OSDC 2009 Rails Turtorial

Rails Tutorial

http://blog.xdite.net http://handlino.com Rails Developer

Project Using Rails bingo.handlino.com sudomake.com VeryXD.net

Project Using Sinatra MrIE6.com VeryXD.net

DRY Don’t Repeat Yourself

Agenda • ActiveRecord • Template / Helper • Library • Plugin

Agenda • ActiveRecord Code • Template / Helper • Library • Plugin

MVC Model - View - Controller

MVC Browser Controller Action Model-View-Controller HTTP request route.rb GET /users/1 UsersController Model def show @user = User.ﬁnd(params[:id]) Database respond_to do |format| format.html format.xml end View #show.html.erb end <html> def index <h1>User Proﬁle</h1> ...... <p><%= @user.nickname %></p> end </html> end

C>M

C>M Code Controller

Refactor to Model ActiveRecord feature

ActiveRecord • validation • callback • counter_cache • named_scope • STI • polymorphic association

validation

validation class Post < ActiveRecord::Base validates_presence_of :subject end

validation

validation validates_exclusion_of :age, :in => 30..60 validates_format_of :email, :with => /\\A([^@\\s]+)@((?:[-a-z0-9]+\\.)+[a-z] {2,})\\Z/i, :on => :create validates_inclusion_of :format, :in => %w( jpg gif png ) validates_length_of :phone, :in => 7..32, :allow_blank => true validates_uniqueness_of :teacher_id, :scope => [:semester_id, :class_id]

Callbacks def create @post = Post.new(params[:post]) @post.content += \" < #{Time.now.to_s} >\" if @post.save flash[:notice] = 'Post was successfully created.' redirect_to blog_path(@post) else render :action => \"new\" end end

Callbacks before_create class Post < ActiveRecord::Base before_create :insert_timestamp def insert_timestamp self.content += \" < #{Time.now.to_s} >\" end end

Callbacks Create Update Destroy before_validation before_validation before_validation_on_create before_validation_on_update after_validatin after_validatin after_validation_on_create after_validation_on_upate before_save before_save before_create before_update before_destroy insert update delete after_create after_update after_destroy after_save after_save

Counter Cache

Counter Cache class Comment < ActiveRecord::Base belongs_to :post def after_save self.update_counter_cache end def after_destroy self.update_counter_cache end def update_conter_cache self.post.comments_count = self.post.comments.size slf.post.save(false) end end

Counter Cache class Comment < ActiveRecord::Base belongs_to :post, :counter_cache => true end class PostCommentsCount < ActiveRecord::Migration def self.up add_column :posts, :comments_count, :integer , :default => 0 end def self.down remove_column :posts,:comments_count end end

Named Scope v.2.1 class Post < ActiveRecord::Base named_scope :publish, :conditions => { :is_blocked => false } named_scope :recent, :order => \"created_at DESC\", :limit => 1 end Post.publish => SELECT * FROM `posts` WHERE (`posts`.`is_blocked` = 0) Post.recent => SELECT * FROM `posts` ORDER BY created_at DESC LIMIT 1 Post.publish.recent => SELECT * FROM `posts` WHERE (`posts`.`is_blocked` = 0) ORDER BY created_at DESC LIMIT 1

STI (Single Table Inheritance ) class Post < ActiveRecord::Base has_many :comments before_create :insert_timestamp def insert_timestamp self.content += \" < #{Time.now.to_s} >\" end named_scope :publish, :conditions => { :is_blocked => false } named_scope :recent, :order => \"created_at DESC\", :limit => 1 end class Article < Post end

Polymorphic Association • Post has_many comments • Photo has_many comments Table ? • News has_many comments post_comment photo_comment news_comment

Polymorphic Association class Post < ActiveRecord::Base has_many :comments, :as => :resource end class Comment < ActiveRecord::Base belongs_to :resource, :polymorphic => true end class PolymorphicComment < ActiveRecord::Migration def self.up remove_column :comments, :post_id add_column :comments, :resource_id, :integer add_column :comments, :resource_type, :string end def self.down add_column :comments, :post_id, :integer remove_column :comments, :resource_id remove_column :comments, :resource_type end end

Polymorphic Association

MVC Model - View - Controller

V>C

V>C Code View ....

