What's New in Rails 5?

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1. What's new in Rails 5? Karol Galanciak Full Stack Developer at Twitter: @Azdaroth Github: Azdaroth https://karolgalanciak.com
2. ActionCable
3. ActionCable • Integration of WebSockets with the rest of your application
4. ActionCable • Integration of WebSockets with the rest of your application • Both client-side and server-side tools
5. ActionCable - server-side
6. ActionCable - server-side • Connections - connection between consumer and the sever
7. ActionCable - server-side • Connections - connection between consumer and the sever • Authentication / authorization goes here
8. 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
9. ActionCable - server-side • Channels - endpoints where the actual logic happens (~ controllers)
10. 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
11. ActionCable - client-side
12. 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) { $(".chat").append("<p>" + data["sent_by"] + ": " + data["body"] + "</p>") } }); App.chatChannel.send({ sent_by: "DHH", body: "OMG, it works!" });
13. Rails API
14. Rails API • rails new rails_5_app --api
15. Rails API • rails new rails_5_app —api • ApplicationController inherits from ActionController::API • Modifies the generators (no views, helpers and assets)
16. Attributes API
17. Attributes API class Order < ActiveRecord::Base attribute :price_in_cents, :money attribute :description, :string, default: "Default description" attribute :ordered_at, :datetime, default: -> { Time.current } attribute :tags_not_backed_by_db, :string, array: true end class MoneyType < ActiveRecord::Type::Integer def deserialize(value) if value.to_s.include?("$") price_in_dollars = value.gsub(/\$/, "").to_d super(price_in_dollars * 100) else super end end end ActiveRecord::Type.register(:money, MoneyType)
18. 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"]
19. Attributes API • custom types (requires #deserialize method for assigning values and #serialize when querying database)
20. Attributes API • custom types (requires #deserialize method for assigning values and #serialize when querying database) • attributes don’t need to be backed by database
21. 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
22. Class / module variables per thread • cattr_accessor / mattr_accessor - but per thread - thread_cattr_accessor / thread_mattr_accessor
23. 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
24. Assets silenced by default in development
25. Assets silenced by default in development • quite_assets gem
26. Assets silenced by default in development • quite_assets gem • No more garbage in logs
27. 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
28. ApplicationRecord
29. ApplicationRecord • New base class for models
30. ApplicationRecord class ApplicationRecord < ActiveRecord::Base include SoftDelete self.abstract_class = true has_paper_trail end class User < ApplicationRecord end
31. Rendering outside controllers
32. Rendering outside controllers OrdersController.render(:show, assigns: { order: Order.find(order_id) })
33. Rendering outside controllers OrdersController.render(:show, assigns: { order: Order.find(order_id) }) OrdersController.render(:_order, assigns: { order: Order.find(order_id) })
34. Rake / Rails commands
35. Rake / Rails commands • All rails commands can be executed with rake and all rake commands can be executed with rails
36. Rake / Rails commands rails db:migrate rake routes | grep some_route -> rails routes -g some_route
37. Caching collections
38. Caching collections • ActiveRecord::Collection#cache_key
39. Caching collections posts.cache_key => "posts/query-c60f5cf40b4d0d6f492ea6961c43ceb6-100-20160927121435182129"
40. Caching collections <% cache(@posts) do %> <% @posts.each do |post| %> <p> <%= render post %> </p> <% end %> <% end %>
41. ActiveRecord no longer halts execution of the callbacks when returning false
42. 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
43. 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 throw(:abort) end end
44. ActiveRecord no longer halts execution of the callbacks when returning false • configurable with ActiveSupport.halt_callback_chains_on_return_false
45. Belongs-to association required by default
46. Belongs-to association required by default class Comment < ApplicationRecord belongs_to :author end
47. Belongs-to association required by default class Comment < ApplicationRecord belongs_to :author, optional: true end
48. Belongs-to association required by default • Configurable with Rails.application.config.active_record.belongs_to_r equired_by_default
49. redirect_back method
50. redirect_back method class UsersController < ApplicationController def update user = find_user user.update(params[:user]) redirect_to :back end end
51. redirect_back method class UsersController < ApplicationController def update user = find_user user.update(params[:user]) redirect_back(fallback_location: root_path) end end
52. ActiveRecord::Base.Suppress
53. ActiveRecord::Base.Suppress
