Cas.php

<?php

require_once 'CAS/CAS.php';

class Nmc_Auth_Adapter_Cas implements Zend_Auth_Adapter_Interface
{
    public function __construct($host, $port, $path)
    {
        phpCAS::client(CAS_VERSION_2_0, $host, $port, $path);
        phpCAS::setNoCasServerValidation();
    }

    public function authenticate()
    {
        $loggedIn = phpCAS::checkAuthentication();
        if ($loggedIn) {
            return new Zend_Auth_Result(true, phpCAS::getUser());
        }
        return new Zend_Auth_Result(false, null, array('Not signed in to CAS.'));
    }
}