ExceptionListener.php

<?php declare(strict_types=1);
namespace ApiMhv\Http\EventListener;

use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpFoundation\JsonResponse;
use Symfony\Component\HttpKernel\Event\ExceptionEvent;
use Symfony\Component\HttpKernel\Exception\HttpExceptionInterface;
// use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;

class ExceptionListener
{
    public function onKernelException(ExceptionEvent $event)
    {
        // You get the exception object from the received event
        $exception = $event->getThrowable();
        $message = sprintf(
            '%s with code: %s',
            $exception->getMessage(),
            $exception->getCode()
        );

        // Customize your response object to display the exception details
        // if($contentType)
        $response = new JsonResponse();
        
        $response->setContent($message);
        // HttpExceptionInterface is a special type of exception that
        // holds status code and header details
        if ($exception instanceof HttpExceptionInterface) {
            $response->setStatusCode($exception->getStatusCode());
            $response->headers->replace($exception->getHeaders());
        } elseif ($exception instanceof NotFoundHttpException) {
            $response->setContent('{"errors": "not_found": "'.$message.'"}');
        } else {
            $response->setStatusCode(Response::HTTP_INTERNAL_SERVER_ERROR);
        }

        // sends the modified response object to the event
        $event->setResponse($response);
    }

}

----



<?php declare(strict_types=1);

namespace ApiMhv\Http\EventListener;

use Symfony\Component\HttpFoundation\Response;

class ExceptionResponseStrategyMap extends CoreFoundExceptionResponseStrategy
{
    protected $map = [];

    public function addResponse($key, ExceptionStrategyResponse $response): self
    {
        $map[$key] = $response;
        return self;
    }

    public function getResponse($key, Response $response, \Exception $exception)
    {
        return $map[$key]->handle($response, $exception);
    }
}

----


<?php declare(strict_types=1);

namespace ApiMhv\Http\EventListener;

use Symfony\Component\HttpFoundation\Response;

class NotFoundExceptionResponseStrategy extends CoreFoundExceptionResponseStrategy
{
    public function handle(Response $response, \Exception $exception)
    {
        $response->setHeaders($response, $exception);
        $response->setStatusCode($response, $exception);
        $response->setContent('{"errors": "not_found": "'.$message.'"}');
        return $response;
    }
}



----


<?php declare(strict_types=1);

namespace ApiMhv\Http\EventListener;

use Symfony\Component\HttpFoundation\Response;

abstract class CoreFoundExceptionStrategyResponse
{
    protected function setStatusCode(Response $response, $exception): Response
    {
        $response->setStatusCode($exception->getStatusCode());
        return $response;
    }
    protected function setHeaders(Response $response, $exception): Resonse
    {
        $response->headers->replace($exception->getHeaders());
        return $response;
    }
}

----




<?php declare(strict_types=1);

namespace ApiMhv\Http\EventListener;

use Symfony\Component\HttpFoundation\JsonResponse;

interface ExceptionStrategyResponse
{
    public function handle(JsonResponse $response, $exception);
}

final class ExceptionListener
{
    /**
     * @var YourStrategy
     */
    private $strategy;
    public function __construct(YourStrategy $strategy)
    {
        $this->strategy = $strategy;
     }

    public function onKernelException(ExceptionEvent $event): Response
    {
        $event->setResponse($this->strategy->createResponse($event->getThrowable());
        // $event->stopPropagation();
    }
}

$strategy = new ArrayStrategy(
	new NullStrategy(),
	new NotFoundStrategy(),
	new ServerErrorStrategy()
);

$listener = new ExceptionListner($strategy);


$listener->onKernelEvent(new Exception('whatever'));

$response // would be done 

interface ResponseFailure 
{
    public function createResponse(Response $response, \Throwable $exception): Response;
    public function supportsExecption(\Throwable $execption): bool;
}

final class ClosureStrategy implements YourStrrategy
{
    private $closure;

    public function __construct(\Closure $closure) {}
    public function modifyResponse(Response $response, \Throwable $exception): Response
    {
        $closure = $this->closure;
        return $closure($response, $exception);
    }
}