Rails 入门

$ rails --version
Rails 8.1.0

$ rails new store

$ cd store

$ bin/rails db:create

$ bin/rails server

=> Booting Puma
=> Rails 8.1.0 application starting in development
=> Run `bin/rails server --help` for more startup options
Puma starting in single mode...
* Puma version: 6.4.3 (ruby 3.3.5-p100) ("The Eagle of Durango")
*  Min threads: 3
*  Max threads: 3
*  Environment: development
*          PID: 12345
* Listening on http://127.0.0.1:3000
* Listening on http://[::1]:3000
Use Ctrl-C to stop

$ bin/rails generate model Product name:string

      invoke  active_record
      create    db/migrate/20240426151900_create_products.rb
      create    app/models/product.rb
      invoke    test_unit
      create      test/models/product_test.rb
      create      test/fixtures/products.yml

class CreateProducts < ActiveRecord::Migration[8.1]
  def change
    create_table :products do |t|
      t.string :name

      t.timestamps
    end
  end
end

$ bin/rails db:migrate

== 20240426151900 CreateProducts: migrating ===================================
-- create_table(:products)
   -> 0.0030s
== 20240426151900 CreateProducts: migrated (0.0031s) ==========================

$ bin/rails console

Loading development environment (Rails 8.1.0)
store(dev)>

store(dev)> Rails.version
=> "8.1.0"

class Product < ApplicationRecord
end

store(dev)> Product.column_names

=> ["id", "name", "created_at", "updated_at"]

store(dev)> product = Product.new(name: "T-Shirt")
=> #<Product:0x000000012e616c30 id: nil, name: "T-Shirt", created_at: nil, updated_at: nil>

store(dev)> product.save
  TRANSACTION (0.1ms)  BEGIN immediate TRANSACTION /*application='Store'*/
  Product Create (0.9ms)  INSERT INTO "products" ("name", "created_at", "updated_at") VALUES ('T-Shirt', '2024-11-09 16:35:01.117836', '2024-11-09 16:35:01.117836') RETURNING "id" /*application='Store'*/
  TRANSACTION (0.9ms)  COMMIT TRANSACTION /*application='Store'*/
=> true

store(dev)> product
=> #<Product:0x00000001221f6260 id: 1, name: "T-Shirt", created_at: "2024-11-09 16:35:01.117836000 +0000", updated_at: "2024-11-09 16:35:01.117836000 +0000">

store(dev)> Product.create(name: "Pants")
  TRANSACTION (0.1ms)  BEGIN immediate TRANSACTION /*application='Store'*/
  Product Create (0.4ms)  INSERT INTO "products" ("name", "created_at", "updated_at") VALUES ('Pants', '2024-11-09 16:36:01.856751', '2024-11-09 16:36:01.856751') RETURNING "id" /*application='Store'*/
  TRANSACTION (0.1ms)  COMMIT TRANSACTION /*application='Store'*/
=> #<Product:0x0000000120485c80 id: 2, name: "Pants", created_at: "2024-11-09 16:36:01.856751000 +0000", updated_at: "2024-11-09 16:36:01.856751000 +0000">

store(dev)> Product.all
  Product Load (0.1ms)  SELECT "products".* FROM "products" /* loading for pp */ LIMIT 11 /*application='Store'*/
=> [#<Product:0x0000000121845158 id: 1, name: "T-Shirt", created_at: "2024-11-09 16:35:01.117836000 +0000", updated_at: "2024-11-09 16:35:01.117836000 +0000">,
 #<Product:0x0000000121845018 id: 2, name: "Pants", created_at: "2024-11-09 16:36:01.856751000 +0000", updated_at: "2024-11-09 16:36:01.856751000 +0000">]

store(dev)> Product.where(name: "Pants")
  Product Load (1.5ms)  SELECT "products".* FROM "products" WHERE "products"."name" = 'Pants' /* loading for pp */ LIMIT 11 /*application='Store'*/
=> [#<Product:0x000000012184d858 id: 2, name: "Pants", created_at: "2024-11-09 16:36:01.856751000 +0000", updated_at: "2024-11-09 16:36:01.856751000 +0000">]

