title: Ruby SAML ACS Logout Request
body: <p>I have created a SAML2 SSO Login(with google assertion consumer service) as follows:</p>
  
  <pre><code>require 'onelogin/ruby-saml'
  
  class Saml
    class &lt;&lt; self
      def init(provider, saml2_idp_url, saml2_issuer_url)
        request = OneLogin::RubySaml::Authrequest.new
  
        request.create(saml_settings)
      end
  
      def consume(params)
        OneLogin::RubySaml::Response.new(params[:SAMLResponse], :settings =&gt; saml_settings)
      end
  
      private
  
      def saml_settings
        idp_metadata_parser = OneLogin::RubySaml::IdpMetadataParser.new
  
        settings = idp_metadata_parser.parse( File.read("acs.xml") )
  
        settings.assertion_consumer_service_url = https://certedrive-dev1.ngrok.io/saml2/idp?idpid=xxxxxx
        settings.issuer                         = https://certedrive-dev1.ngrok.io/saml2?idpid=xxxxxx
        settings
      end
    end
  end
  </code></pre>
  
  <p>But, I'm unable to get the equivalent logout with ACS.</p>
  
  <p>I tried:</p>
  
  <pre><code>logout_req = OneLogin::RubySaml::Logoutrequest.new
  logout_req_url = logout_req.create(saml_settings)
  </code></pre>
  
  <p>But, this throws me:</p>
  
  <blockquote>
    <p>NoMethodError - undefined method `+' for nil:NilClass</p>
  </blockquote>
  
  <p>I feel the Logout method I'm trying is wrong. What may be the correct way to send out Logout request?</p>