Welcome to Rails

Rails is a web-application framework that includes everything needed to create database-backed web applications with the Model-View-Controller (MVC) pattern.

Understanding the MVC pattern is key to understanding Rails. MVC divides your application into three layers: Model, View, and Controller, each with a specific responsibility.

The Model layer represents the domain model (such as Account, Product, Person, Post, etc.) and encapsulates the business logic specific to your application. In Rails, database-backed model classes are derived from ActiveRecord::Base. Active Record allows to present the data from database rows as objects and embellish these data objects with business logic methods. Read more about Active Record in its README. Although most Rails models are backed by a database, models can be ordinary Ruby classes or Ruby classes with a set of interfaces provided by the Active Model module. Read more about Active Model in its README.

The Controller layer is responsible for handling incoming HTTP requests and providing suitable responses. Usually this means returning HTML, but Rails controllers can also generate XML, JSON, PDFs, mobile-specific views, and more. Controllers load and manipulate models, and render view templates to generate appropriate HTTP responses. In Rails, incoming requests are routed by Action Dispatch to an appropriate controller, and controller classes are derived from ActionController::Base. Action Dispatch and Action Controller are bundled together in Action Pack. Read more about Action Pack in its README.

The View layer is composed of "templates" that are responsible for providing appropriate representations of the application's resources. View templates come in various formats, but most templates are HTML with embedded Ruby code (ERB files). Views are typically rendered to generate a controller response or the body of an email. In Rails, View generation is handled by Action View. Read more about Action View in its README.

Active Record, Active Model, Action Pack, and Action View can each be used independently outside Rails. Rails also comes with Action Mailer (README), a library to generate and send emails; Active Job (README), a framework for declaring jobs and making them run on a variety of queueing backends; Action Cable (README), a framework to integrate WebSockets with a Rails application; Active Storage (README), a library to attach cloud and local files to Rails applications; and Active Support (README), a collection of useful utility classes and standard library extensions, and may also be used independently outside Rails.

Getting Started

1. Install Rails at the command prompt if you haven't yet:

    $ gem install rails
   

2. At the command prompt, create a new Rails application:

    $ rails new myapp
   

   where "myapp" is the application name.

3. Change directory to myapp and start the web server:

    $ cd myapp
    $ rails server
   

   Run with --help or -h for options.

4. Go to http://localhost:3000 with a browser and you'll see: "Yay! You’re on Rails!"

5. Follow the guidelines to start developing your application. You may find the following resources handy:

   • Getting Started with Rails
   • Ruby on Rails Guides
   • The API Documentation
   • Ruby on Rails Tutorial

Contributing

We encourage you to contribute to Ruby on Rails! Please check out the Contributing to Ruby on Rails guide for guidelines about how to proceed. Join us!

Trying to report a possible security vulnerability in Rails? Please check out our security policy for guidelines about how to proceed.

Everyone interacting in Rails and its sub-projects' codebases, issue trackers, chat rooms, and mailing lists is expected to follow the Rails code of conduct.

Code Status

License

Ruby on Rails is released under the MIT License.