MirrorMiddleware.php

<?php

namespace UniversityOfCopenhagen\Mirror\Middleware;

use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Message\UriInterface;
use Psr\Http\Server\MiddlewareInterface;
use Psr\Http\Server\RequestHandlerInterface;
use TYPO3\CMS\Core\Cache\Frontend\FrontendInterface;
use TYPO3\CMS\Core\Http\HtmlResponse;
use TYPO3\CMS\Core\Http\RequestFactory;
use TYPO3\CMS\Core\Http\Uri;

final class Mirror implements MiddlewareInterface
{
    public function __construct(
        private RequestFactory $requestFactory,
        private FrontendInterface $cache
    ) {}

    protected static string $host = 'domain.dk';

    protected static array $pathMapping = [
        '/' => 'https://oldcms.domain.dk/',
        '/english' => 'https://oldcms.domain.dk/english'
    ];

    public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
    {
        $uri = $request->getUri();

        if (
            ($uri->getHost() === self::$host || $uri->getHost() === 'www.' . self::$host) &&
            in_array($uri->getPath(), array_keys(self::$pathMapping))
        ) {
            $body = $this->cache->get(sha1((string) $uri));
            if ($body === false) {
                $body = $this->fetch(
                    new Uri(self::$pathMapping[$uri->getPath()])
                );
                $this->cache->set(
                    sha1((string) $uri),
                    $body,
                    [],
                    (60*60*24)
                );
            }

            return new HtmlResponse($body);
        } else {
            return $handler->handle($request);
        }
    }

    private function fetch(UriInterface $uri): string
    {
        $response = $this->requestFactory->request(
            uri: (string) $uri
        );
        return $response->getBody()->getContents();
    }
}