This project aims to assist in setting up a Rails 3 app with an integrated Authentication and Authorization solution for your ORM of choice.

Execute the full_config generator with arguments specifying:

  • The User roles in the app
  • The role strategy to use (both single and multiple roles for each user)
  • ORM to use (Relational or Document based datastores)

The generator will do its magic to your app and (hopefully) you should be set to go with implementing the remainder of your app ;)

Cream targets smooth integration of the following main systems:

Cream also uses CanCan permits to enable use of Permits and Licenses.

The gems devise-links and cancan-rest-links provide helpers to facilitate working with authentication links and REST links with automatic execution of user permission logic!

Cream comes with a suite of specialized generators that should let you configure your Rails 3 app with these systems to a large degree.

Note: Lately Cream also has options for some common customizations such as allowing login using either username or email.

Status update (May 7, 2011)


The project has undergone a lot of bugfixes during 4-7 of May, thanks to @alecslupu who was patient enough to go through all the pain to find the bugs and assist me in fixing them. Thanks! Please use the latest master branches for cream, cancan-permits, roles_active_record, rails_assist and rails_artifactor. If you get problems from any other dependency gems, I recommend that you use their github master branch as the source. I hope to release all gems ASAP when I know they all play nice ;)


  • Integrate a set of widely accepted sub-systems for a fully integrated solution
  • Provide generators that can auto-configure your Rails 3 app with these systems for a given ORM

More info

For more information see the Cream Wiki, which includes overviews of the:

Please let me know of other areas that you think should be covered in the Wiki or on page.

The magic behind the curtain…

Cream leverages an extensive Tool suite I have created specifically to make it much easier/faster to create gems and generators for Rails 3 and spec/test them with RSpec 2, all using more natural DSLs and APIs. If you look into the Cream code you can see extensive usage of this “magic” (especially in the generators).

Status (Jan 15): I’m currently in the process of refactoring and improving this underlying “tool suite”. I might call it rails-mixer or something.

Cream user group

The Cream user group is a google group where you can ask Cream related questions, provide suggestions etc. to the Cream community.

Inspiration and Ideas

Tony Amoyal has written a two part series (Part I, Part II) on how to setup a fully integrated Devise/CanCan solution with Roles. You might want to take a look at this for further customization needs. It might also provide food for thought for suggestions on improvements to the Cream framework ;) I have started work on a devise:customize generator to facilitate some of these customization needs…

Currently there is support for seting up a Guest user and and option to use both username and password as valid credentials.

Design ideas

Please see the Design ideas section on the wiki for possible enhancements you might want to add and/or ideas for further improvments to the framework. Feel free to add your own suggestions and ideas!

Since version 0.8.9 I have added the concept of a Guest user and current_user using the session. Please also see Cream Guest user for more info on the current approach.

The latest design splits up the concepts of role and user_type. The user_types are now the devise classes generated, and each such class can have a role strategy assigned. Ther should be a simple way to define a default role, something like the following.

Example idea:

  class Editor < User
    default_role :editor
    valid_roles_are :publisher, blog_editor

This way, any editor user created will always be given the :editor role on creation and he can later add the :publisher and/or :blog_editor roles. Perhaps it could just use the class name somehow, fx using the lowercase method (this way it would also work with more complex, namespaced classes).

Ideas and suggestions are most welcome!

The path towards 1.0

I will continue the 0.8.9.x line only with bug fixes and other minor fixes or additions.

The 0.9 line will likely be a total redesign/refactoring using what I am learning from reading Jose Valim’s book Crafting Rails Applications. I will create a new project using enginex, complete with one or more dummy apllications and take it from there. Sadly I will likely not have time for this until April 2011, so if anyone has the time and energy, please help me in this effort!

Cream edge, debugging and assisting developing the framework

Cream edge (directly from trunk or a feature branch), might have some extra goodies you could be interested in. To help develop Cream or use the edge version, just do:

gem 'cream', :git => ''

There is also a :branch option to use a specific branch, fx a feature branch.

If you want to develop on Cream: git clone

Optionally switch to particular branch in your local cloned repo: git checkout [feature branch]

Then in your app, tell it to use your local version using the :path option:

gem 'cream', :path => 'path to your cloned cream'

And you’ll be ready to experiment, debug and add features from there :)

Rails 3 demo apps with Cream

The following Rails 3 demo apps use Cream 0.7.7 and above and were created around Dec 1. 2010

You are most welcome to publish your own demo app with a later version of Cream. These apps need to be updated and demonstrate the real functionality of using the various APIs and DSLs that come with Cream and its supporting libs ;)

Authentication systems

Cream targets Devise as the Authentication system of choice

See Devise Configuration options for more details on configuring your devise User models.

Devise links

The project devise links adds more convenience for creating view links to trigger Devise session actions.

Authorization system

There is support for the CanCan Authorization system. I have created a Cancan permits gem that adds the concept of Permits for each role (see below).

Another framework of interest: Aegis – The alternative Authorization solution


I have developed a flexible Roles Generic system which is used as the basis for the default Role system.

