I’ve participated in
several projects with
different contexts
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I’ve seen code
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I’ve seen complex code
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I’ve seen duplicated code
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I’ve seen Rails code
reimplemented in apps
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How often do you see them?
All the time. They're everywhere.
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You get used to it after
some time
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And that’s a big problem
People are afraid to deal with code like that.
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Rails tricks / features
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That might help you
refactor existing code
or improve your developer life a bit
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Web Development
Consultancy
Mainly focused in Ruby and Rails
Based in São Paulo - Brazil
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No content
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❤️
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plataformatec/devise
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plataformatec/simple_form
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elixir-lang/elixir
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Rails Core Team
! Carlos Antonio
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Rails Core Team
José Valim Carlos Antonio Rafael França
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We use pull requests
and code review
All the f*cking time.
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We do cross project
code review
Sometimes, when the time allows us.
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And it’s usual to learn
new things in the process
We’re always learning, right?
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ಠ_ಠ
I had to do this talk after this look of disapproval
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Rails tricks / features
Not used by many
Not very well known and / or documented
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What we will see:
Active Record
Active Model
Action Mailer
Action View
Action Controller
Bonus Stuff
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Active Record
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migrations: change column null
class ChangeNameToNotNullOnAuthors < ActiveRecord::Migration
def up
change_column :authors, :name, :string, null: false
end
!
def down
change_column :authors, :name, :string, null: true
end
end
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migrations: change column null
class ChangeNameToNotNullOnAuthors < ActiveRecord::Migration
def up
change_column_null :authors, :name, false
end
!
def down
change_column_null :authors, :name, true
end
end
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migrations: change column null
class ChangeNameToNotNullOnAuthors < ActiveRecord::Migration
def change
change_column :authors, :name, :string, null: false
end
end
# => ActiveRecord::IrreversibleMigration
!
class ChangeNameToNotNullOnAuthors < ActiveRecord::Migration
def change
change_column_null :authors, :name, false
end
end
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migrations: change column default
class ChangeStatusDefaultOnArticles < ActiveRecord::Migration
def up
change_column :articles, :status, :string, default: 'draft'
end
!
def down
change_column :articles, :status, :string, default: 'published'
end
end
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migrations: change column default
class ChangeStatusDefaultOnArticles < ActiveRecord::Migration
def up
change_column_default :articles, :status, 'draft'
end
!
def down
change_column_default :articles, :status, 'published'
end
end
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migrations: change column default
class ChangeStatusDefaultOnArticles < ActiveRecord::Migration
def change
change_column :articles, :status, :string, default: 'draft'
end
end
# => ActiveRecord::IrreversibleMigration
!
class ChangeStatusDefaultOnArticles < ActiveRecord::Migration
def change
change_column_default :articles, :status, 'draft'
end
end
# => ActiveRecord::IrreversibleMigration
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Relation#merge
class Author < ActiveRecord::Base
has_many :articles
!
scope :with_draft_articles, -> {
uniq.joins(:articles).
where(articles: { status: 'draft' })
}
end
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Relation#merge
>> Author.with_draft_articles.to_sql
!
SELECT DISTINCT "authors".*
FROM "authors"
INNER JOIN "articles" ON "articles"."author_id" = "authors"."id"
WHERE "articles"."status" = 'draft'
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Relation#merge
class Author < ActiveRecord::Base
has_many :articles
!
scope :with_draft_articles, -> {
uniq.joins(:articles).merge(Article.draft)
}
end
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Relation#merge
>> Author.with_draft_articles.to_sql
!
SELECT DISTINCT "authors".*
FROM "authors"
INNER JOIN "articles" ON "articles"."author_id" = "authors"."id"
WHERE "articles"."status" = 'draft'
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group counting
>> Article.group(:status).count
!
SELECT COUNT(*) AS count_all, status AS status
FROM "articles"
GROUP BY status
!
=> {"draft"=>7, "published"=>2}
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group counting: multiple attrs
>> Article.group(:status, :category).count
!
SELECT COUNT(*) AS count_all,
status AS status, category AS category
FROM "articles"
GROUP BY status, category
!
=> {["draft", nil]=>5, ["draft", "Talks"]=>2,
["published", "News"]=>1, ["published", "Releases"]=>1}
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first!
relation = Article.where(title: 'UNKNOWN')
!
relation.first or raise(ActiveRecord::RecordNotFound, 'ZOMG not found')
# => ZOMG Article found (ActiveRecord::RecordNotFound)
!
relation.first!
# => ActiveRecord::RecordNotFound
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last!
relation = Article.where(title: 'UNKNOWN')
!
relation.last or raise(ActiveRecord::RecordNotFound, 'ZOMG not found')
# => ZOMG Article found (ActiveRecord::RecordNotFound)
!
relation.last!
# => ActiveRecord::RecordNotFound
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where.not
class Article < ActiveRecord::Base
scope :not_draft, -> { where 'status != ?', 'draft' }
end
!
>> Article.not_draft.to_sql
!
