custom error handling without try/except in php Slim framework - php

Question

Using php and the Slim Framework, is there a way I can set up the error-handler so my custom Exceptions that can automatically trigger the desired HTTP response, without forcing me to catch all the different exception types?
I know such examples from my projects with python Flask, but not the php equivalent.
For example, regardless where the exception is thrown in the code, I want my custom BadCustomerDataException() to trigger a HTTP 400 response, and the WaitingForResourceException() to trigger a 423 response, and the FaultyServerIsDeadAgainException() to trigger a 500 response.
Currently I'm using Slim version 3, with a planned update to version 4.

Answer 1

In Slim 4 you can add a custom error handler to the ErrorMiddleware. You can also add your own Middleware before the ErrorMiddleware to catch and map your own exceptions:
Example
<?php
use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Server\RequestHandlerInterface;
use Slim\Exception\HttpNotFoundException;
use Slim\Middleware\ErrorMiddleware;
use Slim\Psr7\Response;
// ...
// HttpNotFound Middleware
$app->add(function (
ServerRequestInterface $request,
RequestHandlerInterface $handler
) {
try {
return $handler->handle($request);
} catch (HttpNotFoundException $httpException) {
$response = (new Response())->withStatus(404);
$response->getBody()->write('404 Not found');
return $response;
}
});
$app->add(ErrorMiddleware::class);
Source