Speech of Nihad Abbasov, Backend Engineer at Digital Classifieds, at Ruby Meditation #26 Kyiv 16.02.2019 Next conference - http://www.rubymeditation.com/ What to expect from Rails 6? Review of new features. Announcements and conference materials https://www.fb.me/RubyMeditation News https://twitter.com/RubyMeditation Photos https://www.instagram.com/RubyMeditation The stream of Ruby conferences (not just ours) https://t.me/RubyMeditation

1. New features in
Rails 6
KIEV, UKRAINE, FEB 16 2019
Nihad Abbasov
Digital Classifieds
@NARKOZ

2. Agenda
Rails 6 01
Major Features
Notable changes
Q&A
02
03
04

3. We're intending to release Rails 6.0 by
@RailsConf 2019. Here's the full
"aspirational timeline" 😄.
DHH

4. “ASPIRATIONAL TIMELINE”
https://weblog.rubyonrails.org/2018/12/20/timeline-for-the-release-of-Rails-6-0/
● January 15: Beta 1
● February 1: Beta 2
● March 1: Release Candidate 1
● April 1: Release Candidate 2
● April 30: Final release

5. Ruby 2.5+
REQUIREMENTS

6. GETTING STARTED
$ gem install rails --pre
$ rails new myapp
Uses the latest beta pushed to rubygems

7. GETTING STARTED
$ git clone https://github.com/rails/rails.git
$ rails/railties/exe/rails new myapp
Uses edge from github repository

8. UPGRADING
$ rails app:update

9. MAJOR FEATURES
+ Action Mailbox
+ Action Text
+ Parallel Testing
+ Webpacker as the default
+ Multiple databases

10. Action
Mailbox
FEATURE #1

11. Receive
emails in app

12. DEPRECATED
ActionMailer::Base.receive

13. SUPPORTED INGRESSES
● Amazon SES
● Exim
● Mailgun
● Mandrill
● Postfix
● Postmark
● Qmail
● SendGrid

14. SETUP
$ rails action_mailbox:install
$ rails db:migrate
Configure your SMTP server to pipe inbound emails.
config.action_mailbox.ingress = :relay

15. USE CASES

16. Code

17. app/mailboxes/application_mailbox.rb
class ApplicationMailbox < ActionMailbox::Base
routing "post@example.com" => :posts
routing /Areply-[0-9a-f]+z/i => :comments
end
Route can be a string, regex, lambda/proc, object responding to #match?, :all

18. app/mailboxes/posts_mailbox.rb
class PostsMailbox < ApplicationMailbox
before_processing :ensure_sender_is_a_user
private
def ensure_sender_is_a_user
unless User.exist?(email: mail.from)
bounce_with UserMailer.missing(inbound_email)
end
end
end

19. app/mailboxes/posts_mailbox.rb
def process
User.find_by(email: mail.from)
.posts.create!(post_attrs)
end
private
def post_attrs
{
title: mail.subject || Time.current.to_s,
body: EmailParser.parse(mail.source)
}
end

20. {
InboundEmail statuses
incoming lifecycle
pending
processing
delivered
failed
bounced

21. Action Text
FEATURE #2

22. Rich text
editor

23. NO RAW HTML EDITING MODE
https://github.com/basecamp/trix/issues/42#issuecomment-179905641

24. Code

25. SETUP
$ rails action_text:install
$ rails db:migrate
Creates action text table, installs trix npm package

26. app/models/article.rb
class Article < ApplicationRecord
has_rich_text :content
end
<%= form_with(model: @article) do |form| %>
<%= form.rich_text_area :content %>
<%= form.submit %>
<% end %>
app/views/articles/_form.html.erb

27. OPT-OUT
--skip-action-text

28. Parallel
Testing
FEATURE #3

29. Enabled by
default

30. test/test_helper.rb
class ActiveSupport::TestCase
parallelize(workers: 4, with: :processes)
end
Uses processes. Can be changed to use threads.

31. Run test suite
$ PARALLEL_WORKERS=6 bin/rails test
Overrides number of workers defined in test_helper.rb

32. Webpacker as
the default
FEATURE #4

33. Only for
JavaScript

34. Multi
databases
FEATURE #5

35. Automatic DB
switching

36. Request is sent to the replica
● The request is a read request (GET or HEAD)
● AND It's been 5 seconds since the last write
to the database

37. Request is sent to the primary
● It's not a GET/HEAD request (ie is a POST,
PATCH, etc)
● Has been less than 5 seconds since the last
write to the database

38. config/environments/production.rb
config.active_record.database_selector = {
delay: 10.seconds
}
Uses ActiveRecord::Middleware::DatabaseSelector::Resolver

39. Database connection switching API
Connects a model to the databases specified:
# in your model:
connects_to database: {
writing: :primary,
reading: :primary_replica
}
database
keyword
takes a hash
consisting of
a role and a
database_key

40. Notable
changes

41. Image
Processing
Active Storage

42. {
RESIZE AND PROCESS IMAGES
image_processing
ImageMagick
GraphicsMagick
libvips
https://github.com/janko/image_processing

43. fast image
processing with low
memory needs
LIBVIPS

44. BENCHMARKS
https://github.com/libvips/libvips/wiki/Speed-and-memory-use

45. config/application.rb
config.active_storage.variant_processor = :vips
Use libvips for processing ActiveStorage variants

46. ALLOCATIONS COUNT

47. Enumerable#index_with
post = Post.new(
title: "hey there",
body: "what's up?"
)
%i[title body].index_with do |a|
post.public_send(a)
end
# => { title: "hey there", body:
"what's up?" }
Converts an enumerable to a hash:
keys are
enumerable
items with
the values
returned in
the block

48. ActiveRecord::Base.create_or_find_by
User.create_or_find_by!(
username: "john",
email: "john@example.com"
)
Similar to #find_or_create_by method:
Deals with
race
conditions by
leaning on
unique DB
constraints

49. Command for changing databases
$ rails db:system:change --to=postgresql
$ rails db:system:change --to=sqlite3
Modifies config/database.yml and Gemfile

50. `before?` & `after?` methods in date & time classes
date1.after? date2
date1.before? date2
# same as:
date1 > date2
date1 < date2
For comparing dates and times:
Makes date
and time
comparisons
more human
readable

51. Endless ranges in where
relation.where(
column: 1..Float::INFINITY
)
# is equivalent to:
relation.where(column: (1..))
Support for
endless
ranges
introduced in
Ruby 2.6

52. New uploaded files stored on save
@user.avatar = params[:avatar]
@user.save
The uploaded
file is stored
when @user
is
successfully
saved

53. EXPANDED ROUTES

55. The End.
Questions?
Thanks!