rails best practices_slides

controllers In space

level 1

sad Code

Happy Code

controllers In space

LEVEL 1 controllers In Space

Example

elsif .retweets.where(:user_id =>tweet

tweet.user == current_userif

current_user.id).present?

FAT MODEL, SKINNY CONTROLLER/app/controllers/tweets_controller.rb

class TweetsController < ApplicationController def retweet tweet = Tweet.find(params[:id])

flash[:notice] =

"Sorry, you can't retweet your own tweets"

"You already retweeted!"

t = Tweet.new t.status = "RT #{tweet.user.name}: #{tweet.status}" t.original_tweet = tweet t.user = current_user t.save

flash[:notice] = "Succesfully retweeted"

redirect_to tweet endend

elsif .retweets.where(:user_id =>self

self.user == retweeter

FAT MODEL, SKINNY CONTROLLER/app/controllers/tweets_controller.rb

class TweetsController < ApplicationController def retweet tweet = Tweet.find(params[:id])

flash[:notice] =

"Sorry, you can't retweet your own tweets"

"You already retweeted!"

"Succesfully retweeted"

redirect_to tweet endend

else...

tweet.retweet_by(current_user)

/app/models/tweet.rb

class Tweet < ActiveRecord::Base def retweet_by(retweeter)

endend

retweeter.id).present?

@trending = Topic.find( :all, :conditions => ["started_trending > ?", 1.day.ago], :order => 'mentions desc', :limit => 5 )

Scope it out/app/controllers/tweets_controller.rb

def index @tweets = Tweet. find(

:all, :conditions => {:user_id => current_user.id},::

'created_at desc',order =>=> 10limit

...end

def index @tweets = Tweet.

...end

where( ).( ).( )

:user_id => current_user.id'created_at desc'order

limit 10

@trending = Topic. 'started_trending > ?', 1.day.agoorder 'mentions desc'limit 5

where( ).( ).( )

orderlimit

current_userdef index @tweets =

...end

( ).( )'created_at desc'order

limit 10

current_userdef index @tweets = .tweets.

Scope to the user

...end

'created_at desc'order

limit 10current_userdef index @tweets = .tweets.

...end

recent.

scopeclass Tweet < ActiveRecord::Base

:recent,

default_

...end

'created_at desc'

limit 10current_userdef index @tweets = .tweets.

...end

)scopeclass Tweet < ActiveRecord::Base

limit(5)

...end

/app/models/topic.rb

...end

scopeclass Topic < ActiveRecord::Base

:trending,

def index@trending = Topic.

'started_trending > ?', 1.day.agoorder 'mentions desc'where(

trending

where('started_trending > ?', '12-01-2010 14:02')

Will only work once

where('started_trending > ?', '12-01-2010 14:02')

same time!

limit(5)

...end

:trending,

trending

)).lambda {

...end

:trending,

( )).lambda {

limit(num)

(5)trending

@trending = Topic.trending(5)

@trending = Topic.trending

wrong number of args, 0 for 1

...end

:trending,

( )).lambda {

limit(num)

(5)trending

@trending = Topic.trending(5)

@trending = Topic.trending

| = nil

Ruby 1.9 FTW!

default_

Scope it out

('created_at desc'

...end

)scopeclass Tweet < ActiveRecord::Base

How do we override default scope?

order(:status).limit(10)@tweets = current_user.tweets.unscoped.

@tweets = current_user.tweets.order(:status).limit(10)

t = Tweet.newt.status = "RT #{@tweet.user.name}: #{@tweet.status}"t.original_tweet = @tweet

current_user has many tweets....

t.user = current_usert.save

current_user"RT #{@tweet.user.name}: #{@tweet.status}"status

original_tweet @tweet:: =>)

,=>.tweets.create(

fantastic filters/app/controllers/tweets_controller.rb

class TweetsController < ApplicationController

def edit

def update

def destroy

@tweet = Tweet.find(params[:id])

end...

