Sokushu Rails 5

Setup

通常のrails

rails new normal
cd normal
rails s
open http://localhost:3000

API Modeのrails

rails new backend --api
cd backend
rails s

API Mode

cd backend
rails middleware

diff -u <(cd normal && rails middleware) <(cd backend && rails middleware)

Generatorでviewやhelperを生成しない

rails g scaffold Project title:string started_at:datetime
rails g controller issues index show

railsコマンドへの統一

rails -h
# or
rails

rake -T

ActiveRecord Attributes API

rails g scaffold Book title:string price_in_cents:decimal
rails db:migrate
rails c

# in irb
book = Book.create(title: 'Hello Ruby', price_in_cents: 10.1)
book.price_in_cents

class Book < ActiveRecord::Base
  attribute :price_in_cents, :integer # 追加
end

# in irb
book = Book.create(title: 'Hello Ruby', price_in_cents: 10.1)
book.price_in_cents

ActiveRecord::Relation#in_batches

rails g scaffold User name:string email:string verified:boolean
rails db:migrate

2100.times do |n|
  User.create(name: "user_#{n}", email: "user_#{n}@test.com", verified: false)
end

User.in_batches.class
User.in_batches.update_all(verified: true)
User.in_batches.each do |relation|
  relation.class #=> User::ActiveRecord_Relation
  relation.update_all(verified: true)
  sleep 10
end

ActiveRecordの#saveにtouchオプションが追加

book = Book.find(1)
book.title = "new title!"
book.save(touch: false)

#or

User.where(id: [1,2]).or(User.where(name: "user_0"))

#left_outer_joinsと#left_joins

rails g migration AddAuthorIdToBooks

class AddAuthorIdToBooks < ActiveRecord::Migration[5.0]
  def change
    add_reference :books, :author, index: true
  end
end

rails db:migrate

Author.left_outer_joins(:books)

belongs_toのrequiredがデフォルトでtrueに

class Book < ApplicationRecord
  attribute :price_in_cents, :integer

  belongs_to :author # 追加
end

# in irb
book = Book.create(title: "Hello Rails 5!", author: nil)
book.errors.full_messages

Enumerable#pluck, #without

[{name: 'foo', point: 12}, {name: 'bar', point: 55}].pluck(:name)

["apple", "chocolate", "milk", "cookie"].without("apple", "milk")