ocm controller

Signed-off-by: Maxence Lange <maxence@artificial-owl.com>
2023-09-05 11:42:48 -01:00 · 2023-09-05 11:42:48 -01:00 · 8b9e7e235d
parent d5fc95b661
commit 8b9e7e235d
27 changed files with 1120 additions and 252 deletions
--- a/apps/cloud_federation_api/appinfo/routes.php
+++ b/apps/cloud_federation_api/appinfo/routes.php
@ -6,6 +6,7 @@ declare(strict_types=1);
 * @copyright Copyright (c) 2020 Joas Schilling <coding@schilljs.com>
 *
 * @author Joas Schilling <coding@schilljs.com>
+ * @author Maxence Lange <maxence@artificial-owl.com>
 *
 * @license GNU AGPL version 3 or any later version
 *
@ -27,15 +28,21 @@ return [
 	'routes' => [
 		[
 			'name' => 'RequestHandler#addShare',
-			'url' => '/ocm/shares',
+			'url' => '/shares',
 			'verb' => 'POST',
-			'root' => '',
+			'root' => '/ocm',
 		],
 		[
 			'name' => 'RequestHandler#receiveNotification',
-			'url' => '/ocm/notifications',
+			'url' => '/notifications',
 			'verb' => 'POST',
-			'root' => '',
+			'root' => '/ocm',
 		],
+//		[
+//			'name' => 'RequestHandler#inviteAccepted',
+//			'url' => '/invite-accepted',
+//			'verb' => 'POST',
+//			'root' => '/ocm',
+//		]
 	],
 ];
--- a/apps/cloud_federation_api/lib/Capabilities.php
+++ b/apps/cloud_federation_api/lib/Capabilities.php
@ -1,9 +1,13 @@
 <?php
+
+declare(strict_types=1);
+
 /**
 * @copyright Copyright (c) 2017 Bjoern Schiessle <bjoern@schiessle.org>
 *
 * @author Bjoern Schiessle <bjoern@schiessle.org>
 * @author Kate Döen <kate.doeen@nextcloud.com>
+ * @author Maxence Lange <maxence@artificial-owl.com>
 *
 * @license GNU AGPL version 3 or any later version
 *
@ -21,18 +25,22 @@
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 *
 */
+
 namespace OCA\CloudFederationAPI;

+use OC\OCM\Model\OCMProvider;
+use OC\OCM\Model\OCMResource;
 use OCP\Capabilities\ICapability;
 use OCP\IURLGenerator;
+use OCP\OCM\Exceptions\OCMArgumentException;

 class Capabilities implements ICapability {

-	/** @var IURLGenerator */
-	private $urlGenerator;
+	public const API_VERSION = '1.0-proposal1';

-	public function __construct(IURLGenerator $urlGenerator) {
-		$this->urlGenerator = $urlGenerator;
+	public function __construct(
+		private IURLGenerator $urlGenerator,
+	) {
 	}

 	/**
@ -46,32 +54,33 @@ class Capabilities implements ICapability {
 	 *         resourceTypes: array{
 	 *             name: string,
 	 *             shareTypes: string[],
-	 *             protocols: array{
-	 *                 webdav: string,
-	 *	           },
-	 *	       }[],
-	 *	   },
+	 *             protocols: array<string, string>
+	 *           }[],
+	 *       },
 	 * }
+	 * @throws OCMArgumentException
 	 */
 	public function getCapabilities() {
 		$url = $this->urlGenerator->linkToRouteAbsolute('cloud_federation_api.requesthandlercontroller.addShare');
-		$capabilities = ['ocm' =>
-			[
-				'enabled' => true,
-				'apiVersion' => '1.0-proposal1',
-				'endPoint' => substr($url, 0, strrpos($url, '/')),
-				'resourceTypes' => [
-					[
-						'name' => 'file',
-						'shareTypes' => ['user', 'group'],
-						'protocols' => [
-							'webdav' => '/public.php/webdav/',
-						]
-					],
-				]
-			]
-		];

-		return $capabilities;
+		$provider = new OCMProvider();
+		$provider->setEnabled(true);
+		$provider->setApiVersion(self::API_VERSION);
+
+		$pos = strrpos($url, '/');
+		if (false === $pos) {
+			throw new OCMArgumentException('generated route should contains a slash character');
+		}
+
+		$provider->setEndPoint(substr($url, 0, $pos));
+
+		$resource = new OCMResource();
+		$resource->setName('file')
+				 ->setShareTypes(['user', 'group'])
+				 ->setProtocols(['webdav' => '/public.php/webdav/']);
+
+		$provider->setResourceTypes([$resource]);
+
+		return ['ocm' => $provider->jsonSerialize()];
 	}
 }
--- a/apps/cloud_federation_api/lib/Controller/RequestHandlerController.php
+++ b/apps/cloud_federation_api/lib/Controller/RequestHandlerController.php
@ -4,6 +4,7 @@
 *
 * @author Bjoern Schiessle <bjoern@schiessle.org>
 * @author Christoph Wurst <christoph@winzerhof-wurst.at>
+ * @author Maxence Lange <maxence@artificial-owl.com>
 * @author Roeland Jago Douma <roeland@famdouma.nl>
 * @author Kate Döen <kate.doeen@nextcloud.com>
 *
@ -55,52 +56,19 @@ use Psr\Log\LoggerInterface;
 * @psalm-import-type CloudFederationApiError from ResponseDefinitions
 */
 class RequestHandlerController extends Controller {
-
-	/** @var LoggerInterface */
-	private $logger;
-
-	/** @var IUserManager */
-	private $userManager;
-
-	/** @var IGroupManager */
-	private $groupManager;
-
-	/** @var IURLGenerator */
-	private $urlGenerator;
-
-	/** @var ICloudFederationProviderManager */
-	private $cloudFederationProviderManager;
-
-	/** @var Config */
-	private $config;
-
-	/** @var ICloudFederationFactory */
-	private $factory;
-
-	/** @var ICloudIdManager */
-	private $cloudIdManager;
-
-	public function __construct($appName,
-								IRequest $request,
-								LoggerInterface $logger,
-								IUserManager $userManager,
-								IGroupManager $groupManager,
-								IURLGenerator $urlGenerator,
-								ICloudFederationProviderManager $cloudFederationProviderManager,
-								Config $config,
-								ICloudFederationFactory $factory,
-								ICloudIdManager $cloudIdManager
+	public function __construct(
+		string $appName,
+		IRequest $request,
+		private LoggerInterface $logger,
+		private IUserManager $userManager,
+		private IGroupManager $groupManager,
+		private IURLGenerator $urlGenerator,
+		private ICloudFederationProviderManager $cloudFederationProviderManager,
+		private Config $config,
+		private ICloudFederationFactory $factory,
+		private ICloudIdManager $cloudIdManager
 	) {
 		parent::__construct($appName, $request);
-
-		$this->logger = $logger;
-		$this->userManager = $userManager;
-		$this->groupManager = $groupManager;
-		$this->urlGenerator = $urlGenerator;
-		$this->cloudFederationProviderManager = $cloudFederationProviderManager;
-		$this->config = $config;
-		$this->factory = $factory;
-		$this->cloudIdManager = $cloudIdManager;
 	}