/app/controllers/tweets_controller.rb

def edit

def update

def destroy

@tweet = Tweet.find(params[:id])@tweet = Tweet.find(params[:id])

end...

def get_tweet

before_filter :get_tweet, :only => [:edit, :update, :destroy]

fantastic filters

def edit

def update

def destroyend

end...

def get_tweet

before_filter :get_tweet, :only => [:edit, :update, :destroy]

private

Why are you hiding instance variables?

Tweet.find(params[:id])@tweet = @tweet = @tweet = get_tweetget_tweetget_tweet

fantastic filters

@tweet =

def edit

def update

def destroy

def get_tweet

private

get_tweet

@tweet = get_tweet

Keeping parameters in ac.ons

params[:id])(

(tweet_id)

fantastic filters

tweet_id)Tweet.find(

What should they be used for?

authorization

fantastic filters

Loggingwizards

fantastic filters/app/controllers/tweets_controller.rb

class TweetsController < ApplicationControllerbefore_filter :auth, :only => [:edit, :update, :destroy]

:except => [:index, :create]

class ApplicationController < ActionController::Base before_filter :require_login

class SessionsController < ApplicationController skip_before_filter :require_login, :only => [:new, :create]

But what about the login page itself?

Global Filters

level 2controller command

LEVEL 1 CONTROLLING YOUR CONTROLLERS

Example

/app/models/user.rb

class User < ActiveRecord::Base has_one :account_setting, :dependent => :destroyend

<%= fields_for :account_setting do |a| %>

Nested attributes

/app/views/users/edit.html.erb

LEVEL 2 controller command26

Nested attributes/app/controllers/users_controller.rb

@account_setting.save

@user = User.new(params[:user])@account_setting = AccountSetting.new(params[:account_setting])

class UsersController < ApplicationController def create

if @user.save@account_setting.user = @user

redirect_to(@user, :notice => 'User was successfully created.') else render :action => "new" end end end

Nested attributes/app/controllers/users_controller.rb

@user = User.new(params[:user])

class UsersController < ApplicationController def create

if @user.save redirect_to(@user, :notice => 'User was successfully created.') else render :action => "new" end end end

using Nested A8ributes

/app/models/user.rb

Nested attributes

/app/views/users/edit.html.erb

class UsersController < ApplicationController def new

@user = User.new end end

/app/controllers/users_controller.rb

(:account_setting => AccountSetting.new)

accepts_nested_attributes_for :account_setting

<%= ...

class User < ActiveRecord::Base has_one :account_setting, :dependent => :destroy

fields_for :account_setting do |a| %>

<%= form_for(@user) do |f| %>

Models without the database

/app/views/contact_us/new.html.erb

<h1>Contact Us</h1>

<%= form_for :contact, :url => send_email_path do |f| %> <div class="field"> <%= f.label :name %><br /> <%= f.text_field :name %> </div> <div class="field"> <%= f.label :email %><br /> <%= f.text_field :email %> </div> <div class="field"> <%= f.label :body %><br /> <%= f.text_area :body %> </div> <div class="actions"> <%= f.submit %> </div><% end %>

/app/controllers/contact_us_controller.rb

class ContactUsController < ApplicationController

def new end

def send_email

).deliverflash[:notice] = "Email sent, we'll get back to you"redirect_to root_path

end endend

name, email, body

name.blank? || email.blank? || body.blank?flash.now[:notice] = "Please fill out all fields"

name = params[:contact][:name]email = params[:contact][:email]body = params[:contact][:body]

render :action => 'new'elseNotifications.contact_us(

@contact_form.valid?!

def new

def send_email

).deliver

end endend

@contact_form = ContactForm.new(params[:contact_form])

@contact_form

@contact_form = ContactForm.new

render :action => 'new'elseNotifications.contact_us(flash[:notice] = "Email sent, we'll get back to you"redirect_to root_path

@contact_form.valid?

def new

def send_email

).deliver

end endend

@contact_form

render :action => 'new'else

Notifications.contact_us(flash[:notice] = "Email sent, we'll get back to you"redirect_to root_path

