Don't rewrite your framework - Rubyconfth

Have you ever seen someone rewriting the framework during a code review? After some time studying the Ruby on Rails documentation and doing some research on Reddit, I found some interesting features that are often not known by developers.

This talk was presented at Rubyconfth 2025

1. Vinícius B. Alonso Don’t rewrite your framework The lesser-known r a ils fe a tures
3. Who am I? • Vinícius Bail Alonso • Sr. Software Engineer • Solides Tecnologia contato@viniciusalonso.com @alonsoemacao viniciusalonso Get in touch viniciusbalonso
4. https://vinicius a lonso.com/
5. =
6. api.rubyonrails.org + reddit.com =
7. Validate di ff erent fi elds in di ff erent scenarios
8. Context validations
9. class Customer < ApplicationRecord validates :name, :email, :password, :address_street, :address_city, presence: true end
10. class Customer < ApplicationRecord validates :name, :email, :password, :address_street, :address_city, presence: true end class Customer < ApplicationRecord validates :name, :email, :password, presence: true, on: :create validates :address_street, :address_city, presence: true, on: :account_finish end Validations in two di ff erent contexts
11. customer = Customer.new(name: 'John', email: 'john@google.com', password: '123') customer.valid? # => true customer.save # => true customer.valid?(:account_finish) # => false customer.save(context: :account_finish) # => false
12. customer.address_street = "1105 West Peachtree St" customer.address_city = "Atlanta" customer.valid?(:account_finish) # => true customer.save(context: :account_finish) # => true
13. Threat data as single unit
14. Aggregations
15. class Customer < ApplicationRecord validates :name, :email, :password, :address_street, :address_city, presence: true end
16. https://martinfowler.com/bliki/ValueObject.html
17. class Address attr_reader :street, :city def initialize(street, city) @street = street @city = city end def ==(other) @street == other.street && @city == other.city end end
18. class Customer < ApplicationRecord composed_of :address, mapping: { address_street: :street, address_city: :city } end
19. customer = Customer.new customer.address_street = "123 Main St" customer.address_city = "Anytown" customer.address #<Address:0x0000ffffb045c6c0 @city="Anytown", @street="123 Main St">
20. customer = Customer.new customer.address_street = "123 Main St" customer.address_city = "Anytown" customer.address #<Address:0x0000ffffb045c6c0 @city="Anytown", @street="123 Main St"> address = Address.new("123 Main St", "Anytown") customer = Customer.new customer.address = address
21. customer = Customer.new customer.address_street = "123 Main St" customer.address_city = "Anytown" customer.address #<Address:0x0000ffffb045c6c0 @city="Anytown", @street="123 Main St"> address = Address.new("123 Main St", "Anytown") customer = Customer.new customer.address = address other_address = Address.new("456 Elm St", "Othertown") customer.address == other_address # false
22. customer = Customer.new customer.address_street = "123 Main St" customer.address_city = "Anytown" customer.address #<Address:0x0000ffffb045c6c0 @city="Anytown", @street="123 Main St"> address = Address.new("123 Main St", "Anytown") customer = Customer.new customer.address = address other_address = Address.new("456 Elm St", "Othertown") customer.address == other_address # false Customer.where(address: Address.new("123 Main St", "Anytown"))
23. Side e ff ects when relationships change
24. Association Callbacks
25. class Cart < ApplicationRecord has_many :items end class Item < ApplicationRecord belongs_to :cart end
26. class Cart < ApplicationRecord has_many :items def update_total_price total_price = items.map(&:total_price).sum update(total_price: total_price) end end
27. class Cart < ApplicationRecord has_many :items, after_add: :increment_total_price, after_remove: :decrement_total_price def increment_total_price(item) self.total_price = item.total_price + total_price end def decrement_total_price(item) self.total_price = total_price - item.total_price end end
