Ruby code explainers

ruby

class ToastBroadcaster
  include ActionView::RecordIdentifier
 
  def self.broadcast_to(user, message:, type: :notice)

How Turbo Stream toasts broadcast in Rails

turbo-streams service-object real-time

Intermediate 6 steps

ruby

class TemplateInterpolator
  PLACEHOLDER = /\{\{\s*([\w.]+)\s*\}\}/
 
  def initialize(strict: false)

Interpolating templates with dotted keys in Ruby

regex string-interpolation hash-traversal

Intermediate 6 steps

ruby

class KeyTransformer
  def self.camelize(data)
    new.camelize(data)
  end

Recursively camelizing nested Ruby data

recursion data-transformation pattern-matching

Intermediate 7 steps

ruby

module Paginatable
  extend ActiveSupport::Concern
 
  private

A reusable pagination concern in Rails

pagination concerns http-headers

Intermediate 8 steps

ruby

class Api::MessagesController < ApiController
  before_action :authenticate_api_key!
 
  rate_limit to: 100,

Layered API rate limiting in Rails

rate-limiting api-authentication throttling

Intermediate 9 steps

ruby

class Order < ApplicationRecord
  include AASM
 
  belongs_to :warehouse

Modeling an order lifecycle with AASM in Rails

state machine guards callbacks

Intermediate 10 steps

ruby

require "timeout"
require "net/http"
 
class RemoteInventoryClient

Bounding a slow HTTP call with Timeout in Ruby

timeout error-handling http

Intermediate 6 steps

ruby

require "base64"
require "json"
 
module Attachment

Packing binary attachments into JSON

serialization base64 json

Intermediate 8 steps

ruby

require "yaml"
 
class FrontMatter
  DELIMITER = /\A---\s*\n(.*?)\n---\s*\n?(.*)\z/m

Parsing YAML front matter in Ruby

parsing regular-expressions yaml

Intermediate 8 steps

ruby

module Api
  module Reports
    class DailyOrderTotalsController < Api::BaseController
      def index

Building a daily order totals report in Rails

sql aggregation json api query building

Intermediate 7 steps

ruby

module FixedWidthParser
  FIELDS = [
    { name: :record_type, range: 0...2 },
    { name: :account_id,  range: 2...12, type: :integer },

Parsing fixed-width records in Ruby

parsing data-driven-design type-coercion

Intermediate 5 steps

ruby

module Authenticatable
  extend ActiveSupport::Concern
 
  included do

JWT authentication as a Rails concern

authentication jwt concerns

Intermediate 6 steps

ruby

class Pipeline
  def initialize
    @middlewares = []
  end

Building a middleware pipeline in Ruby

closures middleware composition

Advanced 8 steps

ruby

class Contact < ApplicationRecord
  PHONE_FORMATS = {
    "US" => /\A\+1\d{10}\z/,
    "GB" => /\A\+44\d{10}\z/,

Country-aware phone validation in Rails

validation callbacks regex

Intermediate 6 steps

ruby

module AppConfig
  module_function
 
  def fetch(key, default: nil, required: false)

Typed environment variable config in Ruby

environment-variables type-coercion configuration

Intermediate 7 steps

ruby

class ThumbnailPool
  def initialize(worker_count: 4, capacity: 100)
    @queue = SizedQueue.new(capacity)
    @running = true

A thread pool for thumbnail jobs in Ruby

concurrency thread-pool bounded-queue

Advanced 7 steps

ruby

require "csv"
 
class CsvExporter
  def initialize(records, columns: nil)

Turning records into CSV in Ruby

csv data-export serialization

Intermediate 7 steps

ruby

class CircuitBreaker
  class OpenCircuitError < StandardError; end
 
  def initialize(failure_threshold: 5, reset_timeout: 30, half_open_max: 1)

How a circuit breaker guards failing calls

state-machine fault-tolerance concurrency

Advanced 9 steps