 	/**
@ -128,7 +96,6 @@ class RequestHandlerController extends Controller {
 	 * 501: Share type or the resource type is not supported
 	 */
 	public function addShare($shareWith, $name, $description, $providerId, $owner, $ownerDisplayName, $sharedBy, $sharedByDisplayName, $protocol, $shareType, $resourceType) {
-
 		// check if all required parameters are set
 		if ($shareWith === null ||
 			$name === null ||
@ -253,7 +220,6 @@ class RequestHandlerController extends Controller {
 	 * 501: The resource type is not supported
 	 */
 	public function receiveNotification($notificationType, $resourceType, $providerId, ?array $notification) {
-
 		// check if all required parameters are set
 		if ($notificationType === null ||
 			$resourceType === null ||
@ -311,7 +277,7 @@ class RequestHandlerController extends Controller {
 			);
 		}

-		return new JSONResponse($result,Http::STATUS_CREATED);
+		return new JSONResponse($result, Http::STATUS_CREATED);
 	}

 	/**
--- a/apps/cloud_federation_api/openapi.json
+++ b/apps/cloud_federation_api/openapi.json
@ -76,13 +76,8 @@
                                        },
                                        "protocols": {
                                            "type": "object",
-                                            "required": [
-                                                "webdav"
-                                            ],
-                                            "properties": {
-                                                "webdav": {
-                                                    "type": "string"
-                                                }
+                                            "additionalProperties": {
+                                                "type": "string"
                                            }
                                        }
                                    }
--- a/apps/files_sharing/lib/BackgroundJob/FederatedSharesDiscoverJob.php
+++ b/apps/files_sharing/lib/BackgroundJob/FederatedSharesDiscoverJob.php
@ -6,6 +6,7 @@ declare(strict_types=1);
 * @copyright 2018, Roeland Jago Douma <roeland@famdouma.nl>
 *
 * @author Christoph Wurst <christoph@winzerhof-wurst.at>
+ * @author Maxence Lange <maxence@artificial-owl.com>
 * @author Roeland Jago Douma <roeland@famdouma.nl>
 *
 * @license GNU AGPL version 3 or any later version
@ -29,21 +30,19 @@ namespace OCA\Files_Sharing\BackgroundJob;
 use OCP\AppFramework\Utility\ITimeFactory;
 use OCP\BackgroundJob\TimedJob;
 use OCP\IDBConnection;
+use OCP\OCM\Exceptions\OCMProviderException;
+use OCP\OCM\IOCMDiscoveryService;
 use OCP\OCS\IDiscoveryService;

 class FederatedSharesDiscoverJob extends TimedJob {
-	/** @var IDBConnection */
-	private $connection;
-	/** @var IDiscoveryService */
-	private $discoveryService;

-	public function __construct(ITimeFactory $time,
-								IDBConnection $connection,
-								IDiscoveryService $discoveryService) {
+	public function __construct(
+		ITimeFactory $time,
+		private IDBConnection $connection,
+		private IDiscoveryService $discoveryService,
+		private IOCMDiscoveryService $ocmDiscoveryService
+	) {
 		parent::__construct($time);
-		$this->connection = $connection;
-		$this->discoveryService = $discoveryService;
-
 		$this->setInterval(86400);
 	}

@ -56,6 +55,10 @@ class FederatedSharesDiscoverJob extends TimedJob {
 		$result = $qb->execute();
 		while ($row = $result->fetch()) {
 			$this->discoveryService->discover($row['remote'], 'FEDERATED_SHARING', true);
+			try {
+				$this->ocmDiscoveryService->discover($row['remote'], true);
+			} catch (OCMProviderException $e) {
+			}
 		}
 		$result->closeCursor();
 	}
--- a/apps/files_sharing/lib/Controller/ExternalSharesController.php
+++ b/apps/files_sharing/lib/Controller/ExternalSharesController.php
@ -134,14 +134,14 @@ class ExternalSharesController extends Controller {
 		}

 		if (
-			$this->testUrl('https://' . $remote . '/ocs-provider/') ||
-			$this->testUrl('https://' . $remote . '/ocs-provider/index.php') ||
+			$this->testUrl('https://' . $remote . '/ocm-provider/') ||
+			$this->testUrl('https://' . $remote . '/ocm-provider/index.php') ||
 			$this->testUrl('https://' . $remote . '/status.php', true)
 		) {
 			return new DataResponse('https');
 		} elseif (
-			$this->testUrl('http://' . $remote . '/ocs-provider/') ||
-			$this->testUrl('http://' . $remote . '/ocs-provider/index.php') ||
+			$this->testUrl('http://' . $remote . '/ocm-provider/') ||
+			$this->testUrl('http://' . $remote . '/ocm-provider/index.php') ||
 			$this->testUrl('http://' . $remote . '/status.php', true)
 		) {
 			return new DataResponse('http');
--- a/apps/files_sharing/lib/External/Storage.php
+++ b/apps/files_sharing/lib/External/Storage.php
@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
 * @copyright Copyright (c) 2016, ownCloud, Inc.
 *
@ -8,6 +11,7 @@
 * @author Daniel Kesselberg <mail@danielkesselberg.de>
 * @author Joas Schilling <coding@schilljs.com>
 * @author Lukas Reschke <lukas@statuscode.ch>
+ * @author Maxence Lange <maxence@artificial-owl.com>
 * @author Morris Jobke <hey@morrisjobke.de>
 * @author Robin Appelman <robin@icewind.nl>
 * @author Roeland Jago Douma <roeland@famdouma.nl>
@ -36,8 +40,8 @@ use GuzzleHttp\Exception\ConnectException;
 use GuzzleHttp\Exception\RequestException;
 use OC\Files\Storage\DAV;
 use OC\ForbiddenException;
-use OCA\Files_Sharing\ISharedStorage;
 use OCA\Files_Sharing\External\Manager as ExternalShareManager;
+use OCA\Files_Sharing\ISharedStorage;
 use OCP\AppFramework\Http;
 use OCP\Constants;
 use OCP\Federation\ICloudId;
@ -46,25 +50,23 @@ use OCP\Files\Storage\IDisableEncryptionStorage;
 use OCP\Files\Storage\IReliableEtagStorage;
 use OCP\Files\StorageInvalidException;
 use OCP\Files\StorageNotAvailableException;
-use OCP\Http\Client\LocalServerException;
 use OCP\Http\Client\IClientService;
+use OCP\Http\Client\LocalServerException;
+use OCP\ICacheFactory;
+use OCP\OCM\Exceptions\OCMArgumentException;
+use OCP\OCM\Exceptions\OCMProviderException;
+use OCP\OCM\IOCMDiscoveryService;
+use OCP\Server;
+use Psr\Log\LoggerInterface;

