What's New in Rails 5? - Speaker Deck

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What's new in Rails 5? Karol Galanciak Full Stack Developer at Twitter: @Azdaroth Github: Azdaroth https://karolgalanciak.com

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ActionCable

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ActionCable • Integration of WebSockets with the rest of your application

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ActionCable • Integration of WebSockets with the rest of your application • Both client-side and server-side tools

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ActionCable - server-side

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ActionCable - server-side • Connections - connection between consumer and the sever

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ActionCable - server-side • Connections - connection between consumer and the sever • Authentication / authorization goes here

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ActionCable - connections module ApplicationCable class Connection < ActionCable::Connection::Base identified_by :current_user def connect self.current_user = find_user! end private def find_user! User.find_by(id: cookies.signed[:user_id]) or raise UnauthorizedConnectionError end end end

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ActionCable - server-side • Channels - endpoints where the actual logic happens (~ controllers)

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ActionCable - channels class ChatChannel < ActionCable::Channel::Base def subscribed stream_from "chat_#{params[:room]}" end def receive(payload) ActionCable.server.broadcast("chat_#{params[:room]}", payload) end end

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ActionCable - client-side

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ActionCable - client-side //= require action_cable this.App || (this.App = {}); App.cable = ActionCable.createConsumer(); App.chatChannel = App.cable.subscriptions.create({ channel: "ChatChannel", room: "Rails Core" }, { received: function(data) { $(".chat").append("

" + data["sent_by"] + ": " + data["body"] + "

") } }); App.chatChannel.send({ sent_by: "DHH", body: "OMG, it works!" });

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Rails API

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Rails API • rails new rails_5_app --api

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Rails API • rails new rails_5_app —api • ApplicationController inherits from ActionController::API • Modiﬁes the generators (no views, helpers and assets)

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Attributes API

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Attributes API class Order < ActiveRecord::Base attribute :price_in_cents, :money attribute :description, :string, default: "Default description" attribute :ordered_at, :datetime, default: -> { Time.current } attribute :tags_not_backed_by_db, :string, array: true end class MoneyType < ActiveRecord::Type::Integer def deserialize(value) if value.to_s.include?("$") price_in_dollars = value.gsub(/\$/, "").to_d super(price_in_dollars * 100) else super end end end ActiveRecord::Type.register(:money, MoneyType)

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Attributes API class Order < ActiveRecord::Base attribute :price_in_cents, :money attribute :description, :string, default: "Default description" attribute :ordered_at, :datetime, default: -> { Time.current } attribute :tags_not_backed_by_db, :string, array: true end order = Order.new order.price_in_cents = "$10.0" order.price_in_cents => 1000 order.description => "Default description" order.ordered_at => "2016-01-01 12:00:00 +0200" order.tags_not_backed_by_db = ["WhateverItTakes", "5%", "Rich Piana"] order.tags_not_backed_by_db => ["WhateverItTakes", "5%", "Rich Piana"]

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Attributes API • custom types (requires #deserialize method for assigning values and #serialize when querying database)

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Attributes API • custom types (requires #deserialize method for assigning values and #serialize when querying database) • attributes don’t need to be backed by database

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Attributes API • custom types (requires #deserialize method for assigning values and #serialize when querying database) • attributes don’t need to be backed by database • supports dirty tracking

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Class / module variables per thread • cattr_accessor / mattr_accessor - but per thread - thread_cattr_accessor / thread_mattr_accessor

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Class / module variables per thread module OmgGlobal thread_mattr_accessor :current_user end class ApplicationController < ActionController::Base # Please, don't do it in real code! before_action :set_current_user_globally def set_current_user_globally OmgGlobal.current_user = current_user end end class Post < ActiveRecord::Base after_save :create_version private def create_version Version.create(model: self.class.to_s, attributes: attributes, who_did_it: OmgGlobal.current_user.id) end end

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Assets silenced by default in development

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Assets silenced by default in development • quite_assets gem

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Assets silenced by default in development • quite_assets gem • No more garbage in logs

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Assets silenced by default in development • quite_assets gem • No more garbage in logs Started GET "/assets/public/home.js?body=1" for 127.0.0.1 at 2016-09-27 19:31:46 +0200 Started GET "/assets/bootstrap/collapse.js?body=1" for 127.0.0.1 at 2016-09-27 19:32:04 +0200 Started GET "/assets/font-awesome/fontawesome-webfont.woff2?v=4.5.0" for 127.0.0.1 at 2016-09-27 19:32:04 +0200 Started GET "/assets/public/locales.js?body=1" for 127.0.0.1 at 2016-09-27 19:32:04 +0200

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ApplicationRecord

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ApplicationRecord • New base class for models

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ApplicationRecord class ApplicationRecord < ActiveRecord::Base include SoftDelete self.abstract_class = true has_paper_trail end class User < ApplicationRecord end