store(dev)> Product.order(name: :asc)
  Product Load (0.3ms)  SELECT "products".* FROM "products" /* loading for pp */ ORDER BY "products"."name" ASC LIMIT 11 /*application='Store'*/
=> [#<Product:0x0000000120e02a88 id: 2, name: "Pants", created_at: "2024-11-09 16:36:01.856751000 +0000", updated_at: "2024-11-09 16:36:01.856751000 +0000">,
 #<Product:0x0000000120e02948 id: 1, name: "T-Shirt", created_at: "2024-11-09 16:35:01.117836000 +0000", updated_at: "2024-11-09 16:35:01.117836000 +0000">]

store(dev)> Product.find(1)
  Product Load (0.2ms)  SELECT "products".* FROM "products" WHERE "products"."id" = 1 LIMIT 1 /*application='Store'*/
=> #<Product:0x000000012054af08 id: 1, name: "T-Shirt", created_at: "2024-11-09 16:35:01.117836000 +0000", updated_at: "2024-11-09 16:35:01.117836000 +0000">

store(dev)> product = Product.find(1)
store(dev)> product.update(name: "Shoes")
  TRANSACTION (0.1ms)  BEGIN immediate TRANSACTION /*application='Store'*/
  Product Update (0.3ms)  UPDATE "products" SET "name" = 'Shoes', "updated_at" = '2024-11-09 22:38:19.638912' WHERE "products"."id" = 1 /*application='Store'*/
  TRANSACTION (0.4ms)  COMMIT TRANSACTION /*application='Store'*/
=> true

store(dev)> Product.all

  Product Load (0.3ms)  SELECT "products".* FROM "products" /* loading for pp */ LIMIT 11 /*application='Store'*/
=>
[#<Product:0x000000012c0f7300
  id: 1,
  name: "Shoes",
  created_at: "2024-12-02 20:29:56.303546000 +0000",
  updated_at: "2024-12-02 20:30:14.127456000 +0000">,
 #<Product:0x000000012c0f71c0
  id: 2,
  name: "Pants",
  created_at: "2024-12-02 20:30:02.997261000 +0000",
  updated_at: "2024-12-02 20:30:02.997261000 +0000">]

store(dev)> product = Product.find(1)
store(dev)> product.name = "T-Shirt"
=> "T-Shirt"
store(dev)> product.save
  TRANSACTION (0.1ms)  BEGIN immediate TRANSACTION /*application='Store'*/
  Product Update (0.2ms)  UPDATE "products" SET "name" = 'T-Shirt', "updated_at" = '2024-11-09 22:39:09.693548' WHERE "products"."id" = 1 /*application='Store'*/
  TRANSACTION (0.0ms)  COMMIT TRANSACTION /*application='Store'*/
=> true

store(dev)> product.destroy
  TRANSACTION (0.1ms)  BEGIN immediate TRANSACTION /*application='Store'*/
  Product Destroy (0.4ms)  DELETE FROM "products" WHERE "products"."id" = 1 /*application='Store'*/
  TRANSACTION (0.1ms)  COMMIT TRANSACTION /*application='Store'*/
=> #<Product:0x0000000125813d48 id: 1, name: "T-Shirt", created_at: "2024-11-09 22:39:38.498730000 +0000", updated_at: "2024-11-09 22:39:38.498730000 +0000">

store(dev)> Product.all
  Product Load (1.9ms)  SELECT "products".* FROM "products" /* loading for pp */ LIMIT 11 /*application='Store'*/
=>
[#<Product:0x000000012abde4c8
  id: 2,
  name: "Pants",
  created_at: "2024-11-09 22:33:19.638912000 +0000",
  updated_at: "2024-11-09 22:33:19.638912000 +0000">]

class Product < ApplicationRecord
  validates :name, presence: true
end

store(dev)> reload!
Reloading...

store(dev)> product = Product.new
store(dev)> product.save
=> false

store(dev)> product.errors
=> #<ActiveModel::Errors [#<ActiveModel::Error attribute=name, type=blank, options={}>]>

store(dev)> product.errors.full_messages
=> ["Name can't be blank"]

https://example.org/products?sale=true&sort=asc

Rails.application.routes.draw do
  get "/products", to: "products#index"
end

post "/products", to: "products#create"

get "/products/:id", to: "products#show"

get "/blog/:title", to: "blog#show"

get "/products", to: "products#index"

get "/products/new", to: "products#new"
post "/products", to: "products#create"

get "/products/:id", to: "products#show"

get "/products/:id/edit", to: "products#edit"
patch "/products/:id", to: "products#update"
put "/products/:id", to: "products#update"

delete "/products/:id", to: "products#destroy"

resources :products

$ bin/rails routes

      Prefix Verb   URI Pattern                  Controller#Action
    products GET    /products(.:format)          products#index
             POST   /products(.:format)          products#create
 new_product GET    /products/new(.:format)      products#new
edit_product GET    /products/:id/edit(.:format) products#edit
     product GET    /products/:id(.:format)      products#show
             PATCH  /products/:id(.:format)      products#update
             PUT    /products/:id(.:format)      products#update
             DELETE /products/:id(.:format)      products#destroy

