I gave a talk at Rails World 2023 in Amsterdam on Powerful Rails Features You Might Not Know. If all you've got is a hammer, everything looks like a nail. In tech, there is a constant stream of new features being added every day. Keeping up with the latest Ruby on Rails functionality can help you and your team be far more productive than you might normally be. In this talk, we walk through a bunch of lesser known or easy to miss features in Ruby on Rails that you can use to improve your skills.

1. Chris Oliver
Powerful TypeScript Rails
Features You Might Not know

2. Learn Your Tools

3. ActiveRecord Excluding
User.where.not(id: users.map(&:id))
# SELECT "users".* FROM "users"
WHERE "users"."id" NOT IN (1,2)
User.all.excluding(users)
# SELECT "users".* FROM "users"
WHERE "users"."id" NOT IN (1,2)

4. ActiveRecord Strict Loading
class Project < ApplicationRecord
has_many :comments, strict_loading: true
end
project = Project.first
project.comments
ActiveRecord::StrictLoadingViolationError
`Project` is marked as strict_loading. The Comment association named
`:comments` cannot be lazily loaded.

5. ActiveRecord Strict Loading
project = Project.includes(:comments).first
Project Load (0.3ms) SELECT "projects".* FROM "projects" ORDER BY
"projects"."id" ASC LIMIT ? [["LIMIT", 1]]
Comment Load (0.1ms) SELECT "comments".* FROM "comments" WHERE
"comments"."project_id" = ? [["project_id", 1]]
=> #<Project:0x00000001054af780 id: 1>
project.comments
=> [#<Comment:0x00000001054aed80 id: 1, project_id: 1, body: "Hello
RailsWorld">]

6. Generated Columns
class AddNameVirtualColumnToUsers < ActiveRecord::Migration[7.0]
def change
add_column :users, :full_name, :virtual,
type: :string,
as: "first_name || ' ' || last_name",
stored: true
end
end

7. attr_readonly
class User < ApplicationRecord
attr_readonly :super_admin
end

8. with_options
class Account < ActiveRecord::Base
with_options dependent: :destroy do
has_many :customers
has_many :products
has_many :invoices
has_many :expenses
end
end

9. with_options
I18n.with_options locale: user.locale, scope: 'newsletter' do |i18n|
subject i18n.t :subject
body i18n.t :body, user_name: user.name
end

10. Try
method_name if respond_to?(:method_name)
try(:method_name)
try(:method_name) || default
(method_name if respond_to?(:method_name)) || default

11. ActionText Embeds

12. Searching Users
json.array! @users do |user|
json.sgid user.attachable_sgid
json.content render(
partial: "users/user",
locals: {user: user},
formats: [:html]
)
end

13. Signed GlobalIDs
User.first.attachable_sgid.to_s
"eyJfcmFpbHMiOnsibWVzc2FnZSI6IkJBaEpJaDluYVdRNkx5OXFkVz
F3YzNSaGNuUXRZWEJ3TDFWelpYSXZNUVk2QmtWVSIsImV4cCI
6IjIwMjMtMTAtMjhUMTY6MDY6MTEuMjEyWiIsInB1ciI6ImRlZmF1bH
QifX0=--217284b31bc4e28f6e2cf2890ccee87ca7d3ea2d"

14. ActionText Embeds

15. ActionText Embeds
import Trix from "trix"
let attachment = new Trix.Attachment({
content: "<div><img src=“…”> Chris Oliver</div>",
sgid: "BAh7CEkiCG…"
})
element.editor.insertAttachment(attachment)

16. ActionText Embeds
<p>Hey <action-text-attachment sgid=“BAh7CEkiCG…">
</action-text-attachment>!</p>

17. Signed GlobalIDs
Base64.decode64("eyJfcmFpbHMiOnsibWVzc2FnZSI6IkJBaEpJaDluYVdRNkx5OXFkV
zF3YzNSaGNuUXRZWEJ3TDFWelpYSXZNUVk2QmtWVSIsImV4cCI6IjIwMjMtMTAtMjh
UMTY6MD
Y6MTEuMjEyWiIsInB1ciI6ImRlZmF1bHQifX0=“)
=>
“{"_rails":{"message":"BAhJIh9naWQ6Ly9qdW1wc3RhcnQtYXBwL1VzZXIvMQY6
BkVU","exp":"2023-10-28T16:06:11.212Z","pur":"attachable"}}"

