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SimpleRoles is a Rails Engine providing simple Role System for any Rails 3 app.

Initially it was created as demo role-system to accompany CanTango gem initial installiation and usage, and intended to be very easy to setup & use.

Now it is good to be used as a real role system inspite of or due to its almost maximum simplicity.

Build Status

September 18, 2014. Status Update

I do not maintain this project anymore. I am ready to pass it to any other developer if he wants to take lead on simple_roles: since time I switched to development for iOS some time ago, now I would redesign simple_roles to support different adapters other than ActiveRecord/MySQL and would rewrite its internal code to have more clear and correct design, so if you're interested I can share my thoughts with you and pass this project to you so it will live on.



  • Ruby 1.8.7 or 1.9.3
  • Rails 3 or 4
  • ActiveRecord with MySQL or SQLite
  • User model in your Rails app.

It is a Gem

include in Gemfile:

gem 'simple_roles' 

Set up valid roles you're gonna have in your app and choose a Strategy.

Create file simple_roles.rb in config/initializers and write in it:

# config/initializers/simple_roles.rb
SimpleRoles.configure do |config|
  config.valid_roles = [:user, :admin, :editor]
  config.strategy = :many # Default is :one

or in a nicer way:

# config/initializers/simple_roles.rb
SimpleRoles.configure do
  valid_roles :user, :admin, :editor
  strategy :many # Default is :one

Now it is time to choose beetween two strategies possible:

  • One - each of your users has only one role. It is the most common choice for the most of the apps.
  • Many - your user can be :editor and :curator and :instructor all at the same time. More rare one, setup is slightly more complex.

One Strategy

One strategy assumes your User model has string-typed 'role' column. Add this to your migrations and run them:

class CreateUsers < ActiveRecord::Migration
  def up
    create_table(:users) do |t|
      # ...
      t.string :role

  def down
    drop_table :users

Finally, include 'simple_roles' macros in your User model:

class User

Many strategy

In its background 'Many' strategy has following setup, based on has_many :through relations:

class User < ActiveRecord::Base
  has_many :user_roles
  has_many :roles, :through => :user_roles
class UserRole < ActiveRecord::Base
  belongs_to :user
  belongs_to :role

class Role < ActiveRecord::Base
  has_many :user_roles
  has_many :users, :through => :user_roles

You don't need to create these classes (UserRoles, Roles) and write these associations by hands - all these classes SimpleRoles configures automatically. The only class you need is User and you must have simple_roles in it (see below).

But you need to supply migrations for them - copy and migrate SimpleRoles migrations by following rake task:

rake simple_roles:install:migrations
rake db:migrate

Note! Migrations are based on roles you are to set up as valid (see previous step). If you do not create initializer with valid_roles, then valid_roles will be set up to defaults: :user and :admin.

And finally include 'simple_roles' macros in your User model:

class User


You can skip configuration in initializers and write it the following way:

class User
  simple_roles do
    strategy :one
    valid_roles :user, :editor

Usage example


user = User.create

user.role # => nil

user.role = :admin
user.role # => :admin
user.admin? # => true
user.is_admin? # => true
user.has_role? :admin # => true
user.has_role? :user # => false
user.has_any_role? :user, :editor, :admin # => true

# Accepts strings too 
user.role = 'instructor'
user.role # => :instructor

# #set_role and #update_role are persistent - #save is called also
user.role # => :editor

user.role # => :user


user =
user.roles # => []

user.roles = :admin
user.roles # => [:admin]
user.roles_list # => [:admin]

user.admin? # => true
user.is_admin? # => true

user.roles = [:admin, :user]
user.roles # => [:admin, :user]
user.is_user? # => true

user.add_role :editor
user.roles # => [:admin, :user, :editor]

user.remove_role :user
user.roles # => [:admin, :editor]
user.has_role?(:admin) # => true
user.has_any_role?(:admin, :blip) # => true
user.has_role?(:blogger) # => false

Both strategies

For each of valid roles both strategies automatically define scope methods in User model:

SimpleRoles.config.valid_roles # => [:user, :admin, :editor]

User.users # => []
User.admins # => []
User.editors # => []


Copyright (c) 2012 Stanislaw Pankevich.