GDS-SSO provides everything needed to integrate an application with the sign-on-o-tron single-sign-on (https://github.com/alphagov/sign-on-o-tron) as used by the Government Digital Service, though it will probably also work with a range of other oauth2 providers.
It is a wrapper around omniauth that adds a 'strategy' for oAuth2 integration against sign-on-o-tron, and the necessary controller to support that request flow.
For more details on OmniAuth and oAuth2 integration see https://github.com/intridea/omniauth
Integration with a Rails 3+ app
To use gds-sso tou will need an oauth client ID and secret for sign-on-o-tron or a compatible system. These can be provided by one of the team with admin access to sign-on-o-tron.
Then include the gem in your Gemfile:
gem 'gds-sso', :git => 'https://github.com/alphagov/gds-sso.git'
config/initializers/gds-sso.rb that looks like:
GDS::SSO.config do |config| config.user_model = 'User' # set up ID and Secret in a way which doesn't require it to be checked in to source control... config.oauth_id = ENV['OAUTH_ID'] config.oauth_secret = ENV['OAUTH_SECRET'] # optional config for location of sign-on-o-tron config.oauth_root_url = "http://localhost:3001" # optional config for API Access (requests which accept application/json) config.basic_auth_user = 'api' config.basic_auth_password = 'secret' end
The user model needs to respond to klass.find_by_uid(uid), and must include the GDS::SSO::User module.
You also need to include
GDS::SSO::ControllerMethods in your ApplicationController