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<?php
declare(strict_types=1);
/**
* SPDX-FileCopyrightText: 2022 Nextcloud GmbH and Nextcloud contributors
* SPDX-License-Identifier: AGPL-3.0-or-later
*/
namespace OCP\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\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;
/**
* @since 29.0.0
*/
class LinkReferenceProvider implements IReferenceProvider, IPublicReferenceProvider {
/**
* for image size and webpage header
* @since 29.0.0
*/
public const MAX_CONTENT_LENGTH = 5 * 1024 * 1024;
/**
* @since 29.0.0
*/
public const ALLOWED_CONTENT_TYPES = [
'image/png',
'image/jpg',
'image/jpeg',
'image/gif',
'image/svg+xml',
'image/webp'
];
/**
* @since 29.0.0
*/
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,
) {
}
/**
* @inheritDoc
* @since 29.0.0
*/
public function matchReference(string $referenceText): bool {
if ($this->systemConfig->getValue('reference_opengraph', true) !== true) {
return false;
}
return (bool)preg_match(IURLGenerator::URL_REGEX, $referenceText);
}
/**
* @inheritDoc
* @since 29.0.0
*/
public function resolveReference(string $referenceText): ?IReference {
if ($this->matchReference($referenceText)) {
$reference = new Reference($referenceText);
$this->fetchReference($reference);
return $reference;
}
return null;
}
/**
* @inheritDoc
* @since 30.0.0
*/
public function resolveReferencePublic(string $referenceText, string $sharingToken): ?IReference {
return $this->resolveReference($referenceText);
}
/**
* Populates the reference with OpenGraph data
*
* @param Reference $reference
* @since 29.0.0
*/
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 > self::MAX_CONTENT_LENGTH) {
$this->logger->debug('Skip resolving links pointing to content length > 5 MiB');
return;
}
$linkContentType = $headResponse->getHeader('Content-Type');
$expectedContentTypeRegex = '/^text\/html;?/i';
// check the header begins with the expected content type
if (!preg_match($expectedContentTypeRegex, $linkContentType)) {
$this->logger->debug('Skip resolving links pointing to content type that is not "text/html"');
return;
}
try {
$response = $client->get($reference->getId(), [ 'timeout' => 10 ]);
} catch (\Exception $e) {
$this->logger->debug('Failed to fetch link for obtaining open graph data', ['exception' => $e]);
return;
}
$responseBody = (string)$response->getBody();
// OpenGraph handling
$consumer = new Consumer();
$consumer->useFallbackMode = true;
$object = $consumer->loadHtml($responseBody);
$reference->setUrl($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());
return;
}
$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_CONTENT_LENGTH) {
$stream = Utils::streamFor($response->getBody());
$bodyStream = new LimitStream($stream, self::MAX_CONTENT_LENGTH, 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]);
}
}
}
/**
* @inheritDoc
* @since 29.0.0
*/
public function getCachePrefix(string $referenceId): string {
return $referenceId;
}
/**
* @inheritDoc
* @since 29.0.0
*/
public function getCacheKey(string $referenceId): ?string {
return null;
}
/**
* @inheritDoc
* @since 30.0.0
*/
public function getCacheKeyPublic(string $referenceId, string $sharingToken): ?string {
return null;
}
}
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