 class Storage extends DAV implements ISharedStorage, IDisableEncryptionStorage, IReliableEtagStorage {
-	/** @var ICloudId */
-	private $cloudId;
-	/** @var string */
-	private $mountPoint;
-	/** @var string */
-	private $token;
-	/** @var \OCP\ICacheFactory */
-	private $memcacheFactory;
-	/** @var \OCP\Http\Client\IClientService */
-	private $httpClient;
-	/** @var bool */
-	private $updateChecked = false;
-
-	/** @var ExternalShareManager */
-	private $manager;
+	private ICloudId $cloudId;
+	private string $mountPoint;
+	private string $token;
+	private ICacheFactory $memcacheFactory;
+	private IClientService $httpClient;
+	private bool $updateChecked = false;
+	private ExternalShareManager $manager;

 	/**
 	 * @param array{HttpClientService: IClientService, manager: ExternalShareManager, cloudId: ICloudId, mountpoint: string, token: string, password: ?string}|array $options
@ -72,32 +74,44 @@ class Storage extends DAV implements ISharedStorage, IDisableEncryptionStorage,
 	public function __construct($options) {
 		$this->memcacheFactory = \OC::$server->getMemCacheFactory();
 		$this->httpClient = $options['HttpClientService'];
-
 		$this->manager = $options['manager'];
 		$this->cloudId = $options['cloudId'];
-		$discoveryService = \OC::$server->query(\OCP\OCS\IDiscoveryService::class);
+		$this->logger = Server::get(LoggerInterface::class);
+		$discoveryService = Server::get(IOCMDiscoveryService::class);

-		[$protocol, $remote] = explode('://', $this->cloudId->getRemote());
-		if (str_contains($remote, '/')) {
-			[$host, $root] = explode('/', $remote, 2);
-		} else {
-			$host = $remote;
-			$root = '';
+		// use default path to webdav if not found on discovery
+		try {
+			$ocmProvider = $discoveryService->discover($this->cloudId->getRemote());
+			$webDavEndpoint = $ocmProvider->extractProtocolEntry('file', 'webdav');
+			$remote = $ocmProvider->getEndPoint();
+		} catch (OCMProviderException|OCMArgumentException $e) {
+			$this->logger->notice('exception while retrieving webdav endpoint', ['exception' => $e]);
+			$webDavEndpoint = '/public.php/webdav';
+			$remote = $this->cloudId->getRemote();
 		}
-		$secure = $protocol === 'https';
-		$federatedSharingEndpoints = $discoveryService->discover($this->cloudId->getRemote(), 'FEDERATED_SHARING');
-		$webDavEndpoint = isset($federatedSharingEndpoints['webdav']) ? $federatedSharingEndpoints['webdav'] : '/public.php/webdav';
-		$root = rtrim($root, '/') . $webDavEndpoint;
+
+		$host = parse_url($remote, PHP_URL_HOST);
+		$port = parse_url($remote, PHP_URL_PORT);
+		$host .= (null === $port) ? '' : ':' . $port; // we add port if available
+
+		// in case remote NC is on a sub folder and using deprecated ocm provider
+		$tmpPath = rtrim(parse_url($this->cloudId->getRemote(), PHP_URL_PATH) ?? '', '/');
+		if (!str_starts_with($webDavEndpoint, $tmpPath)) {
+			$webDavEndpoint = $tmpPath . $webDavEndpoint;
+		}
+
 		$this->mountPoint = $options['mountpoint'];
 		$this->token = $options['token'];

-		parent::__construct([
-			'secure' => $secure,
-			'host' => $host,
-			'root' => $root,
-			'user' => $options['token'],
-			'password' => (string)$options['password']
-		]);
+		parent::__construct(
+			[
+				'secure' => ((parse_url($remote, PHP_URL_SCHEME) ?? 'https') === 'https'),
+				'host' => $host,
+				'root' => $webDavEndpoint,
+				'user' => $options['token'],
+				'password' => (string)$options['password']
+			]
+		);
 	}

 	public function getWatcher($path = '', $storage = null) {
@ -255,9 +269,9 @@ class Storage extends DAV implements ISharedStorage, IDisableEncryptionStorage,
 	 */
 	protected function testRemote(): bool {
 		try {
-			return $this->testRemoteUrl($this->getRemote() . '/ocs-provider/index.php')
-				|| $this->testRemoteUrl($this->getRemote() . '/ocs-provider/')
-				|| $this->testRemoteUrl($this->getRemote() . '/status.php');
+			return $this->testRemoteUrl($this->getRemote() . '/ocm-provider/index.php')
+				   || $this->testRemoteUrl($this->getRemote() . '/ocm-provider/')
+				   || $this->testRemoteUrl($this->getRemote() . '/status.php');
 		} catch (\Exception $e) {
 			return false;
 		}
--- a/apps/files_sharing/tests/ExternalStorageTest.php
+++ b/apps/files_sharing/tests/ExternalStorageTest.php
@ -28,6 +28,7 @@
 namespace OCA\Files_Sharing\Tests;

