Ruby on Rails: Web Development

# 1. Pastikan Ruby sudah terinstal (minimal 3.0+)
ruby --version
# ruby 3.3.3 (2024-06-12 revision e12f4fa7f9)

# 2. Pastikan Node.js terinstal (untuk Asset Pipeline)
node --version
# v20.10.0

# 3. Pastikan Yarn atau npm tersedia
yarn --version
# 1.22.19

# 4. Pastikan database tersedia (PostgreSQL atau SQLite)
psql --version  # PostgreSQL
sqlite3 --version  # SQLite

# Instal Rails gem terbaru
gem install rails

# Verifikasi instalasi
rails --version
# Rails 7.1.3

# Jika menggunakan rbenv, rehash setelah instalasi
rbenv rehash

# Instal bundler jika belum terinstal
gem install bundler

# Cek semua gem Rails
gem list | grep rails

# Di Ubuntu/Debian:
sudo apt install postgresql postgresql-contrib libpq-dev

# Buat user PostgreSQL
sudo -u postgres createuser --superuser $USER

# Set password untuk user
sudo -u postgres psql
\password your_username
\q

# Di macOS (Homebrew):
brew install postgresql@16
brew services start postgresql@16

# Verifikasi koneksi
psql postgres
# Anda sekarang di PostgreSQL console
\q  # Keluar

# 1. Browser mengirim request: GET /users
# 2. Router (routes.rb) mencocokkan URL dengan controller action
#    get '/users', to: 'users#index'
# 3. Controller menerima request dan memanggil Model
#    class UsersController < ApplicationController
#      def index
#        @users = User.all  # Query ke database via Model
#      end
#    end
# 4. Model mengambil data dari database
#    SELECT * FROM users;
# 5. Controller mengirim data ke View
#    @users tersedia di view
# 6. View merender HTML dengan data yang diterima
#    <% @users.each do |user| %>
#      <p><%= user.name %></p>
#    <% end %>
# 7. HTML dikembalikan ke browser

# Buat aplikasi Rails baru dengan PostgreSQL
rails new blog_app -d postgresql

# Atau dengan SQLite (untuk pengembangan lokal)
rails new blog_app

# Masuk ke folder proyek
cd blog_app

# Lihat struktur folder yang dibuat
ls -la
# app/          - Kode utama (MVC)
# config/       - Konfigurasi aplikasi
# db/           - Database migrations & seeds
# public/       - File statis (CSS, JS, gambar)
# test/ atau spec/ - Unit test
# Gemfile       - Dependency Ruby
# config.ru     - Rack configuration
# Rakefile      - Rake tasks

# Konfigurasi database di config/database.yml
# Jalankan setup database
rails db:create
rails db:migrate

# Jalankan server Rails
rails server
# => Booting Puma
# => Rails 7.1.3 application starting in development
# => Listening on http://127.0.0.1:3000

# Buka browser: http://localhost:3000
# Anda akan melihat halaman selamat datang Rails!

# Generator sangat penting di Rails
# Menunjukkan semua generator yang tersedia
rails generate --help

# Generate model
rails generate model User name:string email:string age:integer
# Menghasilkan:
# - app/models/user.rb
# - db/migrate/20240101000000_create_users.rb
# - test/models/user_test.rb

# Generate controller
rails generate controller Users index show new edit
# Menghasilkan:
# - app/controllers/users_controller.rb
# - app/views/users/index.html.erb
# - app/views/users/show.html.erb
# - test/controllers/users_controller_test.rb

# Generate scaffold (semua sekaligus: model + controller + views + tests)
rails generate scaffold Post title:string body:text user:references
# Ini menghasilkan CRUD lengkap!