Use the positive inflection

def new

def send_email

).deliver

end endend

@contact_form

render :action => 'new'else

Notifications.contact_us(

use the redirect notice syntax

:notice "Email sent, we'll get back to you"redirect_to root_path, =>

render

def new

def send_email

).deliver

end endend

@contact_form

Notifications.contact_us(

shorten the render

:notice "Email sent, we'll get back to you"redirect_to root_path, =>

/app/views/contact_us/new.html.erb

<%= form_for , :url => send_email_path do |f| %>

<h1>Contact Us</h1>

@contact_form

/app/models/contact_form.rb

class ContactForm

attr_accessor :name, :email, :body

validates_presence_of :name, :email, :body

include ActiveModel::Validationsinclude ActiveModel::Conversion

def initialize(attributes = {}) attributes.each do |name, value| send("#{name}=", value) end end

def persisted? false end

<%= form_for @contact_form

ContactForm.new(params[:contact_form])

really Rest

class UsersController

< ApplicationController

subscribe_mailing_list current_user.subscribe(params[:id]) redirect_to current_user, :notice => "You've been subscribed" end def unsubscribe_mailing_list current_user.unsubscribe(params[:id]) redirect_to current_user, :notice => "You have been unsubscribed" end

/app/controllers/subscrip5ons_controller.rb

really Rest

class SubscriptionsController

< ApplicationController

create current_user.subscribe(params[:id]) redirect_to current_user, :notice => "You've been subscribed" end def destroy current_user.unsubscribe(params[:id]) redirect_to current_user, :notice => "You have been unsubscribed" end

really Rest Use your best judgement

More than 2 levels is bad/users/1/posts/2/comments/3

Not using REST is okay/config/routes.rb

get "contact_us/new"post "contact_us/send_email", :as => "send_email"

Enter the Presenters

Enter the Presenters/app/controllers/tweets_controller.rb

@followers_tweets = current_user.followers_tweets.limit(20) @recent_tweet = current_user.tweets.first @following = current_user.following.limit(5) @followers = current_user.followers.limit(5) @recent_favorite = current_user.favorite_tweets.first @recent_listed = current_user.recently_listed.limit(5) if current_user.trend_option == "worldwide" @trends = Trend.worldwide.by_promoted.limit(10) else @trends = Trend.filter_by(current_user.trend_option).limit(10) end ....

def index

Enter the Presenters/app/controllers/tweets_controller.rb

def index

end@presenter = Tweets::IndexPresenter.new(current_user)

/config/applica5on.rb

config.autoload_paths += [config.root.join("app/presenters")]

/app/presenters/tweets/index_presenter.rb

def initialize(user) @user = user end

class Tweets::IndexPresenter

Enter the Presenters/app/presenters/tweets/index_presenter.rb

def index

Old Controller

@followers_tweets = current_user.followers_tweets.limit(20)@recent_tweet = current_user.tweets.first

if .trend_option == "worldwide"current_user

.trend_option).limit(10)end

current_user

@trends = Trend.worldwide.by_promoted.limit(10)else@trends = Trend.filter_by(

.followers_tweets.limit(20)

.tweets.first

if .trend_option == "worldwide"

.trend_option).limit(10)end

def followers_tweets @user. end

Trend.worldwide.by_promoted.limit(10)elseTrend.filter_by(@user.

@user.

def recent_tweet@user

def trends

/app/views/tweets/index.html.erb

<%= @presenter.recent_tweet.created_at %><%= @presenter.recent_tweet.body %>

def index

end@presenter = Tweets::IndexPresenter.new(current_user)

.tweets.firstdef recent_tweet

Two objects!

@recent_tweet ||= .tweets.firstdef recent_tweet

def index@presenter = Tweets::IndexPresenter.new(current_user)

Memoized

One object!

.tweets.firstdef recent_tweet@user

def index@presenter = Tweets::IndexPresenter.new(current_user)

extend ActiveSupport::Memoizable

memoize :recent_tweet, :followers_tweet, ...

