php - Implement single logout in simplesamlphp -

this in continuation previous question

central login saml , making site work identity provider

now have sessions @ cauth.com , a.com (or b.com).what can best way logout sessions on both site on click of "logout" button.?

this code have witten logout in cauth.com

   public function actionslo(){       $metadata = \simplesaml_metadata_metadatastoragehandler::getmetadatahandler();       $idpentityid = $metadata->getmetadatacurrententityid('saml20-idp-hosted');      $idp = \simplesaml_idp::getbyid('saml2:' . $idpentityid);       \sspmod_saml_idp_saml2::receivelogoutmessage($idp);       assert('false');        //destroy session        session_destroy();        //redirect spentity       $spid = $_get['spentityid'];       header("location:".$spid);     } 

it seems me logout take 3 http redirects

1 . when user click on "logout" requested page cauth.com/slo.

2. then user taken logout of main site (a.com or b.com).

3. user redirected index page of main site.

i want know there way can handle saml logout internally reducing number of http redirects keeping in mind have clear out session variables on both sites ?

try clear user session in

cauth.com( (cauth.com/logout)) 

clear user session need start user session before , destroy current user session by

session_start();     session_unset(); session_destroy();