin.rb. See the release notes for more on this: http://weblog.rubyonrails.org/2012/1/4/rails-3-2-0-rc2-has-been-released

++ need to better describe the structure of plugins
++ need to better describe how Rails 2.3 plugins are loaded within rails

console message and blog post
-- how to turn off the deprecation warning

what are rails engines?

types [mountable, full] core structural components integration with rails

++ note how plugins and engines differ

transformation process with questionnaire_engine

core changes

implemented an isolated namespace
lib/qe/engine.rb

gemspec
++ need to verify gemspec dependencies

models and controllers

we wanted to leverage Ruby Mixins rather than open classing - to more explicitly control engine classes and MainApp class interconnectivity. therefore, ActiveSupport::Concern

views

assets

javascripts
stylesheets
images

++ can you precompile these in the gem?

testing framework

spec/dummy
RSpec configurations
testing tools

put some code here

model_to_be_included.rb

require 'active_support/concerns'

module FooBar::Concerns::Models::One 
	extend ActiveSupport::Concerns

	# HOW TO INCLUDE ACTIVE RECORD ASSOCIATIONS WITHIN MODULES THAT
	# ARE CLASS X < ACITVERECORD::BASE
	# 
	# http://my.safaribooksonline.com/book/web-development/ruby/9780132480345/advanced-active-record/ch09lev1sec10
	# the 'included do' serves as a callback to the module class (IE module One)
	# such that when the module is included in the class 
	# (IE, class SomeClass < ActiveRecord::Base), the module's 
	# 'has_many :child_objects' and 'belongs_to :parent_object' will be executed
	# within the ActiveRecord::Base context rather than this module's context, 
	# which does have have class definitions for 'has_many' and 'belongs_to'.

	included do
		has_many :child_objects
		belongs_to :parent_objects
	end

	# methods in the module are Instance Methods
	def model_methods_treated_as_instance_methods
	end

end

rails_engines.md

Gist to describe the process of adding a namespaced isolated Rails Engine
to a typical Rails application and adding methods to one of the Rails Engine's
controller and model.

Index

1. Rails applicaiton all by itself.
2. Rails application with the Rails Engine (FooBar) mounted.
3. Rails applicaiton partially extending a controller/model from the Rails Engine.

1. Rails application all by itself

MyApp
 |--- controllers
 |             |--- a_controller.rb
 |             |--- b_controller.rb
 |             |--- c_controller.rb
 |
 |-------- models
 |             |--- a.rb
 |             |--- b.rb
 |             |--- c.rb
 |
 |-------- ... and other rails folders

2. Rails applicaiton with the Rails Engine (FooBar) mounted

MyApp
 |--- controllers
 |             |--- a_controller.rb
 |             |--- b_controller.rb
 |             |--- c_controller.rb
 |
 |-------- models
 |             |--- a.rb
 |             |--- b.rb
 |             |--- c.rb             
 |
 |---- config
 |       |---- application.rb ( require 'foobar' )
 |       |---- routes.rb ( mount FooBar::Engine. :at => '/foobar' )
 |
 |-------- Gemfile ... gem 'foo_bar'
 |
 |-------- ... and other rails folders


FooBar
    |--- app
    |     |--- controllers
    |     |           |--- one_controller.rb ( include FooBar::Concerns::Controllers::OneController )
    |     |           |--- two_controller.rb ( include FooBar::Concerns::Controllers::TwoController )
    |     |
    |     |-------- models
    |     |           |--- one.rb ( include FooBar::Concerns::Models::One )
    |     |           |--- two.rb ( include FooBar::Concerns::Models::Two )
    |     |--- views
    |             |--- one
    |             |     |--- add.html.erb
    |             |     |--- subtract.html.erb
    |             |     |--- multiply.html.erb
    |             |     |--- divide.html.erb
    |             |
    |             |--- two
    |                   |--- add.html.erb
    |                   |--- subtract.html.erb
    |                   |--- multiply.html.erb
    |                   |--- divide.html.erb    
    |             
    |---- lib
           |--- foo_bar.rb
           |--- foo_bar
                     |--- engine.rb
                     |--- cocnerns
                             |--- controllers
                             |           |--- one_controller.rb ( within file, extend ActiveSupport::Concern )
                             |           |--- two_controller.rb ( within file, extend ActiveSupport::Concern )
                             | 
                             |-------- models
                                         |--- one.rb ( within file, extend ActiveSupport::Concern )
                                         |--- two.rb ( within file, extend ActiveSupport::Concern ) 

3. Rails application partially extending a controller/model from the Rails Engine.

We want to add a rails engine (FooBar) and expand the functionality of the

• FooBar::Concerns::Controllers::OnesController in a_controller.rb
• FooBar::Concerns::Models::One in a.rb

MyApp
 |--- controllers
 |             |--- a_controller.rb ( include FooBar::Concerns::Controllers::OnesController )
 |             |--- b_controller.rb
 |             |--- c_controller.rb
 |
 |-------- models
 |             |--- a.rb ( include FooBar::Concerns::Models::One )
 |             |--- b.rb
 |             |--- c.rb             
 |
 |---- config
 |       |---- application.rb ( require 'foobar' )
 |       |---- routes.rb ( mount FooBar::Engine. :at => '/foobar' )
 |
 |-------- Gemfile ... gem 'foo_bar'
 |
 |-------- ... and other rails folders


FooBar
    |--- app
    |     |--- controllers
    |     |           |--- one_controller.rb ( include FooBar::Concerns::Controllers::OneController )
    |     |           |--- two_controller.rb ( include FooBar::Concerns::Controllers::TwoController )
    |     |
    |     |-------- models
    |     |           |--- one.rb ( include FooBar::Concerns::Models::One )
    |     |           |--- two.rb ( include FooBar::Concerns;:Models::Two )
    |     |--- views
    |             |--- one
    |             |     |--- add.html.erb
    |             |     |--- subtract.html.erb
    |             |     |--- multiply.html.erb
    |             |     |--- divide.html.erb
    |             |
    |             |--- two
    |                   |--- add.html.erb
    |                   |--- subtract.html.erb
    |                   |--- multiply.html.erb
    |                   |--- divide.html.erb    
    |             
    |---- lib
           |--- foo_bar.rb
           |--- foo_bar
                     |--- engine.rb
                     |--- concerns
                             |--- controllers
                             |           |--- one_controller.rb ( within file, extend ActiveSupport::Concern )
                             |           |--- two_controller.rb ( within file, extend ActiveSupport::Concern )
                             | 
                             |-------- models
                                         |--- one.rb ( within file, extend ActiveSupport::Concern )
                                         |--- two.rb ( within file, extend ActiveSupport::Concern )