Less code in view Render Template & Use Helper

View code

Render Template partial

Write Your Own Helper <td> <tr>

Write Your Own Helper

Don’t re-invent the wheel use the library ( lib/ ), gems

1 HTML +CSS (not ﬂash) Yahoo Open Hack Day

lib/ rubygems

lib/

7326 gems

gems

Rapid Web Development vendor/plugin

1. authentication

restful-authentication ./script/generate authenticated user sessions --include-activation • / / • User model • RESTful Session controller • Activation mailer

open_id_authentication • OpenID • openid session controller • openid migration

openid_pack • restful_authentication + open_id_authentication OpenID ( multiple ) •

2. Model ActiveRecord

attachment_fu has_attachment :storage => :file_system, :path_prefix => 'public/files', :content_type => :image, :resize_to => [50,50] • model • File system / amazon S3 / Database store

restful_authenication attachment_fu

acts_as_taggable_on_steroids • tagging class Post < ActiveRecord::Base acts_as_taggable end p = Post.find(:first) p.tag_list # [] p.tag_list = \"Funny, Silly\" p.save p.tag_list # [\"Funny\", \"Silly\"] p.tag_list.add(\"Great\", \"Awful\") p.tag_list.remove(\"Funny\")

validates_url_of class Foo < ActiveRecord::Base validates_url_of :url, :message => 'is not valid or not responding'.t end • http:// http:// https:// • •

3. Controller&View ActionPack

will_paginate • HTML helper CSS style @posts = Post.paginate :page => params[:page], :per_page => 50 <ol> <% for post in @posts -%> <li>Render `post` in some nice way.</li> <% end -%> </ol> <%= will_paginate @posts %>

will_paginate (cont.) • named_scope Rails 2.1 class Product < ActiveRecord::Base named_scope :cheap, :conditions => { :price => 0..5 } named_scope :recent, lambda { |*args| {:conditions => [\"released_at > ?\", (args.first || 2.weeks.ago)]} } named_scope :visible, :include => :category, :conditions => { 'categories.hidden' => false } end • @products = Product.recent.cheap.paginate :page => params[:page], :per_page => 50

jRails • jQuery byebye! Prototype.js gugod hlb

facebox_render • Facebox is a JQuery-based lightbox http://famspam.com/facebox/

facebox_render (cont.) • facebox class ApplicationController < ActionController::Base include FaceboxRender end Text

facebox_render (cont.) • facebox class ApplicationController < ActionController::Base include FaceboxRender end Text <%= facebox_link_to \"Login\", :url => new_session_url %>

facebox_render (cont.) • facebox class ApplicationController < ActionController::Base include FaceboxRender end Text <%= facebox_link_to \"Login\", :url => new_session_url %> def new # do some thing you want respond_to do |format| format.html format.js { render_facebox } end end

Ajax form submit

<% form_remote_tag :url => batch_event_attendees_path(@event) do %> Ajax form submit

def batch ... respond_to do |format| format.html format.js { render_to_facebox } end end Text

def batch ... respond_to do |format| format.html format.js { render_to_facebox } end end batch.html.erb Text

stickies • ﬂash[:notice] • CSS style Javascript close error_stickie(\"Your account has been disabled\") warning_stickie(\"Your account will expire in 3 days\") notice_stickie(\"Account activated\") debug_stickie(\"This only works when RAILS_ENV is development\") <%= render_stickies %>

4. deployment

ar_mailer • E-mail E-mail Class EventNotifier < ActionMailer::ARMailer def signup_notification(user) ... end end UserNotifier.deliver_signup_notification(@user) ar_sendmail Database daemon

hoptoad • exception (500 error) • log

New Relic • proﬁling your rails app • trace code stack • provide optimize direction

Capistrano deploy 1. ssh to production server 2. svn checkout 3. run some your script (link file/copy config file/ clear cache…etc) 4. restart mongrel cluster

plugin ?

thank you.

Bonus

I18n less pain( Rails 2.2 )

session yml

Template & Engine Ultima lazy solution ( Rails 2.3)

Template • • gem / plugin • route / rake • ... ? • ...... by case • .......... =_=

Templates • (restful / openid / twitter) _authenication • Facebook • Google App Engine

Engine • • MVC code • ... copy • ...... by case • .......... =_=

Twitter XD

Engine plugin • Application Plugin • code • Load • code

thanks again. http://blog.xdite.net http://twitter.com/xdite

OSDC 2009 Rails Turtorial

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