# Generate migration tunggal
rails generate migration AddRoleToUsers role:string

# Generate resource (model + controller + routes)
rails generate resource Article title:string content:text

# Jalankan migration setelah generate
rails db:migrate

# Rollback migration jika salah
rails db:rollback

# Undo generate
rails destroy model User
rails destroy controller Users

# config/routes.rb
Rails.application.routes.draw do

  # Root route (homepage)
  root "pages#home"

  # Basic routes
  get  '/about',   to: 'pages#about'
  get  '/contact', to: 'pages#contact'
  post '/contact', to: 'pages#submit_contact'

  # RESTful routes dengan resource
  resources :users
  # Menghasilkan 7 route:
  # GET    /users          => users#index
  # GET    /users/new      => users#new
  # POST   /users          => users#create
  # GET    /users/:id      => users#show
  # GET    /users/:id/edit => users#edit
  # PATCH  /users/:id      => users#update
  # DELETE /users/:id      => users#destroy

  # Resources dengan pilihan tertentu
  resources :posts, only: [:index, :show, :new, :create]
  # Hanya membuat 4 route yang dipilih

  resources :articles, except: [:destroy]
  # Semua route kecuali destroy

  # Nested resources
  resources :users do
    resources :posts
    # Menghasilkan:
    # GET /users/:user_id/posts
    # GET /users/:user_id/posts/new
    # GET /users/:user_id/posts/:id
    # dll...
  end

  # Member routes (memerlukan ID)
  resources :posts do
    member do
      post :publish
      # POST /posts/:id/publish
      post :archive
      # POST /posts/:id/archive
    end
  end

  # Collection routes (tidak memerlukan ID)
  resources :posts do
    collection do
      get :search
      # GET /posts/search
      get :drafts
      # GET /posts/drafts
    end
  end

  # Namespace untuk API
  namespace :api do
    namespace :v1 do
      resources :posts
      # /api/v1/posts
    end
  end

end

# Ketika Anda mendefinisikan routes, Rails otomatis membuat
# helper methods:

# resources :users menghasilkan:
users_path          # "/users"
user_path(@user)    # "/users/1"
new_user_path       # "/users/new"
edit_user_path(@user) # "/users/1/edit"

# Di controller:
redirect_to users_path
redirect_to user_path(@user)
redirect_to new_user_path

# Di views (ERB):
# <%= link_to "Semua User", users_path %>
# <%= link_to "Lihat User", user_path(@user) %>
# <%= link_to "Edit", edit_user_path(@user) %>
# <%= link_to "Hapus", user_path(@user), method: :delete %>

# Custom named route
get '/dashboard', to: 'pages#dashboard', as: :dashboard
# Menghasilkan: dashboard_path = "/dashboard"

# Cek semua routes yang tersedia:
# rails routes
# Atau di Rails 7+:
# rails routes --controller users

# app/controllers/users_controller.rb
class UsersController < ApplicationController
  before_action :set_user, only: [:show, :edit, :update, :destroy]

  # GET /users
  def index
    @users = User.all.order(created_at: :desc)
    @user_count = @users.count
  end

  # GET /users/:id
  def show
    # @user sudah diset oleh set_user (before_action)
  end

  # GET /users/new
  def new
    @user = User.new
  end

  # POST /users
  def create
    @user = User.new(user_params)

    if @user.save
      redirect_to @user, notice: "User berhasil dibuat!"
    else
      render :new, status: :unprocessable_entity
    end
  end

  # GET /users/:id/edit
  def edit
    # @user sudah diset oleh set_user
  end

  # PATCH /users/:id
  def update
    if @user.update(user_params)
      redirect_to @user, notice: "User berhasil diupdate!"
    else
      render :edit, status: :unprocessable_entity
    end
  end

  # DELETE /users/:id
  def destroy
    @user.destroy
    redirect_to users_path, notice: "User berhasil dihapus!"
  end

  private

  def set_user
    @user = User.find(params[:id])
  end

  # Strong Parameters — whitelist parameter yang diizinkan
  def user_params
    params.require(:user).permit(:name, :email, :age, :role)
  end
end

# app/controllers/application_controller.rb
class ApplicationController < ActionController::Base
  before_action :set_locale

