My current project only has one way to login, via GitHub Omniauth. To handle that, I’m using Devise along with the omniauth-github gem.

By default, Devise provides routes and controller actions for registration and login. However, I only want users to be able to register and login via Github so I disabled the Devise defaults. Here’s how I did it:

Disabling registration

To disable registration, simply remove the registerable module from your Devise model class.

-  devise :database_authenticatable, :registerable,
-         :recoverable, :rememberable, :trackable, :validatable,
+  devise :database_authenticatable, :recoverable, :rememberable, :trackable, :validatable,

Disabling login

To disable login, remove the default Devise login route. Modify the routes file so that the session routes are skipped. The only route that shouldn’t be skipped is sign_out so add that back in manually.

-  devise_for :users, controllers: { omniauth_callbacks: 'users/omniauth_callbacks' }
+  devise_for :users, controllers: { omniauth_callbacks: 'users/omniauth_callbacks' }, skip: [:session]
+  as :user do
+    delete "/sign_out" => "devise/sessions#destroy", :as => :destroy_user_session
+  end

Doing this will remove the routes for both login and registration.