SELECT "articles".*
FROM "articles"
WHERE (status != 'draft')
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where.not
class Article < ActiveRecord::Base
scope :not_draft, -> { where.not status: 'draft' }
end
!
>> Article.not_draft.to_sql
!
SELECT "articles".*
FROM "articles"
WHERE ("articles"."status" != 'draft')
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eager load strategies
>> Article.includes(:author)
!
SELECT "articles".* FROM "articles"
!
SELECT "authors".* FROM "authors"
WHERE "authors"."id" IN (980190962, 298486374)
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eager load strategies
>> Article.includes(:author).order('authors.name')
!
SELECT "articles"."id" AS t0_r0 ………… "authors"."updated_at" AS t1_r4
FROM "articles"
LEFT OUTER JOIN "authors" ON "authors"."id" = “articles"."author_id"
ORDER BY authors.name
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eager load strategies
>> Article.eager_load(:author)
!
SELECT "articles"."id" AS t0_r0 ………… "authors"."updated_at" AS t1_r4
FROM “articles"
LEFT OUTER JOIN "authors" ON "authors"."id" = “articles"."author_id"
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eager load strategies
>> Article.preload(:author)
!
SELECT "articles".* FROM “articles"
!
SELECT "authors".* FROM “authors"
WHERE "authors"."id" IN (980190962, 298486374)
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eager load strategies
>> Article.preload(:author).joins(:author).order('authors.name')
!
SELECT "articles".*
FROM "articles"
INNER JOIN "authors" ON "authors"."id" = "articles"."author_id"
ORDER BY authors.name
!
SELECT "authors".*
FROM "authors"
WHERE "authors"."id" IN (980190962, 298486374)
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order :asc/:desc
class Article < ActiveRecord::Base
scope :recent, -> { order 'created_at DESC' }
end
!
>> Article.recent
!
SELECT "articles".* FROM "articles"
ORDER BY created_at DESC
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order :asc/:desc
class Article < ActiveRecord::Base
scope :recent, -> { order created_at: :desc }
end
!
>> Article.recent
!
SELECT "articles".* FROM "articles"
ORDER BY "articles"."created_at" DESC
benchmark
>> ActiveRecord::Base.benchmark 'SUPER EXPENSIVE OPERATION' do
?> Article.expensive_operation
>> end
SUPER EXPENSIVE OPERATION (2000.9ms)
=> "did something very expensive"
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benchmark
class Article < ActiveRecord::Base
def self.expensive_operation
benchmark 'SUPER EXPENSIVE OPERATION' do
sleep 2
'did something very expensive'
end
end
end
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No content
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http://railsgirlssummerofcode.org/campaign/
And I got a free hug!
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Active Model
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ActiveModel::Model
class EmailContact
attr_accessor :name, :email, :message
!
def deliver
if name.present? && email.present? && message.present?
puts 'deliver email'
end
end
end
ActiveModel::Model
class EmailContact
extend ActiveModel::Naming
extend ActiveModel::Translation
include ActiveModel::Validations
include ActiveModel::Conversion
!
attr_accessor :name, :email, :message
validates :name, :email, :message, presence: true
!
def deliver
if valid?
puts 'deliver email'
end
end
!
def persisted?
false
end
end
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ActiveModel::Model
class EmailContact
include ActiveModel::Model
!
attr_accessor :name, :email, :message
validates :name, :email, :message, presence: true
!
def deliver
if valid?
puts 'deliver email'
end
end
end
ActiveModel::Model
>> contact = EmailContact.new
=> #
!
>> contact.valid?
=> false
!
>> contact.errors.full_messages.to_sentence
=> "Name can't be blank, Email can't be blank, and
Message can't be blank"
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Action Mailer
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Mailer with i18n subject
class Notifier < ActionMailer::Base
default from: "from@example.com"
!
# Subject can be set in your I18n file at config/locales/en.yml
# with the following lookup:
#
# en.notifier.new_article.subject
#
def new_article
@greeting = "Hi"
!
mail to: "to@example.org"
end
end
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Mailer with i18n subject
class Notifier < ActionMailer::Base
default from: "from@example.com"
!
!
!
!
!
!
def new_article
@greeting = "Hi"
!
mail to: "to@example.org", subject: I18n.t('subjects.new_article')
end
end
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Mailer with i18n subject
en:
subjects:
new_article: 'New article just published.'
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Mailer with i18n subject
en:
notifier:
new_article:
subject: 'New article just published.'
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Mailer with i18n subject
class Notifier < ActionMailer::Base
default from: "from@example.com"
!
def new_article
@greeting = "Hi"
!
mail to: "to@example.org"
end
end
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Mailer with i18n subject
class Notifier < ActionMailer::Base
default from: "from@example.com"
!
def new_article
@greeting = "Hi"
!
mail to: "to@example.org",
subject: I18n.t('subjects.new_article', title: 'Clarity is king')
end
end
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Mailer with i18n subject
en:
subjects:
new_article: 'New article: %{title}.'
