Php-Template/src/Controllers/SwaggerController.php

<?php

declare(strict_types=1);

namespace Siteworxpro\App\Controllers;

use Nyholm\Psr7\Response;
use Nyholm\Psr7\ServerRequest;
use OpenApi\Generator;
use Psr\Http\Message\ResponseInterface;

class SwaggerController extends Controller
{
    public function get(ServerRequest $request): ResponseInterface
    {
        $openapi = new Generator()->generate([
            __DIR__ . '/../Controllers',
            __DIR__ . '/../Models',
        ]);

        $response = new Response();

        if (
            $request->getHeaderLine('Accept') === 'application/json' ||
            str_contains($request->getUri()->getPath(), '.json')
        ) {
            $response->getBody()->write($openapi->toJson());
            return $response->withHeader('Content-Type', 'application/json');
        }

        $response->getBody()->write($openapi->toYaml());
        return $response->withHeader('Content-Type', 'application/x-yaml');
    }
}