Memoizationone is better than the other

value is not stored if false or nil is returned

extend ActiveSupport::Memoizablememoize :recent_tweet, :followers_tweet, ...

def expensive(num) # lots of processingend

memoize :expensive

expensive(2)expensive(4)

loaded from cache

reject sql injection

User.where("name = #{params[:name]}")

User.where("name = ?", params[:name])

Tweet.where("created_at >= :start_date AND created_at <= :end_date", {:start_date => params[:start_date], :end_date => params[:end_date]})

Tweet.where(:created_at => (params[:start_date].to_date)..(params[:end_date].to_date))

User.where(:name => params[:name])

Rails 3 responder syntax

do |format| format.html # show.html.erb format.xml { render :xml => @user } end

respond_to

do |format| format.html format.xml { render :xml => @users.to_xml } end

respond_to

def index @users = User.all

end...

def show @user = User.find(params[:id])

class UsersController < ApplicationController

Rails 3 responder syntax

respond_to

def index @users = User.all

end...

def show @user = User.find(params[:id])

class UsersController < ApplicationController:html, :xml, :json

respond_with(@users)

respond_to

respond_with(@user)

level 3

Model Mayhem

LEVEL 3 Model mayhem

Loving your indices

current_user.tweets

class AddIndexesToTables < ActiveRecord::Migration def self.up add_index :tweets, :user_id end

def self.down remove_index :tweets, :user_id endend

current_user.tweets.order('created_at desc').limit(10)Topic.where("started_trending > ?", 1.day.ago).order('mentions desc').limit(5)

class AddIndexesToTables < ActiveRecord::Migration def self.up add_index :tweets, [:user_id, :created_at]

def self.down

endend

remove_index :tweets, [:user_id, :created_at]remove_index :topics, [:started_trending, :mentions]

add_index :topics, [:started_trending, :mentions]

If these queries are run a great deal

Loving your indices

Use your best judgement

More indices, more time it takes to reindex

If a 2 second query runs 5 times a week,

who cares?

Loving your indices

LEVEL 3 Model mayhem59

$ curl -d "user[login]=hacked&user[is_admin]=true&user[password]=password&user[password_confirmation]=password&user[email]=hacked@by.me" http://url_not_shown/users

user[is_admin]=true

protecting your attributes/app/models/user.rb

class User < ActiveRecord::Base attr_protected :is_adminend

/app/models/user.rb

class User < ActiveRecord::Base attr_accessible :email, :password, :password_confirmationend

whitelists are better for security

default values/app/models/account_se7ng.rb

before_create :set_default_timezone def set_default_timezone self.time_zone = "EST"end

class AccountSetting < ActiveRecord::Base belongs_to :user

default values/app/models/account_se7ng.rb

class AccountSetting < ActiveRecord::Base belongs_to :user

class AddDefaultTimeZoneToAccountSettings < ActiveRecord::Migration def self.up change_column_default :account_settings, :time_zone, 'EST' end

def self.down change_column :account_settings, :time_zone, :string, nil endend

/db/migrate/20110119150620_add_default_5me_zone_account_se7ngs.rb

Proper use of callbacks/app/models/topic.rb

Time.now + (60 * 60 * 24 * 7)self.finish_trending = end

class Topic < ActiveRecord::Base

before_create :set_trend_ending

private

def set_trend_ending

1.weekself.finish_trending = end

.from_now

private

1.week

self.finish_trending = end

.from_now

class Topic < ActiveRecord::BaseTRENDING_PERIOD =

TRENDING_PERIOD

Proper use of callbacks

Crea;ng an object

before_validationafter_validationbefore_saveafter_savebefore_createaround_createafter_create

Upda;ng an object Dele;ng an object

before_validationafter_validationbefore_saveafter_savebefore_updatearound_updateafter_update

before_destroyafter_destroyaround_destroy

Rails date helpers

Date Helpers

1.minute2.hour3.days4.week5.months6.year

Modifiers More Modifiers

beginning_of_daybeginning_of_weekbeginning_of_monthbeginning_of_quarterbeginning_of_year

