A simple DSL for role-based permissions.

Inspired by tools like cancan and pundit but intended to be even simpler.

All permissions are identified by a single ability name. No need for objects or methods to manage policies for every type of domain object. Have a complex edge case? Just create a new ability for it specifically.

Add this line to your application's Gemfile:

gem 'rolistic'

And then execute:

$ bundle

Or install it yourself as:

$ gem install rolistic

Create a class to house your roles and their permissions.

class ForumRole
  include Rolistic
  # traits allow you to categorize abilities shared by multiple roles
  trait :moderation, %i(delete_thread edit_thread)

  role :anonymous, %i(vote_in_polls reply_to_thread), default: true

  # roles can inherit abilities from existing roles, plus add their own
  role :registered, :anonymous, %i(edit_own_thread create_thread)

  role :moderator, :registered, :moderation
  role :silent_moderator, :moderation

  # special `everything` trait has access to all abilities, even unnamed ones
  role :developer, :everything
end

Instances of your role class tell you what they can do.

ForumRole.new(:registered).can?(:vote_in_polls) # => true
ForumRole.new("moderator").can?(:edit_thread)   # => true
ForumRole.new(:anonymous).can?(:create_thread)  # => false
ForumRole.new(:developer).can?(:introduce_bugs) # => true

# Use the default role
ForumRole.new.can?(:reply_to_thread) # => true

If you are using ActiveRecord your role class can easily be serialized to any string column.

class User < ApplicationRecord
  serialize :role, ForumRole
  delegate :can?, to: :role
end

User.new(role: "registered").can?(:create_thread) # => true

More usage examples can be found in spec/rolistic_spec.rb.

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/carlzulauf/rolistic. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

The gem is available as open source under the terms of the MIT License.