18. Signed GlobalIDs
Base64.decode64(“BAhJIh9naWQ6Ly9qdW1wc3RhcnQtYXBwL1VzZXIvMQ
Y6BkVU")
=> “x04bI"x1Fgid://jumpstart-pro/User/1x06:x06ET"

19. ActionText Embeds

20. Serialize Coders
module ActionText
class RichText < Record
serialize :body, coder: ActionText::Content
end
end

21. Serialize Coders
class ActionText::Content
def self.load(content)
new(content) if content
end
def self.dump(content)
case content
when nil
nil
when self
content.to_html
end
end
end

22. ActionMailbox Inbound Emails

23. ActionMailbox Inbound Emails
# app/mailboxes/application_mailbox.rb
class ApplicationMailbox < ActionMailbox::Base
routing /@replies./i => :replies
end

24. class RepliesMailbox < ApplicationMailbox
MATCHER = /^reply-(d+)@replies./
def process
conversation.posts.create!(
author: author,
body: body,
message_id: mail.message_id
)
end
private
def conversation
Conversation.find(conversation_id)
end
def conversation_id
mail.recipients.find { |recipient| MATCHER.match?(recipient) }[MATCHER, 1]
end
end
ActionMailbox Inbound Emails

25. Routing constraints
constraints subdomain: :app do
root "dashboard#show"
end
root "homepage#show"

26. Routing constraints
authenticated :user, -> { _1.admin? } do
resource :admin
end
authenticated :user do
root "dashboard#show"
end
root "homepage#show"

27. Routing constraints

28. Draw Routes
Rails.application.routes.draw do
draw :api
# ...
end
# config/routes/api.rb
namespace :api, defaults: {format: :json} do
namespace :v1 do
resources :accounts
end
end

29. Custom Generators
$ bin/rails g api_client OpenAI
--base-url https://api.openai.com

30. Custom Generators
$ bin/rails generate generator ApiClient
creates an ApiClient generator:
lib/generators/api_client/
lib/generators/api_client/api_client_generator.rb
lib/generators/api_client/USAGE
lib/generators/api_client/templates/
test/lib/generators/api_client_generator_test.rb

31. Custom Turbo Stream Actions

32. Custom Turbo Stream Actions
<turbo-stream action="notification" title="Hello world">
</turbo-stream>

33. Custom Turbo Stream Actions
# create.turbo_stream.erb
<%= turbo_stream_action_tag “notification”,
title: “Hello world” %>

34. Custom Turbo Stream Actions
import "@hotwired/turbo-rails"
Turbo.StreamActions.notification = function() {
Notification.requestPermission(function(status) {
if (status == "granted") {
new Notification(this.getAttribute("title"))
}
})
}

35. Custom Turbo Stream Actions

36. truncate_words
content = 'And they found that many people were sleeping better.'
content.truncate_words(5, omission: '... (continued)')
# => "And they found that many... (continued)"

37. starts_at > Time.current
starts_at.after?(Time.current)
starts_at.future?
Time Helpers
starts_at < Time.current
starts_at.before?(Time.current)
starts_at.past?

38. Time.current.all_day
#=> Fri, 06 Oct 2023 00:00:00 UTC +00:00..
Fri, 06 Oct 2023 23:59:59 UTC +00:00
Time.current.all_week
#=> Mon, 02 Oct 2023 00:00:00 UTC +00:00..
Sun, 08 Oct 2023 23:59:59 UTC +00:00
Time.current.all_month
#=> Sun, 01 Oct 2023 00:00:00 UTC +00:00..
Tue, 31 Oct 2023 23:59:59 UTC +00:00
Time Helpers