$ bin/rails generate controller Products index --skip-routes
      create  app/controllers/products_controller.rb
      invoke  erb
      create    app/views/products
      create    app/views/products/index.html.erb
      invoke  test_unit
      create    test/controllers/products_controller_test.rb
      invoke  helper
      create    app/helpers/products_helper.rb
      invoke    test_unit

class ProductsController < ApplicationController
  def index
  end
end

<h1>Products#index</h1>
<p>Find me in app/views/products/index.html.erb</p>

root "products#index"

class ProductsController < ApplicationController
  def index
    @products = Product.all
  end
end

<%= debug @products %>

<h1>Products</h1>

<div id="products">
  <% @products.each do |product| %>
    <div>
      <%= product.name %>
    </div>
  <% end %>
</div>

class ProductsController < ApplicationController
  def index
    @products = Product.all
  end

  def show
    @product = Product.find(params[:id])
  end
end

<h1><%= @product.name %></h1>

<%= link_to "Back", products_path %>

<h1>Products</h1>

<div id="products">
  <% @products.each do |product| %>
    <div>
      <a href="/products/<%= product.id %>">
        <%= product.name %>
      </a>
    </div>
  <% end %>
</div>

  Prefix Verb   URI Pattern             Controller#Action
products GET    /products(.:format)     products#index
 product GET    /products/:id(.:format) products#show

<h1>Products</h1>

<div id="products">
  <% @products.each do |product| %>
    <div>
      <%= link_to product.name, product_path(product.id) %>
    </div>
  <% end %>
</div>

class ProductsController < ApplicationController
  def index
    @products = Product.all
  end

  def show
    @product = Product.find(params[:id])
  end

  def new
    @product = Product.new
  end
end

<h1>Products</h1>

<%= link_to "New product", new_product_path %>

<div id="products">
  <% @products.each do |product| %>
    <div>
      <%= link_to product.name, product_path(product.id) %>
    </div>
  <% end %>
</div>

<h1>New product</h1>

<%= form_with model: @product do |form| %>
  <div>
    <%= form.label :name %>
    <%= form.text_field :name %>
  </div>

  <div>
    <%= form.submit %>
  </div>
<% end %>

<%= link_to "Cancel", products_path %>

<form action="/products" accept-charset="UTF-8" method="post">
  <input type="hidden" name="authenticity_token" value="UHQSKXCaFqy_aoK760zpSMUPy6TMnsLNgbPMABwN1zpW-Jx6k-2mISiF0ulZOINmfxPdg5xMyZqdxSW1UK-H-Q" autocomplete="off">

  <div>
    <label for="product_name">Name</label>
    <input type="text" name="product[name]" id="product_name">
  </div>

  <div>
    <input type="submit" name="commit" value="Create Product" data-disable-with="Create Product">
  </div>
</form>

class ProductsController < ApplicationController
  def index
    @products = Product.all
  end

  def show
    @product = Product.find(params[:id])
  end

  def new
    @product = Product.new
  end

  def create
    @product = Product.new(product_params)
    if @product.save
      redirect_to @product
    else
      render :new, status: :unprocessable_entity
    end
  end

  private
    def product_params
      params.expect(product: [ :name ])
    end
end

redirect_to @product

class ProductsController < ApplicationController
  def index
    @products = Product.all
  end

  def show
    @product = Product.find(params[:id])
  end

  def new
    @product = Product.new
  end

  def create
    @product = Product.new(product_params)
    if @product.save
      redirect_to @product
    else
      render :new, status: :unprocessable_entity
    end
  end

  def edit
    @product = Product.find(params[:id])
  end

  def update
    @product = Product.find(params[:id])
    if @product.update(product_params)
      redirect_to @product
    else
      render :edit, status: :unprocessable_entity
    end
  end

  private
    def product_params
      params.expect(product: [ :name ])
    end
end

