Zend\Mvc

Controller Plugins

When using the AbstractActionController or AbstractRestfulController, or if you implement the setPluginManager method in your custom controllers, you have access to a number of pre-built plugins. Additionally, you can register your own custom plugins with the manager.

The built-in plugins are:

  • Zend\Mvc\Controller\Plugin\FlashMessenger
  • Zend\Mvc\Controller\Plugin\Forward
  • Zend\Mvc\Controller\Plugin\Layout
  • Zend\Mvc\Controller\Plugin\Params
  • Zend\Mvc\Controller\Plugin\PostRedirectGet
  • Zend\Mvc\Controller\Plugin\Redirect
  • Zend\Mvc\Controller\Plugin\Url

If your controller implements the setPluginManager, getPluginManager and plugin methods, you can access these using their shortname via the plugin() method:

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$plugin = $this->plugin('url');

For an extra layer of convenience, both AbstractActionController and AbstractRestfulController have __call() implementations that allow you to retrieve plugins via method calls:

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$plugin = $this->url();

The FlashMessenger

The FlashMessenger is a plugin designed to create and retrieve self-expiring, session-based messages. It exposes a number of methods:

  • setSessionManager() allows you to specify an alternate session manager, if desired.
  • getSessionManager() allows you to retrieve the session manager registered.
  • getContainer() returns the Zend\Session\Container instance in which the flash messages are stored.
  • setNamespace() allows you to specify a specific namespace in the container in which to store or from which to retrieve flash messages.
  • getNamespace() retrieves the name of the flash message namespace.
  • addMessage() allows you to add a message to the current namespace of the session container.
  • hasMessages() lets you determine if there are any flash messages from the current namespace in the session container.
  • getMessages() retrieves the flash messages from the current namespace of the session container.
  • clearMessages() clears all flash messages in current namespace of the session container.
  • hasCurrentMessages() indicates whether any messages were added during the current request.
  • getCurrentMessages() retrieves any messages added during the current request.
  • clearCurrentMessages() removes any messages added during the current request.

Additionally, the FlashMessenger implements both IteratorAggregate and Countable, allowing you to iterate over and count the flash messages in the current namespace within the session container.

Examples

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public function processAction()
{
    // ... do some work ...
    $this->flashMessenger()->addMessage('You are now logged in.');
    return $this->redirect()->toRoute('user-success');
}

public function successAction()
{
    $return = array('success' => true);
    $flashMessenger = $this->flashMessenger();
    if ($flashMessenger->hasMessages()) {
        $return['messages'] = $flashMessenger->getMessages();
    }
    return $return;
}

The Forward Plugin

Occasionally, you may want to dispatch additional controllers from within the matched controller – for instance, you might use this approach to build up “widgetized” content. The Forward plugin helps enable this.

For the Forward plugin to work, the controller calling it must be ServiceLocatorAware; otherwise, the plugin will be unable to retrieve a configured and injected instance of the requested controller.

The plugin exposes a single method, dispatch(), which takes two arguments:

  • $name, the name of the controller to invoke. This may be either the fully qualified class name, or an alias defined and recognized by the ServiceManager instance attached to the invoking controller.
  • $params is an optional array of parameters with which to see a RouteMatch object for purposes of this specific request.

Forward returns the results of dispatching the requested controller; it is up to the developer to determine what, if anything, to do with those results. One recommendation is to aggregate them in any return value from the invoking controller.

As an example:

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$foo = $this->forward()->dispatch('foo', array('action' => 'process'));
return array(
    'somekey' => $somevalue,
    'foo'     => $foo,
);

The Layout Plugin

The Layout plugin allows for changing layout templates from within controller actions.

It exposes a single method, setTemplate(), which takes one argument:

  • $template, the name of the template to set.

As an example:

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$this->layout()->setTemplate('layout/newlayout');

It also implements the __invoke magic method, which allows for even easier setting of the template:

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$this->layout('layout/newlayout');

The Params Plugin

The Params plugin allows for accessing parameters in actions from different sources.

It exposes several methods, one for each parameter source:

  • fromFiles($name=null,$default=null), for retrieving all, or one single file. If $name is null, all files will be returned.
  • fromHeader($header=null,$default=null), for retrieving all, or one single header parameter. If $header is null, all header parameters will be returned.
  • fromPost($param=null,$default=null), for retrieving all, or one single post parameter. If $param is null, all post parameters will be returned.
  • fromQuery($param=null,$default=null), for retrieving all, or one single query parameter. If $param is null, all query parameters will be returned.
  • fromRoute($param=null,$default=null), for retrieving all, or one single route parameter. If $param is null, all route parameters will be returned.

It also implements the __invoke magic method, which allows for short circuiting to the fromRoute method:

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$this->params()->fromRoute('param', $default);
// or
$this->params('param', $default);

The Post/Redirect/Get Plugin

When a user sends a POST request (e.g. after submitting a form), their browser will try to protect them from sending the POST again, breaking the back button, causing browser warnings and pop-ups, and sometimes reposting the form. Instead, when receiving a POST, we should store the data in a session container and redirect the user to a GET request.

This plugin can be invoked with two arguments:

  • $redirect, a string containing the redirect location which can either be a named route or a URL, based on the contents of the second parameter.
  • $redirectToUrl, a boolean that when set to TRUE, causes the first parameter to be treated as a URL instead of a route name (this is required when redirecting to a URL instead of a route). This argument defaults to false.

When no arguments are provided, the current matched route is used.

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// Pass in the route/url you want to redirect to after the POST
$prg = $this->prg('/user/register', true);

if ($prg instanceof \Zend\Http\PhpEnvironment\Response) {
    // returned a response to redirect us
    return $prg;
} elseif ($prg === false) {
    // this wasn't a POST request, but there were no params in the flash messenger
    // probably this is the first time the form was loaded
    return array('form' => $myForm);
}

// $prg is an array containing the POST params from the previous request
$form->setData($prg);

// ... your form processing code here

The Redirect Plugin

Redirections are quite common operations within applications. If done manually, you will need to do the following steps:

  • Assemble a url using the router
  • Create and inject a “Location” header into the Response object, pointing to the assembled URL
  • Set the status code of the Response object to one of the 3xx HTTP statuses.

The Redirect plugin does this work for you. It offers two methods:

  • toRoute($route, array $params = array(), array $options = array()): Redirects to a named route, using the provided $params and $options to assembled the URL.
  • toUrl($url): Simply redirects to the given URL.

In each case, the Response object is returned. If you return this immediately, you can effectively short-circuit execution of the request.

Note

This plugin requires that the controller invoking it implements InjectApplicationEvent, and thus has an MvcEvent composed, as it retrieves the router from the event object.

As an example:

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return $this->redirect()->toRoute('login-success');

The Url Plugin

Often you may want to generate URLs from route definitions within your controllers – in order to seed the view, generate headers, etc. While the MvcEvent object composes the router, doing so manually would require this workflow:

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$router = $this->getEvent()->getRouter();
$url    = $router->assemble($params, array('name' => 'route-name'));

The Url helper makes this slightly more convenient:

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$url = $this->url()->fromRoute('route-name', $params);

The fromRoute() method is the only public method defined, and has the following signature:

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public function fromRoute($route, array $params = array(), array $options = array())

Note

This plugin requires that the controller invoking it implements InjectApplicationEvent, and thus has an MvcEvent composed, as it retrieves the router from the event object.

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