Ruby code explainers

ruby

class ProjectsController < ApplicationController
  before_action :set_project, only: %i[show update destroy]
 
  def create

Scoping a Rails API controller to Current.account

multitenancy strong-parameters nested-attributes

Intermediate 7 steps

ruby

class SearchController < ApplicationController
  def index
    @query = params[:q].to_s.strip
  end

Live search suggestions in a Rails controller

controllers sql-injection query-building

Intermediate 6 steps

ruby

class TasksController < ApplicationController
  before_action :set_project
 
  def reorder

Bulk task reordering with upsert_all in Rails

bulk-update upsert authorization

Intermediate 8 steps

ruby

require "openssl"
require "json"
require "base64"

Building signed session tokens in Ruby

hmac authentication cryptography

Intermediate 8 steps

ruby

class Product < ApplicationRecord
  belongs_to :category, touch: true
 
  has_many :reviews, dependent: :destroy

How Rails models wire up associations

active record associations validations

Intermediate 7 steps

ruby

require "net/http"
require "json"
require "uri"
require "base64"

Paginating an HTTP API with a Ruby enumerator

pagination http enumerator

Intermediate 7 steps

ruby

class DateRangeMerger
  def initialize(ranges)
    @ranges = ranges
  end

Merging overlapping date ranges in Ruby

sorting interval-merging enumerable

Intermediate 5 steps

ruby

module SlowQueryLogger
  SLOW_QUERY_THRESHOLD_MS = 200.0
  IGNORED_PAYLOAD_NAMES = %w[SCHEMA TRANSACTION].freeze

Logging slow SQL queries in Rails

instrumentation logging pub-sub

Intermediate 7 steps

ruby

require "phonelib"
 
class PhoneNumber
  class InvalidNumber < StandardError; end

Wrapping phone parsing in a Ruby value object

value-object memoization validation

Intermediate 7 steps

ruby

class PaymentGateway
  class MissingCredentialError < StandardError; end
 
  def initialize(env: Rails.env)

Wrapping Rails credentials in a gateway

encapsulation credentials error handling

Intermediate 6 steps

ruby

class WelcomeSequenceOrchestrator
  STEPS = [
    { mailer: :welcome_email,      delay: 0.hours },
    { mailer: :getting_started,    delay: 1.day },

Scheduling a drip email sequence in Rails

mailers background jobs scheduling

Intermediate 6 steps

ruby

class QueryProxy
  ALLOWED = %i[where limit offset order includes distinct].freeze
 
  def initialize(relation, operations = [])

Building a lazy query proxy in Ruby

metaprogramming method_missing lazy-evaluation

Advanced 7 steps

ruby

class Debouncer
  def initialize(delay:)
    @delay = delay
    @mutex = Mutex.new

A thread-safe debouncer in Ruby

concurrency debouncing mutex

Advanced 5 steps

ruby

require "net/http"
require "json"
 
class UrlFetcher

A thread-pool URL fetcher in Ruby

concurrency thread-pool queues

Intermediate 8 steps

ruby

class SyncContactsJob < ApplicationJob
  queue_as :external_api
 
  MAX_CONCURRENCY = 5

Rate-limited CRM sync in a Rails job

background-jobs rate-limiting redis

Advanced 9 steps

ruby

module DeepImmutable
  module_function
 
  def deep_freeze(obj)

Deep-freezing config with recursive immutability

immutability recursion deep-copy

Intermediate 8 steps

ruby

class Admin::OrdersExportController < Admin::BaseController
  include ActionController::Live
 
  def show

Streaming a CSV export in Rails

streaming csv-export batching

Advanced 8 steps

ruby

class DatasetImportJob < ApplicationJob
  queue_as :default
 
  def perform(import)

Streaming import progress with a Rails job

background-jobs turbo-streams progress-tracking

Intermediate 9 steps