Ruby on Rails code explainers

ruby

class NewCommentNotifier < ApplicationNotifier
  deliver_by :database
 
  deliver_by :email do |config|

Multi-channel notifications with Noticed in Rails

notifications delivery-methods fan-out

Intermediate 6 steps

ruby

class DocumentsController < ApplicationController
  before_action :authenticate_user!
  before_action :set_document

Serving secure file downloads in Rails

authorization signed-urls active-storage

Intermediate 8 steps

ruby

class ApplicationJob < ActiveJob::Base
  retry_on ActiveRecord::Deadlocked, wait: 5.seconds, attempts: 3
  discard_on ActiveJob::DeserializationError

Instrumenting every job in Rails

active-job structured-logging retries

Intermediate 6 steps

ruby

class PasswordResetsController < ApplicationController
  RESET_PURPOSE = :password_reset
  RESET_EXPIRY = 15.minutes

Password resets with signed global IDs in Rails

authentication signed-tokens global-id

Intermediate 9 steps

ruby

module ProductsHelper
  def cached_product_row(product)
    cache [product, current_user.role] do
      render partial: "products/row", locals: { product: product }

Russian doll caching that busts itself in Rails

fragment-caching cache-invalidation associations

Intermediate 4 steps

ruby

class DigestMailer < ApplicationMailer
  default from: "notifications@example.com"
 
  def weekly_digest(user)

Building a weekly digest email in Rails

mailers active-record query-scopes

Intermediate 6 steps

ruby

class OrdersController < ApplicationController
  rescue_from ActiveRecord::RecordNotUnique, with: :handle_duplicate_submission
 
  def create

Idempotent order creation in Rails

idempotency database-constraints error-handling

Intermediate 8 steps

ruby

class InventoryItem < ApplicationRecord
  belongs_to :warehouse
 
  validates :quantity, numericality: { greater_than_or_equal_to: 0 }

Safe inventory updates in Rails

concurrency pessimistic-locking optimistic-locking

Advanced 7 steps

ruby

class PaymentMethod < ApplicationRecord
  belongs_to :account
 
  encrypts :card_number, deterministic: false

How Rails encrypts sensitive payment fields

encryption validation scopes

Intermediate 9 steps

ruby

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

Normalizing user input in Rails models

normalization validation data integrity

Intermediate 6 steps

ruby

class Account < ApplicationRecord
  has_many :projects, dependent: :destroy_async
  has_many :memberships, dependent: :destroy_async
  has_many :invoices, dependent: :restrict_with_error

Safely closing an Account in Rails

associations callbacks transactions

Intermediate 9 steps

ruby

require "csv"
 
class Api::V1::ProductImportsController < Api::V1::BaseController
  MAX_ROWS = 10_000

Bulk CSV imports with upsert_all in Rails

bulk-insert csv-parsing upsert

Intermediate 8 steps

ruby

class HealthController < ApplicationController
  skip_before_action :authenticate_user!, raise: false
  skip_forgery_protection

Building a health check endpoint in Rails

health-check monitoring error-handling

Intermediate 7 steps

ruby

module Instrumentation
  module Timing
    def self.[](*method_names)
      Module.new do

Timing methods with a prepended module in Ruby in Rails

metaprogramming prepend instrumentation

Advanced 7 steps

ruby

class BulkImporter
  BATCH_SIZE = 500
 
  def initialize(records)

Batching bulk inserts in Rails

batching bulk-insert deduplication

Intermediate 5 steps

ruby

module Multitenant
  extend ActiveSupport::Concern
 
  included do

How a multitenant concern scopes Rails models

multitenancy default-scope concern

Advanced 8 steps

ruby

module Api
  module V1
    class BaseController < ActionController::API
      rescue_from StandardError, with: :render_internal_error

Centralized API error handling in Rails

error-handling rescue-from json-api

Intermediate 7 steps

ruby

class CartMergeService
  def initialize(guest_cart:, user_cart:)
    @guest_cart = guest_cart
    @user_cart = user_cart

Merging a guest cart into a user cart in Rails

service object transactions idempotency

Intermediate 7 steps