/* login form */
<?php echo $this->form; ?>

/* Form class */
<?php
class Application_Form_LoginForm extends Zend_Form
{
   public function __construct() {
      parent::__construct();
   }

   public function init() {
      $this->setAction('/login/auth');
      $this->setMethod('post');

  		$username = new Zend_Form_Element_Text('Username');
		$username->setLabel('Username:')
			->setOptions(array ('size' => '35'))
			->setRequired(true)
			->addFilter('HtmlEntities')
			->addFilter('StringTrim');

		$this->addElement($username);

	    $password = new Zend_Form_Element_Password('Password');
		$password->setLabel('Password:')
			->setOptions(array ('size' => '35'))
			->setRequired(true)
			->addFilter('HtmlEntities')
			->addFilter('StringTrim');

		$this->addElement($password);

		$submit = new Zend_Form_Element_Submit('submit');
		$submit->setLabel('Submit')
				->setOrder(100)
				->setOptions(array('class' => 'submit button'));

		$this->addElement($submit);
   }
}

/* controller */

class LoginController extends Zend_Controller_Action {
   public function loginAction () {
      $form = new Application_Form_LoginForm();
	  $this->view->form = $form;
   }

   public function authAction () {
 		$data = $this->GetRequest()->getParams();

 		$username = $data['Username'];
 		$password = $data['Password'];

        $params = array ('host' => '127.0.0.1', 'username' => 'zf-training', 'password' => 'zf-training', 'dbname' => 'zf_training');
 		$db = Zend_Db::factory('PDO_MYSQL', $params);

 		$auth = new Zend_Auth_Adapter_DbTable($db);

 		$auth->setTableName('test')
 		      ->setIdentityColumn('username')
 		      ->setCredentialColumn('password')
 		      ->setIdentity($username)
 		      ->setCredential($password);

        $result = $auth->authenticate();
        if ($result->isValid()) {
           $this->view->loggedIn = true;
        }
   }
}

/* auth form */
<?php if ($this->loggedIn) : ?>
You're logged in
<?php else: ?>
You're not logged in
<?php endif; ?>