Rails 5What’s in it for me?

@_cha1tanya@BigBinary

@Srijan

Overview of Rails 5

Rails.5.started_on?

Nov, 2014

9359+ Commits

Beta 3

RC 1 coming soon

Lots of new features

Bug fixes

Improvements

DHH Features

Major features

Ruby 2.2.2+Rails 5 will require that your apps runs on Ruby 2.2.2 or latest.

Symbol GC

Incremental GC

Chance to cleanupRails internals

Keyword argumentsRails code can use keyword arguments internally as now it only supports Ruby 2.2.2 +

Module#prepend

Action CableDHH talking about Action Cable https://www.youtube.com/watch?v=n0WUjGkDFS0

Full StackIt has both Ruby side as well as JavaScript side.

Pub/Sub

Seamless integration with

other parts

module ApplicationCable class Connection < ActionCable::Connection::Base identified_by :current_user

def connect self.current_user = find_verified_user end

protected def find_verified_user id = cookies.signed[:user_id] if current_user = User.find_by(id: id) current_user else reject_unauthorized_connection end end endend

Ruby sideInitially it was started with hard dependency on event machine.It was later dropped in https://github.com/rails/rails/commit/74497eabd52f2f9f8c383808b11286283046c2b2.

Now Action Cable does not have hard dependency on Event machine

These are the 3 dependencies of Action Cable on Ruby side:

websocket-drivernio4rconcurrent-ruby

Adapters

InlineAsync

Good for development and test mode.

Evented RedisNon-Evented Redis

PostgresqlFor production mode.

Rendering a template

outside of controller

ActionController::Renderer.render

Basecamp 3

API only apps

What is an API only app

Twitter APIGithub API

Supplementary APIs where apps are still traditional web apps

Proliferation of client side

frameworks

Rails as a Back EndWhich results into using Rails only as

back end app.

No HTML, only JSON!

Slim version of Rails

No view layer

Limited set of middlewares

JBuilderActiveModel::SerializerThese can be used with API only apps to generate JSON

Still Rails!(But for API)

Create new Rails API only appwith

rails new api_app --api

Convert existing app to API only app

config.api_only = true

development

PumaPuma is default web server now

config/puma.rb

Newly created Rails 5 apps will come with a config/puma.rb by default.

New Welcome page

`rails` CLI

rake db:migrate

rails server

Why some rake and some rails?

In Rails 5, just use `rails`

rails db:migrate

rails server

rails assets:precompile

One `rails` command to bind

them all!

Rake Proxy

rake db:migrate #works

rails restartAbility to restart Rails app in

development.https://github.com/rails/rails/issues/188

76

tmp/restart.txt

Similar to how passenger restarts app by touching tmp/restart.txt

Works with Pow,Puma

rails dev:cache

Caching in development modeIn previous Rails versions, caching does not work automatically in development.

Now it will work in Rails 5.

Toggles caching in development

Also restarts app

Filtering routeshttps://github.com/rails/rails/issues/189

02Ability to filter routes.

Have thousands of routes?

Filtering is easier now

rails routes -c users

rails routes -c admin/users

rails routes -c PostsController

rails routes -g PATCH

rails routes -g admin

Evented File system monitor

Reloading in development

Rails reloads all code in development when something changes. For that it has to do a

complete walkthrough of all files.

Check something has changed or not

config.file_watcher

gem ‘listen’

test

Test RunnerRails 5 has added Rspec like test runner

http://blog.bigbinary.com/2016/01/03/test-runner-in-rails-5.html

bin/rails test

Running a single test by line number$ bin/rails test test/models/user_test.rb:27

$ bin/rails test test/models test/jobs

Improved failure message

$ bin/rails tRun options: --seed 51858

# Running:

.F

Failure:PostsControllerTest#test_should_get_new:Expected response to be a <success>, but was a <302> redirect to <http://test.host/posts>

bin/rails test test/controllers/posts_controller_test.rb:15

Failing fast

$ bin/rails t -fRun options: -f --seed 59599

# Running:

..F

Failure:PostsControllerTest#test_should_get_new:Expected response to be a <success>, but was a <302> redirect to <http://test.host/posts>

bin/rails test test/controllers/posts_controller_test.rb:15

Interrupted. Exiting...