  # Helper method untuk semua controllers & views
  helper_method :current_user, :logged_in?

  private

  def current_user
    @current_user ||= User.find_by(id: session[:user_id])
  end

  def logged_in?
    current_user.present?
  end

  def require_login
    unless logged_in?
      redirect_to login_path, alert: "Anda harus login terlebih dahulu!"
    end
  end

  def set_locale
    I18n.locale = params[:locale] || I18n.default_locale
  end
end

<%# app/views/users/index.html.erb %>

<h1>Daftar User (<%= @user_count %>)</h1>

<%# Flash messages %>
<% if notice %>
  <div class="alert alert-success">
    <%= notice %>
  </div>
<% end %>

<% if @users.any? %>
  <table class="table">
    <thead>
      <tr>
        <th>Nama</th>
        <th>Email</th>
        <th>Umur</th>
        <th>Aksi</th>
      </tr>
    </thead>
    <tbody>
      <% @users.each do |user| %>
        <tr>
          <td><%= user.name %></td>
          <td><%= user.email %></td>
          <td><%= user.age %></td>
          <td>
            <%= link_to "Lihat", user_path(user), class: "btn btn-info" %>
            <%= link_to "Edit", edit_user_path(user), class: "btn btn-warning" %>
            <%= link_to "Hapus", user_path(user),
                data: { turbo_method: :delete, turbo_confirm: "Yakin?" },
                class: "btn btn-danger" %>
          </td>
        </tr>
      <% end %>
    </tbody>
  </table>
<% else %>
  <p>Belum ada user.</p>
<% end %>

<%= link_to "Buat User Baru", new_user_path, class: "btn btn-primary" %>

# Partial diawali dengan underscore: _user.html.erb
# app/views/users/_user.html.erb

<div class="user-card">
  <h3><%= user.name %></h3>
  <p>Email: <%= user.email %></p>
  <p>Umur: <%= user.age %> tahun</p>
  <%= link_to "Lihat Detail", user_path(user) %>
</div>

# Menggunakan partial di view utama:
# app/views/users/index.html.erb

<% @users.each do |user| %>
  <%= render partial: "user", locals: { user: user } %>
  <%# Atau shorthand: %>
  <%= render user %>
<% end %>

# Partial dengan collection
<%= render partial: "user", collection: @users %>
# Setiap item otomatis tersedia sebagai 'user' di partial

# Layout partial (shared/_header.html.erb)
<%= render "shared/header" %>

# Yield untuk content_for di layout
<% content_for :title, "Daftar User" %>

# app/views/layouts/application.html.erb
# <title><%= content_for?(:title) ? yield(:title) : "BeebaneLabs" %></title>

# app/helpers/users_helper.rb
module UsersHelper
  def user_avatar(user, size: 50)
    if user.avatar.attached?
      image_tag user.avatar, size: "#{size}x#{size}", class: "avatar"
    else
      image_tag "default_avatar.png", size: "#{size}x#{size}", class: "avatar"
    end
  end

  def format_umur(umur)
    case umur
    when 0..12  then "#{umur} tahun (Anak-anak)"
    when 13..17 then "#{umur} tahun (Remaja)"
    when 18..64 then "#{umur} tahun (Dewasa)"
    else             "#{umur} tahun (Lansia)"
    end
  end

  def status_badge(user)
    if user.active?
      content_tag :span, "Aktif", class: "badge badge-success"
    else
      content_tag :span, "Nonaktif", class: "badge badge-danger"
    end
  end
end

# Menggunakan di view:
# <%= user_avatar(@user, size: 100) %>
# <%= format_umur(@user.age) %>
# <%= status_badge(@user) %>

# app/models/user.rb
class User < ApplicationRecord
  # Validations
  validates :name, presence: true, length: { minimum: 2, maximum: 100 }
  validates :email, presence: true, uniqueness: true,
                    format: { with: URI::MailTo::EMAIL_REGEXP }
  validates :age, numericality: { greater_than: 0, less_than: 150 }