2.weeks.ago3.weeks.from_now

next_weeknext_monthnext_year

* singular or plural

* end can be used

* prev can be used

/app/models/following.rb

class Following < ActiveRecord::Base after_create :send_follower_notification

def send_follower_notificationifqueue_new_follower_email

endend

self.followed_user.receive_emails?

class Following < ActiveRecord::Base after_create :

self.followed_user.receive_emails?def followed_can_receive_emails?

queue_new_follower_email

endend

:if => :followed_can_receive_emails?queue_new_follower_email,

class Following < ActiveRecord::Base after_create :queue_new_follower_email

:if => ,

Proc.new {|f| .followed_user.receive_emails?f }

improved validation

.errors.add(:name, 'is inappropriate')selfunless ContentModerator.is_suitable?( .name)

selfend

def validate

improved validation

.errors.add(:name, 'is inappropriate')

class Topic < ActiveRecord::Basevalidate :appropriate_content

private

def appropriate_contentselfunless ContentModerator.is_suitable?( .name)

selfend

improved validation

endend

class Topic < ActiveRecord::Basevalidates :name, :appropriate => true

/lib/appropriate_validator.rb

class AppropriateValidator < ActiveRecord::EachValidator def validate_each(record, attribute, value)

.errors.add( , 'is inappropriate')unless ContentModerator.is_suitable?(value)

endrecord attribute

Don’t forget to require this/lib isn’t auto-‐loaded by default

Sowing the Seeds

/db/migrate/20110114221048_create_topics.rb

class CreateTopics < ActiveRecord::Migration def self.up create_table :topics do |t| t.string :name t.datetime :started_trending t.integer :mentions

t.timestamps end

def self.down drop_table :topics endend

Topic.create(Topic.create(Topic.create(

)):name => "Ruby5", :mentions => 2312

:name => "Top Ruby Jobs", :mentions => 231:name => "Rails for Zombies", :mentions => 1023)

Sowing the Seeds

/db/seeds.rb

$ rake db:seed

Run from command line

mentions Won’t be set!

class Topic < ActiveRecord::Base attr_protected :mentionsend

Topic.create(Topic.create(Topic.create(

):name => "Ruby5", :mentions => 2312:name => "Top Ruby Jobs", :mentions => 231:name => "Rails for Zombies", :mentions => 1023

Sowing the Seeds

/db/seeds.rb

:name => "Ruby5", :mentions => 2312:name => "Top Ruby Jobs", :mentions => 231:name => "Rails for Zombies", :mentions => 1023

topics.each do |attributes|Topic.create do |t|t.name = attributes[:name]

topics = [{ },{ },{ }

What if we want to be able to update the seed?

t.mentions = attributes[:mentions] endend

Sowing the Seeds

/db/seeds.rb

topics.each do |attributes|Topic.create do |t|t.name = attributes[:name]

topics = [{ },{ },{ }

Topic.destroy_all

Dangerous if there are lots of relationships

t.mentions = attributes[:mentions] endend

Sowing the Seeds

/db/seeds.rb

topics.each do |attributes|Topic. attributes[:name]

topics = [{ },{ },{ }

find_or_initialize_by_name( ).tap do |t| t.mentions = attributes[:mentions]

endend

t.save!

Level 4Model Bert

N+1 is not for fun/app/models/user.rb

class User def recent_followers self.followers.recent.collect{ |f| f.user.name }.to_sentence endend

=> "Gregg, Eric, Dray, and Nate"

Select followers where user_id=1

Select user where id=2

LEVEL 4 Model Bert83

N+1 is not for fun/app/models/user.rb

class User def recent_followers self.followers.recent .collect{ |f| f.user.name }.to_sentence endend

.includes(:user)

Select followers where user_id=1

Select users where user_id in (2,3,4,5)

2 queries instead of 5!