 use OC\Federation\CloudId;
+use OCA\Files_Sharing\External\Manager as ExternalShareManager;
 use OCP\Http\Client\IClient;
 use OCP\Http\Client\IClientService;
 use OCP\Http\Client\IResponse;
@ -75,6 +76,7 @@ class ExternalStorageTest extends \Test\TestCase {
 	private function getTestStorage($uri) {
 		$certificateManager = \OC::$server->getCertificateManager();
 		$httpClientService = $this->createMock(IClientService::class);
+		$manager = $this->createMock(ExternalShareManager::class);
 		$client = $this->createMock(IClient::class);
 		$response = $this->createMock(IResponse::class);
 		$client
@ -98,7 +100,7 @@ class ExternalStorageTest extends \Test\TestCase {
 				'mountpoint' => 'remoteshare',
 				'token' => 'abcdef',
 				'password' => '',
-				'manager' => null,
+				'manager' => $manager,
 				'certificateManager' => $certificateManager,
 				'HttpClientService' => $httpClientService,
 			]
--- a/build/files-checker.php
+++ b/build/files-checker.php
@ -79,7 +79,6 @@ $expectedFiles = [
 	'jest.config.ts',
 	'lib',
 	'occ',
-	'ocm-provider',
 	'ocs',
 	'ocs-provider',
 	'package-lock.json',
--- a/build/psalm-baseline.xml
+++ b/build/psalm-baseline.xml
@ -43,6 +43,11 @@
      <code>IEventListener</code>
    </MissingTemplateParam>
  </file>
+  <file src="apps/cloud_federation_api/lib/Capabilities.php">
+    <LessSpecificImplementedReturnType>
+      <code>array</code>
+    </LessSpecificImplementedReturnType>
+  </file>
  <file src="apps/comments/lib/Listener/CommentsEntityEventListener.php">
    <MissingTemplateParam>
      <code>IEventListener</code>
--- a/core/Controller/OCMController.php
+++ b/core/Controller/OCMController.php
@ -0,0 +1,92 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 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\Core\Controller;
+
+use Exception;
+use OCP\AppFramework\Controller;
+use OCP\AppFramework\Http;
+use OCP\AppFramework\Http\Attribute\IgnoreOpenAPI;
+use OCP\AppFramework\Http\DataResponse;
+use OCP\AppFramework\Http\Response;
+use OCP\IConfig;
+use OCP\IRequest;
+use OCP\Server;
+use Psr\Container\ContainerExceptionInterface;
+use Psr\Log\LoggerInterface;
+
+/**
+ * Controller about the endpoint /ocm-provider/
+ *
+ * @since 28.0.0
+ */
+class OCMController extends Controller {
+	public function __construct(
+		IRequest $request,
+		private IConfig $config,
+		private LoggerInterface $logger
+	) {
+		parent::__construct('core', $request);
+	}
+
+	/**
+	 * generate a OCMProvider with local data and send it as DataResponse.
+	 * This replaces the old PHP file ocm-provider/index.php
+	 *
+	 * @PublicPage
+	 * @NoCSRFRequired
+	 *
+	 * @return Response
+	 */
+	#[IgnoreOpenAPI]
+	public function discovery(): Response {
+		try {
+			$cap = Server::get(
+				$this->config->getAppValue(
+					'core',
+					'ocm_providers',
+					'\OCA\CloudFederationAPI\Capabilities'
+				)
+			);
+
+			return new DataResponse(
+				$cap->getCapabilities()['ocm'] ?? ['enabled' => false],
+				Http::STATUS_OK,
+				[
+					'X-NEXTCLOUD-OCM-PROVIDERS' => true,
+					'Content-Type' => 'application/json'
+				]
+			);
+		} catch (ContainerExceptionInterface|Exception $e) {
+			$this->logger->error('issue during OCM discovery request', ['exception' => $e]);
+
+			return new DataResponse(
+				['message' => '/ocm-provider/ not supported'],
+				Http::STATUS_INTERNAL_SERVER_ERROR
+			);
+		}
+	}
+}
--- a/core/openapi.json
+++ b/core/openapi.json
@ -4988,6 +4988,10 @@
        {
            "name": "guest_avatar",
            "description": "This controller handles guest avatar requests."
+        },
+        {
+            "name": "ocm",
+            "description": "Controller about the endpoint /ocm-provider/"
        }
    ]
 }
--- a/core/routes.php
+++ b/core/routes.php
@ -13,6 +13,7 @@ declare(strict_types=1);
 * @author John Molakvoæ <skjnldsv@protonmail.com>
 * @author Julius Härtl <jus@bitgrid.net>
 * @author Lukas Reschke <lukas@statuscode.ch>
+ * @author Maxence Lange <maxence@artificial-owl.com>
 * @author Michael Weimann <mail@michael-weimann.eu>
 * @author Roeland Jago Douma <roeland@famdouma.nl>
 * @author Thomas Müller <thomas.mueller@tmit.eu>
@ -103,6 +104,9 @@ $application->registerRoutes($this, [
 		// Well known requests https://tools.ietf.org/html/rfc5785
 		['name' => 'WellKnown#handle', 'url' => '.well-known/{service}'],

