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kamipo Refactor to lazy construct join table aliases
Early constructed join table aliases are not always used for eager
loading, and it is required refactoring to improve eager loading
duplicated through associations.
Latest commit 590b045 May 25, 2020


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.github Add rubocop group to Gemfile for use in CI Mar 27, 2020
actioncable Update pg gem required version to 1.1 Apr 27, 2020
actionmailbox Unify raise_on_missing_translations for views and controllers May 19, 2020
actionmailer Revert "Remove deprecated `ActionMailer::DeliveryJob` and `ActionMail… May 12, 2020
actionpack Update rubocop-performance gem and enable Performance/DeletePrefix an… May 24, 2020
actiontext Unify raise_on_missing_translations for views and controllers May 19, 2020
actionview require "active_support/core_ext/symbol/starts_ends_with" for Ruby 2.6 May 24, 2020
activejob Support procs for assert_{enqueued,performed}_with May 7, 2020
activemodel Optimise serializable_hash when options are empty May 21, 2020
activerecord Refactor to lazy construct join table aliases May 25, 2020
activestorage Test Attached::Many in Attached::Many test May 23, 2020
activesupport Test that Array#extract_options! extracts ActiveSupport::OrderedOptions May 24, 2020
ci Remove .travis.yml and ci/travis.rb Jan 2, 2020
guides Fix typo [ci skip] May 24, 2020
railties require "active_support/core_ext/symbol/starts_ends_with" for Ruby 2.6 May 24, 2020
tasks Fix release task Nov 27, 2019
tools Enable `Layout/EmptyLinesAroundAccessModifier` cop Jun 13, 2019
.gitattributes adds .gitattributes to enable Ruby-awareness Mar 16, 2016
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.rubocop.yml Update rubocop-performance gem and enable Performance/DeletePrefix an… May 24, 2020
.yardopts Updating .yardopts to document .rb files in [GEM]/app Aug 20, 2019
.yarnrc Make Webpacker the default JavaScript compiler for Rails 6 (#33079) Oct 1, 2018
Brewfile Address `Error: caskroom/cask was moved. Tap homebrew/cask-cask inste… Dec 18, 2019 Updated links from http to https in guides, docs, etc Mar 9, 2019 Update the Rails mailing list URLs to new discuss discourse URL [ci s… Apr 2, 2020
Gemfile Lock benchmark-ips version < 2.8 May 1, 2020
Gemfile.lock Update rubocop-performance gem and enable Performance/DeletePrefix an… May 24, 2020
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RAILS_VERSION Start Rails 6.1 development Apr 24, 2019 remove reference to global rails command and replace with bin/rails Dec 27, 2019 update https urls [ci skip] Oct 3, 2019
Rakefile Use frozen string literal in root files Aug 13, 2017
package.json Install JavaScript packages before run test Feb 11, 2019
rails.gemspec Update the Rails mailing list URLs to new discuss discourse URL [ci s… Apr 2, 2020
version.rb Start Rails 6.1 development Apr 24, 2019
yarn.lock Upgrade kind-of Apr 20, 2020

Welcome to Rails

What's Rails?

Rails is a web-application framework that includes everything needed to create database-backed web applications according to 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.

Model layer

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 you to present the data from database rows as objects and embellish these data objects with business logic methods. Although most Rails models are backed by a database, models can also be ordinary Ruby classes, or Ruby classes that implement a set of interfaces as provided by the Active Model module.

Controller layer

The Controller layer is responsible for handling incoming HTTP requests and providing a suitable response. 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 in order to generate the appropriate HTTP response. 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.

View layer

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

Frameworks and libraries

Active Record, Active Model, Action Pack, and Action View can each be used independently outside Rails. In addition to that, Rails also comes with Action Mailer, a library to generate and send emails; Action Mailbox, a library to receive emails within a Rails application; Active Job, a framework for declaring jobs and making them run on a variety of queuing backends; Action Cable, a framework to integrate WebSockets with a Rails application; Active Storage, a library to attach cloud and local files to Rails applications; Action Text, a library to handle rich text content; and Active Support, a collection of utility classes and standard library extensions that are useful for Rails, 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
     $ bin/rails server

    Run with --help or -h for options.

  4. Go to http://localhost:3000 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:


Code Triage Badge

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

Build Status


Ruby on Rails is released under the MIT License.

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