This document summarizes new features in Rails 4.1, including Spring preloading to reduce app boot time, storing API keys securely in secrets.yml, using ActiveRecord enums to define state columns, generating signed tokens with ApplicationMessageVerifier, rendering device-specific views with ApplicationPackVariants, and previewing emails with ApplicationMailerPreviews.

1. What’s new in
4.1(Chennai.rb March meetup)

2. (@vysakh0)
Vysakh Sreenivasan
Just want to build cool apps for me and
others

3. - Rails app probably take around ~5
seconds to boot.
- 50 times a day (test, rails s, rails g...)
i.e You waste 5days in a YEAR

4. #1 Spring preloader
built in integration in Rails 4.1

5. keeps app running in the background
No booting every time you run a test,
rake task or migration

6. PARTY IN THOSE 5 DAYS

7. How do you load api keys in Rails?
- create .yml, .rb file and load or
- figaro gem or
- dotenv gem.

8. #2 config/secrets.yml
generated by Rails 4.1

9. Just put your api keys in secrets.yml
# config/secrets.yml
development:
facebook_consumer_key: “random skdfjks”
facebook_consumer_secret: “its a secret”
# config/secrets.yml
development:
facebook_consumer_key: “random key”
facebook_consumer_secret: “its a secret”
# config/initializers/devise.rb
…..
config.omniauth :facebook, Rails.application.secrets.facebook_consumer_key , Rails.
application.secrets.facebook_consumer_secret
…..
Just use it like this

10. Config

11. How do you change the state of Order
- to pending.
- to completed.
- to refunded

12. Create separate columns?
- completed(:boolean) , refunded(:boolean)
Create an integer column?
- 0 -> pending
- 1 -> completed
- 2-> refunded

13. #3 Active Record enums
in Rails 4.1

14. # app/modes/order.rb
class Order < ActiveRecord::Base
# status is an integer column in orders table
enum status: {
pending: 0,
completed: 1,
refunded: 2
}
end

15. Now enum gives us
handy helper methods

16. @order.pending?
@order.completed!
@order.completed?
@order.refunded!
@order.refunded?

18. #4 Application Message Verifier
built in helper in Rails 4.1

19. irb> @user.id
# => 1
irb> user_token = Rails.application.message_verifier
(“remember_me”). generate(@user.id)
=> "BAhpBg==--859750a419640d18d7c24e3166541a9405a42786"
irb> get_back_user_id = Rails.application.
message_verifier(“remember_me”). verify(user_token)
=> 1

20. USE CASES
- Password reset
- Invite links
- Oauth tokens
- and more

21. Show different templates to
phone/browsers/tablets ?

23. #5 Application Pack Variants
(Code example taken from
http://coherence.io/blog/2013/12/17/whats-new-in-rails-4-1.html )

24. class ApplicationController < ActionController ::Base
before_action :detect_device_variant
private
def detect_device_variant
case request.user_agent
when /iPad/i
request.variant = :tablet
when /iPhone/i
request.variant = :phone
end
end
end

25. class PostController < ApplicationController
def show
@post = Post.find(params[:id])
respond_to do |format|
format.json
format.html # /app/views/posts/show.html.erb
format.html.phone # /app/views/posts/show.html+phone.erb
format.html.tablet do
@show_edit_link = false
end
end
end
end

26. #6 Application Mailer Previews

27. class NotifierPreview < ActionMailer::Preview
def welcome
Notifier.welcome(User.first)
end
end
# test/mailers/notifier_preview.rb

28. List of all mailer previews
http://localhost:3000/rails/mailers