Ruby_On_Rails

What is Ruby on Rails?

Ruby on Rails, or simply Rails, is an open-source web application framework written in Ruby. It is a model-view-controller (MVC) framework, providing default structures for a database, a web service, and web pages.

Setting Up a Rails Project

A new Rails project can be created with a single command in the terminal.

rails new myapp

MVC Architecture

Rails follows the MVC architecture where Models represent database data, Views display the data, and Controllers handle user interaction and business logic.

// Rails doesn't have a direct code example for this section.

Routing

Routes in Rails determine how an HTTP request is routed to your controller's actions. They are defined in the `config/routes.rb` file.

get 'welcome/index', to: 'welcome#index'

Controllers

Controllers respond to user requests, and provide it to the Model and View. Controllers are the middleman between Models and Views.

class ApplicationController < ActionController::Base
end

Active Record Basics

Active Record is the M in MVC, the layer of the system responsible for representing business data and logic. Active Record facilitates the creation and use of objects whose data requires persistent storage to a database.

class Product < ApplicationRecord
end

Migrations

Migrations are a convenient way to alter your database schema over time in a consistent and organized manner.

class CreateProducts < ActiveRecord::Migration[5.0]
  def change
    create_table :products do |t|
      t.string :name
      t.text :description

      t.timestamps
    end
  end
end

Working with Views

Views are what the user sees, they represent the V in the MVC pattern. In Rails, views are often HTML files with embedded Ruby code.

<%= @article.title %>
<%= @article.text %>

Layouts and Rendering

With layouts and rendering, you can decide how to combine the current view with different templates and partials, providing great flexibility in building up your final webpage.

<%= render 'shared/menu' %>
<%= yield %>

Authentication

Rails provides several tools to help you implement user login/logout functionality and protect your pages from unauthenticated access.

class SessionsController < ApplicationController
  def create
    user = User.find_by(email: params[:session][:email].downcase)
    if user && user.authenticate(params[:session][:password])
      log_in user
      redirect_to user
    else
      render 'new'
    end
  end
end

Authorization

Authorization in Rails can be handled using a variety of techniques, and it ensures that users can only perform actions they are permitted to.

class UsersController < ApplicationController
  def edit
    @user = User.find(params[:id])
    redirect_to(root_url) unless current_user?(@user)
  end
end

CSRF Protection

Rails comes with built-in CSRF protection in the form of a token placed in a meta tag. This token is required any time a non-GET request is made.

<%= csrf_meta_tags %>