+		// OCM Provider requests https://github.com/cs3org/OCM-API
+		['name' => 'OCM#discovery', 'url' => '/ocm-provider/'],
+
 		// Unsupported browser
 		['name' => 'UnsupportedBrowser#index', 'url' => 'unsupported'],
 	],
--- a/lib/composer/composer/autoload_classmap.php
+++ b/lib/composer/composer/autoload_classmap.php
@ -536,6 +536,11 @@ return array(
    'OCP\\Notification\\IManager' => $baseDir . '/lib/public/Notification/IManager.php',
    'OCP\\Notification\\INotification' => $baseDir . '/lib/public/Notification/INotification.php',
    'OCP\\Notification\\INotifier' => $baseDir . '/lib/public/Notification/INotifier.php',
+    'OCP\\OCM\\Exceptions\\OCMArgumentException' => $baseDir . '/lib/public/OCM/Exceptions/OCMArgumentException.php',
+    'OCP\\OCM\\Exceptions\\OCMProviderException' => $baseDir . '/lib/public/OCM/Exceptions/OCMProviderException.php',
+    'OCP\\OCM\\IOCMDiscoveryService' => $baseDir . '/lib/public/OCM/IOCMDiscoveryService.php',
+    'OCP\\OCM\\IOCMProvider' => $baseDir . '/lib/public/OCM/IOCMProvider.php',
+    'OCP\\OCM\\IOCMResource' => $baseDir . '/lib/public/OCM/IOCMResource.php',
    'OCP\\OCS\\IDiscoveryService' => $baseDir . '/lib/public/OCS/IDiscoveryService.php',
    'OCP\\PreConditionNotMetException' => $baseDir . '/lib/public/PreConditionNotMetException.php',
    'OCP\\Preview\\BeforePreviewFetchedEvent' => $baseDir . '/lib/public/Preview/BeforePreviewFetchedEvent.php',
@ -1074,6 +1079,7 @@ return array(
    'OC\\Core\\Controller\\LostController' => $baseDir . '/core/Controller/LostController.php',
    'OC\\Core\\Controller\\NavigationController' => $baseDir . '/core/Controller/NavigationController.php',
    'OC\\Core\\Controller\\OCJSController' => $baseDir . '/core/Controller/OCJSController.php',
+    'OC\\Core\\Controller\\OCMController' => $baseDir . '/core/Controller/OCMController.php',
    'OC\\Core\\Controller\\OCSController' => $baseDir . '/core/Controller/OCSController.php',
    'OC\\Core\\Controller\\PreviewController' => $baseDir . '/core/Controller/PreviewController.php',
    'OC\\Core\\Controller\\ProfileApiController' => $baseDir . '/core/Controller/ProfileApiController.php',
@ -1463,6 +1469,9 @@ return array(
    'OC\\Notification\\Action' => $baseDir . '/lib/private/Notification/Action.php',
    'OC\\Notification\\Manager' => $baseDir . '/lib/private/Notification/Manager.php',
    'OC\\Notification\\Notification' => $baseDir . '/lib/private/Notification/Notification.php',
+    'OC\\OCM\\Model\\OCMProvider' => $baseDir . '/lib/private/OCM/Model/OCMProvider.php',
+    'OC\\OCM\\Model\\OCMResource' => $baseDir . '/lib/private/OCM/Model/OCMResource.php',
+    'OC\\OCM\\OCMDiscoveryService' => $baseDir . '/lib/private/OCM/OCMDiscoveryService.php',
    'OC\\OCS\\CoreCapabilities' => $baseDir . '/lib/private/OCS/CoreCapabilities.php',
    'OC\\OCS\\DiscoveryService' => $baseDir . '/lib/private/OCS/DiscoveryService.php',
    'OC\\OCS\\Exception' => $baseDir . '/lib/private/OCS/Exception.php',
--- a/lib/composer/composer/autoload_static.php
+++ b/lib/composer/composer/autoload_static.php
@ -569,6 +569,11 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
        'OCP\\Notification\\IManager' => __DIR__ . '/../../..' . '/lib/public/Notification/IManager.php',
        'OCP\\Notification\\INotification' => __DIR__ . '/../../..' . '/lib/public/Notification/INotification.php',
        'OCP\\Notification\\INotifier' => __DIR__ . '/../../..' . '/lib/public/Notification/INotifier.php',
+        'OCP\\OCM\\Exceptions\\OCMArgumentException' => __DIR__ . '/../../..' . '/lib/public/OCM/Exceptions/OCMArgumentException.php',
+        'OCP\\OCM\\Exceptions\\OCMProviderException' => __DIR__ . '/../../..' . '/lib/public/OCM/Exceptions/OCMProviderException.php',
+        'OCP\\OCM\\IOCMDiscoveryService' => __DIR__ . '/../../..' . '/lib/public/OCM/IOCMDiscoveryService.php',
+        'OCP\\OCM\\IOCMProvider' => __DIR__ . '/../../..' . '/lib/public/OCM/IOCMProvider.php',
+        'OCP\\OCM\\IOCMResource' => __DIR__ . '/../../..' . '/lib/public/OCM/IOCMResource.php',
        'OCP\\OCS\\IDiscoveryService' => __DIR__ . '/../../..' . '/lib/public/OCS/IDiscoveryService.php',
        'OCP\\PreConditionNotMetException' => __DIR__ . '/../../..' . '/lib/public/PreConditionNotMetException.php',
        'OCP\\Preview\\BeforePreviewFetchedEvent' => __DIR__ . '/../../..' . '/lib/public/Preview/BeforePreviewFetchedEvent.php',
@ -1107,6 +1112,7 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
        'OC\\Core\\Controller\\LostController' => __DIR__ . '/../../..' . '/core/Controller/LostController.php',
        'OC\\Core\\Controller\\NavigationController' => __DIR__ . '/../../..' . '/core/Controller/NavigationController.php',
        'OC\\Core\\Controller\\OCJSController' => __DIR__ . '/../../..' . '/core/Controller/OCJSController.php',
+        'OC\\Core\\Controller\\OCMController' => __DIR__ . '/../../..' . '/core/Controller/OCMController.php',
        'OC\\Core\\Controller\\OCSController' => __DIR__ . '/../../..' . '/core/Controller/OCSController.php',
        'OC\\Core\\Controller\\PreviewController' => __DIR__ . '/../../..' . '/core/Controller/PreviewController.php',
        'OC\\Core\\Controller\\ProfileApiController' => __DIR__ . '/../../..' . '/core/Controller/ProfileApiController.php',
@ -1496,6 +1502,9 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
        'OC\\Notification\\Action' => __DIR__ . '/../../..' . '/lib/private/Notification/Action.php',
        'OC\\Notification\\Manager' => __DIR__ . '/../../..' . '/lib/private/Notification/Manager.php',
        'OC\\Notification\\Notification' => __DIR__ . '/../../..' . '/lib/private/Notification/Notification.php',
+        'OC\\OCM\\Model\\OCMProvider' => __DIR__ . '/../../..' . '/lib/private/OCM/Model/OCMProvider.php',
+        'OC\\OCM\\Model\\OCMResource' => __DIR__ . '/../../..' . '/lib/private/OCM/Model/OCMResource.php',
+        'OC\\OCM\\OCMDiscoveryService' => __DIR__ . '/../../..' . '/lib/private/OCM/OCMDiscoveryService.php',
        'OC\\OCS\\CoreCapabilities' => __DIR__ . '/../../..' . '/lib/private/OCS/CoreCapabilities.php',
        'OC\\OCS\\DiscoveryService' => __DIR__ . '/../../..' . '/lib/private/OCS/DiscoveryService.php',
        'OC\\OCS\\Exception' => __DIR__ . '/../../..' . '/lib/private/OCS/Exception.php',
--- a/lib/private/Federation/CloudFederationProviderManager.php
+++ b/lib/private/Federation/CloudFederationProviderManager.php
@ -1,9 +1,13 @@
 <?php
+
+declare(strict_types=1);
+
 /**
 * @copyright Copyright (c) 2018 Bjoern Schiessle <bjoern@schiessle.org>
 *
 * @author Bjoern Schiessle <bjoern@schiessle.org>
 * @author Christoph Wurst <christoph@winzerhof-wurst.at>
+ * @author Maxence Lange <maxence@artificial-owl.com>
 *
 * @license GNU AGPL version 3 or any later version
 *
@ -32,6 +36,9 @@ use OCP\Federation\ICloudFederationProviderManager;
 use OCP\Federation\ICloudFederationShare;
 use OCP\Federation\ICloudIdManager;
 use OCP\Http\Client\IClientService;
+use OCP\IConfig;
+use OCP\OCM\Exceptions\OCMProviderException;
+use OCP\OCM\IOCMDiscoveryService;
 use Psr\Log\LoggerInterface;

 /**
@ -43,40 +50,16 @@ use Psr\Log\LoggerInterface;
 */
 class CloudFederationProviderManager implements ICloudFederationProviderManager {
 	/** @var array list of available cloud federation providers */
-	private $cloudFederationProvider;
+	private array $cloudFederationProvider = [];

