Eaco

Eacus, the holder of the keys of Hades, is an ACL-based authorization framework for Ruby.

"Aeacus telemon by user Ravenous at en.wikipedia.org - Public domain through Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Aeacus_telemon.jpg"

Design

Eaco provides your application's Resources discretionary access. Access to the Resource is determined matching an ACL against an Actor.

Different Actors can have different levels of access to the same Resource, depending on their role as determined by the ACL.

To each role are granted a set of possible abilities, and access is verified by checking whether a given actor can perform a specific ability.

Actors are described by their Designators, a pluggable mechanism whose details are up to your application. For instance, an Actor can have many designators that describe either its identity or its belonging to a group or occupying a position in a department.

Designators are Ruby classes that can embed any sort of custom behaviour that your application requires.

ACLs are hashes with designators as keys and roles as values. Extracting authorized collections requires only an hash key lookup mechanism in your database. Adapters are provided for PG's +jsonb+ and for CouchDB-Lucene.

Installation

Add this line to your application's Gemfile:

gem 'eaco'

And then execute:

$ bundle

Usage

Create config/authorization.rb (rdoc)

# Defines `Document` to be an authorized resource.
#
# Adds Document.accessible_by and Document#allows?
#
authorize Document, using: :pg_jsonb do
  roles :owner, :editor, :reader

  permissions do
    reader   :read
    editor   reader, :edit
    owner    editor, :destroy
  end
end

# Defines an actor and the sources from which the
# designators are harvested.
#
# Adds User#designators
#
actor User do
  admin do |user|
    user.admin?
  end

  designators do
    user  from: :id
    group from: :groups
    tag   from: :tags
  end
end

Given a Resource (rdoc) with an ACL (rdoc):

# An example ACL
>> document = Document.first
=> #<Document id:42 name:"President's report for loans.docx" [...]>

>> document.acl
=> #<Document::ACL {"user:10" => :owner, "group:reviewers" => :reader}>

and an Actor (rdoc):

# An example Actor
>> user = User.find(10)
=> #<User id:10 name:"Bob Fropp" group_ids:['employees'], tags:['english']>

>> user.designators
=> #<Set{ #<Designator(User) value:10>, #<Designator(Group) value:"employees">, #<Designator(Tag) value:"english"> }

you can check if the Actor can perform a specific action on the Resource:

>> user.can? :read, document
=> true

>> document.allows? :read, user
=> true

and which access level (role) the Actor has for this Resource:

>> document.role_of user
=> :owner

>> boss = User.find_by_group('reviewer').first
=> #<User id:42 name:"Jake Leister" group_ids:['reviewers', 'bosses']>

>> document.role_of boss
=> :reader

>> boss.can? :read, document
=> true

>> boss.can? :destroy, document
=> false

>> user.can? :destroy, document
=> true

Grant reader access to a specific user:

>> user
=> #<User id:42 name:"Bob Frop">

>> document.grant :reader, :user, user.id
=> #<Document::ACL "user:42" => :reader>

>> user.can? :read, document
=> true

Grant reader access to a group:

>> user
=> #<User id:42 groups:['reviewers']>

>> document.grant :reader, :group, 3
=> #<Document::ACL "group:reviewers" => :reader>

>> user.can? :read, document
=> true

>> document.allows? :read, user
=> true

Obtain a collection of Resources accessible by a given Actor (rdoc):

>> Document.accessible_by(user)

Check whether a controller action can be accessed by an user. Your Controller must respond to current_user for this to work. (rdoc)

class DocumentsController < ApplicationController
  before_filter :find_document

  authorize :show, [:document, :read]
  authorize :edit, [:document, :edit]

  private
    def find_document
      @document = Document.find(params[:id])
    end
end

Running specs

You need a running postgresql 9.4 instance.

Create an user and a database:

$ sudo -u postgres psql

postgres=# CREATE ROLE eaco LOGIN;
CREATE ROLE

postgres=# CREATE DATABASE eaco OWNER eaco ENCODING 'utf8';
CREATE DATABASE

postgres=# ^D

Create features/active_record.yml with your database configuration, see features/active_record.example.yml for an example.

Run bundle once. This will install the base bundle.

Run appraisal once. This will install the supported Rails versions and +pg+.

Run rake. This will run the specs and cucumber features and report coverage.

Specs are run against the supported rails versions in turn. If you want to focus on a single release, use appraisal rails-X.Y rake, where X.Y can be 3.2, 4.0, 4.1 or 4.2.

Contributing

1. Fork it ( https://github.com/ifad/eaco/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Denominazione d'Origine Controllata

This software is Made in Italy 🇮🇹 😄.