<%= form_with model: product do |form| %>
  <% if form.object.errors.any? %>
    <p class="error"><%= form.object.errors.full_messages.first %></p>
  <% end %>

  <div>
    <%= form.label :name %>
    <%= form.text_field :name %>
  </div>

  <div>
    <%= form.submit %>
  </div>
<% end %>

<h1>New product</h1>

<%= render "form", product: @product %>
<%= link_to "Cancel", products_path %>

<h1>Edit product</h1>

<%= render "form", product: @product %>
<%= link_to "Cancel", @product %>

<h1><%= @product.name %></h1>

<%= link_to "Back", products_path %>
<%= link_to "Edit", edit_product_path(@product) %>

class ProductsController < ApplicationController
  before_action :set_product, only: %i[ show edit update ]

  def index
    @products = Product.all
  end

  def show
  end

  def new
    @product = Product.new
  end

  def create
    @product = Product.new(product_params)
    if @product.save
      redirect_to @product
    else
      render :new, status: :unprocessable_entity
    end
  end

  def edit
  end

  def update
    if @product.update(product_params)
      redirect_to @product
    else
      render :edit, status: :unprocessable_entity
    end
  end

  private
    def set_product
      @product = Product.find(params[:id])
    end

    def product_params
      params.expect(product: [ :name ])
    end
end

class ProductsController < ApplicationController
  before_action :set_product, only: %i[ show edit update destroy ]

  def index
    @products = Product.all
  end

  def show
  end

  def new
    @product = Product.new
  end

  def create
    @product = Product.new(product_params)
    if @product.save
      redirect_to @product
    else
      render :new, status: :unprocessable_entity
    end
  end

  def edit
  end

  def update
    if @product.update(product_params)
      redirect_to @product
    else
      render :edit, status: :unprocessable_entity
    end
  end

  def destroy
    @product.destroy
    redirect_to products_path
  end

  private
    def set_product
      @product = Product.find(params[:id])
    end

    def product_params
      params.expect(product: [ :name ])
    end
end

<h1><%= @product.name %></h1>

<%= link_to "Back", products_path %>
<%= link_to "Edit", edit_product_path(@product) %>
<%= button_to "Delete", @product, method: :delete, data: { turbo_confirm: "Are you sure?" } %>

$ bin/rails generate authentication

$ bin/rails db:migrate

$ bin/rails console

store(dev)> User.create! email_address: "you@example.org", password: "s3cr3t", password_confirmation: "s3cr3t"

$ bin/rails server

<!DOCTYPE html>
<html>
  <!-- ... -->
  <body>
    <nav>
      <%= link_to "Home", root_path %>
      <%= button_to "Log out", session_path, method: :delete if authenticated? %>
    </nav>

    <main>
      <%= yield %>
    </main>
  </body>
</html>

class ProductsController < ApplicationController
  allow_unauthenticated_access only: %i[ index show ]
  # ...
end

<%= link_to "New product", new_product_path if authenticated? %>

<%= link_to "Login", new_session_path unless authenticated? %>

<h1><%= @product.name %></h1>

<%= link_to "Back", products_path %>
<% if authenticated? %>
  <%= link_to "Edit", edit_product_path(@product) %>
  <%= button_to "Delete", @product, method: :delete, data: { turbo_confirm: "Are you sure?" } %>
<% end %>

<% cache @product do %>
  <h1><%= @product.name %></h1>
<% end %>

$ bin/rails dev:cache

Read fragment views/products/show:a5a585f985894cd27c8b3d49bb81de3a/products/1-20240918154439539125 (1.6ms)
Write fragment views/products/show:a5a585f985894cd27c8b3d49bb81de3a/products/1-20240918154439539125 (4.0ms)

Read fragment views/products/show:a5a585f985894cd27c8b3d49bb81de3a/products/1-20240918154439539125 (1.3ms)

$ bin/rails action_text:install
$ bundle install
$ bin/rails db:migrate

class Product < ApplicationRecord
  has_rich_text :description
  validates :name, presence: true
end

<%= form_with model: product do |form| %>
  <%# ... %>

  <div>
    <%= form.label :description, style: "display: block" %>
    <%= form.rich_textarea :description %>
  </div>