-	/** @var IAppManager */
-	private $appManager;
-
-	/** @var IClientService */
-	private $httpClientService;
-
-	/** @var ICloudIdManager */
-	private $cloudIdManager;
-
-	private LoggerInterface $logger;
-
-	/** @var array cache OCM end-points */
-	private $ocmEndPoints = [];
-
-	private $supportedAPIVersion = '1.0-proposal1';
-
-	/**
-	 * CloudFederationProviderManager constructor.
-	 *
-	 * @param IAppManager $appManager
-	 * @param IClientService $httpClientService
-	 * @param ICloudIdManager $cloudIdManager
-	 */
-	public function __construct(IAppManager $appManager,
-								IClientService $httpClientService,
-								ICloudIdManager $cloudIdManager,
-								LoggerInterface $logger) {
-		$this->cloudFederationProvider = [];
-		$this->appManager = $appManager;
-		$this->httpClientService = $httpClientService;
-		$this->cloudIdManager = $cloudIdManager;
-		$this->logger = $logger;
+	public function __construct(
+		private IConfig $config,
+		private IAppManager $appManager,
+		private IClientService $httpClientService,
+		private ICloudIdManager $cloudIdManager,
+		private IOCMDiscoveryService $discoveryService,
+		private LoggerInterface $logger
+	) {
 	}


@ -130,16 +113,18 @@ class CloudFederationProviderManager implements ICloudFederationProviderManager

 	public function sendShare(ICloudFederationShare $share) {
 		$cloudID = $this->cloudIdManager->resolveCloudId($share->getShareWith());
-		$ocmEndPoint = $this->getOCMEndPoint($cloudID->getRemote());
-		if (empty($ocmEndPoint)) {
+		try {
+			$ocmProvider = $this->discoveryService->discover($cloudID->getRemote());
+		} catch (OCMProviderException $e) {
 			return false;
 		}

 		$client = $this->httpClientService->newClient();
 		try {
-			$response = $client->post($ocmEndPoint . '/shares', [
+			$response = $client->post($ocmProvider->getEndPoint() . '/shares', [
 				'body' => json_encode($share->getShare()),
 				'headers' => ['content-type' => 'application/json'],
+				'verify' => !$this->config->getSystemValueBool('sharing.federation.allowSelfSignedCertificates', false),
 				'timeout' => 10,
 				'connect_timeout' => 10,
 			]);
@ -168,17 +153,18 @@ class CloudFederationProviderManager implements ICloudFederationProviderManager
 	 * @return array|false
 	 */
 	public function sendNotification($url, ICloudFederationNotification $notification) {
-		$ocmEndPoint = $this->getOCMEndPoint($url);
-
-		if (empty($ocmEndPoint)) {
+		try {
+			$ocmProvider = $this->discoveryService->discover($url);
+		} catch (OCMProviderException $e) {
 			return false;
 		}

