ruby rails overview
TRANSCRIPT
Ruby & Rails Overviewbrought by Michal Poczwardowski and
Gdansk 11/05/15
Michal PoczwardowskiRuby on Rails [email protected]
Software houseweb&mobile
Software houseweb&mobile
Agenda
Part 1
ruby
Part 2
rails
Part 1
ruby
Ruby is a dynamic, scripting, object-oriented language...
‘Programming languages must feel natural to programmers.’
Yukihiro "Matz" Matsumoto
hello = ‘Hello world!’puts hello
Hello world
Try ruby in a browser!
tryruby.org
www.bloc.io/ruby-warrior
Control brave knight using ruby
Why ruby is so cool?
#1: puts ‘Yes’ if ‘Work’.starts_with? ‘W’
#2: population = 12_000_000
#3: misterious_number.between?(10, 20)
Like a natural language
def really? trueend
Aesthetic
1: numbers = []2: for i in [1,2,3,4]3: numbers << i ** 24: end5: numbers # => [1,4,9,16]
Elegant - NON ruby-way solution
numbers = [1,2,3,4].map { |i| i ** 2 }
numbers # => [1,4,9,16]
Elegant - ruby-way solution
Everything is an object!
42
42.times { puts ‘Awesome’ }
Fixnum object
:001 > 1.class => Fixnum :002 > (2.2).class => Float :003 > [].class => Array :004 > "Politechnika Gdańska".class => String :005 > nil.class => NilClass :006 > {}.class => Hash
Output from irb
Classes, objects
01: class School02: attr_reader :name03: 04: def initialize(name)05: @name = name06: end07:08: def hello09: puts “Hello #{name}”10: end11: end
school = School.new(‘PG’)school.hello
# => ‘Hello PG’
- high performance / lower level stuff- multi-threading- graphics / data analysis
Avoid ruby in case of
Ruby is great at...
Metaprogramming
Example with send
01: class Rubyist02: def face(mood)03: send(mood)04: end05: 06: private07: 08: def happy09: ‘:)’10: end11:12: def sad13: ‘:(‘14: end15: end
dev = Rubyist.new
dev.face(:happy)# => ‘:)’
dev.face(:sad)# => ‘:(’
Handle missing methods
1: class Rubyist2: def happy; ‘:)’ end3: def sad; ‘:(‘ end4: 5: def method_missing(name)6: ‘:?’7: end8: end
dev = Rubyist.new
dev.happy# => ‘:)’
dev.sad# => ‘:(’
dev.excited# => ‘:?’
dev.worried# => ‘:?’
Define own methods
01: class Rubyist02: FACES = {03: happy: ‘:)’,04: sad: ‘:(’,05: excited: ‘;D’,06: angry: ‘:[‘07: }08: 09: FACES.each do |key, value|10: define_method(key) { value }11: end12: end
dev = Rubyist.new
dev.happy# => ‘:)’
dev.sad# => ‘:(’
dev.angry# => ‘:[’
dev.excited# => ‘;D’
Everything changes
1: class String2: def with_smile3: self + ‘ :)’4: end5: end
‘Sad string’.with_smile# => ‘Sad string :)’
‘With great power comes great responsibility.’Unkle Ben
Write tests!
Example rspec
describe Rubyist do subject { described_class.new }
describe ‘#happy’ do it ‘returns happy face’ expect(subject.happy).to eq ‘:)’ end endend
library -> gem
rubygems.org/stats - 9/05/15
Gemfile
01: source 'https://rubygems.org'02: 03: gem ‘rails’, ‘4.2.1’04: gem ‘nokogiri’05: gem 'stripe', git: 'https://github.com/stripe/stripe-ruby'06:07: group :test do08: gem ‘rspec-rails’09: end
Part 2
ruby on rails
Rails is a web application development framework
‘Powerful web applications that formerly might have taken weeks or months to develop can be produced in
a matter of days.’Tim O’Reilly
Websites powered by Rails
isitrails.com
Convention over Configuration
Structure
controllers
modelsviews
routes.rb, database.yml
Gemfile
MVC
controller
model view
browser
DB
routes
web server
Let’s prepare some code
$ rails generate model Post title:string content:text invoke active_record create db/migrate/20150509232514_create_posts.rb create app/models/post.rb invoke rspec create spec/models/post_spec.rb invoke factory_girl create spec/factories/posts.rb
Magic spells
01: class CreatePosts < ActiveRecord::Migration02: def change03: create_table :posts do |t|04: t.string :title05: t.text :content06: 07: t.timestamps08: end09: end10: end
Migration
MVC in action
http://localhost:3000/
127.0.0.1 - GET /index.html HTTP/1.0" 200 2326
get ‘/’, to: ‘welcome#index’
class WelcomeController < ApplicationController def index @posts = Post.all endend
class Post < ActiveRecord::Baseend
class Post < ActiveRecord::Baseend
class WelcomeController < ApplicationController def index @posts = Post.all endend
<ul> <% @posts.each do |post| %> <li> <%= post.title %> </li> <% end %></ul>
ERB
%ul - @posts do |post| %li =post.title
HAML
<html> … <body> … <%= yield %> … </body></html>
http://localhost:3000/
This is almost the end...
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