1 files changed, 137 insertions, 0 deletions
diff --git a/lib/private/OCM/OCMDiscoveryService.php b/lib/private/OCM/OCMDiscoveryService.php
new file mode 100644
index 00000000000..ac9bf2a3965
--- /dev/null
+++ b/lib/private/OCM/OCMDiscoveryService.php
@@ -0,0 +1,137 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2023, Maxence Lange <maxence@artificial-owl.com>
+ *
+ * @author Maxence Lange <maxence@artificial-owl.com>
+ *
+ * @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\OCM;
+
+use JsonException;
+use OCP\AppFramework\Http;
+use OCP\Http\Client\IClientService;
+use OCP\ICache;
+use OCP\ICacheFactory;
+use OCP\IConfig;
+use OCP\OCM\Exceptions\OCMProviderException;
+use OCP\OCM\IOCMDiscoveryService;
+use OCP\OCM\IOCMProvider;
+use Psr\Log\LoggerInterface;
+
+/**
+ * @since 28.0.0
+ */
+class OCMDiscoveryService implements IOCMDiscoveryService {
+	private ICache $cache;
+	private array $supportedAPIVersion =
+		[
+			'1.0-proposal1',
+			'1.0',
+			'1.1'
+		];
+
+	public function __construct(
+		ICacheFactory $cacheFactory,
+		private IClientService $clientService,
+		private IConfig $config,
+		private IOCMProvider $provider,
+		private LoggerInterface $logger,
+	) {
+		$this->cache = $cacheFactory->createDistributed('ocm-discovery');
+	}
+
+
+	/**
+	 * @param string $remote
+	 * @param bool $skipCache
+	 *
+	 * @return IOCMProvider
+	 * @throws OCMProviderException
+	 */
+	public function discover(string $remote, bool $skipCache = false): IOCMProvider {
+		$remote = rtrim($remote, '/');
+
+		if (!$skipCache) {
+			try {
+				$this->provider->import(json_decode($this->cache->get($remote) ?? '', true, 8, JSON_THROW_ON_ERROR) ?? []);
+				if ($this->supportedAPIVersion($this->provider->getApiVersion())) {
+					return $this->provider; // if cache looks valid, we use it
+				}
+			} catch (JsonException|OCMProviderException $e) {
+				// we ignore cache on issues
+			}
+		}
+
+		$client = $this->clientService->newClient();
+		try {
+			$response = $client->get(
+				$remote . '/ocm-provider/',
+				[
+					'timeout' => 10,
+					'verify' => !$this->config->getSystemValueBool('sharing.federation.allowSelfSignedCertificates'),
+					'connect_timeout' => 10,
+				]
+			);
+
+			if ($response->getStatusCode() === Http::STATUS_OK) {
+				$body = $response->getBody();
+				// update provider with data returned by the request
+				$this->provider->import(json_decode($body, true, 8, JSON_THROW_ON_ERROR) ?? []);
+				$this->cache->set($remote, $body, 60 * 60 * 24);
+			}
+		} catch (JsonException|OCMProviderException $e) {
+			throw new OCMProviderException('data returned by remote seems invalid - ' . ($body ?? ''));
+		} catch (\Exception $e) {
+			$this->logger->warning('error while discovering ocm provider', [
+				'exception' => $e,
+				'remote' => $remote
+			]);
+			throw new OCMProviderException('error while requesting remote ocm provider');
+		}
+
+		if (!$this->supportedAPIVersion($this->provider->getApiVersion())) {
+			throw new OCMProviderException('API version not supported');
+		}
+
+		return $this->provider;
+	}
+
+	/**
+	 * Check the version from remote is supported.
+	 * The minor version of the API will be ignored:
+	 *    1.0.1 is identified as 1.0
+	 *
+	 * @param string $version
+	 *
+	 * @return bool
+	 */
+	private function supportedAPIVersion(string $version): bool {
+		$dot1 = strpos($version, '.');
+		$dot2 = strpos($version, '.', $dot1 + 1);
+
+		if ($dot2 > 0) {
+			$version = substr($version, 0, $dot2);
+		}
+
+		return (in_array($version, $this->supportedAPIVersion));
+	}
+}