Merge pull request #24702 from nextcloud/enhancement/well-known-handler-api

Add well known handlers API

1 files changed, 124 insertions, 0 deletions

diff --git a/lib/private/Http/WellKnown/RequestManager.php b/lib/private/Http/WellKnown/RequestManager.php
new file mode 100644
index 00000000000..d17ea5c671b
--- /dev/null
+++ b/lib/private/Http/WellKnown/RequestManager.php
@@ -0,0 +1,124 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * @copyright 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @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\Http\WellKnown;
+
+use OC\AppFramework\Bootstrap\Coordinator;
+use OCP\AppFramework\QueryException;
+use OCP\Http\WellKnown\IHandler;
+use OCP\Http\WellKnown\IRequestContext;
+use OCP\Http\WellKnown\IResponse;
+use OCP\Http\WellKnown\JrdResponse;
+use OCP\IRequest;
+use OCP\IServerContainer;
+use Psr\Log\LoggerInterface;
+use RuntimeException;
+use function array_reduce;
+
+class RequestManager {
+
+	/** @var Coordinator */
+	private $coordinator;
+
+	/** @var IServerContainer */
+	private $container;
+
+	/** @var LoggerInterface */
+	private $logger;
+
+	public function __construct(Coordinator $coordinator,
+								IServerContainer $container,
+								LoggerInterface $logger) {
+		$this->coordinator = $coordinator;
+		$this->container = $container;
+		$this->logger = $logger;
+	}
+
+	public function process(string $service, IRequest $request): ?IResponse {
+		$handlers = $this->loadHandlers();
+		$context = new class($request) implements IRequestContext {
+			/** @var IRequest */
+			private $request;
+
+			public function __construct(IRequest $request) {
+				$this->request = $request;
+			}
+
+			public function getHttpRequest(): IRequest {
+				return $this->request;
+			}
+		};
+
+		$subject = $request->getParam('resource');
+		$initialResponse = new JrdResponse($subject ?? '');
+		$finalResponse = array_reduce($handlers, function (?IResponse $previousResponse, IHandler $handler) use ($context, $service) {
+			return $handler->handle($service, $context, $previousResponse);
+		}, $initialResponse);
+
+		if ($finalResponse instanceof JrdResponse && $finalResponse->isEmpty()) {
+			return null;
+		}
+
+		return $finalResponse;
+	}
+
+	/**
+	 * @return IHandler[]
+	 */
+	private function loadHandlers(): array {
+		$context = $this->coordinator->getRegistrationContext();
+
+		if ($context === null) {
+			throw new RuntimeException("Well known handlers requested before the apps had been fully registered");
+		}
+
+		$registrations = $context->getWellKnownHandlers();
+		$this->logger->debug(count($registrations) . " well known handlers registered");
+
+		return array_filter(
+			array_map(function (array $registration) {
+				$class = $registration['class'];
+
+				try {
+					$handler = $this->container->get($class);
+
+					if (!($handler) instanceof IHandler) {
+						$this->logger->error("Well known handler $class is invalid");
+
+						return null;
+					}
+
+					return $handler;
+				} catch (QueryException $e) {
+					$this->logger->error("Could not load well known handler $class", [
+						'exception' => $e,
+					]);
+
+					return null;
+				}
+			}, $registrations)
+		);
+	}
+}