Zend_Controller_Action is an abstract class you may use for implementing Action Controllers for use with the Front Controller when building a website based on the Model-View-Controller (MVC) pattern.

To use Zend_Controller_Action, you will need to subclass it in your actual action controller classes (or subclass it to create your own base class for action controllers). The most basic operation is to subclass it, and create action methods that correspond to the various actions you wish the controller to handle for your site. Zend_Controller's routing and dispatch handling will autodiscover any methods ending in 'Action' in your class as potential controller actions.

For example, let's say your class is defined as follows:

class FooController extends Zend_Controller_Action
{
    public function barAction()
    {
        // do something
    }

    public function bazAction()
    {
        // do something
    }
}

The above FooController class (controller foo) defines two actions, bar and baz.

There's much more that can be accomplished than this, such as custom initialization actions, default actions to call should no action (or an invalid action) be specified, pre- and post-dispatch hooks, and a variety of helper methods. This chapter serves as an overview of the action controller functionality

class FooController extends Zend_Controller_Action
{
    public function init()
    {
        // Local to this controller only; affects all actions,
        // as loaded in init:
        $this->_helper->viewRenderer->setNoRender(true);

        // Globally:
        $this->_helper->removeHelper('viewRenderer');

        // Also globally, but would need to be in conjunction with the
        // local version in order to propagate for this controller:
        Zend_Controller_Front::getInstance()
            ->setParam('noViewRenderer', true);
    }
}

class FooController extends Zend_Controller_Action
{
    public function barAction()
    {
        // disable autorendering for this action only:
        $this->_helper->viewRenderer->setNoRender();
    }
}

While you can always override the action controller's constructor, we do not recommend this. Zend_Controller_Action::__construct() performs some important tasks, such as registering the request and response objects, as well as any custom invocation arguments passed in from the front controller. If you must override the constructor, be sure to call parent::__construct($request, $response, $invokeArgs).

The more appropriate way to customize instantiation is to use the init() method, which is called as the last task of __construct(). For example, if you want to connect to a database at instantiation:

class FooController extends Zend_Controller_Action
{
    public function init()
    {
        $this->db = Zend_Db::factory('Pdo_Mysql', array(
            'host'     => 'myhost',
            'username' => 'user',
            'password' => 'XXXXXXX',
            'dbname'   => 'website'
        ));
    }
}

Zend_Controller_Action specifies two methods that may be called to bookend a requested action, preDispatch() and postDispatch(). These can be useful in a variety of ways: verifying authentication and ACL's prior to running an action (by calling _forward() in preDispatch(), the action will be skipped), for instance, or placing generated content in a sitewide template (postDispatch()).

A number of objects and variables are registered with the object, and each has accessor methods.

Zend_Controller_Action provides a rudimentary and flexible mechanism for view integration. Two methods accomplish this, initView() and render(); the former method lazy-loads the $view public property, and the latter renders a view based on the current requested action, using the directory hierarchy to determine the script path.

applicationOrModule/
    controllers/
        IndexController.php
    views/
        scripts/
            index/
                index.phtml
        helpers/
        filters/

string render(string $action = null,
              string $name = null,
              bool $noController = false);

class MyController extends Zend_Controller_Action
{
    public function fooAction()
    {
        // Renders my/foo.phtml
        $this->render();

        // Renders my/bar.phtml
        $this->render('bar');

        // Renders baz.phtml
        $this->render('baz', null, true);

        // Renders my/login.phtml to the 'form' segment of the
        // response object
        $this->render('login', 'form');

        // Renders site.phtml to the 'page' segment of the response
        // object; does not use the 'my/' subirectory
        $this->render('site', 'page', true);
    }

    public function bazBatAction()
    {
        // Renders my/baz-bat.phtml
        $this->render();
    }
}

Besides the accessors and view integration methods, Zend_Controller_Action has several utility methods for performing common tasks from within your action methods (or from pre- and post-dispatch).

By design, Zend_Controller_Action must be subclassed in order to create an action controller. At the minimum, you will need to define action methods that the controller may call.

Besides creating useful functionality for your web applications, you may also find that you're repeating much of the same setup or utility methods in your various controllers; if so, creating a common base controller class that extends Zend_Controller_Action could solve such redundancy.

class MyController extends Zend_Controller_Action
{
    public function __call($method, $args)
    {
        if ('Action' == substr($method, -6)) {
            // If the action method was not found, render the error
            // template
            return $this->render('error');
        }

        // all other methods throw an exception
        throw new Exception('Invalid method "'
                            . $method
                            . '" called',
                            500);
    }
}

class MyController extends Zend_Controller_Action
{
    public function indexAction()
    {
        $this->render();
    }

    public function __call($method, $args)
    {
        if ('Action' == substr($method, -6)) {
            // If the action method was not found, forward to the
            // index action
            return $this->_forward('index');
        }

        // all other methods throw an exception
        throw new Exception('Invalid method "'
                            . $method
                            . '" called',
                            500);
    }
}

Besides overriding __call(), each of the initialization, utility, accessor, view, and dispatch hook methods mentioned previously in this chapter may be overridden in order to customize your controllers. As an example, if you are storing your view object in a registry, you may want to modify your initView() method with code resembling the following:

abstract class My_Base_Controller extends Zend_Controller_Action
{
    public function initView()
    {
        if (null === $this->view) {
            if (Zend_Registry::isRegistered('view')) {
                $this->view = Zend_Registry::get('view');
            } else {
                $this->view = new Zend_View();
                $this->view->setBasePath(dirname(__FILE__) . '/../views');
            }
        }

        return $this->view;
    }
}

Hopefully, from the information in this chapter, you can see the flexibility of this particular component and how you can shape it to your application's or site's needs.