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<?php
declare(strict_types=1);
/**
* @copyright Copyright (c) 2022 Julius Härtl <jus@bitgrid.net>
*
* @author Julius Härtl <jus@bitgrid.net>
*
* @license GNU AGPL version 3 or any later version
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
namespace OC\Collaboration\Reference;
use Fusonic\OpenGraph\Consumer;
use GuzzleHttp\Exception\GuzzleException;
use GuzzleHttp\Psr7\LimitStream;
use GuzzleHttp\Psr7\Utils;
use OC\Security\RateLimiting\Exception\RateLimitExceededException;
use OC\Security\RateLimiting\Limiter;
use OC\SystemConfig;
use OCP\Collaboration\Reference\IReference;
use OCP\Collaboration\Reference\IReferenceProvider;
use OCP\Collaboration\Reference\Reference;
use OCP\Files\AppData\IAppDataFactory;
use OCP\Files\NotFoundException;
use OCP\Http\Client\IClientService;
use OCP\IRequest;
use OCP\IURLGenerator;
use OCP\IUserSession;
use Psr\Log\LoggerInterface;
class LinkReferenceProvider implements IReferenceProvider {
public const MAX_PREVIEW_SIZE = 1024 * 1024;
public const ALLOWED_CONTENT_TYPES = [
'image/png',
'image/jpg',
'image/jpeg',
'image/gif',
'image/svg+xml',
'image/webp'
];
public function __construct(
private IClientService $clientService,
private LoggerInterface $logger,
private SystemConfig $systemConfig,
private IAppDataFactory $appDataFactory,
private IURLGenerator $urlGenerator,
private Limiter $limiter,
private IUserSession $userSession,
private IRequest $request,
) {
}
public function matchReference(string $referenceText): bool {
if ($this->systemConfig->getValue('reference_opengraph', true) !== true) {
return false;
}
return (bool)preg_match(IURLGenerator::URL_REGEX, $referenceText);
}
public function resolveReference(string $referenceText): ?IReference {
if ($this->matchReference($referenceText)) {
$reference = new Reference($referenceText);
$this->fetchReference($reference);
return $reference;
}
return null;
}
private function fetchReference(Reference $reference): void {
try {
$user = $this->userSession->getUser();
if ($user) {
$this->limiter->registerUserRequest('opengraph', 10, 120, $user);
} else {
$this->limiter->registerAnonRequest('opengraph', 10, 120, $this->request->getRemoteAddress());
}
} catch (RateLimitExceededException $e) {
return;
}
$client = $this->clientService->newClient();
try {
$headResponse = $client->head($reference->getId(), [ 'timeout' => 10 ]);
} catch (\Exception $e) {
$this->logger->debug('Failed to perform HEAD request to get target metadata', ['exception' => $e]);
return;
}
$linkContentLength = $headResponse->getHeader('Content-Length');
if (is_numeric($linkContentLength) && (int) $linkContentLength > 5 * 1024 * 1024) {
$this->logger->debug('[Head] Skip resolving links pointing to content length > 5 MiB');
return;
}
$linkContentType = $headResponse->getHeader('Content-Type');
$expectedContentType = 'text/html';
$suffixedExpectedContentType = $expectedContentType . ';';
$startsWithSuffixed = str_starts_with($linkContentType, $suffixedExpectedContentType);
// check the header begins with the expected content type
if ($linkContentType !== $expectedContentType && !$startsWithSuffixed) {
$this->logger->debug('Skip resolving links pointing to content type that is not "text/html"');
return;
}
try {
$response = $client->get($reference->getId(), [ 'timeout' => 10, 'stream' => true ]);
} catch (\Exception $e) {
$this->logger->debug('Failed to fetch link for obtaining open graph data', ['exception' => $e]);
return;
}
$body = $response->getBody();
if (is_resource($body)) {
$responseContent = fread($body, 5 * 1024 * 1024);
if (!feof($body)) {
$this->logger->debug('[Get] Skip resolving links pointing to content length > 5 MiB');
return;
}
} else {
$this->logger->error('[Get] Impossible to check content length');
return;
}
// OpenGraph handling
$consumer = new Consumer();
$consumer->useFallbackMode = true;
$object = $consumer->loadHtml($responseContent);
$reference->setUrl($reference->getId());
if ($object->title) {
$reference->setTitle($object->title);
}
if ($object->description) {
$reference->setDescription($object->description);
}
if ($object->images) {
try {
$host = parse_url($object->images[0]->url, PHP_URL_HOST);
if ($host === false || $host === null) {
$this->logger->warning('Could not detect host of open graph image URI for ' . $reference->getId());
} else {
$appData = $this->appDataFactory->get('core');
try {
$folder = $appData->getFolder('opengraph');
} catch (NotFoundException $e) {
$folder = $appData->newFolder('opengraph');
}
$response = $client->get($object->images[0]->url, ['timeout' => 10]);
$contentType = $response->getHeader('Content-Type');
$contentLength = $response->getHeader('Content-Length');
if (in_array($contentType, self::ALLOWED_CONTENT_TYPES, true) && $contentLength < self::MAX_PREVIEW_SIZE) {
$stream = Utils::streamFor($response->getBody());
$bodyStream = new LimitStream($stream, self::MAX_PREVIEW_SIZE, 0);
$reference->setImageContentType($contentType);
$folder->newFile(md5($reference->getId()), $bodyStream->getContents());
$reference->setImageUrl($this->urlGenerator->linkToRouteAbsolute('core.Reference.preview', ['referenceId' => md5($reference->getId())]));
}
}
} catch (GuzzleException $e) {
$this->logger->info('Failed to fetch and store the open graph image for ' . $reference->getId(), ['exception' => $e]);
} catch (\Throwable $e) {
$this->logger->error('Failed to fetch and store the open graph image for ' . $reference->getId(), ['exception' => $e]);
}
}
}
public function getCachePrefix(string $referenceId): string {
return $referenceId;
}
public function getCacheKey(string $referenceId): ?string {
return null;
}
}
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