Ruby On Rails: Login

gem 'omniauth-auth0', '~> 3.0'
gem 'omniauth-rails_csrf_protection', '~> 1.0' # prevents forged authentication requests

# ./config/auth0.yml
development:
  auth0_domain: YOUR_DOMAIN
  auth0_client_id: YOUR_CLIENT_ID
  auth0_client_secret: <YOUR AUTH0 CLIENT SECRET>

# ./config/initializers/auth0.rb
AUTH0_CONFIG = Rails.application.config_for(:auth0)

Rails.application.config.middleware.use OmniAuth::Builder do
  provider(
    :auth0,
    AUTH0_CONFIG['auth0_client_id'],
    AUTH0_CONFIG['auth0_client_secret'],
    AUTH0_CONFIG['auth0_domain'],
    callback_path: '/auth/auth0/callback',
    authorize_params: {
      scope: 'openid profile'
    }
  )
end

# ./app/controllers/auth0_controller.rb
class Auth0Controller < ApplicationController
  def callback
    # OmniAuth stores the information returned from Auth0 and the IdP in request.env['omniauth.auth'].
    # In this code, you will pull the raw_info supplied from the id_token and assign it to the session.
    # Refer to https://github.com/auth0/omniauth-auth0/blob/master/EXAMPLES.md#example-of-the-resulting-authentication-hash for complete information on 'omniauth.auth' contents.
    auth_info = request.env['omniauth.auth']
    session[:userinfo] = auth_info['extra']['raw_info']

    # Redirect to the URL you want after successful auth
    redirect_to '/dashboard'
  end

  def failure
    # Handles failed authentication -- Show a failure page (you can also handle with a redirect)
    @error_msg = request.params['message']
  end

  def logout
    # you will finish this in a later step
  end
end

# ./config/routes.rb
Rails.application.routes.draw do
  # ..
  get '/auth/auth0/callback' => 'auth0#callback'
  get '/auth/failure' => 'auth0#failure'
  get '/auth/logout' => 'auth0#logout'
end

<!-- Place a login button anywhere on your application -->
  <%= button_to 'Login', '/auth/auth0', method: :post %>

# ./app/controllers/auth0_controller.rb
class Auth0Controller < ApplicationController
  # ..
  # ..Insert the code below
  def logout
    reset_session
    redirect_to logout_url
  end

  private

  def logout_url
    request_params = {
      returnTo: root_url,
      client_id: AUTH0_CONFIG['auth0_client_id']
    }

    URI::HTTPS.build(host: AUTH0_CONFIG['auth0_domain'], path: '/v2/logout', query: request_params.to_query).to_s
  end
end

<!-- Place a logout button anywhere on your application -->
  <%= button_to 'Logout', 'auth/logout', method: :get %>

# ./app/controllers/concerns/secured.rb
module Secured
  extend ActiveSupport::Concern

  included do
    before_action :logged_in_using_omniauth?
  end

  def logged_in_using_omniauth?
    redirect_to '/' unless session[:userinfo].present?
  end
end

# ./app/controllers/dashboard_controller.rb
class DashboardController < ApplicationController
  include Secured

  def show
    # session[:userinfo] was saved earlier on Auth0Controller#callback
    @user = session[:userinfo]
  end
end

<!-- ./app/views/dashboard/show.html.erb -->
<div>
  <p>Normalized User Profile:<%= JSON.pretty_generate(@user[:info])%></p>
  <p>Full User Profile:<%= JSON.pretty_generate(@user[:extra][:raw_info])%></p>
</div>