  # Associations
  has_many :posts, dependent: :destroy
  has_many :comments, dependent: :destroy

  # Scopes
  scope :active, -> { where(active: true) }
  scope :recent, -> { order(created_at: :desc).limit(10) }
  scope :by_role, ->(role) { where(role: role) }

  # Callbacks
  before_save :downcase_email

  # Instance methods
  def full_info
    "#{name} (#{email})"
  end

  def post_count
    posts.count
  end

  # Class methods
  def self.search(keyword)
    where("name LIKE ? OR email LIKE ?", "%#{keyword}%", "%#{keyword}%")
  end

  private

  def downcase_email
    self.email = email.downcase
  end
end

# Buka Rails console:
# rails console  (atau: rails c)

# ===== CREATE =====
# Method 1: new + save
user = User.new(name: "Budi", email: "budi@mail.com", age: 25)
user.save  # => true

# Method 2: create (new + save sekaligus)
User.create(name: "Rina", email: "rina@mail.com", age: 22)

# Method 3: create! (raises error jika gagal)
User.create!(name: "Andi", email: "andi@mail.com", age: 30)

# ===== READ =====
User.all                   # Semua user
User.find(1)               # Cari berdasarkan ID
User.find_by(email: "budi@mail.com")  # Cari berdasarkan atribut
User.where(age: 25)        # Filter
User.where("age > ?", 20) # Filter dengan raw SQL
User.order(name: :asc)     # Urutkan
User.limit(5)              # Batasi 5 record
User.first                 # Record pertama
User.last                  # Record terakhir
User.count                 # Jumlah record
User.exists?(email: "budi@mail.com")  # Cek keberadaan

# Chaining queries
User.active.recent.by_role("admin").where("age > ?", 18)

# ===== UPDATE =====
user = User.find(1)
user.name = "Budi Santoso"
user.save  # => true

# Atau dengan update
user.update(name: "Budi Santoso", age: 26)

# Atau dengan update! (raises error)
user.update!(name: "Budi Santoso")

# Update multiple records
User.where(active: false).update_all(active: true)

# ===== DELETE =====
user = User.find(1)
user.destroy  # Menghapus record dan memanggil callbacks

# Delete by condition
User.where("created_at < ?", 1.year.ago).destroy_all

# Generate migration
rails generate migration CreateUsers name:string email:string age:integer

# Hasilnya: db/migrate/20240101120000_create_users.rb
class CreateUsers < ActiveRecord::Migration[7.1]
  def change
    create_table :users do |t|
      t.string :name, null: false
      t.string :email, null: false
      t.integer :age
      t.boolean :active, default: true
      t.string :role, default: "user"
      t.timestamps  # created_at dan updated_at otomatis
    end

    # Tambahkan index
    add_index :users, :email, unique: true
    add_index :users, :role
  end
end

# Jalankan migration
rails db:migrate
# == 20240101120000 CreateUsers: migrating ===================================
# -- create_table(:users)
#    -> 0.0123s
# == 20240101120000 CreateUsers: migrated (0.0123s) =========================

# Jalankan semua migration yang belum dijalankan
rails db:migrate

# Rollback migration terakhir
rails db:rollback

# Rollback 3 migration terakhir
rails db:rollback STEP=3

# Jalankan migration ke versi tertentu
rails db:migrate VERSION=20240101120000

# Reset database (drop + create + migrate + seed)
rails db:reset

# Seed data dari db/seeds.rb
rails db:seed

# Lihat status migration
rails db:migrate:status

# Cek skema database saat ini
cat db/schema.rb

# Generate migration untuk menambah kolom
rails generate migration AddPhoneToUsers phone:string
# Hasil: db/migrate/20240102120000_add_phone_to_users.rb

class AddPhoneToUsers < ActiveRecord::Migration[7.1]
  def change
    add_column :users, :phone, :string
    add_column :users, :address, :text
    add_column :users, :date_of_birth, :date
  end
end

