D-Talk: What's awesome about Ruby 2.x and Rails 4

RUBY 2.X

Thursday, October 10, 13

2012Thursday, October 10, 13

+ berljivost+ površinska enostavnost+ polno objektni jezik+ funkcijsko programiranje+ metaprogramiranje+ ekosistem+ RubyGems

- metaprogramiranje- hitrost vs. Scala, Java, C- znanost (SciPy)

(0..10).each do |x| puts "The number is: #{x}"end

<?php for ($x=0; $x<=10; $x++){ echo "The number is: $x";}?>

for x in range(0, 11): print 'The number is: %d' % (x)

Ruby PHP Python

for x in 0..10 puts 'The number is: %d' % [x]end

Ruby PHP Python

0.upto(10).each { |x| printf('The number is: %d', x)}

Ruby PHP Python

11.times do |x| puts "The number is: #{x}"end

Ruby PHP Python

puts (0..10).map{|x| "The number is: #{x}"}

Ruby PHP Python

puts (0..10).map{|x| "The number is: #{x}"}

puts ("The number is N\n" * 11).gsub('N').with_index{|_,i| i}

RUBY 2.0Thursday, October 10, 13

KEYWORD ARGUMENTI# Ruby < 2def run(options = {}) options.reverse_merge!( opt1: "default" ) raise ArgumentError unless options.keys.in?([:opt1, :opt2]) options[:opt1]end

# Ruby 2def run(opt1: "default", opt2: nil) opt1end

run(opt2: "x")run(opt2: "x", opt3: "y") # ArgumentError

def run(opt1: "default", opt2: nil, **options) opt1end

run(opt2: "x", opt3: "y")

MODULE#PREPEND

class Bar

def hello puts 1 endend

Bar.new.hello

Bar.ancestors๏ BasicObject๏ Kernel๏ Object๏ Bar

class Foo def hello puts 'hello' endend

class Bar < Foo

def hello puts 1 super endend

Bar.new.hello

Bar.ancestors๏ BasicObject๏ Kernel๏ Object๏ Foo๏ Bar

module FooBar def hello puts 2 super endend

class Bar < Foo include FooBar def hello puts 1 super endend

Bar.new.hello

Bar.ancestors๏ BasicObject๏ Kernel๏ Object๏ Foo๏ FooBar๏ Bar

class Bar < Foo include FooBar def hello puts 1 super endend

Bar.new.hello

Bar.ancestors๏ BasicObject๏ Kernel๏ Object๏ Foo๏ FooBar๏ Bar

12hello

class Bar < Foo prepend FooBar def hello puts 1 super endend

Bar.new.hello

Bar.ancestors๏ BasicObject๏ Kernel๏ Object๏ Foo๏ Bar๏ FooBar

class Bar < Foo prepend FooBar def hello puts 1 super endend

Bar.new.hello

Bar.ancestors๏ BasicObject๏ Kernel๏ Object๏ Foo๏ Bar๏ FooBar

21hello

LAZY ENUMERATIONS

ENUMERATIONS

[1, 2, 3, 4] .map { |i| i * 2 } # => [2, 4, 6, 8] .take(2) # => [2, 4] .reduce(&:+) # => 6

[1, 2, 3, 4] .lazy # => #<Enumerator::Lazy: [1, 2, 3, 4]> .map { |i| i * 2 } # => #<Enumerator::Lazy: [1, 2, 3, 4]>:map> .take(2) # => #<Enumerator::Lazy: #<Enumerator::Lazy: [1, 2, 3, 4]>:map>:take(2)> .reduce(&:+) # => 6

(1..Float::INFINITY) .lazy .map { |i| i * 2 } .take(2) .reduce(&:+)

GENERATIONAL GARBAGE COLLECTOR

If you care about GC, just use JRuby.

GENERATIONAL GARBAGE COLLECTOR

If you care about GC, just use JRuby.

switch to JRubyThursday, October 10, 13

RUBY 2.0: REFINEMENTS

RUBY 2.1: REFINEMENTSmodule BalkanString refine String do def debalkanize ActiveSupport::Inflector.transliterate(self) end endend

class User < ActiveRecord::Base using BalkanString

def name @name.debalkanize if @name endend

"test".debalkanize # NoMethodError

RUBY ON RAILS

Django146,869 LOC

Rails162,084 LOC

CakePHP147,738 LOC

Lines of code

100% MODULAREN

Rails‣lepilo

‣Model

‣View‣Controller

Rails‣lepilo

‣Model

Rails‣railties 16,017 LOC ‣activesupport 25,710 LOC

‣Model

Rails‣railties‣activesupport‣Model

Rails‣railties‣activesupport‣activemodel 5,694 LOC

‣activerecord 53,435 LOC

Rails‣railties‣activesupport‣activemodel‣activerecord‣View‣Controller

Rails‣railties‣activesupport‣activemodel‣activerecord‣actionview 22,501 LOC

‣Controller

Rails‣railties‣activesupport‣activemodel‣activerecord‣actionview‣Controller

Rails‣railties‣activesupport‣activemodel‣activerecord‣actionview‣actionpack 35,538 LOC

Rails‣railties‣activesupport‣activemodel‣activerecord‣actionview‣actionpack

DEPLOY

Unicorn

Rainbows!