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Rendering outside controllers

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Rendering outside controllers OrdersController.render(:show, assigns: { order: Order.find(order_id) })

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Rendering outside controllers OrdersController.render(:show, assigns: { order: Order.find(order_id) }) OrdersController.render(:_order, assigns: { order: Order.find(order_id) })

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Rake / Rails commands

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Rake / Rails commands • All rails commands can be executed with rake and all rake commands can be executed with rails

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Rake / Rails commands rails db:migrate rake routes | grep some_route -> rails routes -g some_route

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Caching collections

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Caching collections • ActiveRecord::Collection#cache_key

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Caching collections posts.cache_key => "posts/query-c60f5cf40b4d0d6f492ea6961c43ceb6-100-20160927121435182129"

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Caching collections <% cache(@posts) do %> <% @posts.each do |post| %>

<%= render post %>

<% end %> <% end %>

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ActiveRecord no longer halts execution of the callbacks when returning false

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ActiveRecord no longer halts execution of the callbacks when returning false class Product < ActiveRecord::Base before_save :set_availability_status def set_availability_status self.available = somehow_compute_availability_status_which_returns_false end end product.save! => ActiveRecord::RecordNotSaved: ActiveRecord::RecordNotSaved

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ActiveRecord no longer halts execution of the callbacks when returning false • conﬁgurable with ActiveSupport.halt_callback_chains_on_return_false

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Belongs-to association required by default

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Belongs-to association required by default class Comment < ApplicationRecord belongs_to :author end

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Belongs-to association required by default class Comment < ApplicationRecord belongs_to :author, optional: true end

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Belongs-to association required by default • Conﬁgurable with Rails.application.conﬁg.active_record.belongs_to_r equired_by_default

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redirect_back method

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redirect_back method class UsersController < ApplicationController def update user = find_user user.update(params[:user]) redirect_to :back end end

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redirect_back method class UsersController < ApplicationController def update user = find_user user.update(params[:user]) redirect_back(fallback_location: root_path) end end

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ActiveRecord::Base.Suppress

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ActiveRecord::Base.Suppress

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ActiveRecord::Base.Suppress class Comment < ApplicationRecord belongs_to :author has_many :notifications after_save :send_notification def publish! update!(published_at: Time.current) end private def send_notification notifications.create(message: content, author: author) end end

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ActiveRecord::Base.Suppress class Comment < ApplicationRecord belongs_to :author has_many :notifications after_save :send_notification def publish! update!(published_at: Time.current) end def publish_without_notification! Notification.suppress do publish! end end private def send_notification notifications.create(message: content, author: author) end end

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Left Outer Join Support

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Left Outer Join Support User.left_outer_joins(:posts, :comments, :notifications) User.left_joins(:posts, :comments, :notifications)

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Conﬁg for UUIDs as primary keys

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Conﬁg for UUIDs as primary keys create_table :orders, id: :uuid do |t| end

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Config for UUIDs as primary keys • Configurable with: config.active_record.primary_key = :uuid

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Queue adapter conﬁgurable per job

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Queue adapter conﬁgurable per job config.active_job.queue_adapter = :delayed_job

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Queue adapter conﬁgurable per job class DoSomethingExpensiveInBackgroundJob < ActiveJob::Base self.queue_adapter = :sidekiq end

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ApplicationJob base class

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ApplicationJob base class class ApplicationJob < ActiveJob::Base end

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Validation of multiple contexts

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Validation of multiple contexts class User < ActiveRecord::Base validate :validate_confirmation_info, on: :confirmation validate :validate_updatable, on: :update end

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Validation of multiple contexts • Before: user.valid?(:confirmation) && user.valid?(:update)

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Validation of multiple contexts • Now: user.valid?([:confirmation, :update])

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Additional details for validations

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Additional details for validations comment = Comment.new comment.valid? => false comment.errors.messages => {content: ["can’t be blank"]} comment.errors.details => {content:=>[{error: :blank}]} comment.errors.add(:content, :too_short, "Content is too short") comment.errors.details => {content: [{error: :blank}, {error: :too_short}]}

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Saving records without timestamp update

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Saving records without timestamp update user = User.first user.save(touch: false)

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Bidirectional destroy

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Bidirectional destroy • Doesn’t cause SystemStackError

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Bidirectional destroy class Account < ActiveRecord::Base has_one :billing_address, dependent: :destroy end class BillingAddress < ActiveRecord::Base belongs_to :account, dependent: :destroy end

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ActiveModel::AttributesAssi gnment

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ActiveModel::AttributesAssi gnment class UserForm include ActiveModel::AttributeAssignment attr_accessor :email, :password, :password_confirmation end form = UserForm.new form.assign_attributes(email: "[email protected]")

