Tiddle provides Devise strategy for token authentication in API-only Ruby on Rails applications. Its main feature is support for multiple tokens per user.

Tiddle is lightweight and non-configurable. It does what it has to do and leaves some manual implementation to you.

Add this line to your application's Gemfile:

gem 'tiddle'

And then execute:

$ bundle

1. Add :token_authenticatable inside your Devise-enabled model:

class User < ActiveRecord::Base
  devise :database_authenticatable, :registerable,
         :recoverable, :trackable, :validatable,
         :token_authenticatable
end

2. Generate the model which stores authentication tokens. The model name is not important, but the Devise-enabled model should have association called authentication_tokens.

rails g model AuthenticationToken body:string:index user:references last_used_at:datetime expires_in:integer ip_address:string user_agent:string

class User < ActiveRecord::Base
  has_many :authentication_tokens
end

body, last_used_at, ip_address and user_agent fields are required.

3. Customize Devise::SessionsController. You need to create and return token in #create and expire the token in #destroy.

class Users::SessionsController < Devise::SessionsController

  def create
    user = warden.authenticate!(auth_options)
    token = Tiddle.create_and_return_token(user, request)
    render json: { authentication_token: token }
  end

  def destroy
    Tiddle.expire_token(current_user, request) if current_user
    render json: {}
  end

  private

    # this is invoked before destroy and we have to override it
    def verify_signed_out_user
    end
end

4. Require authentication for some controller:

class PostsController < ApplicationController
  before_action :authenticate_user!

  def index
    render json: Post.all
  end
end

5. Send X-USER-EMAIL and X-USER-TOKEN as headers of every request which requires authentication.

You can read more in a blog post dedicated to Tiddle - https://blog.sundaycoding.com/blog/2015/04/04/token-authentication-with-tiddle/

The safest solution in API-only application is not to rely on Rails session at all and disable it. Put this line in your application.rb:

config.middleware.delete ActionDispatch::Session::CookieStore

More: https://blog.sundaycoding.com/blog/2015/04/04/token-authentication-with-tiddle/#rails-session

Change config.authentication_keys in Devise intitializer and Tiddle will use this value.

Usually it makes sense to remove user's tokens after a password change. Depending on the project and on your taste, this can be done using various methods like running user.authentication_tokens.destroy_all after the password change or with an after_save callback in your model which runs authentication_tokens.destroy_all if encrypted_password_changed?.

In case of a security breach, remove all existing tokens.

Tokens are expiring after certain period of inactivity. This behavior is optional. If you want your token to expire, create it passing expires_in option:

token = Tiddle.create_and_return_token(user, request, expires_in: 1.month)