Finished in 0.179125s, 16.7481 runs/s, 22.3308 assertions/s.

3 runs, 4 assertions, 1 failures, 0 errors, 0 skips

Backtrace

See complete backtrace with -b switch$ bin/rails t -b

Error:PostsControllerTest#test_should_create_post:NameError: undefined local variable or method `boom' for #<PostsController:0x007fc53c4eb868> /rails-5-test-runner-app/app/controllers/posts_controller.rb:29:in `create' /sources/rails/actionpack/lib/action_controller/metal/basic_implicit_render.rb:4:in `send_action' /sources/rails/actionpack/lib/abstract_controller/base.rb:183:in `process_action' /sources/rails/actionpack/lib/action_controller/metal/rendering.rb:30:in `process_action' /sources/rails/actionpack/lib/abstract_controller/callbacks.rb:20:in `block in process_action' /sources/rails/activesupport/lib/active_support/callbacks.rb:126:in `call'..... /sources/rails/activesupport/lib/active_support/testing/assertions.rb:71:in `assert_difference' /rails-5-test-runner-app/test/controllers/posts_controller_test.rb:19:in `block in <class:PostsControllerTest>'

Colored output

Controller tests

assignsassert_template

assignsassert_template

Why?

gem ‘action-controller_testing’

Controller tests are integration tests

def test_index get :index assert_response :successend

Example of changed controller test.

def test_index get posts_url

assert_response :successend

https://github.com/rails/rails/issues/22076

ActionController::TestCase

In Rails 4.x this was the superclass for all controller tests.

ActionDispatch::IntegrationTest

Now it is this one. Also a lot of effort has gone into making these tests faster.

More focus onintegration testing

caching

http_cache_forever

def index http_cache_forever do render ‘index’ endend

Use it with caution!It will literally set the cache control headers for ‘forever’. Make sure that you are using it with static content only.

Collection Caching

@users = User.where(city: 'Pune')

No record is deleted. No record is added.

Caching of collections

ActiveRecord::Relation#cache_key

@users.cache_key=> "users/query-67ed32b36805123"

cache(@users) do ………end

LimitationsDoesn’t work well with limits and groups.

Partials caching

# index.html.erb<%= render partial: 'todo', collection: @todos %>

# _todo.html.erb<% cache todo do %> <%= todo.name %><% end %>

multi_fetch_fragments gem

Folded in Rails 5

Just pass `cached: true` and Rails will fetch all caches at once.

# index.html.erb<%= render partial: 'todo', collection: @todos, cached: true %>

# _todo.html.erb<% cache todo do %> <%= todo.name %><% end %>

Caching Action Mailer views

Active Record

ApplicationRecordApplicationRecord is a new superclass for all app models, analogous to app controllers subclassing ApplicationController instead of ActionController::Base. This gives apps a single spot to configure app-wide model behavior

class Post < ActiveRecord::Baseend

class Post < ApplicationRecordend

#orAdded the #or method on ActiveRecord::Relation, allowing use of the OR operator to combine WHERE or HAVING clauses

Post.where('id = 1').or(Post.where('id = 2'))

# => SELECT * FROM posts WHERE (id = 1) OR (id = 2)

has_secure_token Added ActiveRecord::SecureToken in order to encapsulate generation of unique tokens for attributes in a model using SecureRandomhttps://github.com/rails/rails/pull/18217

class User < ApplicationRecord has_secure_tokenend

>> user = User.new>> user.save=> true

>> user.token=> 'qjCbex522DfVEVd5ysUWppWQ'

URL safe

Fixed length strings

Base 58 encoding

Regenerating also possible

>> user = User.first=> <User id: 11, name: 'John', email: 'john@example.com', token: "jRMcN645BQyDr67yHR3qjsJF", token: "qjCbex522DfVEVd5ysUWppWQ">

>> user.token=> "qjCbex522DfVEVd5ysUWppWQ"

>> user.regenerate_token=> true

>> user.token=> "tYYVjnCEd1LAXvmLCyyQFzbm"

Versioned migrations

Backward compatibility

But API must change

For eg. in Rails 4.x

t.timestamps null: false

But in Rails 5, there is no `null: false` still it adds `NULL` constraint when the migration is run in

Rails 5.

t.timestamps # Rails 5

Compatibility Layer

ActiveRecord::Migration[5.0]

Superclass of migrations in Rails 5. Tells Rails for which version this migration was generated.

