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

RUBY 2.X

Thursday, October 10, 13

2012Thursday, October 10, 13

RUBY

+ 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





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


LAZY

[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


LAZY

(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

Meh.


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‣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

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