28. cart.items << item cart.update_total_price cart.items << item cart.save Before After
29. Process large datasets
30. Batches
31. class ReportProcessorJob < ApplicationJob queue_as :default def perform(*args) Customer.all.each do |customer| ReportProcessor.new(customer).process end end end
32. class ReportProcessorJob < ApplicationJob queue_as :default def perform(*args) Customer.all.each do |customer| ReportProcessor.new(customer).process end end end 2 problems here: * Full table scan * All customers being loaded in memory at same time
33. class ReportProcessorJob < ApplicationJob queue_as :default def perform(*args) Customer.find_each do |customer| ReportProcessor.new(customer).process end end end
34. class ReportProcessorJob < ApplicationJob queue_as :default def perform(*args) Customer.find_in_batches do |batch| batch.each do |customer| ReportProcessor.new(customer).process end end end end
35. class ReportProcessorJob < ApplicationJob queue_as :default def perform(*args) Customer.find_in_batches(batch_size: 100) do |batch| batch.each do |customer| ReportProcessor.new(customer).process end end end end
36. Split 200 customers into two workers customers_ids = Customer.ids
37. Split 200 customers into two workers customers_ids = Customer.ids # Worker 1 Customer.find_in_batches(finish: customers_ids[99]) do |batch| batch.each do |customer| ReportProcessor.new(customer).process end end
38. Split 200 customers into two workers customers_ids = Customer.ids # Worker 1 Customer.find_in_batches(finish: customers_ids[99]) do |batch| batch.each do |customer| ReportProcessor.new(customer).process end end # Worker 2 Customer.find_in_batches(start: customers_ids[100]) do |batch| batch.each do |customer| ReportProcessor.new(customer).process end end
39. Avoid concurrent problems
40. Optimistic Locking
41. class AddLockVersionToCustomers < ActiveRecord::Migration[7.0] def change add_column :customers, :lock_version, :integer end end
42. =
43. Pessimistic Locking
44. Customer.lock.find(1)
45. Customer.lock.find(1) Customer Load (7.3ms) SELECT "customers".* FROM "customers" WHERE "customers"."id" = $1 LIMIT $2 FOR UPDATE [["id", 1], ["LIMIT", 1]]
46. Customer.lock.find(1) Customer Load (7.3ms) SELECT "customers".* FROM "customers" WHERE "customers"."id" = $1 LIMIT $2 FOR UPDATE [["id", 1], ["LIMIT", 1]] Row-level lock
47. Customer.transaction do customer = Customer.lock.find(3) sleep(10) customer.address_city = "São Paulo" customer.save! end Customer.transaction do customer = Customer.lock.find(3) customer.address_city = "Curitiba" customer.save! end Process 1 Process 2
49. Standardize attribute values
50. Normalize
51. class User < ApplicationRecord before_save :sanitize_fields private def sanitize_fields self.email = email.strip.downcase if email.present? self.phone = phone.delete("^0-9") if phone.present? end end
52. class User < ApplicationRecord normalizes :email, with: -> email { email.strip.downcase } normalizes :phone, with: -> phone { phone.delete("^0-9") } end
53. user = User.create(email: " CRUISE-CONTROL@EXAMPLE.COM\n") user.email # => "cruise-control@example.com" https://api.rubyonrails.org/classes/ActiveRecord/Normalization/ClassMethods.html
54. user = User.create(email: " CRUISE-CONTROL@EXAMPLE.COM\n") user.email # => "cruise-control@example.com" https://api.rubyonrails.org/classes/ActiveRecord/Normalization/ClassMethods.html User.exists?(email: "\tCRUISE-CONTROL@EXAMPLE.COM ") # => true User.exists?(["email = ?", "\tCRUISE-CONTROL@EXAMPLE.COM "]) # => false
55. user = User.create(email: " CRUISE-CONTROL@EXAMPLE.COM\n") user.email # => "cruise-control@example.com" https://api.rubyonrails.org/classes/ActiveRecord/Normalization/ClassMethods.html User.exists?(email: "\tCRUISE-CONTROL@EXAMPLE.COM ") # => true User.exists?(["email = ?", "\tCRUISE-CONTROL@EXAMPLE.COM "]) # => false User.normalize_value_for(:phone, "+1 (555) 867-5309") # => "15558675309"
56. Composing reusable in database queries
57. Query methods
58. .extending module FilterByRole def only_admin where(role_name: :admin) end def only_manager where(role_name: :manager) end end