  <div>
    <%= form.submit %>
  </div>
<% end %>

    # Only allow a list of trusted parameters through.
    def product_params
      params.expect(product: [ :name, :description ])
    end

<% cache @product do %>
  <h1><%= @product.name %></h1>
  <%= @product.description %>
<% end %>

class Product < ApplicationRecord
  has_one_attached :featured_image
  has_rich_text :description
  validates :name, presence: true
end

<%= form_with model: product do |form| %>
  <%# ... %>

  <div>
    <%= form.label :featured_image, style: "display: block" %>
    <%= form.file_field :featured_image, accept: "image/*" %>
  </div>

  <div>
    <%= form.submit %>
  </div>
<% end %>

    # Only allow a list of trusted parameters through.
    def product_params
      params.expect(product: [ :name, :description, :featured_image ])
    end

<%= image_tag @product.featured_image if @product.featured_image.attached? %>

<h1><%= t "hello" %></h1>

en:
  hello: "Hello world"

es:
  hello: "Hola mundo"

class ApplicationController < ActionController::Base
  # ...

  around_action :switch_locale

  def switch_locale(&action)
    locale = params[:locale] || I18n.default_locale
    I18n.with_locale(locale, &action)
  end
end

<h1><%= t ".title" %></h1>

en:
  hello: "Hello world"
  products:
    index:
      title: "Products"

es:
  hello: "Hola mundo"
  products:
    index:
      title: "Productos"

$ bin/rails generate migration AddInventoryCountToProducts inventory_count:integer

class AddInventoryCountToProducts < ActiveRecord::Migration[8.1]
  def change
    add_column :products, :inventory_count, :integer, default: 0
  end
end

$ bin/rails db:migrate

<%= form_with model: product do |form| %>
  <%# ... %>

  <div>
    <%= form.label :inventory_count, style: "display: block" %>
    <%= form.number_field :inventory_count %>
  </div>

  <div>
    <%= form.submit %>
  </div>
<% end %>

    def product_params
      params.expect(product: [ :name, :description, :featured_image, :inventory_count ])
    end

class Product < ApplicationRecord
  has_one_attached :featured_image
  has_rich_text :description

  validates :name, presence: true
  validates :inventory_count, numericality: { greater_than_or_equal_to: 0 }
end

$ bin/rails generate model Subscriber product:belongs_to email

class CreateSubscribers < ActiveRecord::Migration[8.1]
  def change
    create_table :subscribers do |t|
      t.belongs_to :product, null: false, foreign_key: true
      t.string :email

      t.timestamps
    end
  end
end

$ bin/rails db:migrate

class Product < ApplicationRecord
  has_many :subscribers, dependent: :destroy
  has_one_attached :featured_image
  has_rich_text :description

  validates :name, presence: true
  validates :inventory_count, numericality: { greater_than_or_equal_to: 0 }
end

class SubscribersController < ApplicationController
  allow_unauthenticated_access
  before_action :set_product

  def create
    @product.subscribers.where(subscriber_params).first_or_create
    redirect_to @product, notice: "You are now subscribed."
  end

  private
    def set_product
      @product = Product.find(params[:product_id])
    end

    def subscriber_params
      params.expect(subscriber: [ :email ])
    end
end

<html>
  <!-- ... -->
  <body>
    <div class="notice"><%= flash[:notice] %></div>
    <div class="alert"><%= flash[:alert] %></div>
    <!-- ... -->
  </body>
</html>

  resources :products do
    resources :subscribers, only: [ :create ]
  end

<% if product.inventory_count.positive? %>
  <p><%= product.inventory_count %> in stock</p>
<% else %>
  <p>Out of stock</p>
  <p>Email me when available.</p>

  <%= form_with model: [product, Subscriber.new] do |form| %>
    <%= form.email_field :email, placeholder: "you@example.com", required: true %>
    <%= form.submit "Submit" %>
  <% end %>
<% end %>

<%= render "inventory", product: @product %>

$ bin/rails g mailer Product in_stock

class ProductMailer < ApplicationMailer
  # Subject can be set in your I18n file at config/locales/en.yml
  # with the following lookup:
  #
  #   en.product_mailer.in_stock.subject
  #
  def in_stock
    @product = params[:product]
    mail to: params[:subscriber].email
  end
end

<h1>Good news!</h1>

<p><%= link_to @product.name, product_url(@product) %> is back in stock.</p>

Good news!

