One way to do authorization in Zend Framework

ZendFramework_Auth.php

<?php

// .. bootstrap
Zend_Registry::set('identity', new Zend_Session_Namespace());

// .. login
$result = $this->_auth->authenticate($adapter);
if ($result->isValid()) {
  $ident = $this->_auth->getIdentity();
  $model = new Model_User;
  $data = $model->getSessionData($ident);
  $identity = Zend_Registry::get('identity');
  foreach($data as $fld => $val) {
    $identity->{$fld} = $val;
  }
}

// .. logout
Zend_Auth::getInstance()->clearIdentity();
Zend_Registry::get('identity')->unsetAll();