RAILS 4

TURBOLINKSVideo (57:10)

Rails Conf 2013 Patterns of Basecamp's Application Architecture by David Heinemeier Hansson

http://www.youtube.com/watch?v=yhseQP52yIY

THREAD SAFEJBoss, 200 threads, OK

DON’T JUST TRY, TRY!# Rails 3

[10].try(:count) # => 15.try(:count) # NoMethodErrornil.try(:count) # => nil

# Rails 4

5.try(:count) # => nil5.try!(:count) # NoMethodErrornil.try(:count) #=> nilnil.try!(:count) #=> nil

ACTIONCONTROLLER::LIVEclass MyController < ActionController::Base include ActionController::Live

def stream response.headers['Content-Type'] = 'text/event-stream' 100.times { response.stream.write "hello world\n" sleep 1 } ensure response.stream.close endend

avtomatsko naredi thread

POSTGRESQLArray

POSTGRESQL ARRAY

class CreateDocuments < ActiveRecord::Migration def change create_table :documents do |t| t.string :title t.string :tags, array: true, default: [] t.timestamps end endend

POSTGRESQL ARRAY

Document.create(title: "PostgreSQL", tags: ["pg","rails"])Document.where("'pg' = ANY (tags)")

POSTGRESQLhstore (Hash/Dictionary)

POSTGRESQL HSTORE

class AddHstoreExtension < ActiveRecord::Migration def up execute 'CREATE EXTENSION hstore' end

def down execute 'DROP EXTENSION hstore' endend

class AddPropertiesToComics < ActiveRecord::Migration def change add_column :comics, :properties, :hstore endend

POSTGRESQL HSTORE

class Comic < ActiveRecord::Baseend

Comic.create(properties: { issued: 1.year.ago })

Comic.where("properties -> 'issued' > ?", 2.years.ago)

POSTGRESQL HSTORE

class Comic < ActiveRecord::Base store_accessor :properties, :issuedend

Comic.create(issued: 1.year.ago)

Comic.where("properties -> 'issued' > ?", 2.years.ago)

Ali sploh rabiš hstore v tem primeru?Thursday, October 10, 13

ACTIVERECORDIn Rails 4

SCOPES

class User < ActiveRecord::Base # Rails 3 scope :newest, where("created_at > ?", 1.week.ago)

# Rails 4 scope :newest, -> { where("created_at > ?", 1.week.ago) }end

WHERE.NOT

# Rails 3User.where('role != ?', 'admin')User.where('nickname IS NOT NULL')

# Rails 4User.where.not(role: 'admin')User.where.not(nickname: nil)

MIGRACIJE PREJclass ChangeProductsPrice < ActiveRecord::Migration def up change_table :products do |t| t.change :price, :string end end

def down change_table :products do |t| t.change :price, :integer end endend

MIGRACIJEclass ChangeProductsPrice < ActiveRecord::Migration def change reversible do |dir| change_table :products do |t| dir.up { t.change :price, :string } dir.down { t.change :price, :integer } end end endend

NONE RELATIONclass User < ActiveRecord::Base scope :with_role, ->(role) { if User.role_valid? role where(role: role) else none end }end

User.with_role(params[:role]).where.not(nick: nil)

STRONG PARAMETERS

PROBLEM

• User

• name

• is_admin

RAILS 3class User < ActiveRecord::Base attr_accessible :nameend

# controller

user.update_attributes(params[:user])

# admin

user.update_attributes(is_admin: true) # :-(

user.is_admin = trueuser.save

RAILS 3

class User < ActiveRecord::Base attr_accessible :nameend

# controller

v čem je v resnici problem?

RAILS 3

class User < ActiveRecord::Base attr_accessible :nameend

# controller

user.update_attributes(is_admin: true) # :-(

non-sanitizeduser input

STRONG PARAMETERS

class User < ActiveRecord::Baseend

# controller

def user_params params.require(:user).permit(:name)end

user.update_attributes(user_params)

user.update_attributes(params[:user])# error: Unpermitted parameters

user.update_attributes(is_admin: true) # OK :-)

CACHING

• avtomatski expire pri spremembi modela

• avtomatski expire pri spremembi viewa

• russian doll (nested) caching

• Rails Conf 2013 Patterns of Basecamp's Application Architecture by David Heinemeier Hansson

• http://www.youtube.com/watch?v=yhseQP52yIY

ACTIVESUPPORT::CONCERNmodule Commentable extend ActiveSupport::Concern

included do has_many :comments end

def has_comments? !comments.empty? end

module ClassMethods def comments_count joins(:comments) .references(:comments) .pluck("COUNT(comments.id)") end endend

class Post < ActiveRecord::Base include Commentableend

User.posts.comment_countPost.first.commentsPost.first.has_comments?

Rails 4 ima direktorij za concerne.Whatever.

THE END

D-Talk: What's awesome about Ruby 2.x and Rails 4

Technology

Ruby + Rails

Ruby On Rails - 3. Rails Addons

Ruby outside Rails

Ruby off Rails

Ruby (on Rails)

BCR Ruby on Rails - Boston Computing Review : Ruby on Rails

Ruby on Rails no Brasil (PPT) - Ruby on Rails

Rails 2 - Drew University for Ruby, Rails and other material are held by their respective owners. Install Ruby and Rails • Ruby -

Ruby Rails Overview

Ruby Beyond Rails

Ruby&Rails For Rails Side

Ruby on rails

Ruby On Rails - 2. Rails Introduction

Ruby on rails porque usar rails?!

Ruby over Rails

Ruby On Rails - 1. Ruby Introduction

Introduction to Ruby, Rails, and Ruby on Rails

Chinaon Rails Free Ruby Rails Books

Ruby de Rails

Ruby on Rails [ Ruby On Rails.ppt ] - [Ruby - [Ruby-Doc.org