1 files changed, 262 insertions, 0 deletions
diff --git a/lib/private/Collaboration/Reference/ReferenceManager.php b/lib/private/Collaboration/Reference/ReferenceManager.php
new file mode 100644
index 00000000000..9287b66b2a2
--- /dev/null
+++ b/lib/private/Collaboration/Reference/ReferenceManager.php
@@ -0,0 +1,262 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2022 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OC\Collaboration\Reference;
+
+use OC\AppFramework\Bootstrap\Coordinator;
+use OC\Collaboration\Reference\File\FileReferenceProvider;
+use OCP\Collaboration\Reference\IDiscoverableReferenceProvider;
+use OCP\Collaboration\Reference\IPublicReferenceProvider;
+use OCP\Collaboration\Reference\IReference;
+use OCP\Collaboration\Reference\IReferenceManager;
+use OCP\Collaboration\Reference\IReferenceProvider;
+use OCP\Collaboration\Reference\Reference;
+use OCP\ICache;
+use OCP\ICacheFactory;
+use OCP\IConfig;
+use OCP\IURLGenerator;
+use OCP\IUserSession;
+use Psr\Container\ContainerInterface;
+use Psr\Log\LoggerInterface;
+use Throwable;
+
+class ReferenceManager implements IReferenceManager {
+	public const CACHE_TTL = 3600;
+
+	/** @var IReferenceProvider[]|null */
+	private ?array $providers = null;
+	private ICache $cache;
+
+	public function __construct(
+		private LinkReferenceProvider $linkReferenceProvider,
+		ICacheFactory $cacheFactory,
+		private Coordinator $coordinator,
+		private ContainerInterface $container,
+		private LoggerInterface $logger,
+		private IConfig $config,
+		private IUserSession $userSession,
+	) {
+		$this->cache = $cacheFactory->createDistributed('reference');
+	}
+
+	/**
+	 * Extract a list of URLs from a text
+	 *
+	 * @return string[]
+	 */
+	public function extractReferences(string $text): array {
+		preg_match_all(IURLGenerator::URL_REGEX, $text, $matches);
+		$references = $matches[0] ?? [];
+		return array_map(function ($reference) {
+			return trim($reference);
+		}, $references);
+	}
+
+	/**
+	 * Try to get a cached reference object from a reference string
+	 */
+	public function getReferenceFromCache(string $referenceId, bool $public = false, string $sharingToken = ''): ?IReference {
+		$matchedProvider = $this->getMatchedProvider($referenceId, $public);
+
+		if ($matchedProvider === null) {
+			return null;
+		}
+
+		$cacheKey = $this->getFullCacheKey($matchedProvider, $referenceId, $public, $sharingToken);
+		return $this->getReferenceByCacheKey($cacheKey);
+	}
+
+	/**
+	 * Try to get a cached reference object from a full cache key
+	 */
+	public function getReferenceByCacheKey(string $cacheKey): ?IReference {
+		$cached = $this->cache->get($cacheKey);
+		if ($cached) {
+			return Reference::fromCache($cached);
+		}
+
+		return null;
+	}
+
+	/**
+	 * Get a reference object from a reference string with a matching provider
+	 * Use a cached reference if possible
+	 */
+	public function resolveReference(string $referenceId, bool $public = false, $sharingToken = ''): ?IReference {
+		$matchedProvider = $this->getMatchedProvider($referenceId, $public);
+
+		if ($matchedProvider === null) {
+			return null;
+		}
+
+		$cacheKey = $this->getFullCacheKey($matchedProvider, $referenceId, $public, $sharingToken);
+		$cached = $this->cache->get($cacheKey);
+		if ($cached) {
+			return Reference::fromCache($cached);
+		}
+
+		$reference = null;
+		if ($public && $matchedProvider instanceof IPublicReferenceProvider) {
+			$reference = $matchedProvider->resolveReferencePublic($referenceId, $sharingToken);
+		} elseif ($matchedProvider instanceof IReferenceProvider) {
+			$reference = $matchedProvider->resolveReference($referenceId);
+		}
+		if ($reference) {
+			$cachePrefix = $matchedProvider->getCachePrefix($referenceId);
+			if ($cachePrefix !== '') {
+				// If a prefix is used we set an additional key to know when we need to delete by prefix during invalidateCache()
+				$this->cache->set('hasPrefix-' . md5($cachePrefix), true, self::CACHE_TTL);
+			}
+			$this->cache->set($cacheKey, Reference::toCache($reference), self::CACHE_TTL);
+			return $reference;
+		}
+
+		return null;
+	}
+
+	/**
+	 * Try to match a reference string with all the registered providers
+	 * Fallback to the link reference provider (using OpenGraph)
+	 *
+	 * @return IReferenceProvider|IPublicReferenceProvider|null the first matching provider
