TIP: How to Immitate init() inside Controllers in ZF2

For ZF1 users there is the convenient init() method that you can use on every controller but in ZF2 the init() does not exist anymore for design purposes.

There are sometimes advantages though of having an init() type functionality inside the constructor. For example, checking the ACL.

A little background. One of the problems of working directly inside the constructor in ZF2 is because the dispatch event has not occured yet, you cannot grab important objects like controller plugins so doing the bellow wont work.

// assume we are inside a controller
public function __construct()
{
    $this->redirect()->toRoute('someroute'); // I will not work!
}

Solution:
There are tons of ways to do this but I find this a little easier:

class IndexController extends AbstractActionController
{
    public function __construct()
    {
        $resource = $this->getResourceId();
        $this->getEventManager()->attach('dispatch', function ($e) use ($resource) {
            $controller = $e->getTarget(); // this will return your controller instance

            // there is no ACL plugin ok! I created that!
            if (!$controller->acl()->isAllowed('me', $resource)) {
                // now i can use controller plugins!
                return $controller->redirect()->toRoute('authenticate');
            }     
        });
    }

    public function getResourceId()
    {
        return 'some_resource';
    }
}

Reference:
http://mwop.net/blog/2012-07-30-the-new-init.html