<%= @product.name %> is back in stock.
<%= product_url(@product) %>

store(dev)> product = Product.first
store(dev)> subscriber = product.subscribers.find_or_create_by(email: "subscriber@example.org")
store(dev)> ProductMailer.with(product: product, subscriber: subscriber).in_stock.deliver_later

ProductMailer#in_stock: processed outbound mail in 63.0ms
Delivered mail 66a3a9afd5d4a_108b04a4c41443@local.mail (33.1ms)
Date: Fri, 26 Jul 2024 08:50:39 -0500
From: from@example.com
To: subscriber@example.com
Message-ID: <66a3a9afd5d4a_108b04a4c41443@local.mail>
Subject: In stock
Mime-Version: 1.0
Content-Type: multipart/alternative;
 boundary="--==_mimepart_66a3a9afd235e_108b04a4c4136f";
 charset=UTF-8
Content-Transfer-Encoding: 7bit


----==_mimepart_66a3a9afd235e_108b04a4c4136f
Content-Type: text/plain;
 charset=UTF-8
Content-Transfer-Encoding: 7bit

Good news!

T-Shirt is back in stock.
https://:3000/products/1


----==_mimepart_66a3a9afd235e_108b04a4c4136f
Content-Type: text/html;
 charset=UTF-8
Content-Transfer-Encoding: 7bit

<!-- BEGIN app/views/layouts/mailer.html.erb --><!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <style>
      /* Email styles need to be inline */
    </style>
  </head>

  <body>
    <!-- BEGIN app/views/product_mailer/in_stock.html.erb --><h1>Good news!</h1>

<p><a href="https://:3000/products/1">T-Shirt</a> is back in stock.</p>
<!-- END app/views/product_mailer/in_stock.html.erb -->
  </body>
</html>
<!-- END app/views/layouts/mailer.html.erb -->
----==_mimepart_66a3a9afd235e_108b04a4c4136f--

Performed ActionMailer::MailDeliveryJob (Job ID: 5e2bd5f2-f54f-4088-ace3-3f6eb15aaf46) from Async(default) in 111.34ms

class Product < ApplicationRecord
  has_many :subscribers, dependent: :destroy
  has_one_attached :featured_image
  has_rich_text :description

  validates :name, presence: true
  validates :inventory_count, numericality: { greater_than_or_equal_to: 0 }

  after_update_commit :notify_subscribers, if: :back_in_stock?

  def back_in_stock?
    inventory_count_previously_was.zero? && inventory_count.positive?
  end

  def notify_subscribers
    subscribers.each do |subscriber|
      ProductMailer.with(product: self, subscriber: subscriber).in_stock.deliver_later
    end
  end
end

module Product::Notifications
  extend ActiveSupport::Concern

  included do
    has_many :subscribers, dependent: :destroy
    after_update_commit :notify_subscribers, if: :back_in_stock?
  end

  def back_in_stock?
    inventory_count_previously_was.zero? && inventory_count.positive?
  end

  def notify_subscribers
    subscribers.each do |subscriber|
      ProductMailer.with(product: self, subscriber: subscriber).in_stock.deliver_later
    end
  end
end

class Product < ApplicationRecord
  include Notifications

  has_one_attached :featured_image
  has_rich_text :description

  validates :name, presence: true
  validates :inventory_count, numericality: { greater_than_or_equal_to: 0 }
end

Rails.application.routes.draw do
  # ...
  resources :products do
    resources :subscribers, only: [ :create ]
  end
  resource :unsubscribe, only: [ :show ]

class Subscriber < ApplicationRecord
  belongs_to :product
  generates_token_for :unsubscribe
end

class UnsubscribesController < ApplicationController
  allow_unauthenticated_access
  before_action :set_subscriber

  def show
    @subscriber&.destroy
    redirect_to root_path, notice: "Unsubscribed successfully."
  end

  private
    def set_subscriber
      @subscriber = Subscriber.find_by_token_for(:unsubscribe, params[:token])
    end
end

<h1>Good news!</h1>

<p><%= link_to @product.name, product_url(@product) %> is back in stock.</p>

<%= link_to "Unsubscribe", unsubscribe_url(token: params[:subscriber].generate_token_for(:unsubscribe)) %>

Good news!