+	 */
+	private function getMatchedProvider(string $referenceId, bool $public): null|IReferenceProvider|IPublicReferenceProvider {
+		$matchedProvider = null;
+		foreach ($this->getProviders() as $provider) {
+			if ($public && !($provider instanceof IPublicReferenceProvider)) {
+				continue;
+			}
+			$matchedProvider = $provider->matchReference($referenceId) ? $provider : null;
+			if ($matchedProvider !== null) {
+				break;
+			}
+		}
+
+		if ($matchedProvider === null && $this->linkReferenceProvider->matchReference($referenceId)) {
+			$matchedProvider = $this->linkReferenceProvider;
+		}
+
+		return $matchedProvider;
+	}
+
+	/**
+	 * Get a hashed full cache key from a key and prefix given by a provider
+	 */
+	private function getFullCacheKey(IReferenceProvider $provider, string $referenceId, bool $public, string $sharingToken): string {
+		if ($public && !($provider instanceof IPublicReferenceProvider)) {
+			throw new \RuntimeException('Provider doesn\'t support public lookups');
+		}
+		$cacheKey = $public
+			? $provider->getCacheKeyPublic($referenceId, $sharingToken)
+			: $provider->getCacheKey($referenceId);
+		return md5($provider->getCachePrefix($referenceId)) . (
+			$cacheKey !== null ? ('-' . md5($cacheKey)) : ''
+		);
+	}
+
+	/**
+	 * Remove a specific cache entry from its key+prefix
+	 */
+	public function invalidateCache(string $cachePrefix, ?string $cacheKey = null): void {
+		if ($cacheKey === null) {
+			// clear might be a heavy operation, so we only do it if there have actually been keys set
+			if ($this->cache->remove('hasPrefix-' . md5($cachePrefix))) {
+				$this->cache->clear(md5($cachePrefix));
+			}
+
+			return;
+		}
+
+		$this->cache->remove(md5($cachePrefix) . '-' . md5($cacheKey));
+	}
+
+	/**
+	 * @return IReferenceProvider[]
+	 */
+	public function getProviders(): array {
+		if ($this->providers === null) {
+			$context = $this->coordinator->getRegistrationContext();
+			if ($context === null) {
+				return [];
+			}
+
+			$this->providers = array_filter(array_map(function ($registration): ?IReferenceProvider {
+				try {
+					/** @var IReferenceProvider $provider */
+					$provider = $this->container->get($registration->getService());
+				} catch (Throwable $e) {
+					$this->logger->error('Could not load reference provider ' . $registration->getService() . ': ' . $e->getMessage(), [
+						'exception' => $e,
+					]);
+					return null;
+				}
+
+				return $provider;
+			}, $context->getReferenceProviders()));
+
+			$this->providers[] = $this->container->get(FileReferenceProvider::class);
+		}
+
+		return $this->providers;
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function getDiscoverableProviders(): array {
+		// preserve 0 based index to avoid returning an object in data responses
+		return array_values(
+			array_filter($this->getProviders(), static function (IReferenceProvider $provider) {
+				return $provider instanceof IDiscoverableReferenceProvider;
+			})
+		);
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function touchProvider(string $userId, string $providerId, ?int $timestamp = null): bool {
+		$providers = $this->getDiscoverableProviders();
+		$matchingProviders = array_filter($providers, static function (IDiscoverableReferenceProvider $provider) use ($providerId) {
+			return $provider->getId() === $providerId;
+		});
+		if (!empty($matchingProviders)) {
+			if ($timestamp === null) {
+				$timestamp = time();
+			}
+
+			$configKey = 'provider-last-use_' . $providerId;
+			$this->config->setUserValue($userId, 'references', $configKey, (string)$timestamp);
+			return true;
+		}
+		return false;
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function getUserProviderTimestamps(): array {
+		$user = $this->userSession->getUser();
+		if ($user === null) {
+			return [];
+		}
+		$userId = $user->getUID();
+		$keys = $this->config->getUserKeys($userId, 'references');
+		$prefix = 'provider-last-use_';
+		$keys = array_filter($keys, static function (string $key) use ($prefix) {
+			return str_starts_with($key, $prefix);
+		});
+		$timestamps = [];
+		foreach ($keys as $key) {
+			$providerId = substr($key, strlen($prefix));
+			$timestamp = (int)$this->config->getUserValue($userId, 'references', $key);
+			$timestamps[$providerId] = $timestamp;
+		}
+		return $timestamps;
+	}
+}