h"ps://github.com/flyerhzm/bulletBullet gem

To find all your n+1 queries

counter_cache Money/app/views/tweets/index.html.erb

<% @tweets.each do |tweet| %>

2 ReTweets1 ReTweets0 ReTweets

Bad English

pluralize( , "ReTweet")

2 ReTweets1 ReTweet0 ReTweets

, "ReTweet")

1. Select all retweets where user_id=X2. Populate an array of tweet objects3. Call length on that array

For Each tweetLots of unneeded objects

pluralize(

1. Select all retweets where user_id=X2. do a count query for retweets

For Each tweet

possibly 10+ count queriesLEVEL 4 Model Bert

1. Select all retweets where user_id=XFor Each tweet

There is no step 2

with counter_cache

counter_cache Money

Tweet Tweet

retweets

original_tweet

has_many

belongs_to

original retweet

has_many :retweets, :class_name => 'Tweet', :foreign_key => :tweet_idend

class Tweet < ActiveRecord::Base belongs_to :original_tweet, :class_name => 'Tweet', :foreign_key => :tweet_id

class AddCountRetweets def self.up add_column :tweets, :retweets_count, :integer, :default => 0 end ...

Our migra;on

retweets_count

counter_cache Money

true:counter_cache =>

class Tweet < ActiveRecord::Base belongs_to :original_tweet, :class_name => 'Tweet', :foreign_key => :tweet_id

retweets_count

, unable to find tweets_count

counter_cache Money

:counter_cache =>

class Tweet < ActiveRecord::Base belongs_to :original_tweet, :class_name => 'Tweet', :foreign_key => :tweet_id,

retweets_count:

current_user.tweets.create( :status => "RT #{self.user.name}: #{self.status}", :original_tweet => self )

UPDATE "tweets" SET "retweets_count" = "retweets_count" + 1 WHERE ("tweets"."id" = 42)

will cause an insert AND

counter_cache Money

t.retweets.length pull all recordsthen calls .length

pull all recordsthen calls .length

t.retweets.count count query count query

t.retweets.size count queryno query

look at cache

Without Cache Counter With Cache Counter

Batches of find_each/lib/tasks/long_running_task.rake

Not so good if you have millions of tweets

desc 'Task involving all tweets'task :tweet_task => :environment do

Tweet.all.each do |tweet| p "task for #{tweet}" end

Tweet each do |tweet| p "task for #{tweet}" end

.find_

pulls batches of 1,000 at a time

Tweet each do |tweet| p "task for #{tweet}" end

.find_ (:batch_size => 200)

pulls batches of 200 at a time

Law of DemeterEach unit should have limited knowledge about other units

“don’t talk to strangers”

tweet user account settings

XLEVEL 4 Model Bert

Law of Demeter/app/models/tweet.rb

The tweet shouldn’t know about account_setting!

class Tweet < ActiveRecord::Base def location_data if self.user.account_setting.location_on_tweets self.location else "unavailable" end endend

Law of Demeter/app/models/tweet.rb

class Tweet < ActiveRecord::Base def location_data if self.user.location_on_tweets self.location else "unavailable" end endend

delegate :location_on_tweets,

/app/models/user.rb

:to => :account_setting:public_email,

Additional MethodsLEVEL 4 Model Bert

Law of Demeter

/app/models/user.rb

:to => :account_setting:public_email,

tweet user account settingsX

self.user.location_on_tweets

ERROR!! account_setting is nil!

