AWS SSO Omniauth

readme.md

• Using this gem https://github.com/omniauth/omniauth-saml
• Assumes you have a simple AuthConcern mixin for current user session. Or use devise.

omniauth.rb

metadata = Rails.root.join 'config', 'myapp_ins-8d2c1e14da9ca2bc.xml'
idpdata = File.read(metadata)
parser = OneLogin::RubySaml::IdpMetadataParser.new
SAML_SETTINGS = parser.parse_to_hash(idpdata)
Rails.application.config.middleware.use OmniAuth::Builder do
  provider :saml, SAML_SETTINGS.merge(
    issuer: 'myapp'
  )
end

sessions_controller.rb

class SessionsController < ApplicationController
  skip_before_action :verify_authenticity_token

  def create
    self.current_user = aws_attributes
    redirect_to root_url
  end

  def destroy
    self.current_user = nil
    redirect_to SAML_SETTINGS[:idp_slo_target_url]
  end

  protected

  def aws_attributes
    { username: session['saml_uid'],
      email: saml_attributes['email'] }
  end

  def saml_attributes
    saml_response.attributes
  end

  def saml_response
    auth_hash.extra.response_object
  end

  def auth_hash
    request.env['omniauth.auth']
  end
end