Add DataMapper support to devise for Rails authentication
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dm-devise lets you use devise ( with DataMapper. The gem gives you the options of 2 ORM setups depending on what library you wish to use for validations:


Uses dm-validations. This involves a bit of monkey-patching, but you need to use this if you want auto-validations in any of your models.


Uses ActiveModel::Validations. Do not use if you require 'dm-validations' anywhere in your app (or include it in your Gemfile). Things will break. The advantage to this is ActiveModel's I18n support for error messages, and it uses the same validations lib as devise does by default.

dm-devise is intended for use with Rails 3 and devise >= 1.1. It may work with earlier versions, but it's not been tested (if you try, please let Jared Morgan ( know how it goes.)

This README only covers dm-devise specifics. Make sure to read the devise README

Last tested against devise master: 2011-07-26, commit 33d7644b4fc13de68da8 Last tested against devise release 1.4.2


Add dm-devise and dm gems to your Gemfile. The following gems are required:

gem 'dm-core',           '~> 1.1.0'
gem 'dm-sqlite-adapter', '~> 1.1.0' # or your preferred adapter
gem 'dm-serializer',     '~> 1.1.0'
gem 'dm-timestamps',     '~> 1.1.0'
gem 'dm-rails',          '~> 1.1.0'
gem 'dm-validations',    '~> 1.1.0' # Do not include if using data_mapper_active_model
gem 'dm-devise',         '~> 1.4.0'

If you're using data_mapper_active_model do not include dm-validations in your Gemfile.

dm-devise works with versions of DataMapper gems >= 1.0.2 on the 1.0 branch and >= 1.1.0.rc3 on the 1.1 branch.

Run the generator:

rails generate devise:install

The generator will install an initializer which describes ALL Devise's configuration options and you MUST take a look at it. Make sure to specify either data_mapper (for using dm-validations) or data_mapper_active_model (ActiveModel::Validations) as the orm in the configuration file.

To add Devise to any of your models using the generator:

rails generate data_mapper:devise MODEL

Read the README for devise at


  • Example app

  • Rails templates


The dm-devise test rake task runs all of devise's tests using the data_mapper and data_mapper_active_model ORM setups. In order to run tests, you'll need a local copy of devise (a gem is fine as long as you specify the path). By default, dm-devise looks for devise in [path-to-dm-devise]/../devise. You can override this by setting a DEVISE_PATH env variable. For example:

rake test DEVISE_PATH=/path/to/devise

Tests of the master branch should be run against devise master. Tests of the 1.1 branch should be run against the devise 1.1 branch (or a 1.1.x gem).

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.



Bugs and Feedback

For dm-devise specific issues, please create an issue on GitHub at:


Copyright © 2010 Jared Morgan. See LICENSE for details.