RoleModel¶ ↑

RoleModel is the framework agnostic, efficient and declarative way to do (user) roles. Assigned roles will be efficiently stored as a bitmask directly into your model within a configurable attribute.

It works like this:

# given a User class with a roles_mask attribute
require 'rubygems'
require 'role_model'

class User
  attr_accessor :roles_mask   # just for demo purposes
  # in real life this would usually be a persistent attribute,
  # e.g. if your User model is persisted in a SQL-DB add an integer
  # column named roles_mask to your users table -- just remove/replace
  # above attr_accessor line with whatever is needed for your
  # persistence solution

  include RoleModel

  # if you want to use a different integer attribute to store the
  # roles in, set it with roles_attribute :my_roles_attribute,
  # :roles_mask is the default name
  roles_attribute :roles_mask

  # declare the valid roles -- do not change the order if you add more
  # roles later, always append them at the end!
  roles :admin, :manager, :author
end

#
# Test drive (check the RDoc or source for additional finesse)
#

>> u = User.new
=> #<User ...>

# role assignment
>> u.roles = [:admin]  # ['admin'] works as well
=> [:admin]

# adding roles (remove via delete or re-assign)
>> u.roles << :manager
=> [:admin, :manager]

# querying roles...

# get all valid roles that have been declared
>> User.valid_roles
=> [:admin, :manager, :author]

# ... retrieve all assigned roles
>> u.roles # also: u.role_symbols for DeclarativeAuthorization compatibility
=> [:admin, :manager]

# ... check for individual roles
>> u.has_role? :author  # has_role? is also aliased to is?
=> false

# ... check for individual roles with dynamic methods (set dynamic: false to disable)
>> u.is_author?
=> false

# ... check for multiple roles
>> u.has_any_role? :author, :manager  # has_any_role? is also aliased to is_any_of?
=> true

>> u.has_all_roles? :author, :manager  # has_all_roles? is also aliased to is?
=> false

# see the internal bitmask representation (3 = 0b0011)
>> u.roles_mask
=> 3

# see the role mask for certain role(s)
>> User.mask_for :admin, :author
=> 5

Once you have included RoleModel, your model is perfectly fit to be used together with a role-based authorization solution, such as github.com/ryanb/cancan or github.com/stffn/declarative_authorization .

Installation¶ ↑

gem install role_model

Reasoning¶ ↑

Whenever I introduce a role-based authorization scheme into a project, the code gets coupled somehow to the available roles. So it usually does not make any sense to have a separate Role model stored within the database. This Role model will contain a predefined set of roles anyhow – changing that set will need to be reflected within the authorization code. Putting the available roles right into the model that actually uses them, makes things much easier and efficient.

Note on Patches/Pull Requests¶ ↑

• Fork the project.

• Make your feature addition or bug fix.

• Add tests for it. This is important so I don’t break it in a future version unintentionally.

• Commit, do not mess with Rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)

• Send me a pull request. Bonus points for topic branches.

Credits¶ ↑

RoleModel is an implementation of the Role Based Authorization scheme proposed by Ryan Bates (wiki.github.com/ryanb/cancan/role-based-authorization).

Copyright¶ ↑

Copyright © 2010 Martin Rehfeld. See LICENSE for details.