# Migration untuk menambah foreign key
rails generate migration AddUserRefToPosts user:references
# Hasil: db/migrate/20240103120000_add_user_ref_to_posts.rb

class AddUserRefToPosts < ActiveRecord::Migration[7.1]
  def change
    add_reference :posts, :user, null: false, foreign_key: true
    # Atau:
    # add_column :posts, :user_id, :bigint, null: false
    # add_foreign_key :posts, :users
  end
end

# Migration untuk mengubah kolom
class ChangeAgeInUsers < ActiveRecord::Migration[7.1]
  def up
    change_column :users, :age, :integer, default: 0
  end

  def down
    change_column :users, :age, :integer, default: nil
  end
end

# Migration untuk rename kolom
class RenameNameToFullNameInUsers < ActiveRecord::Migration[7.1]
  def change
    rename_column :users, :name, :full_name
  end
end

# User — has_many Posts
class User < ApplicationRecord
  has_many :posts, dependent: :destroy
  has_many :comments, dependent: :destroy
  has_many :post_comments, through: :posts, source: :comments
  has_one :profile, dependent: :destroy
  has_and_belongs_to_many :roles
end

# Post — belongs_to User, has_many Comments
class Post < ApplicationRecord
  belongs_to :user
  has_many :comments, dependent: :destroy
  has_many :tags, dependent: :destroy
  has_one_attached :image
end

# Comment — belongs_to User and Post
class Comment < ApplicationRecord
  belongs_to :user
  belongs_to :post
end

# Profile — belongs_to User
class Profile < ApplicationRecord
  belongs_to :user
end

# Tag — belongs_to Post
class Tag < ApplicationRecord
  belongs_to :post
end

# Mendapatkan relasi
user = User.find(1)
user.posts          # Semua post milik user ini
user.comments       # Semua comment milik user ini
user.profile        # Profile milik user ini

post = Post.find(1)
post.user           # User yang memiliki post ini
post.comments       # Semua comment pada post ini

# Membuat relasi baru
user.posts.create(title: "Post Baru", body: "Isi post")
user.posts.build(title: "Draft", body: "Draft post")  # Tanpa save

# Mengakses data relasi dengan chaining
user.posts.published.recent  # Post published milik user, urut terbaru

# Eager loading — menghindari N+1 query problem
# BAD — akan menjalankan N+1 queries:
users = User.all
users.each { |u| puts u.posts.count }  # 1 query per user!

# GOOD — eager loading dengan includes:
users = User.includes(:posts).all
users.each { |u| puts u.posts.count }  # Hanya 2 queries!

# Preload dan eager_load
User.preload(:posts)         # 2 terpisah queries
User.eager_load(:posts)      # 1 query dengan LEFT JOIN
User.includes(:posts).where(posts: { published: true })  # Hybrid

# app/models/post.rb
class Post < ApplicationRecord
  belongs_to :user

  # Validasi dasar
  validates :title, presence: true,
                    length: { minimum: 5, maximum: 200 }
  validates :body, presence: true,
                   length: { minimum: 10 }
  validates :status, inclusion: { in: %w[draft published archived] }
  validates :slug, uniqueness: true, allow_nil: true

  # Custom validation
  validate :title_not_profanity

  # Conditional validation
  validates :publish_date, presence: true, if: :published?

  # Numericality
  validates :view_count, numericality: {
    greater_than_or_equal_to: 0,
    only_integer: true
  }

  # Format validation
  validates :slug, format: {
    with: /\A[a-z0-9\-]+\z/,
    message: "hanya boleh huruf kecil, angka, dan dash"
  }

  private

  def title_not_profanity
    bad_words = ["spam", "scam"]
    if bad_words.any? { |word| title.downcase.include?(word) }
      errors.add(:title, "mengandung kata yang tidak diizinkan")
    end
  end
end

