cedricwider/omniauth-oauth2

An abstract OAuth2 strategy for OmniAuth.

OmniAuth OAuth2

This gem contains a generic OAuth2 strategy for OmniAuth. It is meant to serve as a building block strategy for other strategies and not to be used independently (since it has no inherent way to gather uid and user info).

Creating an OAuth2 Strategy

To create an OmniAuth OAuth2 strategy using this gem, you can simply subclass it and add a few extra methods like so:

require 'omniauth-oauth2'

module OmniAuth
  module Strategies
    class SomeSite < OmniAuth::Strategies::OAuth2
      # Give your strategy a name.
      option :name, "some_site"

      # This is where you pass the options you would pass when
      # initializing your consumer from the OAuth gem.
      option :client_options, {:site => "https://api.somesite.com"}

      # These are called after authentication has succeeded. If
      # possible, you should try to set the UID without making
      # additional calls (if the user id is returned with the token
      # or as a URI parameter). This may not be possible with all
      # providers.
      uid{ raw_info['id'] }

      info do
        {
          :name => raw_info['name'],
          :email => raw_info['email']
        }
      end

      extra do
        {
          'raw_info' => raw_info
        }
      end

      def raw_info
        @raw_info ||= access_token.get('/me').parsed
      end
    end
  end
end

That's pretty much it!