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Pull request Compare This branch is 15710 commits behind rails:master.

Module#delegate checks nilness rather that falsehood if :allow_nil is…

… true, and avoids multiple evaluation of the target method


1) I hope nilness is a word.

2) See rationale for avoiding multiple evaluation in a comment in the patch, credit goes to @jeremy for pointing out this gotcha in the existing implementation.

3) Embeds a little joke dedicated to @pixeltrix (it could be worse! :D).

References #10347.
latest commit 65850baf98
@fxn fxn authored
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actionmailer copy-edit pass in AM changelog [ci skip]
actionpack Revert "Merge pull request #10337 from eimermusic/fix_template_digest…
activemodel Merge pull request #10286 from neerajdotname/fix-wrong-test-name-and-…
activerecord ActiveRecord -> Active Record
activesupport Module#delegate checks nilness rather that falsehood if :allow_nil is…
ci Fix copy table index test; Change == to ! on false in travis.rb
guides ActiveRecord -> Active Record
railties Moved the check for the rails test environment into rails/test_unit s…
tasks Fix release task after ceb3b87
tools Remove REE GC stats since master is 1.9.3
.gitignore encapsulates API generation in Rails::API::Task
.yardopts Let YARD document the railties gem refer to the contributing guide on how to create issues.
Gemfile Use the same uglifier version that the generated applications
RAILS_VERSION Preparing for 4.0.0.beta1 release fix README links in the main
RELEASING_RAILS.rdoc Don't use hash fragment for travis link
Rakefile unifies API generation
install.rb Do not use --local option when installing the gems
load_paths.rb require "rubygems" is obsolete in Ruby 1.9.3
rails.gemspec Use sprockets-rails 2.0.0.rc4
version.rb Fix release task after ceb3b87

Welcome to 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, each with a specific responsibility.

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).

The Model layer represents your domain model (such as Account, Product, Person, Post, etc.) and encapsulates the business logic that is 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. You can read more about Active Record in its README.

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 manipulate models and render view templates in order to generate the appropriate HTTP response.

In Rails, the Controller and View layers are handled together by Action Pack. These two layers are bundled in a single package due to their heavy interdependence. This is unlike the relationship between Active Record and Action Pack, which are independent. Each of these packages can be used independently outside of Rails. You can read more about Action Pack in its README.

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 and you'll see: "Welcome aboard: You're riding Ruby on Rails!"

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


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!

Code Status

  • Build Status
  • Dependencies


Ruby on Rails is released under the MIT License.

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