Modify ViewModel after controller dispatch - php

Question

I'm trying to intercept the ViewModel, prior to it being rendered, and add it to another 'parent' view model - much like the way that the ZF2 layout wraps around the controllers returned content.
The simple (working) way to do this would be in each controller action.
public function dashboardAction() {
$dashboardContent = new ViewModel(array('foo' => 'bar'));
$parent = new ViewModel();
$parent->setTemplate('foo/bar/parent-template');
$parent->addChild($dashboardContent, 'content');
return $parent;
}
This works as expected and the 'child' view is correctly nested within the 'parent' in the final output.
As I have a number of controllers/actions that should all behave in the same way (resolved via their route name); I was hoping to encapsulate this in an event listener.
public function onBootstrap(MvcEvent $event)
{
$application = $event->getApplication();
$eventManager = $application->getEventManager();
$eventManager->attach(MvcEvent::EVENT_DISPATCH, array($this, 'addUserAccountLayout'), -100);
}
public function addUserAccountLayout(EventInterface $event)
{
$routeMatch = $event->getRouteMatch();
$controller = $event->getTarget();
$result = $event->getResult();
if (! $result instanceof ViewModel || $result instanceof JsonModel) {
return;
}
if (! $routeMatch instanceof RouteMatch || 0 !== strpos($routeMatch->getMatchedRouteName(), 'zfcuser') || $result->terminate()) {
return;
}
$application = $event->getApplication();
$serviceManager = $application->getServiceManager();
$accountService = $serviceManager->get('JobboardUser\Service\AccountService');
$user = $accountService->getCurrentUser();
$parent = new ViewModel();
$parent->setVariables(compact('user'));
$parent->setTemplate('jobboard-user/widget/user-account');
$parent->addChild($result, 'content');
$event->setResult($parent);
}
This however is not working; the normal view is rendered (without the parent). My guess is because I am either not using the correct event or event priority OR $event->setResult($view) is not the correct way to assign the result.
How can I modify and then re-assign the view from within an event listener?

Answer 1

I can't offer an explanation as to 'why', but a priority of -10 seems to be the sweet spot to get this working with the code you already have.
I do have one suggestion though, instead of listening to every dispatch event triggered by every module controller and then having to check if it's a zfcuser route, you can instead make use of the shared events manager to listen specifically to the ZfcUser controller you're interested in ...
public function onBootstrap(MvcEvent $event)
{
$application = $event->getApplication();
$eventManager = $application->getEventManager();
$sharedEvents = $eventManager->getSharedManager();
$sharedEvents->attach(
'ZfcUser\Controller\UserController', // controller FQCN to listen to
MvcEvent::EVENT_DISPATCH,
array($this, 'addUserAccountLayout'),
-10
);
}
If you do that, you can remove the routematch check 0 !== strpos($routeMatch->getMatchedRouteName(), 'zfcuser') in your callback entirely.

Answer 2

It's been a little while since I asked this; however I did find the solution I was after. It was indeed related to how the new ViewModel is attached back to the MvcEvent.
Previously I had tried to set the event's result property with no luck :
$mvcEvent->setResult($myNewViewModel);
The key was to first fetch the MvcEvent's own view model and then attach my custom one to it as a child.
$mvcEvent->getViewModel()->addChild($myNewViewModel, 'content');
I've also incorporated the point that #Crisp made regarding the event managers target. Previously, I was attaching to the main application dispatch event meaning that the listener would be called on every dispatch event.
I now specifically target the controllers I want to listen to.
$eventManager->attach(array(
'JobboardUser\Controller\AccountController',
'JobboardUser\Controller\ProfileController'
),
MvcEvent::EVENT_DISPATCH,
array($this, 'addUserAccountLayout'),
-80
);
The final listener code looks like this
public function addUserAccountLayout(EventInterface $event)
{
$result = $event->getResult();
if (! $result instanceof ViewModel || $result instanceof JsonModel) {
return;
}
$application = $event->getApplication();
$serviceManager = $application->getServiceManager();
$accountService = $serviceManager->get('JobboardUser\Service\AccountService');
$currentUser = $accountService->getCurrentUser();
$layout = new ViewModel();
$layout->setVariables(array('user' => $currentUser));
$layout->setTemplate('jobboard-user/widget/user-account');
$layout->addChild($result, 'userContent');
$event->getViewModel()->addChild($layout, 'content');
}