Law of Demeter

/app/models/user.rb

:to => :account_setting:public_email

tweet user account settingsX

self.user.location_on_tweets

:allow_nil => true

Returns nil when Account_Settings is missing

Head to to_s /app/models/user.rb

<%= @user.display_name %>

class User < ActiveRecord::Base def display_name "#{first_name} #{last_name}" endend

Head to to_s /app/models/user.rb

<%= @user %>

class User < ActiveRecord::Base def to_s "#{first_name} #{last_name}" endend

to_param-alama ding dong

/post/2133

class Topic < ActiveRecord::Base def to_param "#{id}-#{name.parameterize}" endend

/post/rails-best-practices

SEO Friendly URLS

/post/2133-rails-best-practices

to_param-alama ding dong/app/models/topic.rb

class Topic < ActiveRecord::Base def to_param "#{id}-#{name.parameterize}" endend

/post/2133-rails-best-practices

<%= link_to topic.name, topic %>

Will generate

Topic.find(params[:id])

{:id => "2133-rails-best-practices"}

Will call to_i

Topic.find(2133)

Level 5Froggy Views

The example

LEVEL 5 Froggy Views107

LEVEL 5 Froggy Views

No queries in your view!/app/views/tweets/index.html.erb

current_user.who_to_follow.limit(5)<% <li><%= f.name %> - <%= link_to "Follow", follow_user_path(f) %></li><% end %>

.each do |f| %>

Query shouldn’t be in our view!

No queries in your view!/app/views/tweets/index.html.erb

<% <li><%= f.name %> - <%= link_to "Follow", follow_user_path(f) %></li><% end %>

.each do |f| %>

def index @who_to_follow = end

current_user.who_to_follow.limit(5)

@who_to_follow

Helper Skelter/app/views/tweets/index.html.erb

@followers_count %></span><% @recent_followers.each do |f| %>

<div class="followers">Followers<span><%=

Following<span><%= @following_count %></span><% @recent_following.each do |f| %>

@followers_count @recent_followers@following_count @recent_following

<%= follow_box(<%= follow_box(

"Followers", , ) %>"Following", , ) %>FollowersFollowing

/app/helpers/tweets_helper.rb

def follow_box(title, count, recent)

str = "<div class=\"#{title.downcase \">" + "#{title}<span>#{count}</span>"

recent.each do |user|str += "<a href=\"#{user_path(user)}\">"str += "<img src=\"#{user.avatar.url(:thumb)}\">"str += "</a>"

Use proper link_to and image_tag

+= "</div>")raw(str

Helper Skelter

"Followers", , ) %>"Following", , ) %>

str = "<div class=\"#{title.downcase \">" + "#{title}<span>#{count}</span>"

recent.each do |user|str +=

user.avatar.url(:thumb)link_to user do

image_tag(end

Use html helpers?

+= "</div>")raw(str

Helper Skelter

title.downcasetitle count

recent.each do |user|str +=

image_tag(end

content_tag :div, :class => dostr = )

raw(str

+ content_tag(:span,

Annoying str variable

Helper Skelter

title.downcase

titlecount

recent.

image_tag(end

content_tag :div, :class => do

content_tag(:span, +collect do |user|

Helper Skelter

The Example

Partial sanity/app/views/tweets/index.html.erb

/app/views/tweets/_trending.html.erb

<% end %></ul>

<%= render :partial => 'trending' %><h2>Trends</h2>

<% end %></ul>

<%= render 'trending' %><h2>Trends</h2>

There are instance variables

in our partial!

<h3><%=

@user.trending_area

%></h3><ul> <%

@trending

.each do |topic| %><li> <%= link_to topic.name, topic %> <% if topic.promoted? %> <%= link_to image_tag('promoted.jpg'), topic %> <% end %></li>

<% end %></ul>

<%= render 'trending'%>

<h2>Trends</h2>, :area => ,:topics =>

topics

Partial sanity/app/views/tweets/_trending.html.erb

<% end %></ul>

topics

/app/views/topics/_topic.html.erb

<%= render topic %>'topics/topic', :topic =>

<% end %></ul>

topics

<%= render topic %>

Using Class name to find partial

topics

<%= render<ul>

%>:partial => 'topics/topic', :collection =>

topics

<%= render<ul>

empty string things

<% if @user.email.blank? %>

<% unless @user.email? %>

<% if @user.email.present? %>

<% if @user.email? %>

empty string things

<%= @user.city || @user.state || "Unknown" %>

If city is empty “” it will print “”

city = @user.city if @user.city.present?state = @user.state if @user.state.present?