54. 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
55. 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
56. Left Outer Join Support
57. Left Outer Join Support User.left_outer_joins(:posts, :comments, :notifications) User.left_joins(:posts, :comments, :notifications)
58. Config for UUIDs as primary keys
59. Config for UUIDs as primary keys create_table :orders, id: :uuid do |t| end
60. Config for UUIDs as primary keys • Configurable with: config.active_record.primary_key = :uuid
61. Queue adapter configurable per job
62. Queue adapter configurable per job config.active_job.queue_adapter = :delayed_job
63. Queue adapter configurable per job class DoSomethingExpensiveInBackgroundJob < ActiveJob::Base self.queue_adapter = :sidekiq end
64. ApplicationJob base class
65. ApplicationJob base class class ApplicationJob < ActiveJob::Base end
66. Validation of multiple contexts
67. Validation of multiple contexts class User < ActiveRecord::Base validate :validate_confirmation_info, on: :confirmation validate :validate_updatable, on: :update end
68. Validation of multiple contexts • Before: user.valid?(:confirmation) && user.valid?(:update)
69. Validation of multiple contexts • Now: user.valid?([:confirmation, :update])
70. Additional details for validations
71. 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}]}
72. Saving records without timestamp update
73. Saving records without timestamp update user = User.first user.save(touch: false)
74. Bidirectional destroy
75. Bidirectional destroy • Doesn’t cause SystemStackError
76. Bidirectional destroy class Account < ActiveRecord::Base has_one :billing_address, dependent: :destroy end class BillingAddress < ActiveRecord::Base belongs_to :account, dependent: :destroy end
77. ActiveModel::AttributesAssi gnment
78. ActiveModel::AttributesAssi gnment class UserForm include ActiveModel::AttributeAssignment attr_accessor :email, :password, :password_confirmation end form = UserForm.new form.assign_attributes(email: "email@example.com")
79. ActionController::Parameters is not a HashWithIndifferentAccess
80. 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
81. 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
82. Comments in migrations
83. 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
84. 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
85. Updating collection with callbacks and validations
86. Updating collection with callbacks and validations • ActiveRecord::Relation.update_all doesn’t trigger validations and callbacks
87. Updating collection with callbacks and validations • ActiveRecord::Relation.update_all doesn’t trigger validations and callbacks • But new ActiveRecord::Relation.update does ;)
88. 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: "")
89. Expression indexes
90. Expression indexes Author.where("lower(fullname) = ?", fullname.to_s.downcase)
91. Expression indexes add_index :authors, "lower(fullname)"
92. Indexed errors for nested attributes
93. 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: "$$$$") > item_2 = Item.new > invoice.items = [item_1, item_2] > invoice.save > invoice.error.messages => {:"items.description"=>["can't be blank"]}
94. Indexed errors for nested attributes class Invoice < ApplicationRecord has_many :items, index_errors: true accepts_nested_attributes_for :items end class Item < ApplicationRecord validates :description, presence: true end >> invoice = Invoice.new >> item_1 = Item.new(description: "$$$$") >> item_2 = Item.new >> invoice.items = [item_1, item_2] >> invoice.save >> invoice.error.messages => {:"items[1].description"=>["can’t be blank"]}
95. Indexed errors for nested attributes • Configurable with config.active_record.index_nested_attribute_errors
96. No more ambiguous columns errors
97. 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
98. New option for find_in_batches: finish
99. 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
100. OR support in queries
101. OR support in queries
102. OR support in queries Article.where(author_name: "DHH").or(Article.where(category_name: "Basecamp"))
103. Acceptance validations works properly ;)
104. Acceptance validations works properly ;) • Problem: validates_acceptance_of accepts only "1" as truthy value
105. Acceptance validations works properly ;) • Problem: validates_acceptance_of accepts only "1" as truthy value • Now it supports both "1" and true
106. Acceptance validations works properly ;)
107. Acceptance validations works properly ;) • Bonus: configurable values
108. Acceptance validations works properly ;) • Bonus: configurable values class Comment < ActiveRecord::Base validates_acceptance_of :agreement, accept: [true, "y", "yes", "1", 1, "Rails"] end
109. fields_for accepts lambdas for child_index
110. fields_for accepts lambdas for child_index • My first Rails contribution ;)
111. 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 %>
112. 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 %> '<input id="invoice_items_attributes_abc_description" name="invoice[items_attributes] [1475065682][description]" type="text" value="" />'