Welcome to PurposeOnRails

Purpose on Rails is an extension of the Ruby on Rails web-framework that offers support for purpose-aware and purpose-respecting applications. Purpose Limitation is one of the major principles of the new European Law, the GDPR. Also, purpose limitation is generally a pretty nice idea! With PurposeOnRails (PoR) you can easily allow users to manage purposes of their data items and respect them when querying.

Basics

Create a new application using the normal rails new my_app command. There is a new optional flag (default is true) that allows you to create a purposeful application: --purposeful=true. This will create a demo purpose tree file that you can use to model your purposes, as well as some files for automatic view creation etc. For example, there's a Purpose Mode, View, Controller setup baked right in. Just add it to your routes and off you go.

Scaffolding has also been adapted to generate purpose-aware data. For every column (unless specified otherwise) a purpose partner column is automatically generated. Controllers can handle these partner attributes out of the box and generated views also include an editor for them for the user.

ActiveRecord has been extended by a for method. When writing queries, don't forget to specify for which purpose you are querying. A normal query should now look something like this:

User.where(name: 'Jane Doe')
    .where("age > ?", 50)
    .select(:email)
    .for(purpose_id)

If you don't include a purpose_id when querying, no data will be returned. If you include a purpose_id, only the data is returned that the user whitelisted for that specific purpose.

So what is Ruby on Rails anyways?

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; Active Job, a framework for declaring jobs and making them run on a variety of queueing 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; 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
    $ 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:

   • 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.