Giới thiệu Ruby on Rails

Rails là gì?

Rails là framework web full-stack viết bằng Ruby, nổi tiếng với triết lý "Convention over Configuration" và "Don't Repeat Yourself".

Ưu điểm

• Convention over Configuration: Ít config, nhiều convention
• ActiveRecord ORM: ORM mạnh mẽ
• Scaffolding: Tạo CRUD nhanh
• Migration: Quản lý schema
• Testing: Tích hợp sẵn
• Hotwire: Modern frontend không cần nhiều JS

Cài đặt

Yêu cầu

• Ruby 3.2+
• Rails 7+
• Node.js (cho asset pipeline)
• Database (PostgreSQL khuyến nghị)

Install Ruby

# macOS với rbenv
brew install rbenv ruby-build
rbenv install 3.3.0
rbenv global 3.3.0

# Ubuntu
sudo apt install ruby-full

Install Rails

gem install rails
rails --version

Tạo project

rails new myapp --database=postgresql
cd myapp
bin/rails db:create
bin/rails server

Cấu trúc project

myapp/
├── app/
│   ├── controllers/
│   ├── models/
│   ├── views/
│   ├── helpers/
│   ├── jobs/
│   ├── mailers/
│   └── assets/
├── config/
│   ├── routes.rb
│   ├── database.yml
│   └── initializers/
├── db/
│   ├── migrate/
│   ├── schema.rb
│   └── seeds.rb
├── lib/
├── public/
├── test/ (hoặc spec/)
├── Gemfile
└── Gemfile.lock

MVC Flow

Request → Routes → Controller → Model → View → Response
                          ↓
                     Database

Scaffolding

Tạo full CRUD

rails generate scaffold Post title:string body:text published:boolean
rails db:migrate

Điều này tạo ra:

• Model, Migration
• Controller với 7 actions
• Views (index, show, new, edit)
• Routes
• Tests

Controller cơ bản

# app/controllers/posts_controller.rb
class PostsController < ApplicationController
  before_action :set_post, only: [:show, :edit, :update, :destroy]

  def index
    @posts = Post.all
  end

  def show
  end

  def new
    @post = Post.new
  end

  def create
    @post = Post.new(post_params)

    if @post.save
      redirect_to @post, notice: 'Post was successfully created.'
    else
      render :new, status: :unprocessable_entity
    end
  end

  def update
    if @post.update(post_params)
      redirect_to @post, notice: 'Post was successfully updated.'
    else
      render :edit, status: :unprocessable_entity
    end
  end

  def destroy
    @post.destroy
    redirect_to posts_url, notice: 'Post was successfully destroyed.'
  end

  private

  def set_post
    @post = Post.find(params[:id])
  end

  def post_params
    params.require(:post).permit(:title, :body, :published)
  end
end

Routes

# config/routes.rb
Rails.application.routes.draw do
  root 'home#index'

  resources :posts
  resources :users, only: [:index, :show]

  # Nested routes
  resources :posts do
    resources :comments, only: [:create, :destroy]
  end

  # API namespace
  namespace :api do
    namespace :v1 do
      resources :posts
    end
  end

  # Custom routes
  get '/about', to: 'pages#about'
  post '/contact', to: 'pages#contact'
end

Rails Console

bin/rails console
# hoặc ngắn gọn
bin/rails c

# Trong console
Post.all
Post.first
Post.where(published: true)
post = Post.new(title: 'Hello')
post.save

Generators

# Model
rails g model Product name:string price:decimal stock:integer

# Controller
rails g controller Products index show

# Migration
rails g migration AddPublishedToPosts published:boolean

# Scaffold
rails g scaffold Category name:string

Bài tập thực hành

Hãy tạo ứng dụng blog đơn giản với scaffold!