What's new in Rails 6? - Speaker Deck

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Vipul A M RAILS 6! WHAT'S NEW IN

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Vipul A M Saeloun

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https://blog.saeloun.com/

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Kyoto Typhoon last year

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Alaska 7.2 Earthquake from 9th Floor

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NY Manhattan Blackout last week

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Vipul A M RAILS 6! WHAT'S NEW IN

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14 13!

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NEW 15

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ACTION MAILBOX 16

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class Mailman < ActionMailer::Base def receive(email) page = Page.find_by(address: email.to.first) page.emails.create( subject: email.subject, body: email.body ) if email.has_attachments? email.attachments.each do |attachment| page.attachments.create({file: attachment,  description:email.subject}) end end end end $ rails runner 'Mailman.receive(STDIN.read)' 18

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rails action_mailbox:install rails db:migrate # config/environments/ production.rb config.action_mailbox.ingress = :mailgun 19

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-SMTP Relay -Mailgun -Mandrill -Postfix -Postmark -Qmail -Sendgrid 20

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# app/mailboxes/application_mailbox.rb class ApplicationMailbox < ActionMailbox::Base routing /forward@/i => :forwards routing /contact@/i => :contacts routing /leads@/i => :leads end 21

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# Generate new mailbox rails generate mailbox forwards # frozen_string_literal: true class ForwardsMailbox < ApplicationMailbox def process if forwarder record_forward else bounce_with Forwards::BounceMailer.missing_forward( inbound_email, forwarder: forwarder ) end end private def forwarder Person.where(email_address: mail.from) end def record_forward Forward.new forwarder: forwarder, subject: message.subject, content: mail.content end end 22

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-bounced! -bounce_with -Incineration / IncinerationJob 23

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class ForwardsMailboxTest < ActionMailbox::TestCase test "directly recording a client forward for a forwarder and forwardee corresponding to one project" do assert_difference -> { people(:david).buckets.first.recordings.count } do receive_inbound_email_from_mail \ to: 'save@example.com', from: people(:david).email_address, subject: "Fwd: Status update?", body: <<~BODY --- Begin forwarded message --- From: Frank Holland What's the status? BODY end recording = people(:david).buckets.first.recordings.last assert_equal people(:david), recording.creator assert_equal "Status update?", recording.forward.subject assert_match "What's the status?", recording.forward.content.to_s end end 24

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NEW 25

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ZIETWERK 26 @ fxn

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$ spring stop && rails s 27

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28 https://github.com/rails/rails/issues?q=is%3Aissue+autoload+is%3Aclosed

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$ bin/rails zeitwerk:check Hold on, I am eager loading the application. All is good! -classic mode infers file names from missing constant names (underscore):   "FOO".underscore is "foo" -zeitwerk mode infers constant names from file names (camelize):   "foo".camelize is "Foo", not "FOO"

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# Autoloading in this class' body matches Ruby semantics now. class Admin::UsersController < ApplicationController # ... end # Before class Foo::Bar Baz end   # Now class Foo::Bar Foo::Baz end 30

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app/models app/models/concerns app/models/concerns/foo.rb  => Foo not Concerns::Foo 31

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# One file one constant # app/models/foo.rb class Foo end class Bar end 32

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-Constant autoloading is thread-safe in zeitwerk mode. -Works with Bootsnap > 1.4.2 33

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#app/models/foo.rb class Bar end Autoload vs Eager load in class vs zietwerk mode    34

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# config/application.rb config.load_defaults "6.0" config.autoloader = :classic 35

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NEW 36

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ACTION TEXT 37

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rails action_text:install # app/models/message.rb class Message < ApplicationRecord has_rich_text :content end <%# app/views/messages/_form.html.erb %> <%= form_with(model: message) do |form| %>

<%= form.label :content %> <%= form.rich_text_area :content %>

<% end %> 38

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# Display <%= @message.content %> class MessagesController < ApplicationController def create message = Message.create  params.require(:message).permit(:title, :content) redirect_to message end end 39

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In Action 40

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RAILTIES 41

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- Webpacker is the new default JavaScript compiler - Guard against DNS rebinding attacks by default - bin/rails db:system:change --to=postgresql - Secrets => Credentials and multi-env credentials 42

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https://indiancybersecuritysolutions.com/wp-content/uploads/2018/03/DNSRebindingAttackReadpermitted_it%E2%80%99sthesameorigin.jpg 43

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ActionDispatch::HostAuthorization Rails.application.config.hosts = [ IPAddr.new("0.0.0.0/0"), # All IPv4 addresses. IPAddr.new("::/0"), # All IPv6 addresses. "localhost" # The localhost reserved domain. ] # Allow requests only from `product.com` Rails.application.config.hosts << "product.com" # Allow requests from subdomains like `www.product.com` and # `beta1.product.com`. Rails.application.config.hosts << /.*\.product\.com/ 44

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ACTION PACK 46

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=> cookies.signed[:lastname] = {value: "Smith", expires: Time.now + 1.hour } 47 - Purpose and expiry metadata is now embedded inside   signed and encrypted cookies for increased security

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class SomeControllerTest < ActionController::TestCase def test_some_action post :action, body: { foo: 'bar' } assert_equal({ "foo" => "bar" }, response.parsed_body) end end 48

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- Add ActionController::Parameters#each_value - Expose ActionController::Parameters#each_key 49

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ACTION VIEW 50

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- image_alt has been removed - Rails npm packages moved into a @rails scope.  @rails/webpacker  @rails/rails-ujs 51

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ACTIVE STORAGE 52

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- mini_magick replaced by image_processing gem - Wrapper for mini_magick and vips gem(libvips) - New variant formats: BMP, TIFF, progressive JPEG 53

