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Zend Framework 2 Documentation (Manual)

File: /_sources/modules/zend.mvc.examples.txt

.. _zend.mvc.examples:

Examples
========

.. _zend.mvc.examples.controllers:

Controllers
-----------

.. _zend.mvc.examples.controllers.accessing-the-request-and-response:

Accessing the Request and Response
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

When using ``AbstractActionController`` or ``AbstractRestfulController``, the request and response object are
composed directly into the controller as soon as ``dispatch()`` is called. You may access them in the following
ways:

.. code-block:: php
   :linenos:

   // Using explicit accessor methods
   $request  = $this->getRequest();
   $response = $this->getResponse();

   // Using direct property access
   $request  = $this->request;
   $response = $this->response;

Additionally, if your controller implements ``InjectApplicationEventInterface`` (as both
``AbstractActionController`` and ``AbstractRestfulController`` do), you can access these objects from the attached
``MvcEvent``:

.. code-block:: php
   :linenos:

   $event    = $this->getEvent();
   $request  = $event->getRequest();
   $response = $event->getResponse();

The above can be useful when composing event listeners into your controller.

.. _zend.mvc.examples.controllers.accessing-routing-parameters:

Accessing routing parameters
^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The parameters returned when routing completes are wrapped in a ``Zend\Mvc\Router\RouteMatch`` object. This object
is detailed in the section on :ref:`Routing <zend.mvc.routing>`.

Within your controller, if you implement ``InjectApplicationEventInterface`` (as both ``AbstractActionController``
and ``AbstractRestfulController`` do), you can access this object from the attached ``MvcEvent``:

.. code-block:: php
   :linenos:

   $event   = $this->getEvent();
   $matches = $event->getRouteMatch();

Once you have the ``RouteMatch`` object, you can pull parameters from it.

The same can be done using the :ref:`Params plugin<zend.mvc.controller-plugins.params>`.

.. _zend.mvc.examples.controllers.returning-early:

Returning early
^^^^^^^^^^^^^^^

You can effectively short-circuit execution of the application at any point by returning a ``Response`` from your
controller or any event. When such a value is discovered, it halts further execution of the event manager, bubbling
up to the ``Application`` instance, where it is immediately returned.

As an example, the ``Redirect`` plugin returns a ``Response``, which can be returned immediately so as to complete
the request as quickly as possible. Other use cases might be for returning JSON or XML results from web service
endpoints, returning "401 Unauthorized" results, etc.

.. _zend.mvc.examples.bootstrapping:

Bootstrapping
-------------

.. _registering-module-specific-listeners:

Registering module-specific listeners
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Often you may want module-specific listeners. As an example, this would be a simple and effective way to introduce
authorization, logging, or caching into your application.

Each ``Module`` class can have an optional ``onBootstrap()`` method. Typically, you'll do module-specific
configuration here, or setup event listeners for you module here. The ``onBootstrap()`` method is called for
**every** module on **every** page request and should **only** be used for performing **lightweight** tasks such as
registering event listeners.

The base ``Application`` class shipped with the framework has an ``EventManager`` associated with it, and once the
modules are initialized, it triggers the :ref:`bootstrap <zend.mvc.mvc-event.bootstrap>` event, with a
``getApplication()`` method on the event.

So, one way to accomplish module-specific listeners is to listen to that event, and register listeners at that
time. As an example:

.. code-block:: php
   :linenos:

   namespace SomeCustomModule;

   class Module
   {
       /**
        * @param  \Zend\Mvc\MvcEvent $e The MvcEvent instance
        * @return void
        */
       public function onBootstrap($e)
       {
           $application = $e->getApplication();
           $config      = $application->getConfig();
           $view        = $application->getServiceManager()->get('ViewHelperManager');
           // You must have these keys in you application config
           $view->headTitle($config['view']['base_title']);

           // This is your custom listener
           $listener   = new Listeners\ViewListener();
           $listener->setView($view);
           $application->getEventManager()->attachAggregate($listener);
       }
   }

The above demonstrates several things. First, it demonstrates a listener on the application's
:ref:`bootstrap <zend.mvc.mvc-event.bootstrap>` event (the ``onBootstrap()`` method). Second, it demonstrates that
listener, and how it can be used to register listeners with the application. It grabs the ``Application`` instance;
from the ``Application``, it is able to grab the attached service manager and configuration. These are then used to
retrieve the view, configure some helpers, and then register a listener aggregate with the application event
manager.