 		$client = $this->httpClientService->newClient();
 		try {
-			$response = $client->post($ocmEndPoint . '/notifications', [
+			$response = $client->post($ocmProvider->getEndPoint() . '/notifications', [
 				'body' => json_encode($notification->getMessage()),
 				'headers' => ['content-type' => 'application/json'],
+				'verify' => !$this->config->getSystemValueBool('sharing.federation.allowSelfSignedCertificates', false),
 				'timeout' => 10,
 				'connect_timeout' => 10,
 			]);
@ -202,36 +188,4 @@ class CloudFederationProviderManager implements ICloudFederationProviderManager
 	public function isReady() {
 		return $this->appManager->isEnabledForUser('cloud_federation_api');
 	}
-	/**
-	 * check if server supports the new OCM api and ask for the correct end-point
-	 *
-	 * @param string $url full base URL of the cloud server
-	 * @return string
-	 */
-	protected function getOCMEndPoint($url) {
-		if (isset($this->ocmEndPoints[$url])) {
-			return $this->ocmEndPoints[$url];
-		}
-
-		$client = $this->httpClientService->newClient();
-		try {
-			$response = $client->get($url . '/ocm-provider/', ['timeout' => 10, 'connect_timeout' => 10]);
-		} catch (\Exception $e) {
-			$this->ocmEndPoints[$url] = '';
-			return '';
-		}
-
-		$result = $response->getBody();
-		$result = json_decode($result, true);
-
-		$supportedVersion = isset($result['apiVersion']) && $result['apiVersion'] === $this->supportedAPIVersion;
-
-		if (isset($result['endPoint']) && $supportedVersion) {
-			$this->ocmEndPoints[$url] = $result['endPoint'];
-			return $result['endPoint'];
-		}
-
-		$this->ocmEndPoints[$url] = '';
-		return '';
-	}
 }
--- a/lib/private/OCM/Model/OCMProvider.php
+++ b/lib/private/OCM/Model/OCMProvider.php
@ -0,0 +1,211 @@
+<?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\Model;
+
+use JsonSerializable;
+use OCP\OCM\Exceptions\OCMArgumentException;
+use OCP\OCM\Exceptions\OCMProviderException;
+use OCP\OCM\IOCMProvider;
+
+/**
+ * @since 28.0.0
+ */
+class OCMProvider implements IOCMProvider, JsonSerializable {
+	private bool $enabled = false;
+	private string $apiVersion = '';
+	private string $endPoint = '';
+	/** @var OCMResource[] */
+	private array $resourceTypes = [];
+
+	/**
+	 * @param bool $enabled
+	 *
+	 * @return OCMProvider
+	 */
+	public function setEnabled(bool $enabled): self {
+		$this->enabled = $enabled;
+
+		return $this;
+	}
+
+	/**
+	 * @return bool
+	 */
+	public function isEnabled(): bool {
+		return $this->enabled;
+	}
+
+	/**
+	 * @param string $apiVersion
+	 *
+	 * @return OCMProvider
+	 */
+	public function setApiVersion(string $apiVersion): self {
+		$this->apiVersion = $apiVersion;
+
+		return $this;
+	}
+
+	/**
+	 * @return string
+	 */
+	public function getApiVersion(): string {
+		return $this->apiVersion;
+	}
+
+	/**
+	 * @param string $endPoint
+	 *
+	 * @return OCMProvider
+	 */
+	public function setEndPoint(string $endPoint): self {
+		$this->endPoint = $endPoint;
+
+		return $this;
+	}
+
+	/**
+	 * @return string
+	 */
+	public function getEndPoint(): string {
+		return $this->endPoint;
+	}
+
+	/**
+	 * @param OCMResource $resource
+	 *
+	 * @return $this
+	 */
+	public function addResourceType(OCMResource $resource): self {
+		$this->resourceTypes[] = $resource;
+
+		return $this;
+	}
+
+	/**
+	 * @param OCMResource[] $resourceTypes
+	 *
+	 * @return OCMProvider
+	 */
+	public function setResourceTypes(array $resourceTypes): self {
+		$this->resourceTypes = $resourceTypes;
+
+		return $this;
+	}
+
+	/**
+	 * @return OCMResource[]
+	 */
+	public function getResourceTypes(): array {
+		return $this->resourceTypes;
+	}
+
+	/**
+	 * @param string $resourceName
+	 * @param string $protocol
+	 *
+	 * @return string
+	 * @throws OCMArgumentException
+	 */
+	public function extractProtocolEntry(string $resourceName, string $protocol): string {
+		foreach ($this->getResourceTypes() as $resource) {
+			if ($resource->getName() === $resourceName) {
+				$entry = $resource->getProtocols()[$protocol] ?? null;
+				if (is_null($entry)) {
+					throw new OCMArgumentException('protocol not found');
+				}
+
+				return (string)$entry;
+			}
+		}
+
+		throw new OCMArgumentException('resource not found');
+	}
+
+	/**
+	 * import data from an array
+	 *
+	 * @param array $data
+	 *
+	 * @return self
+	 * @throws OCMProviderException in case a descent provider cannot be generated from data
+	 * @see self::jsonSerialize()
+	 */
+	public function import(array $data): self {
+		$this->setEnabled(is_bool($data['enabled'] ?? '') ? $data['enabled'] : false)
+			 ->setApiVersion((string)($data['apiVersion'] ?? ''))
+			 ->setEndPoint($data['endPoint'] ?? '');
+
+		$resources = [];
+		foreach (($data['resourceTypes'] ?? []) as $resourceData) {
+			$resource = new OCMResource();
+			$resources[] = $resource->import($resourceData);
+		}
+		$this->setResourceTypes($resources);
+
+		if (!$this->looksValid()) {
+			throw new OCMProviderException('remote provider does not look valid');
+		}
+
+		return $this;
+	}
+
+
+	/**
+	 * @return bool
+	 */
+	private function looksValid(): bool {
+		return ($this->getApiVersion() !== '' && $this->getEndPoint() !== '');
+	}
+
+
+	/**
+	 * @return array{
+	 *     enabled: bool,
+	 *     apiVersion: string,
+	 *     endPoint: string,
+	 *     resourceTypes: array{
+	 *              name: string,
+	 *              shareTypes: string[],
+	 *              protocols: array<string, string>
+	 *            }[]
+	 *   }
+	 */
+	public function jsonSerialize(): array {
+		$resourceTypes = []; // this is needed for psalm
+		foreach ($this->getResourceTypes() as $res) {
+			$resourceTypes[] = $res->jsonSerialize();
+		}
+
+		return [
+			'enabled' => $this->isEnabled(),
+			'apiVersion' => $this->getApiVersion(),
+			'endPoint' => $this->getEndPoint(),
+			'resourceTypes' => $resourceTypes
+		];
+	}
+}
--- a/lib/private/OCM/Model/OCMResource.php
+++ b/lib/private/OCM/Model/OCMResource.php
@ -0,0 +1,125 @@
+<?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\Model;
+
+use JsonSerializable;
+use OCP\OCM\IOCMResource;
+
+/**
+ * @since 28.0.0
+ */
+class OCMResource implements IOCMResource, JsonSerializable {
+	private string $name = '';
+	/** @var string[] */
+	private array $shareTypes = [];
+	/** @var array<string, string> */
+	private array $protocols = [];
+
+	/**
+	 * @param string $name
+	 *
+	 * @return OCMResource
+	 */
+	public function setName(string $name): self {
+		$this->name = $name;
+
+		return $this;
+	}
+
+	/**
+	 * @return string
+	 */
+	public function getName(): string {
+		return $this->name;
+	}
+
+	/**
+	 * @param string[] $shareTypes
+	 *
+	 * @return OCMResource
+	 */
+	public function setShareTypes(array $shareTypes): self {
+		$this->shareTypes = $shareTypes;
+
+		return $this;
+	}
+
+	/**
+	 * @return string[]
+	 */
+	public function getShareTypes(): array {
+		return $this->shareTypes;
+	}
+
+	/**
+	 * @param array<string, string> $protocols
+	 *
+	 * @return $this
+	 */
+	public function setProtocols(array $protocols): self {
+		$this->protocols = $protocols;
+
+		return $this;
+	}
+
+	/**
+	 * @return array<string, string>
+	 */
+	public function getProtocols(): array {
+		return $this->protocols;
+	}
+
+	/**
+	 * import data from an array
+	 *
+	 * @param array $data
+	 *
+	 * @return self
+	 * @see self::jsonSerialize()
+	 */
+	public function import(array $data): self {
+		return $this->setName((string)($data['name'] ?? ''))
+					->setShareTypes($data['shareTypes'] ?? [])
+					->setProtocols($data['protocols'] ?? []);
+	}
+
+	/**
+	 *
+	 * @return array{
+	 *     name: string,
+	 *     shareTypes: string[],
+	 *     protocols: array<string, string>
+	 * }
+	 */
+	public function jsonSerialize(): array {
+		return [
+			'name' => $this->getName(),
+			'shareTypes' => $this->getShareTypes(),
+			'protocols' => $this->getProtocols()
+		];
+	}
+}
--- a/lib/private/OCM/OCMDiscoveryService.php
+++ b/lib/private/OCM/OCMDiscoveryService.php
@ -0,0 +1,138 @@
+<?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 OC\OCM\Model\OCMProvider;
+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 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, '/');
+		$provider = new OCMProvider();
+
+		if (!$skipCache) {
+			try {
+				$provider->import(json_decode($this->cache->get($remote) ?? '', true, 8, JSON_THROW_ON_ERROR) ?? []);
+				if ($this->supportedAPIVersion($provider->getApiVersion())) {
+					return $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
+				$provider->import(json_decode($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($provider->getApiVersion())) {
+			throw new OCMProviderException('API version not supported');
+		}
+
+		return $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));
+	}
+}
--- a/lib/private/Server.php
+++ b/lib/private/Server.php
@ -124,6 +124,7 @@ use OC\Metadata\Capabilities as MetadataCapabilities;
 use OC\Metadata\IMetadataManager;
 use OC\Metadata\MetadataManager;
 use OC\Notification\Manager;
+use OC\OCM\OCMDiscoveryService;
 use OC\OCS\DiscoveryService;
 use OC\Preview\GeneratorHelper;
 use OC\Preview\IMagickSupport;
@ -228,6 +229,7 @@ use OCP\Lock\ILockingProvider;
 use OCP\Lockdown\ILockdownManager;
 use OCP\Log\ILogFactory;
 use OCP\Mail\IMailer;
+use OCP\OCM\IOCMDiscoveryService;
 use OCP\Remote\Api\IApiFactory;
 use OCP\Remote\IInstanceFactory;
 use OCP\RichObjectStrings\IValidator;
@ -1306,6 +1308,7 @@ class Server extends ServerContainer implements IServerContainer {
 				$c->get(IClientService::class)
 			);
 		});
+		$this->registerAlias(IOCMDiscoveryService::class, OCMDiscoveryService::class);