=> “”

<%= city || state || "Unknown" %>

empty string things

<%= @user.city || @user.state || "Unknown" %>

<%= @user.city.presence || @user.state.presence || "Unknown" %>

empty string things

city is nil

undefined method `titleize' for nil:NilClass

<%= @user.city.titleize %>|| "Unknown"

empty string things

<%= @user.city.titleize %><% if @user.city %>

<% else %> Unknown<% end %>

<%= @user.city ? @user.city.titleize : "Unknown" %>

<%= @user.city.try(:titleize) || "Unknown" %>

The example

rock your block helpers

<% @presenter.tweets.each do |tweet| %>

<% end %>

<div id="tweet_<%= tweet.id %>" class="<%= 'favorite' if tweet.is_a_favorite?(current_user) %>"><%= tweet.status %>

</div>

rock your block helpers

<% @presenter.tweets.each do |tweet| %>

<% end %>

<%= tweet.status %>

<%= tweet_div_for(tweet, current_user) do %>

<% end %>

def tweet_div_for(tweet, user, &block)klass = 'favorite' if tweet.is_a_favorite?(user)

content_tag tweet klass do yield endend

, :class =>

id="tweet_<%= tweet.id %>"

Yield to the content_for/app/views/layouts/applica5on.html.erb

<!DOCTYPE html><html><body> <h1>Twitter</h1>

Need to insert content here!

<% if flash[:notice] %> <span style="color: green"><%= flash[:notice] %></span> <% end %> <%= yield %></body></html>

Yield to the content_for/app/views/layouts/applica5on.html.erb

<!DOCTYPE html><html><body> <h1>Twitter</h1>

<%= yield :sidebar %>

<% content_for(:sidebar) do %> ... html here ...<% end %>

<% if flash[:notice] %> <span style="color: green"><%= flash[:notice] %></span> <% end %> <%= yield %></body></html>

what if all actions in the tweet controller need the sidebar?

class TweetsController < ApplicationControllerlayout 'with_sidebar'

/app/views/layouts/with_sidebar.html.erb

<% content_for(:sidebar) do %> ... html here ...<% end %><%= render :file => 'layouts/application' %>

/app/views/layouts/applica5on.html.erb

<%= yield :sidebar %>

<% if flash[:notice] %> <span style="color: green"><%= flash[:notice] %></span> <% end %> <%= yield %>

The example

meta Yield/app/views/layouts/applica5on.html.erb

cluttering your controller

& polluting with view concerns

class TweetsController < ApplicationController def show @tweet = Tweet.find(params[:id]) @title = @tweet.user.name @description = @tweet.status @keywords = @tweet.hash_tags.join(",") endend

@description || "The best way ..." %>"> <meta name ="keywords" content="<%= @keywords || "social,tweets ..." %>">...

<!DOCTYPE html><html><head> <title>Twitter <%= %></title> <meta name="description" content="<%=

@title

meta Yield/app/views/layouts/applica5on.html.erb

<% content_for(:title, @tweet.user.name)content_for(:description, @tweet.status)content_for(:keywords, @tweet.hash_tags.join(","))%>

/app/views/tweets/show.html.erb

<!DOCTYPE html><html><head> <title>Twitter <%= %></title> <meta name="description" content="<%=

yield(:title)

yield(:description)

yield(:keywords)

|| "The best way ..." %>">

|| "social,tweets ..." %>">

meta Yield

<% title @tweet.user.name description @tweet.status keywords @tweet.hash_tags.join(",")%>

/app/views/tweets/show.html.erb

/app/helpers/applica5on_helper.rb

def title(title) content_for(:title, title)end

def description(description) content_for(:description, description)end

def keywords(keywords) content_for(:keywords, keywords)end

rails best practices_slides

alama ding

top ruby jobs

databaseclass

rbclass tweetscontroller

class userscontroller

rb def initialize

fromnowclass

endscopeclass

Education

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introduction à rails - paris on rails 2006

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conferencia rails: integracion continua y rails