39. 123 -> 123
1234 -> 1,234
10512 -> 10.5K
2300123 -> 2.3M
Abbreviated numbers

40. Abbreviated numbers
number_to_human(123) # => "123"
number_to_human(12345) # => "12.3 Thousand"
number_to_human(1234567) # => "1.23 Million"
number_to_human(489939, precision: 2) # => "490 Thousand"
number_to_human(489939, precision: 4) # => "489.9 Thousand"
number_to_human(1234567, precision: 4,
significant: false)# => "1.2346 Million"

41. def number_to_social(number)
return number_with_delimiter(number) if number < 10_000
number_to_human(number,
precision: 1,
round_mode: :down,
significant: false,
format: "%n%u",
units: {thousand: "K", million: "M", billion: "B"}
)
end
Abbreviated numbers

42. Abbreviated numbers
number_to_social(123) #=> 123
number_to_social(1_234) #=> 1,234
number_to_social(10_512) #=> 10.5K
number_to_social(2_300_123) #=> 2.3M

44. Rails.env.local?
Rails.env.development? || Rails.env.test?
Rails.env.local?

45. ActiveSupport Inquiry
"production".inquiry.production? # => true
"active".inquiry.inactive? # => false

46. Unused routes
$ rails routes --unused
Found 4 unused routes:
Prefix Verb URI Pattern Controller#Action
edit_comment GET /comments/:id/edit(.:format) comments#edit
PATCH /comments/:id(.:format) comments#update
PUT /comments/:id(.:format) comments#update
DELETE /comments/:id(.:format) comments#destroy

47. Template strict locals
<%# locals: (message:) -%>
<%= tag.div id: dom_id(message) do %>
<%= message %>
<% end %>
<%= render partial: “message” %>
ArgumentError: missing local: :message
<%= render partial: “message”,
locals: {message: @message} %>

48. Template strict locals
<%# locals: (message: “Hello”) -%>
<div>
<%= message %>
</div>
<%= render partial: “message” %>
<%= render partial: “message”,
locals: {message: “Hey”} %>

49. Template strict locals
<%# locals: () -%>
<div>
Hello RailsWorld!
</div>
<%= render partial: “message” %>

50. normalizes
class User < ApplicationRecord
end
def email=(value)
super value&.strip&.downcase
end

51. normalizes
class User < ApplicationRecord
end
normalizes :email, with: ->(email) { email.strip.downcase }
normalizes :email, with: ->{ _1.strip.downcase }

52. has_secure_password
authenticate_by & password_challenge

53. authenticate_by
class User < ApplicationRecord
has_secure_password
end
User.find_by(email: "chris@gorails.com")
&.authenticate(“railsworld2023")
#=> false or user
User.authenticate_by(
email: "chris@gorails.com",
password: "railsworld2023"
) #=> user or nil

54. password_challenge
Current.user.update(password_params)
def password_params
params.require(:user).permit(
:password,
:password_confirmation,
:password_challenge
).with_defaults(password_challenge: "")
end

55. generates_token_for

56. generates_token_for
class User < ApplicationRecord
generates_token_for :password_reset, expires_in: 15.minutes do
# BCrypt salt changes when password is updated
BCrypt::Password.new(password_digest).salt[-10..]
end
end

57. generates_token_for
User.find_by_token_for(:password_reset, params[:token])
#=> User or nil
user.generate_token_for(:password_reset)
“eyJfcmFpbHMiOnsiZGF0YSI6WzkwMjU0MTYzNSwiaC9oTkRJck9uL…”

58. ActiveStorage Variants

59. Named variants
class User < ApplicationRecord
has_one_attached :avatar do |attachable|
attachable.variant :thumbnail,
resize_to_limit: [200, 200]
end
end

60. Preprocessed variants
class User < ApplicationRecord
has_one_attached :avatar do |attachable|
attachable.variant :thumbnail,
resize_to_limit: [200, 200],
preprocessed: true
end
end

61. if @project.file.previewable?
@project.file.preview(:thumbnail)
elsif @project.file.variable?
@project.file.variant(:thumbnail)
end
# Render a preview or variant
@project.file.represenation(:thumbnail)
Representations

62. Fact
L Learn