Is there a way to make Symfony controller return nothing?

Question

I use Symfony 6.1 and PHP 8.1. I'm wondering if there is a way to make a Symfony controller return nothing. The why is I'm using Botman and unfortunalty it send itself a response to the client... So I need to make my controller to return nothing.

/**
 * @param Request $request
 *
 * @return Response
 */
#[Route('/botman', methods: 'POST')]
public function test(Request $request): Response
{
    DriverManager::loadDriver(WebDriver::class);
    $adapter = new FilesystemAdapter();

    $botman = BotManFactory::create([], new SymfonyCache($adapter), $request);

    $botman->hears('hello', static function (BotMan $bot) {
        $bot->reply('Yoooooo'); //<- Send a response to the client
    });

    $botman->fallback(static function (BotMan $bot) {
        $bot->reply('try again'); //<- Send a response to the client
    });

    $botman->listen(); // Launch the maching callback

    return new Response(); //Crash because a response have already been sent
}

This is what I get on my browser inspector.

{
    "status": 200,
    "messages": [
        {
            "type": "text",
            "text": "try again",
            "attachment": null,
            "additionalParameters": []
        }
    ]
}{
    "type": "https:\/\/tools.ietf.org\/html\/rfc2616#section-10",
    "title": "An error occurred",
    "status": 500,
    "detail": "Warning: Cannot modify header information - headers already sent by (output started at C:\\Users\\cimba\\Documents\\botman\\vendor\\symfony\\http-foundation\\Response.php:1265)",
    "class": "ErrorException",
    "trace": [...]
}

The only solution I have is to exit(); or die(); instead of the return but I it's not clean for production... Maybe there is a way to avoid BotMan to send it's response or to tell Symfony that I want my controller to return nothing (because botman does without symfony).

No if i return null Symfony send an error `The controller must return a \"Symfony\\Component\\HttpFoundation\\Response\" object but it returned null.` — Loicyeu, Aug 04 '22 at 15:43
Try changing the function `test`'s return type to include a question mark before Response like this `public function test(Request $request): ?Response`. This means the function can return a Response object or null. — mark_b, Aug 04 '22 at 15:46
Still the same error. The problem is that Symfony refuses `null` as valid return value — Loicyeu, Aug 04 '22 at 15:57
Looks like the driver itself calls `Response::send()` so it flushes and terminates the request. I'm afraid you'll have to fudge the driver so you can hook into the symfony event system. Probably listening to the [`kernel.view`](https://github.com/symfony/symfony/blob/8a6fa52d6bbe5134e433d6dcfd2feede5916cce1/src/Symfony/Component/HttpKernel/HttpKernel.php#L166) event should work? I'd love to hear the solution. — msg, Aug 04 '22 at 16:16

Cerad · Accepted Answer · 2022-08-04T19:54:51.470

I have not used BotMan myself so this is a bit of a guess. You might try seeing if there a BotMan bundle because I suspect that if such a bundle exists then it would deal with this sort of thing as well as eliminating the need to use the static factory method.

However returning an empty response (which means no headers or content) might do the trick as well.

# src/Http/EmptyResponse.php
namespace App\Http;

use Symfony\Component\HttpFoundation\Response;

class EmptyResponse extends Response
{
    public function send(): static
    {
        // Skip sending headers and content
        // $this->sendHeaders();
        // $this->sendContent();

        // Keep some standard Symfony magic
        if (\function_exists('fastcgi_finish_request')) {
            fastcgi_finish_request();
        } elseif (\function_exists('litespeed_finish_request')) {
            litespeed_finish_request();
        } elseif (!\in_array(\PHP_SAPI, ['cli', 'phpdbg'], true)) {
            static::closeOutputBuffers(0, true);
        }

        return $this;
    }
}

Then just return new EmptyResponse(); in your controller.

I tested this in a regular controller action and Symfony did not complain. But again I have no BotMan setup to test against. Be curious to see if it works.

Is there a way to make Symfony controller return nothing?

1 Answers1