Omniauth::Whiplash

Whiplash OAuth2 Strategy for OmniAuth.

Add this line to your application's Gemfile:

gem 'omniauth-whiplash'

And then execute:

$ bundle

Or install it yourself as:

$ gem install omniauth-whiplash

OmniAuth::Strategies::Whiplash is simply a Rack middleware. Read the omniauth-oauth2 docs for detailed instructions.

Here's a quick example, adding the middleware to a Rails app in config/initializers/omniauth.rb:

Rails.application.config.middleware.use OmniAuth::Builder do
  provider :whiplash, ENV.fetch('WHIPLASH_CLIENT_ID'), ENV.fetch('WHIPLASH_CLIENT_SECRET'), scope: ENV.fetch('WHIPLASH_CLIENT_SCOPE'), client_options: {site: ENV.fetch('WHIPLASH_API_URL')}
end

If you are using Devise, you can skip the above and instead include this to your Devise configuration in initializers/devise.rb:

config.omniauth :whiplash, ENV.fetch('WHIPLASH_CLIENT_ID'), ENV.fetch('WHIPLASH_CLIENT_SECRET'), scope: ENV.fetch('WHIPLASH_CLIENT_SCOPE'), client_options: {site: ENV.fetch('WHIPLASH_API_URL')}

Please refer to the Whiplash API documentation for information regarding scopes.

There are a few steps to follow to get SSO configured via Oauth2. The solution below uses Devise. You don't have to use Devise, but it provides some of the OAuth2 legwork and so that is what we recommend.

Note: User accounts that are admin-level on Whiplash will automatically authorize your application. That means admins redirected to Whiplash for authentication will be immediately redirected back to your application if the permissions were configured correctly.

Add to your Gemfile:

gem 'devise', '~> 4.3.0'

Install Devise:

rails generate devise:install

Create a User model:

rails generate devise User

You can remove some default Devise columns as we will not be using a standard Devise configuration.

Here is a sample migration that includes all the fields returned by the Whiplash OAuth endpoint:

class DeviseCreateUsers < ActiveRecord::Migration[5.1]
  def change
    enable_extension("citext")

    create_table :users do |t|
      t.citext :email,              null: false, default: ""

      t.string :provider
      t.string :uid
      t.string :first_name
      t.string :last_name
      t.string :role
      t.string :whiplash_id

      t.timestamps null: false
    end

    add_index :users, :email, unique: true
  end
end

Please Note: We are using the case-insensitive Postgres column type (citext) here. If you are using MySQL, you will want to switch this to string as that defaults to case-insensitive.

You can add any additional validations or methods as per usual to the User model. This is just the base setup to get SSO working.

class User < ApplicationRecord

  devise :omniauthable, omniauth_providers: [:whiplash]

  def self.from_omniauth(omniauth_params)
    User.find_or_create_by(email: omniauth_params.info['email']) do |u|
      u.first_name  = omniauth_params.info['first_name']
      u.last_name   = omniauth_params.info['last_name']
      u.whiplash_id = omniauth_params.info['id']
      u.role        = omniauth_params.info['role']
    end
  end

end

The self.from_omniauth method is called automatically when a user is signing in. It will create a User record for new users and return existing users for previously created ones.

Create the controller in controllers/users/omniauth_callbacks_controller.rb:

class Users::OmniauthCallbacksController < Devise::OmniauthCallbacksController

  skip_before_action :require_user

  def whiplash
    @user = User.from_omniauth(request.env["omniauth.auth"])

    if @user.persisted?
      sign_in_and_redirect(@user, event: :authentication)
    end
  end

  def failure
    redirect_to root_path
  end

end

Please Note: We have a before_action defined here called require_user. We have that defined in ApplicationController like so:

def require_user
  unless current_user
    redirect_to user_whiplash_omniauth_authorize_path
  end
end

Any controller you would like to place behind the SSO login, you can add the respective before_action :require_user.

Lastly, create the route in routes.rb

devise_for :users, controllers: { omniauth_callbacks: "users/omniauth_callbacks" }

You are done. Just make sure you have set the environment variables and Devise configuration degined in the Usage section.

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment. Run bundle exec omniauth-whiplash to use the gem in this directory, ignoring other installed copies of this gem.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/whiplashmerch/omniauth-whiplash.

The gem is available as open source under the terms of the MIT License.