OmniAuth Identity

The OmniAuth Identity gem provides a way for applications to utilize a traditional username/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.

Compatibility

This gem is compatible with, as of Feb 2021, version 3:

Latest released version of omniauth, v2.0.2
Ruby 2.4, 2.5, 2.6, 2.7, 3.0, ruby-head

Installation

To acquire the latest release from RubyGems add the following to your Gemfile:

gem 'omniauth-identity'

If the git repository has new commits not yet in an official release, simply specify the repo instead:

gem 'omniauth-identity', git: 'https://github.com/intridea/omniauth-identity.git'

Usage

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. In rails, this would be created by an initializer, such as config/initializers/omniauth.rb. The basic setup for a email/password authentication would look something like this:

use OmniAuth::Builder do
  provider :identity,                        #mandatory: tells OA that the Identity strategy is being used
           model: Identity,                  # optional: specifies the name of the "Identity" model. Defaults to "Identity"
           fields: %i[email custom1 custom2] # optional: list of custom fields that are in the model's table
end

Next, you need to create a model (called Identity by default, or specified with :model argument above) 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.

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.

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.

ActiveRecord

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
  auth_key :email    # optional: specifies the field within the model that will be used during the login process
                     # defaults to email, but may be username, uid, login, etc.

  # Anything else you want!
end

Sequel

Sequel is an alternative to ActiveRecord.

Just include OmniAuth::Identity::Models::Sequel mixin, and specify whatever else you will need.

class SequelTestIdentity < Sequel::Model
  include OmniAuth::Identity::Models::Sequel
  auth_key :email
  # whatever else you want!
end

Mongoid

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
end

CouchPotato

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))
  end

  view :by_email, key: :email
end

NoBrainer

NoBrainer is an ORM for RethinkDB.

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

class Identity
  include NoBrainer::Document
  include OmniAuth::Identity::Models::NoBrainer

  auth_key :email
end

Ruby Object Mapper

Would love to add a mixin for the Ruby Object Mapper (ROM) if anyone wants to work on it!

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
end

NOTE: In the above example, MyCustomClass must have a class method called auth_key that returns the default (email) or custom auth_key to use.

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)
end

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:

use OmniAuth::Builder do
  provider :identity,
           locate_conditions: ->(req) { { model.auth_key => req['auth_key'] } }
    # ...
end

locate_conditions takes a Proc object, and must return a Hash object, which will be used as the argument to the locate method for your ORM. The proc is evaluated in the callback context, and has access to your 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!

Customizing Other Things

From the code - here are the options we have for you, a couple of which are documented above, and the rest are documented... in the specs we hope!?

option :fields, %i[name email]

      # Primary Feature Switches:
option :enable_registration, true   # See #other_phase and #request_phase
option :enable_login, true          # See #other_phase

      # Customization Options:
option :on_login, nil               # See #request_phase
option :on_validation, nil          # See #registration_phase
option :on_registration, nil        # See #registration_phase
option :on_failed_registration, nil # See #registration_phase
option :locate_conditions, ->(req) { { model.auth_key => req['auth_key'] } }

Please contribute some documentation if you have the gumption! The maintainer's time is limited, and sometimes the authors of PRs with new options don't update the this readme. 😭

License

MIT License. See LICENSE for details.