<%= @product.name %> is back in stock.
<%= product_url(@product) %>

Unsubscribe: <%= unsubscribe_url(token: params[:subscriber].generate_token_for(:unsubscribe)) %>

body {
  font-family: Arial, Helvetica, sans-serif;
  padding: 1rem;
}

nav {
  justify-content: flex-end;
  display: flex;
  font-size: 0.875em;
  gap: 0.5rem;
  max-width: 1024px;
  margin: 0 auto;
  padding: 1rem;
}

nav a {
  display: inline-block;
}

main {
  max-width: 1024px;
  margin: 0 auto;
}

.alert,
.error {
  color: red;
}

.notice {
  color: green;
}

section.product {
  display: flex;
  gap: 1rem;
  flex-direction: row;
}

section.product img {
  border-radius: 8px;
  flex-basis: 50%;
  max-width: 50%;
}

<p><%= link_to "Back", products_path %></p>

<section class="product">
  <%= image_tag @product.featured_image if @product.featured_image.attached? %>

  <section class="product-info">
    <% cache @product do %>
      <h1><%= @product.name %></h1>
      <%= @product.description %>
    <% end %>

    <%= render "inventory", product: @product %>

    <% if authenticated? %>
      <%= link_to "Edit", edit_product_path(@product) %>
      <%= button_to "Delete", @product, method: :delete, data: { turbo_confirm: "Are you sure?" } %>
    <% end %>
  </section>
</section>

# Pin npm packages by running ./bin/importmap

pin "application"
pin "@hotwired/turbo-rails", to: "turbo.min.js"
pin "@hotwired/stimulus", to: "stimulus.min.js"
pin "@hotwired/stimulus-loading", to: "stimulus-loading.js"
pin_all_from "app/javascript/controllers", under: "controllers"
pin "trix"
pin "@rails/actiontext", to: "actiontext.esm.js"

tshirt:
  name: T-Shirt
  inventory_count: 15

david:
  product: tshirt
  email: david@example.org

chris:
  product: tshirt
  email: chris@example.org

require "test_helper"

class ProductTest < ActiveSupport::TestCase
  include ActionMailer::TestHelper

  test "sends email notifications when back in stock" do
    product = products(:tshirt)

    # Set product out of stock
    product.update(inventory_count: 0)

    assert_emails 2 do
      product.update(inventory_count: 99)
    end
  end
end

$ bin/rails test test/models/product_test.rb
Running 1 tests in a single process (parallelization threshold is 50)
Run options: --seed 3556

# Running:

.

Finished in 0.343842s, 2.9083 runs/s, 5.8166 assertions/s.
1 runs, 2 assertions, 0 failures, 0 errors, 0 skips

require "test_helper"

class ProductMailerTest < ActionMailer::TestCase
  test "in_stock" do
    mail = ProductMailer.with(product: products(:tshirt), subscriber: subscribers(:david)).in_stock
    assert_equal "In stock", mail.subject
    assert_equal [ "david@example.org" ], mail.to
    assert_equal [ "from@example.com" ], mail.from
    assert_match "Good news!", mail.body.encoded
  end
end

$ bin/rails test
Running 2 tests in a single process (parallelization threshold is 50)
Run options: --seed 16302

# Running:

..

Finished in 0.665856s, 3.0037 runs/s, 10.5128 assertions/s.
2 runs, 7 assertions, 0 failures, 0 errors, 0 skips

$ bin/rubocop

Inspecting 53 files
.....................................................

53 files inspected, no offenses detected

$ bin/rubocop -a

$ bin/brakeman
Loading scanner...
...

== Overview ==

Controllers: 6
Models: 6
Templates: 15
Errors: 0
Security Warnings: 0

== Warning Types ==


No warnings found

# Name of your application. Used to uniquely configure containers.
service: store

# Name of the container image.
image: your-user/store

# Deploy to these servers.
servers:
  web:
    - 192.168.0.1

# Credentials for your image host.
registry:
  # Specify the registry server, if you're not using Docker Hub
  # server: registry.digitalocean.com / ghcr.io / ...
  username: your-user

proxy:
  ssl: true
  host: app.example.com

export KAMAL_REGISTRY_PASSWORD=your-access-token

$ bin/kamal setup

$ bin/kamal deploy

$ bin/kamal console

store(prod)> User.create!(email_address: "you@example.org", password: "s3cr3t", password_confirmation: "s3cr3t")