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Ryuta Kamizono ab8b12eaf6 PERF: 35% faster attributes for readonly usage
Instantiating attributes hash from raw database values is one of the
slower part of attributes.

Why that is necessary is to detect mutations. In other words, that isn't
necessary until mutations are happened.

`LazyAttributeHash` which was introduced at 0f29c21 is to instantiate
attribute lazily until first accessing the attribute (i.e.
`Model.find(1)` isn't slow yet, but `Model.find(1).attr_name` is still
slow).

This introduces `LazyAttributeSet` to instantiate attribute more lazily,
it doesn't instantiate attribute until first assigning/dirty checking
the attribute (i.e. `Model.find(1).attr_name` is no longer slow).

It makes attributes access about 35% faster for readonly (non-mutation)
usage.

https://gist.github.com/kamipo/4002c96a02859d8fe6503e26d7be4ad8

Before:

```
IPS
Warming up --------------------------------------
    attribute access     1.000  i/100ms
Calculating -------------------------------------
    attribute access      3.444  (± 0.0%) i/s -     18.000  in   5.259030s
MEMORY
Calculating -------------------------------------
    attribute access    38.902M memsize (     0.000  retained)
                       350.044k objects (     0.000  retained)
                        15.000  strings (     0.000  retained)
```

After (with `immutable_strings_by_default = true`):

```
IPS
Warming up --------------------------------------
    attribute access     1.000  i/100ms
Calculating -------------------------------------
    attribute access      4.652  (±21.5%) i/s -     23.000  in   5.034853s
MEMORY
Calculating -------------------------------------
    attribute access    27.782M memsize (     0.000  retained)
                       170.044k objects (     0.000  retained)
                        15.000  strings (     0.000  retained)
```
2020-06-13 16:01:08 +09:00
.github Don't mark issues on a milestone as stale 2020-05-29 10:54:17 +01:00
actioncable Use indifferent access for config hash in actioncable postgresql test 2020-06-10 13:52:43 +01:00
actionmailbox Replace 'Stubs out' with 'Generates' in generator USAGE's [ci skip] 2020-06-03 08:51:47 +02:00
actionmailer Replace 'Stubs out' with 'Generates' in generator USAGE's [ci skip] 2020-06-03 08:51:47 +02:00
actionpack Add application config for URL-safe Base64 CSRF tokens 2020-06-11 11:39:37 -04:00
actiontext Remove white list word 2020-06-09 13:41:51 -04:00
actionview Fixup CHANGELOGs [ci skip] 2020-06-07 12:58:22 +09:00
activejob Set retry_jitter to 0.0 for upgraded applications 2020-05-27 22:15:19 +01:00
activemodel PERF: 35% faster attributes for readonly usage 2020-06-13 16:01:08 +09:00
activerecord Merge pull request #39599 from kamipo/sg-immutable-strings-by-default 2020-06-13 15:51:42 +09:00
activestorage ActiveStorage::Attachment#signed_id must return a signed *blob* ID 2020-05-28 09:20:49 -04:00
activesupport Fix Active Support failure for redis 4.2.0 with Ruby 2.8.0-dev 2020-06-10 09:25:03 +09:00
ci Remove .travis.yml and ci/travis.rb 2020-01-02 09:27:53 +09:00
guides Fix broken references to classic mode guide where possible and use new guide where appropriate (#39603) [ci skip] 2020-06-12 00:18:16 +05:30
railties Add application config for URL-safe Base64 CSRF tokens 2020-06-11 11:39:37 -04:00
tasks Fix release task 2019-11-27 12:24:31 -03:00
tools
.gitattributes
.gitignore
.rubocop.yml Update rubocop-performance gem and enable Performance/DeletePrefix and Performance/DeleteSuffix cops 2020-05-24 12:51:35 +03:00
.yardopts
.yarnrc
Brewfile Address Error: caskroom/cask was moved. Tap homebrew/cask-cask instead. 2019-12-18 18:50:57 +09:00
CODE_OF_CONDUCT.md
CONTRIBUTING.md Update the Rails mailing list URLs to new discuss discourse URL [ci skip] 2020-04-02 22:00:28 +05:30
Gemfile Revert "Lock benchmark-ips version "< 2.8"" 2020-06-05 10:22:27 +09:00
Gemfile.lock Fix Active Support failure for redis 4.2.0 with Ruby 2.8.0-dev 2020-06-10 09:25:03 +09:00
MIT-LICENSE Bump license years from 2019 to 2020 [ci skip] 2020-01-01 15:10:31 +05:30
package.json
rails.gemspec Update the Rails mailing list URLs to new discuss discourse URL [ci skip] 2020-04-02 22:00:28 +05:30
RAILS_VERSION
Rakefile
README.md remove reference to global rails command and replace with bin/rails 2019-12-27 19:32:37 +00:00
RELEASING_RAILS.md update https urls [ci skip] 2019-10-03 11:01:32 +02:00
version.rb
yarn.lock Upgrade kind-of 2020-04-19 23:59:27 -03:00

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! Youre on Rails!"

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

Contributing

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

License

Ruby on Rails is released under the MIT License.