Mailer with i18n subject
class Notifier < ActionMailer::Base
default from: "from@example.com"
!
def new_article
@greeting = "Hi"
!
mail to: "to@example.org",
subject: default_i18n_subject(title: 'Clarity is king')
end
end
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Action View
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content_tag_for
<%= content_tag_for :article, @articles do |article| %>
<%= article.title %>
<%= simple_format article.body %>
<% end %>
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content_tag_for
Rails 4.2.0 is going to be more Adequate
Rails 4.2.0 is going to be made more Adequate by
Tenderlove and Gorby Puff
Rails 4.1.0 Released
Rails 4.1.0 was just released before RailsConf
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content_tag_for
<%= content_tag_for :section, @author do |author| %>
redirects with params
get '/articles/:id' => redirect('/articles/%{id}/edit')
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exceptions handling
$ ls public/*.html
!
404.html 422.html 500.html
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exceptions handling
# config/application.rb
!
# Use the app's own router to display error pages.
config.exceptions_app = self.routes
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exceptions handling
# config/routes.rb
!
get "/404", to: "errors#not_found"
get "/422", to: "errors#unprocessable_entity"
get "/500", to: "errors#server_error"
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exceptions handling
class ErrorsController < ApplicationController
layout "error"
!
def not_found
render status: :not_found
end
!
def server_error
render status: :server_error
end
!
def unprocessable_entity
render status: :unprocessable_entity
end
end
app
>> app.author_path(Author.first)
=> “/authors/298486374"
!
>> app.get _
Started GET "/authors/298486374" for 127.0.0.1 at 2014-04-22 19:31:04
-0500
Processing by AuthorsController#show as HTML
…
Rendered authors/show.html.erb within layouts/application (1.1ms)
Completed 200 OK in 9ms (Views: 7.7ms | ActiveRecord: 0.2ms)
=> 200
!
>> app.class
=> ActionDispatch::Integration::Session
application console helpers
# lib/console_helpers.rb
module ConsoleHelpers
def a(id)
Article.find(id)
end
end
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application console helpers
# config/application.rb
module RailsConf2014
class Application < Rails::Application
console do
require 'console_helpers'
Rails::ConsoleMethods.send :include, ConsoleHelpers
end
end
end
console sandbox
$ rails console --sandbox
…
Any modifications you make will be rolled back on exit
!
!
!
>> exit
rollback transaction
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Annotations
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annotations
class Author < ActiveRecord::Base
# TODO: create inactive scope
scope :active, -> { where active: true }
end
!
class Article < ActiveRecord::Base
# FIXME: Fix for RailsConf
scope :published, -> { where status: 'published' }
end
!
class AuthorsController < ApplicationController
# OPTIMIZE: eager load stuff
def show
@author = Author.find(params[:id])
end
end
rails update
$ rake rails:update
identical config/boot.rb
exist config
conflict config/routes.rb
./railsconf2014-404/config/routes.rb? (enter "h" for help) [Ynaqdh] h
Y - yes, overwrite
n - no, do not overwrite
a - all, overwrite this and all others
q - quit, abort
d - diff, show the differences between the old and the new
h - help, show this help
./railsconf2014-404/config/routes.rb? (enter "h" for help) [Ynaqdh] a
force config/routes.rb
…
exist config/initializers
identical config/initializers/backtrace_silencers.rb
create config/initializers/cookies_serializer.rb
identical config/initializers/filter_parameter_logging.rb
…
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rails update
$ git status
On branch master
Changes not staged for commit:
(use "git add ..." to update what will be committed)
(use "git checkout -- ..." to discard changes in working directory)
!
modified: Gemfile
modified: Gemfile.lock
modified: config/environment.rb
modified: config/environments/development.rb
modified: config/environments/production.rb
modified: config/environments/test.rb
modified: config/initializers/mime_types.rb
modified: config/initializers/session_store.rb
modified: config/routes.rb
!
Untracked files:
(use "git add ..." to include in what will be committed)
!
config/initializers/cookies_serializer.rb
config/secrets.yml
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Every single part of
Rails has hidden tricks
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They are sometimes
hard to spot
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But they can make you
much more productive
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So every time you start
something new
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Before ever considering
about pattern X, Y or Z
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Ask yourself:
How Rails can help me?
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Search
API
Guidelines
Google
Stack Overflow
…
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Ask
Stack Overflow
Rails Talk mailing list
IRC
…
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Follow
Changelogs
Release Notes
Upgrading Guides
Commits (if you can)
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And if you do find some
hidden trick, remember…
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With great moustache!
!
!
!
comes great responsibility
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Share
Tweet
Blog post
Tell your friends
…
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Contribute
Back to Rails
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And please ping me too!
!
@cantoniodasilva
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Thank you ❤️
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Stickers!
@plataformatec
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Questions?
Get one of these mugs (5 only :D)
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Tricks that Rails!
didn’t tell you about
Carlos Antonio - @cantoniodasilva