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ActionController::Parameters is not a HashWithIndifferentAccess

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ActionController::Parameters is not a HashWithIndifferentAccess • Gotcha: def to_h if permitted? @parameters.to_h else slice(*self.class.always_permitted_parameters).permit!.to_h end end

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ActionController::Parameters is not a HashWithIndifferentAccess • Gotcha: def to_h if permitted? @parameters.to_h else slice(*self.class.always_permitted_parameters).permit!.to_h end end def user_params params.permit!.to_h end def user_params params.to_unsafe_h end

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Comments in migrations

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Comments in migrations class CreateOrders < ActiveRecord::Migration[5.0] def change create_table :orders, comment: "Orders table" do |t| t.string :description, comment: "Description of the order" t.integer :owner_id, comment: "Owner of the order" t.timestamps end add_index :orders, :owner_id, name: "index_name", comment: "Index for owner_id" end end

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Comments in migrations ActiveRecord::Schema.define(version: 20160928091043) do create_table "orders", force: :cascade, comment: "Orders table" do |t| t.string "description", comment: "Description of the order" t.integer "owner_id", comment: "Owner of the order" t.index ["owner_id"], name: "index_name",using: :btree, comment: "Index for owner_id" end end

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Updating collection with callbacks and validations

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Updating collection with callbacks and validations • ActiveRecord::Relation.update_all doesn’t trigger validations and callbacks

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Updating collection with callbacks and validations • ActiveRecord::Relation.update_all doesn’t trigger validations and callbacks • But new ActiveRecord::Relation.update does ;)

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Updating collection with callbacks and validations • ActiveRecord::Relation.update_all doesn’t trigger validations and callbacks • But new ActiveRecord::Relation.update does ;) Comment.limit(10).update(content: "")

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Expression indexes

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Expression indexes Author.where("lower(fullname) = ?", fullname.to_s.downcase)

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Expression indexes add_index :authors, "lower(fullname)"

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Indexed errors for nested attributes

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Indexed errors for nested attributes class Invoice < ApplicationRecord has_many :items accepts_nested_attributes_for :items end class Item < ApplicationRecord validates :description, presence: true end > invoice = Invoice.new > item_1 = Item.new(description: "$$$$") > item_2 = Item.new > invoice.items = [item_1, item_2] > invoice.save > invoice.error.messages => {:"items.description"=>["can't be blank"]}

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Indexed errors for nested attributes class Invoice < ApplicationRecord has_many :items, index_errors: true accepts_nested_attributes_for :items end class Item < ApplicationRecord validates :description, presence: true end >> invoice = Invoice.new >> item_1 = Item.new(description: "$$$$") >> item_2 = Item.new >> invoice.items = [item_1, item_2] >> invoice.save >> invoice.error.messages => {:"items[1].description"=>["can’t be blank"]}

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Indexed errors for nested attributes • Conﬁgurable with conﬁg.active_record.index_nested_attribute_errors

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No more ambiguous columns errors

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No more ambiguous columns errors class Post < ApplicationRecord belongs_to :author has_many :comments end class Comment < ApplicationRecord belongs_to :author belongs_to :post end Post.joins(:comments).group(:author_id).count

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New option for ﬁnd_in_batches: ﬁnish

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New option for ﬁnd_in_batches: ﬁnish Comment.find_in_batches(start: 1001, finish: 10000, batch_size: 1000) do |group| group.each { |comment| do_some_stuff_with_comment(comment) } end

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OR support in queries

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OR support in queries

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OR support in queries Article.where(author_name: "DHH").or(Article.where(category_name: "Basecamp"))

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Acceptance validations works properly ;)

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Acceptance validations works properly ;) • Problem: validates_acceptance_of accepts only "1" as truthy value

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Acceptance validations works properly ;) • Problem: validates_acceptance_of accepts only "1" as truthy value • Now it supports both "1" and true

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Acceptance validations works properly ;)

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Acceptance validations works properly ;) • Bonus: conﬁgurable values

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Acceptance validations works properly ;) • Bonus: conﬁgurable values class Comment < ActiveRecord::Base validates_acceptance_of :agreement, accept: [true, "y", "yes", "1", 1, "Rails"] end

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ﬁelds_for accepts lambdas for child_index

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ﬁelds_for accepts lambdas for child_index • My ﬁrst Rails contribution ;)

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ﬁelds_for accepts lambdas for child_index • My ﬁrst Rails contribution ;) <%= f.simple_fields_for :items, item, child_index: -> { Time.current.to_i } do |builder| %> <% end %>

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ﬁelds_for accepts lambdas for child_index • My ﬁrst Rails contribution ;) <%= f.simple_fields_for :items, item, child_index: -> { Time.current.to_i } do |builder| %> <% end %> ''