OmniAuth Identity

The OmniAuth Identity gem provides a way for applications to utilize a traditional login/password based authentication system without the need to give up the simple authentication flow provided by OmniAuth. Identity is designed on purpose to be as featureless as possible: it provides the basic construct for user management and then gets out of the way.


This can be a bit hard to understand the first time. Luckily, Ryan Bates made a Railscast about it!

You use omniauth-identity just like you would any other OmniAuth provider: as a Rack middleware. The basic setup for a email/password authentication would look something like this:

use OmniAuth::Builder do
  provider :identity, :fields => [:email]

Next, you need to create a model (called Identity by default) that will be able to persist the information provided by the user. Luckily for you, there are pre-built models for popular ORMs that make this dead simple.

Note: OmniAuth Identity is different from many other user authentication systems in that it is not built to store authentication information in your primary User model. Instead, the Identity model should be associated with your User model giving you maximum flexibility to include other authentication strategies such as Facebook, Twitter, etc.


Just subclass OmniAuth::Identity::Models::ActiveRecord and provide fields in the database for all of the fields you are using.

class Identity < OmniAuth::Identity::Models::ActiveRecord
  # Add whatever you like!


Include the OmniAuth::Identity::Models::Mongoid mixin and specify fields that you will need.

class Identity
  include Mongoid::Document
  include OmniAuth::Identity::Models::Mongoid

  field :email, type: String
  field :name, type: String
  field :password_digest, type: String


Unfortunately MongoMapper is not supported in omniauth-identity from >= v2.0 as a result of it not being maintained for several years.

It wasn't possible to include Mongoid and MongoMapper due to incompatible gem version requirements. Therefore precedence was given to Mongoid as it is significantly more popular and actively maintained.


Include the OmniAuth::Identity::Models::DataMapper mixin and specify fields that you will need.

class Identity
  include DataMapper::Resource
  include OmniAuth::Identity::Models::DataMapper

  property :id,              Serial
  property :email,           String
  property :password_digest, Text

  attr_accessor :password_confirmation



Include the OmniAuth::Identity::Models::CouchPotatoModule mixin and specify fields that you will need.

class Identity
  include CouchPotato::Persistence
  include OmniAuth::Identity::Models::CouchPotatoModule

  property :email
  property :password_digest

  def self.where search_hash
    CouchPotato.database.view Identity.by_email(:key => search_hash)

  view :by_email, :key => :email

Once you've got an Identity persistence model and the strategy up and running, you can point users to /auth/identity and it will request that they log in or give them the opportunity to sign up for an account. Once they have authenticated with their identity, OmniAuth will call through to /auth/identity/callback with the same kinds of information it would had the user authenticated through an external provider. Simple!

Custom Auth Model

To use a class other than the default, specify the :model option to a different class.

use OmniAuth::Builder do
  provider :identity, :fields => [:email], :model => MyCustomClass

Customizing Registration Failure

To use your own custom registration form, create a form that POSTs to '/auth/identity/register' with 'password', 'password_confirmation', and your other fields.

<%= form_tag '/auth/identity/register' do |f| %>
  <h1>Create an Account</h1>
  <%= text_field_tag :email %>
  <%= password_field_tag :password %>
  <%= password_field_tag :password_confirmation %>
  <%= submit_tag %>
<% end %>

Beware not to nest your form parameters within a namespace. This strategy looks for the form parameters at the top level of the post params. If you are using simple_form, then you can avoid the params nesting by specifying :input_html.

<%= simple_form_for @identity, :url => '/auth/identity/register' do |f| %>
  <h1>Create an Account</h1>
  <%# specify :input_html to avoid params nesting %>
  <%= f.input :email, :input_html => {:name => 'email'} %>
  <%= f.input :password, :as => 'password', :input_html => {:name => 'password'} %>
  <%= f.input :password_confirmation, :label => "Confirm Password", :as => 'password', :input_html => {:name => 'password_confirmation'} %>
  <button type='submit'>Sign Up</button>
<% end %>

Next you'll need to let OmniAuth know what action to call when a registration fails. In your OmniAuth configuration, specify any valid rack endpoint in the :on_failed_registration option.

use OmniAuth::Builder do
  provider :identity,
    :fields => [:email],
    :on_failed_registration => UsersController.action(:new)

For more information on rack endpoints, check out this introduction and ActionController::Metal

Customizing Locate Conditions

You can customize the way that matching records are found when authenticating. For example, for a site with multiple domains, you may wish to scope the search within a particular subdomain. To do so, add :locate_conditions to your config. The default value is:

:locate_conditions => lambda { |req| { model.auth_key => req['auth_key']} }

locate_conditions takes a Proc object, and must return a hash. The resulting hash is used as a parameter in the locate method for your ORM. The proc is evaluated in the callback context, and has access to the Identity model (using model) and receives the request object as a parameter. Note that model.auth_key defaults to 'email', but is also configurable.

Note: Be careful when customizing locate_conditions. The best way to modify the conditions is to copy the default value, and then add to the hash. Removing the default condition will almost always break things!


MIT License. See LICENSE for details.

Copyright (c) 2020- Andrew Roberts, and Jellybooks Ltd. Copyright (c) 2010-2015 Michael Bleigh, and Intridea, Inc.