# Callbacks tersedia dalam urutan berikut:
# before_validation    → sebelum validasi
# after_validation     → setelah validasi
# before_save          → sebelum save (create & update)
# after_save           → setelah save
# before_create        → sebelum create
# after_create         → setelah create
# before_update        → sebelum update
# after_update         → setelah update
# before_destroy       → sebelum destroy
# after_destroy        → setelah destroy

class Post < ApplicationRecord
  before_save :generate_slug, :set_published_at
  after_create :notify_followers
  before_destroy :archive_content

  private

  def generate_slug
    self.slug = title.parameterize if title.present? && slug.blank?
  end

  def set_published_at
    if status_changed? && status == "published"
      self.published_at = Time.current
    end
  end

  def notify_followers
    # Kirim notifikasi ke followers
    NotificationService.new_post(self)
  end

  def archive_content
    ArchivedPost.create!(
      title: title,
      body: body,
      user_id: user_id,
      archived_at: Time.current
    )
  end
end

<%# app/views/users/_form.html.erb %>

<%= form_with(model: @user, local: true) do |form| %>
  <%# Tampilkan error jika ada %>
  <% if @user.errors.any? %>
    <div class="error-messages">
      <h3><%= pluralize(@user.errors.count, "error") %> terjadi:</h3>
      <ul>
        <% @user.errors.full_messages.each do |message| %>
          <li><%= message %></li>
        <% end %>
      </ul>
    </div>
  <% end %>

  <div class="form-group">
    <%= form.label :name, "Nama Lengkap" %>
    <%= form.text_field :name, class: "form-control",
        placeholder: "Masukkan nama..." %>
  </div>

  <div class="form-group">
    <%= form.label :email, "Email" %>
    <%= form.email_field :email, class: "form-control",
        placeholder: "contoh@email.com" %>
  </div>

  <div class="form-group">
    <%= form.label :age, "Umur" %>
    <%= form.number_field :age, class: "form-control", min: 1, max: 150 %>
  </div>

  <div class="form-group">
    <%= form.label :role, "Role" %>
    <%= form.select :role,
        options_for_select([
          ["User", "user"],
          ["Admin", "admin"],
          ["Moderator", "moderator"]
        ], @user.role),
        {}, { class: "form-control" } %>
  </div>

  <div class="form-group">
    <%= form.label :bio, "Bio" %>
    <%= form.text_area :bio, class: "form-control", rows: 5 %>
  </div>

  <div class="form-group">
    <%= form.label :active, "Aktif?" %>
    <%= form.check_box :active %>
  </div>

  <div class="form-actions">
    <%= form.submit "Simpan", class: "btn btn-primary" %>
    <%= link_to "Batal", users_path, class: "btn btn-secondary" %>
  </div>
<% end %>

<%# app/views/users/show.html.erb %>

<div class="user-detail">
  <div class="user-header">
    <h1><%= @user.name %></h1>
    <%= status_badge(@user) %>
  </div>

  <div class="user-info">
    <p><strong>Email:</strong> <%= @user.email %></p>
    <p><strong>Umur:</strong> <%= format_umur(@user.age) %></p>
    <p><strong>Role:</strong> <%= @user.role.capitalize %></p>
    <p><strong>Bergabung:</strong> <%= l(@user.created_at, format: :long) %></p>
  </div>

  <% if @user.posts.any? %>
    <h2>Posts (<%= @user.posts.count %>)</h2>
    <% @user.posts.each do |post| %>
      <div class="post-card">
        <h3><%= post.title %></h3>
        <p><%= truncate(post.body, length: 200) %></p>
        <%= link_to "Baca selengkapnya", post_path(post) %>
      </div>
    <% end %>
  <% end %>

  <div class="actions">
    <%= link_to "Edit", edit_user_path(@user), class: "btn btn-warning" %>
    <%= link_to "Hapus", user_path(@user),
        data: { turbo_method: :delete, turbo_confirm: "Yakin?" },
        class: "btn btn-danger" %>
    <%= link_to "Kembali", users_path, class: "btn btn-secondary" %>
  </div>
</div>