59. .extending module FilterByRole def only_admin where(role_name: :admin) end def only_manager where(role_name: :manager) end end User.extending(FilterByRole).only_admin SELECT "users".* FROM "users" WHERE "users"."role_name" = $1 [["role_name", "admin"]]
60. .extending module Pagination def page(number) # pagination code goes here end end scope = Model.all.extending(Pagination) scope.page(params[:page])
61. Observing application behavior
62. Instrumentation
63. def index @contacts = Contact.all end
64. def index ActiveSupport::Notifications.instrument('contacts', extra: :information) do @contacts = Contact.all end end
65. def index ActiveSupport::Notifications.instrument('contacts', extra: :information) do @contacts = Contact.all end end ActiveSupport::Notifications.subscribe('contacts') do |event| event.name # => "contacts" event.duration # => 7.537125000031665ms event.payload # => { extra: :information } event.allocations # => 556 (objects) end
67. ActiveSupport::Notifications.subscribe "process_action.action_controller" do |event| event.name # => "process_action.action_controller" event.duration # => 10 (in milliseconds) event.allocations # => 1826 event.payload # => {:extra=>information} Rails.logger.info "#{event} Received!" end
68. Writing intention-revealing conditional logic
69. String Inquirer
70. Rails.env.production?
71. Rails.env.production? env = ActiveSupport::StringInquirer.new(‘production') env.production? # => true env.test? # => false
72. Custom callbacks
73. Active Support Callbacks
74. class ApplicationRecord < ActiveRecord::Base include ActiveSupport::Callbacks define_callbacks :notify_customer def run_notify_customer_callbacks(&block) run_callbacks :notify_customer, &block end end
75. class Customer < ApplicationRecord set_callback :notify_customer, :after, :send_email def activate! run_notify_customer_callbacks do update!(active: true) end end private def send_email CustomerMailer.activation_email(self).deliver_later end end
76. Share data between layers inside a request
77. Current Attributes
78. class Current < ActiveSupport::CurrentAttributes attribute :session, :user attribute :user_agent, :ip_address end
79. def show @products = Current.user.products.order(:name) end <h1>Welcome, <%= Current.user.name %>!</h1> Controller action View
80. Naming transformations across the framework
81. In fl ector
82. Rails.application.routes.draw do namespace :api do root "home#index" end end class API::HomeController < ApplicationController def index render plain: 'API Home' end end
84. ActiveSupport::Inflector.inflections(:en) do |inflect| inflect.acronym "API" end con fi g/initializers/in fl ections.rb
85. 'posts'.singularize # => "post" 'post'.pluralize # => "posts" 'x-men: the last stand'.titleize # => "X Men: The Last Stand" 'employee_salary'.humanize # => "Employee salary"
86. Composing large routing fi les
87. Draw
88. Rails.application.routes.draw do root "landing#index" namespace :admin do root "home#index" resources :contacts, only: [:index, :show, :destroy] end namespace :manager do root "home#index" resources :categories resources :products resources :tables resources :users end end
89. namespace :admin do root "home#index" resources :contacts, only: [:index, :show, :destroy] end namespace :manager do root "home#index" resources :categories resources :products resources :tables resources :users end con fi g/routes/admin.rb con fi g/routes/manager.rb
90. Rails.application.routes.draw do root "landing#index" draw :admin draw :manager end con fi g/routes.rb
91. Custom routes
92. Direct routes
93. Rails.application.routes.draw do # ... direct :docs do "https://docs.myapi.com" end direct :landing do { controller: 'landing', action: 'index', subdomain: 'www' } end end
94. rails console app.docs_url => "https://docs.myapi.com" app.landing_url => "http://www.example.com/"
95. Conclusion
96. The documentation is your best friend Everything in programming involves trade-o ff s. Make smart choices In this talk, there are a lot of uncovered features
97. Thank you!
98. https://www.viniciusalonso.com/2025/04/01/tropicalrails-references.html References