The Roles Generic API has been implemented for the following ORMs

Any role system can be substituted as long as you have a method #has_role? on the user which returns true or false given a string or symbol that identifies the role.

Role Groups

Document DBs such as Mongo and Riak are ideal for modeling a role-group hierarchical relationship.

Currently Role groups are supported as class level methods on the User class using a class level in-memory hash map.

See Roles Group API

The Group API allows multiple roles to be grouped.


Say you have the admin roles:

  • Admin
  • Super admin

And the customer roles

  • Individual customer
  • Company customer

You might want to group them like this:

  User.add_role_group :customers => [:individual_customer, :company_customer]
  User.add_role_group :admins => [:admin, :super_admin]  

Then you can handle any user with regards to his/her role group relationship like this:

  # do this only for users in the admin role group (user has either :admin or :super_admin role) 
  current_user.is_in_group? :admins do

In your views you can guard view code with Role Group conditions:

  # do this only for users in the admin role group (user has either :admin or :super_admin role) 
  for_user_in_group :customers do

  # Cream 0.8.9 (edge)
  not_for_user_in_group :admins do


In general, it should now finally be pretty easy to set up a Rails 3 app, with a full Authentication and an Authorization system linked to a Role system using one of the following supported Cream ORMs.

Relational Databases:

  • Active Record
  • Data Mapper

Document stores:

  • Mongo Mapper
  • Mongoid
  • Couch DB

These ORMs are also supported for the CanCan Permits and Roles systems.

Installation and configuration

This gem has been designed for Rails 3 and Ruby 1.9 only. Some users have notified me that it doesn’t work on Ruby 1.8.7, so be advised!

Install gems


gem ‘cream’
in your Rails 3 Gemfile
$ bundle install

Role system

Role strategies can be set up using the Roles Generic gem or any of the ORM specific roles gems such as Roles Active Record.


Role based authorization for CanCan can be achieved by creating a Permit class for each role.


A Permit lets a user in a given role do certain actions as defined in the Permit. A Permit can also reuse permission logic in the form of Licenses for a more fine grained design if needed.

CanCan Permits comes with generators to generate Permit files which are placed in ‘/app/permits’. You can then edit the Permits to suit your needs.

The project CanCan REST links provides a convenient way to handle CanCan REST links, using a flexible API.

Check out Cancan permits for more info for how to use Permits.

Cancan permits support all the ORMs that both Devise and Roles support.

Permits Editor

I have recently created a Permits editor application that demonstrates how you can let the user edit the Permits, Licenses and even individual User permissions directly as part of an admin section of the web app.

The Permits editor updates yaml files that are now part of the cancan-permits infrastructure (if present and registered). I plan to refactor the Permits Editor into a mountable app when I have the time.


For more advanced authorization scenarios you can create reusable permission logic in license classed that are placed in ‘/app/licenses/’. A License can be reused in multiple Permits.

See CanCan permits demo app for an example of how to use cancan-permits and licenses.

Role specific Customization of Routing and User classes

Please see Customizing Routes and User classes for Roles

The generator now generates initial Routes configuration for each role in order to facilitate Registration page customization for each role if needed. A User subclass is now generated for each role by default in order to allow more User customization and for the above mentioned routing customization to function.


Please see Cream generators overview for more details.

The following generators are currently available:

Main generator:

  • cream:full_config – Configure Rails 3 application with Cream (master generator)

Config generators:

Devise (authentication)

  • devise:config – Configure Rails 3 application with Devise
  • devise:users – Configure Rails 3 application with Devise users
  • devise:customize – Customize devise configuration

Authorization incl. roles

  • cancan:config – Configures app with CanCan
  • permits:config – Configures app with CanCan Permits
  • roles:config – Configures app with Roles

Other generators:

  • cancan:restlinks – Create REST links locale file
  • devise:links – Create devise links locale file (should I rename this to authlinks?)
  • cream:views – Generates partials for menu items (outdated)

All the above generators have specs included in cream that demonstrate how to use them and should verify that they work as expected.

The cream:full_config generator should call all the sub-generators in succession to fully configure the Rails 3 app according to your preferences.

Full Config Generator

Master cream generator which calls the sub-generators in succession.

  • strategy : role strategy to use (see roles_generic gem)
  • orm : orm to be used
  • roles : list of valid roles and permits to use


rails g cream:full_config --strategy admin_flag --orm AR

By default creates :guest and :admin roles.

Sub generators

To view the run options of any of the sub generators, simply type $ rails g [GENERATOR_NAME]

Example: rails g permits:config

Cream Views Generator

Moves ‘user menu’ partials views into app/views/_user_menu

rails g cream:views [scope] [--haml]

  • (scope) : The scope/namespace folder under views to copy the partials to, ‘cream’ is the default
  • (haml) : Use HAML as template language (default is erb)

The views generator is based on a similar generator from the devise project. The Views generator and partials have been updated (Jan 6, 2011). The partials generated are useful for creating menu items for login/logout and registration. The links are automatically displayed or hidden depending on the current state of the user.

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.


Copyright © 2010 Kristian Mandrup. See LICENSE for details.