Active Support

Improvements to Date/Time

next_day/prev_day

Time.current=> Fri, 12 Feb 2016 08:53:31 UTC +00:00

Time.current.next_day=> Sat, 13 Feb 2016 08:53:31 UTC +00:00

Time.current.prev_day=> Thu, 11 Feb 2016 08:53:31 UTC +00:00

next week with same time

Time.current=> Fri, 12 Feb 2016 09:15:10 UTC +00:00

Time.current.next_week=> Mon, 15 Feb 2016 00:00:00 UTC +00:00

Time.current.next_week(same_time: true)=> Mon, 15 Feb 2016 09:15:20 UTC +00:00

on_weekend?

Time.current=> Fri, 12 Feb 2016 09:47:40 UTC +00:00

Time.current.on_weekend?=> false

Time.current.tomorrow=> Sat, 13 Feb 2016 09:48:47 UTC +00:00

Time.current.tomorrow.on_weekend?=> tru

on_weekday?

Time.current=> Fri, 12 Feb 2016 09:47:40 UTC +00:00

Time.current.on_weekday?=> true

Time.current.tomorrow=> Sat, 13 Feb 2016 09:48:47 UTC +00:00

Time.current.tomorrow.on_weekday?=> false

Time.current=> Fri, 12 Feb 2016 09:47:40 UTC +00:00

Time.current.next_weekday=> Mon, 15 Feb 2016 09:55:14 UTC +00:00

Time.current.prev_weekday=> Thu, 11 Feb 2016 09:55:33 UTC +00:00

Enumerable#pluck

users = [{id: 1, name: 'Max'},

{id: 2, name: 'Mark'}, {id: 3, name: 'Jen'}]

users.pluck(:name)=> ["Max", "Mark", "Jen"]

users = [{id: 1, name: 'Max'},

{id: 2, name: 'Mark'}, {id: 3, name: 'Jen'}]

users.pluck(:id, :name)=> [[1, "Max"], [2, "Mark"], [3, "Jen"]]

Improvement to Active Record’s pluck

# In Rails 4.xusers = User.allSELECT `users`.* FROM `users`

users.pluck(:id, :name)# SELECT "users"."id", "users"."name" FROM “users"=> [[1, "Max"], [2, "Mark"], [3, "George"]]

# In Rails 5users = User.allSELECT `users`.* FROM `users`

users.pluck(:id, :name)=> [[1, "Max"], [2, "Mark"], [3, "George"]]

Enumerable#without

vehicles = ['Car', 'Bike', 'Truck', 'Bus']

vehicles.without("Car", "Bike")=> ["Truck", "Bus"]

vehicles = {car: 'Hyundai', bike: 'Honda', bus: 'Mercedes', truck: 'Tata'}

vehicles.without(:bike, :bus)=> {:car=>"Hyundai", :truck=>"Tata"}

Halting callback chainChanged the way in which callback chains can be halted. The preferred method to halt a callback chain from now on is to explicitly throw(:abort).https://github.com/rails/rails/pull/17227

return false from one of the `before` callbacks

Stop entire callback chain

Rails 5 no longer has this side effect!

throw(:abort)

Explicitly throw(:abort) to stop it.

While upgrading, it will still haltFor older apps getting upgraded to Rails 5, the callback will still halt with returning false, as this is a breaking change.

ActiveSupport.halt_callback_chains_on_return_false

Once you are ready, toggle this flag and it will use new behaviour of throw.

Performance

https://github.com/rails/rails/pull/21057https://github.com/rails/rails/pull/18643https://github.com/rails/rails/pull/21411https://github.com/rails/rails/pull/21155https://github.com/rails/rails/pull/20946

And more…

Attributes API

Sprockets 3/4

Turbolinks 5

What’s next?

If you are new to Rails, check out the Rails Doctrine to understand the philosophy behind Rails.

rubyonrails.org/doctrine/

5.0.0.RC1

weblog.rubyonrails.org

@rails

github.com/rails/rails

This week in Rails

rails-weekly.goodbits.io

blog.bigbinary.com/categories/Rails%205

Try RC

Report bugs

Fix bugs!

Let’s make Rails better

Thank you!@_cha1tanya@BigBinary

@Srijan