1 files changed, 143 insertions, 0 deletions
diff --git a/apps/dav/lib/CalDAV/WebcalCaching/Connection.php b/apps/dav/lib/CalDAV/WebcalCaching/Connection.php
new file mode 100644
index 00000000000..3d12c92c49a
--- /dev/null
+++ b/apps/dav/lib/CalDAV/WebcalCaching/Connection.php
@@ -0,0 +1,143 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCA\DAV\CalDAV\WebcalCaching;
+
+use Exception;
+use GuzzleHttp\RequestOptions;
+use OCP\Http\Client\IClientService;
+use OCP\Http\Client\LocalServerException;
+use OCP\IAppConfig;
+use Psr\Log\LoggerInterface;
+use Sabre\VObject\Reader;
+
+class Connection {
+	public function __construct(
+		private IClientService $clientService,
+		private IAppConfig $config,
+		private LoggerInterface $logger,
+	) {
+	}
+
+	/**
+	 * gets webcal feed from remote server
+	 */
+	public function queryWebcalFeed(array $subscription): ?string {
+		$subscriptionId = $subscription['id'];
+		$url = $this->cleanURL($subscription['source']);
+		if ($url === null) {
+			return null;
+		}
+
+		$allowLocalAccess = $this->config->getValueString('dav', 'webcalAllowLocalAccess', 'no');
+
+		$params = [
+			'nextcloud' => [
+				'allow_local_address' => $allowLocalAccess === 'yes',
+			],
+			RequestOptions::HEADERS => [
+				'User-Agent' => 'Nextcloud Webcal Service',
+				'Accept' => 'text/calendar, application/calendar+json, application/calendar+xml',
+			],
+		];
+
+		$user = parse_url($subscription['source'], PHP_URL_USER);
+		$pass = parse_url($subscription['source'], PHP_URL_PASS);
+		if ($user !== null && $pass !== null) {
+			$params[RequestOptions::AUTH] = [$user, $pass];
+		}
+
+		try {
+			$client = $this->clientService->newClient();
+			$response = $client->get($url, $params);
+		} catch (LocalServerException $ex) {
+			$this->logger->warning("Subscription $subscriptionId was not refreshed because it violates local access rules", [
+				'exception' => $ex,
+			]);
+			return null;
+		} catch (Exception $ex) {
+			$this->logger->warning("Subscription $subscriptionId could not be refreshed due to a network error", [
+				'exception' => $ex,
+			]);
+			return null;
+		}
+
+		$body = $response->getBody();
+
+		$contentType = $response->getHeader('Content-Type');
+		$contentType = explode(';', $contentType, 2)[0];
+		switch ($contentType) {
+			case 'application/calendar+json':
+				try {
+					$jCalendar = Reader::readJson($body, Reader::OPTION_FORGIVING);
+				} catch (Exception $ex) {
+					// In case of a parsing error return null
+					$this->logger->warning("Subscription $subscriptionId could not be parsed", ['exception' => $ex]);
+					return null;
+				}
+				return $jCalendar->serialize();
+
+			case 'application/calendar+xml':
+				try {
+					$xCalendar = Reader::readXML($body);
+				} catch (Exception $ex) {
+					// In case of a parsing error return null
+					$this->logger->warning("Subscription $subscriptionId could not be parsed", ['exception' => $ex]);
+					return null;
+				}
+				return $xCalendar->serialize();
+
+			case 'text/calendar':
+			default:
+				try {
+					$vCalendar = Reader::read($body);
+				} catch (Exception $ex) {
+					// In case of a parsing error return null
+					$this->logger->warning("Subscription $subscriptionId could not be parsed", ['exception' => $ex]);
+					return null;
+				}
+				return $vCalendar->serialize();
+		}
+	}
+
+	/**
+	 * This method will strip authentication information and replace the
+	 * 'webcal' or 'webcals' protocol scheme
+	 *
+	 * @param string $url
+	 * @return string|null
+	 */
+	private function cleanURL(string $url): ?string {
+		$parsed = parse_url($url);
+		if ($parsed === false) {
+			return null;
+		}
+
+		if (isset($parsed['scheme']) && $parsed['scheme'] === 'http') {
+			$scheme = 'http';
+		} else {
+			$scheme = 'https';
+		}
+
+		$host = $parsed['host'] ?? '';
+		$port = isset($parsed['port']) ? ':' . $parsed['port'] : '';
+		$path = $parsed['path'] ?? '';
+		$query = isset($parsed['query']) ? '?' . $parsed['query'] : '';
+		$fragment = isset($parsed['fragment']) ? '#' . $parsed['fragment'] : '';
+
+		$cleanURL = "$scheme://$host$port$path$query$fragment";
+		// parse_url is giving some weird results if no url and no :// is given,
+		// so let's test the url again
+		$parsedClean = parse_url($cleanURL);
+		if ($parsedClean === false || !isset($parsedClean['host'])) {
+			return null;
+		}
+
+		return $cleanURL;
+	}
+}