ruby

# Basic middleware structure
class RequestTimerMiddleware
  def initialize(app)
    @app = app
  end

class DownloadsController < ApplicationController
  before_action :authenticate_user!

  def show
    report = current_account.reports.find(params[:report_id])
    authorize! :download, report

<h1>Create your account</h1>

<%= render "error_summary", record: @user %>

<%= form_with model: @user, url: signups_path do |f| %>
  <div class="field">

module Middleware
  class RateLimiter
    def initialize(app, redis:, limit:, window:)
      @app = app
      @limiter = SlidingWindowLimiter.new(redis: redis, limit: limit, window: window)
      @limit = limit

<%# Fragment caching - caches rendered HTML %>
<% cache @product do %>
  <h1><%= @product.name %></h1>
  <p><%= @product.description %></p>
  <p>Price: $<%= @product.price %></p>
<% end %>

class CreateCustomerRevenueSummaries < ActiveRecord::Migration[7.0]
  def change
    create_view :customer_revenue_summaries, materialized: true, version: 1

    add_index :customer_revenue_summaries,
              :customer_id,

require "securerandom"
require "digest"

class SlidingWindowLimiter
  Result = Struct.new(:allowed, :count, :remaining)

<div class="dashboard">
  <header class="dashboard__header">
    <h1>Overview</h1>
    <p class="muted">Real-time metrics update as they load.</p>
  </header>

class ArticlesController < ApplicationController
  before_action :set_article, only: %i[edit update]

  def new
    @article = Article.new
  end

module Api
  module V1
    class UsersController < ApplicationController
      before_action :authenticate_user!, except: [:index, :show]
      before_action :set_user, only: [:show, :update, :destroy]

class Comment < ApplicationRecord
  belongs_to :post
  belongs_to :author, class_name: "User"

  validates :body, presence: true, length: { maximum: 2_000 }

class DailySignupRollup < ApplicationRecord
  validates :day, presence: true, uniqueness: true
  validates :total, :verified, numericality: { greater_than_or_equal_to: 0 }

  scope :for_range, ->(from, to) do
    where(day: from.to_date..to.to_date).order(:day)