Using middleware within event listeners

Within the MVC workflow, you can use middleware within event listeners by converting the request and response objects composed in the event to PSR-7 equivalents using zend-psr7bridge.

As an example, consider the following AuthorizationMiddleware:

namespace Application\Middleware;

use Psr\Http\Message\ServerRequestInterface as RequestInterface;
use Psr\Http\Message\ResponseInterface;

class AuthorizationMiddleware
    public function __invoke(RequestInterface $request, ResponseInterface $response, callable $next = null)
        // handle authorization here...

Since the request and response composed in MvcEvent instances are specifically from zend-http, we will use zend-psr7bridge to convert them to PSR-7 equivalents. As an example, consider the following module declaration, which registers a dispatch listener to invoke the above middleware:

namespace Application;

use Psr\Http\Message\ResponseInterface;
use Zend\Psr7Bridge\Psr7ServerRequest;
use Zend\Psr7Bridge\Psr7Response;

class Module
    public function onBootstrap($e)
        $app          = $e->getApplication();
        $eventManager = $app->getEventManager();
        $services     = $app->getServiceManager();

        $eventManager->attach($e::EVENT_DISPATCH, function ($e) use ($services) {
            $request  = Psr7ServerRequest::fromZend($e->getRequest());
            $response = Psr7Response::fromZend($e->getResponse());
            $done     = function ($request, $response) {

            $result   = ($services->get(Middleware\AuthorizationMiddleware::class))(

            if ($result) {
                return Psr7Response::toZend($result);
        }, 2);

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