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class User < ApplicationRecord has_many_attached :highlights end user.highlights.attach(filename: "funky.jpg", ...) user.higlights.count # => 1 blob = ActiveStorage::Blob.create_after_upload!(filename: "town.jpg", user.update!(highlights: [ blob ]) user.highlights.count # => 2 user.highlights.first.filename # => "funky.jpg" user.highlights.second.filename # => "town.jpg" 54

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user.highlights.attach(filename: "funky.jpg", ...) user.highlights.count # => 1 blob = ActiveStorage::Blob.create_after_upload!(filename: "town.jpg", user.update!(highlights: [ blob ]) user.highlights.count # => 1 user.highlights.first.filename # => "town.jpg" 55

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NEW 56

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PARALLEL TESTING 57

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https://github.com/grosser/parallel_tests 58

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class ActiveSupport::TestCase parallelize(workers: 2) end # On CI PARALLEL_WORKERS=15 rails test 59

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class ActiveSupport::TestCase parallelize_setup do |worker| # setup databases end parallelize_teardown do |worker| # cleanup databases end parallelize(workers: :number_of_processors, with: :threads) end 60

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ACTIVE JOB 61

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ACTIVE SUPPORT 62

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- Lots of improvements due to removal of AS::Multibyte::Unicode table - Remove ActiveSupport::Multibyte::Unicode#downcase/upcase/swapcase - Removes ActiveSupport::Multibyte::Chars wrappers around String methods: - #downcase, #upcase, #swapcase, and #capitalize.  - Reduce memory usage(about 1M) - Reduce repo/gem size(about 1M) 63

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- before? and after? methods to Date, DateTime, Time, and TimeWithZone  Time.current.before?(2.weeks.ago) - Add ActiveSupport::ParameterFilter  ActiveSupport::ParameterFilter.new(["credit_card.code"]) => replaces { credit_card: {code: "xxxx"} } with "[FILTERED]", does not change { file: { code: "xxxx"} } 64

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[ 1, 2, 3, 4, 5 ].excluding([4, 5]) => [ 1, 2, 3 ] [1, 2, 3 ].including(4, 5) => [ 1, 2, 3, 4, 5 ] post.authors.including(Current.person) numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] odd_numbers = numbers.extract! { |number| number.odd? }   # => [1, 3, 5, 7, 9] numbers # => [0, 2, 4, 6, 8] 65

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ACTIVE MODEL 66

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ACTIVE RECORD 67

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Vipul A M ACTIVE RECORD WHAT'S NEW IN

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- rails db:prepare to create a database if it doesn't exist, and run its migrations. - rails db:seed:replant that truncates tables of each database   for the current environment and loads the seeds 70

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-touch_all -destroy_by / delete_by -reselect  => unscope(:select).select(fields)  -insert_all/insert_all!/upsert_all  => Post.insert_all([row1, row2]  -account.memberships.extract_associated(:user) => account.memberships.preload(:user).collect(&:user)  -after_save_commit   => after_commit :hook, on: [ :create, :update ]  -Person.where(id: 1).pick(:name)   => Person.limit(1).pluck(column_name).first 71 AR RELATION

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- Relation#annotate for SQL comments    Post.annotate("this is a comment").where(id: 123).to_sql  => # SELECT "posts".* FROM "posts" WHERE "posts"."id" = 123 /* this is a comment */ - Add support for setting Optimizer Hints on databases  class Job < ApplicationRecord default_scope { optimizer_hints("MAX_EXECUTION_TIME(50000) NO_INDEX_MERGE(jobs)") } end 72

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-Lots of changes to support Multi-DB -Add the ability to automatically switch database connections. -while_preventing_writes => prevent writes to DB in block -ActiveRecord::Base.find_or_create_by/! => ActiveRecord::Base.create_or_find_by/! / SELECT/INSERT race condition 73

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NEW 75

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ACTION CABLE / TESTING 76

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# app/channels/application_cable/connection.rb module ApplicationCable class Connection < ActionCable::Connection::Base identified_by :current_user def connect self.current_user = find_verified_user end private def find_verified_user ... end end end 77

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class ApplicationCable::ConnectionTest < ActionCable::Connection::TestCase test "connects with params" do # Simulate a connection opening by calling the `connect` method connect params: { user_id: 42 } # You can access the Connection object via `connection` in tests assert_equal connection.user_id, "42" end test "rejects connection without params" do # Use `assert_reject_connection` matcher to verify that # connection is rejected assert_reject_connection { connect } end end 78

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# app/channels/application_cable/channel.rb module ApplicationCable class Channel < ActionCable::Channel::Base end end # app/channels/chat_channel.rb class ChatChannel < ApplicationCable::Channel end 79

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require "test_helper" class ChatChannelTest < ActionCable::Channel::TestCase test "subscribes and stream for room" do # Simulate a subscription creation by calling `subscribe` subscribe room: "15" # You can access the Channel object via `subscription` in tests assert subscription.confirmed? assert_has_stream "chat_15" end end 80

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# app/jobs/chat_relay_job.rb class ChatRelayJob < ApplicationJob def perform_later(room, message) ChatChannel.broadcast_to room, text: message end end # test/jobs/chat_relay_job_test.rb require 'test_helper' class ChatRelayJobTest < ActiveJob::TestCase include ActionCable::TestHelper test "broadcast message to room" do room = rooms(:all) assert_broadcast_on(ChatChannel.broadcasting_for(room), text: "Hi!") do ChatRelayJob.perform_now(room, "Hi!") end end end 81