 		$this->registerService(ICloudIdManager::class, function (ContainerInterface $c) {
 			return new CloudIdManager(
@ -1321,9 +1324,11 @@ class Server extends ServerContainer implements IServerContainer {

 		$this->registerService(ICloudFederationProviderManager::class, function (ContainerInterface $c) {
 			return new CloudFederationProviderManager(
+				$c->get(\OCP\IConfig::class),
 				$c->get(IAppManager::class),
 				$c->get(IClientService::class),
 				$c->get(ICloudIdManager::class),
+				$c->get(IOCMDiscoveryService::class),
 				$c->get(LoggerInterface::class)
 			);
 		});
--- a/lib/public/OCM/Exceptions/OCMArgumentException.php
+++ b/lib/public/OCM/Exceptions/OCMArgumentException.php
@ -0,0 +1,34 @@
+<?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 OCP\OCM\Exceptions;
+
+use Exception;
+
+/**
+ * @since 28.0.0
+ */
+class OCMArgumentException extends Exception {
+}
--- a/lib/public/OCM/Exceptions/OCMProviderException.php
+++ b/lib/public/OCM/Exceptions/OCMProviderException.php
@ -0,0 +1,34 @@
+<?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 OCP\OCM\Exceptions;
+
+use Exception;
+
+/**
+ * @since 28.0.0
+ */
+class OCMProviderException extends Exception {
+}
--- a/lib/public/OCM/IOCMDiscoveryService.php
+++ b/lib/public/OCM/IOCMDiscoveryService.php
@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 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 OCP\OCM;
+
+use OCP\OCM\Exceptions\OCMProviderException;
+
+/**
+ * Discover remote OCM services
+ *
+ * @since 28.0.0
+ */
+interface IOCMDiscoveryService {
+	/**
+	 * Discover remote OCM services
+	 *
+	 * @param string $remote address of the remote provider
+	 * @param bool $skipCache ignore cache, refresh data
+	 *
+	 * @return IOCMProvider
+	 * @throws OCMProviderException if no valid discovery data can be returned
+	 * @since 28.0.0
+	 */
+	public function discover(string $remote, bool $skipCache = false): IOCMProvider;
+}
--- a/lib/public/OCM/IOCMProvider.php
+++ b/lib/public/OCM/IOCMProvider.php
@ -0,0 +1,143 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 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 OCP\OCM;
+
+use OC\OCM\Model\OCMResource;
+use OCP\OCM\Exceptions\OCMArgumentException;
+use OCP\OCM\Exceptions\OCMProviderException;
+
+/**
+ * Model based on the Open Cloud Mesh Discovery API
+ * @link https://github.com/cs3org/OCM-API/
+ * @since 28.0.0
+ */
+interface IOCMProvider {
+	/**
+	 * enable OCM
+	 *
+	 * @param bool $enabled
+	 *
+	 * @return self
+	 * @since 28.0.0
+	 */
+	public function setEnabled(bool $enabled): self;
+
+	/**
+	 * is set as enabled ?
+	 *
+	 * @return bool
+	 * @since 28.0.0
+	 */
+	public function isEnabled(): bool;
+
+	/**
+	 * get set API Version
+	 *
+	 * @param string $apiVersion
+	 *
+	 * @return self
+	 * @since 28.0.0
+	 */
+	public function setApiVersion(string $apiVersion): self;
+
+	/**
+	 * returns API version
+	 *
+	 * @return string
+	 * @since 28.0.0
+	 */
+	public function getApiVersion(): string;
+
+	/**
+	 * configure endpoint
+	 *
+	 * @param string $endPoint
+	 *
+	 * @return self
+	 * @since 28.0.0
+	 */
+	public function setEndPoint(string $endPoint): self;
+
+	/**
+	 * get configured endpoint
+	 *
+	 * @return string
+	 * @since 28.0.0
+	 */
+	public function getEndPoint(): string;
+
+	/**
+	 * add a single resource to the object
+	 *
+	 * @param OCMResource $resource
+	 *
+	 * @return self
+	 * @since 28.0.0
+	 */
+	public function addResourceType(OCMResource $resource): self;
+
+	/**
+	 * set resources
+	 *
+	 * @param OCMResource[] $resourceTypes
+	 *
+	 * @return self
+	 * @since 28.0.0
+	 */
+	public function setResourceTypes(array $resourceTypes): self;
+
+	/**
+	 * get all set resources
+	 *
+	 * @return IOCMResource[]
+	 * @since 28.0.0
+	 */
+	public function getResourceTypes(): array;
+
+	/**
+	 * extract a specific string value from the listing of protocols, based on resource-name and protocol-name
+	 *
+	 * @param string $resourceName
+	 * @param string $protocol
+	 *
+	 * @return string
+	 * @throws OCMArgumentException
+	 * @since 28.0.0
+	 */
+	public function extractProtocolEntry(string $resourceName, string $protocol): string;
+
+	/**
+	 * import data from an array
+	 *
+	 * @param array<string, int|string|bool|array> $data
+	 *
+	 * @return self
+	 * @throws OCMProviderException in case a descent provider cannot be generated from data
+	 * @since 28.0.0
+	 */
+	public function import(array $data): self;
+}
--- a/lib/public/OCM/IOCMResource.php
+++ b/lib/public/OCM/IOCMResource.php
@ -0,0 +1,99 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 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 OCP\OCM;
+
+/**
+ * Model based on the Open Cloud Mesh Discovery API
+ *
+ * @link https://github.com/cs3org/OCM-API/
+ * @since 28.0.0
+ */
+interface IOCMResource {
+	/**
+	 * set name of the resource
+	 *
+	 * @param string $name
+	 *
+	 * @return self
+	 * @since 28.0.0
+	 */
+	public function setName(string $name): self;
+
+	/**
+	 * get name of the resource
+	 *
+	 * @return string
+	 * @since 28.0.0
+	 */
+	public function getName(): string;
+
+	/**
+	 * set share types
+	 *
+	 * @param string[] $shareTypes
+	 *
+	 * @return self
+	 * @since 28.0.0
+	 */
+	public function setShareTypes(array $shareTypes): self;
+
+	/**
+	 * get share types
+	 *
+	 * @return string[]
+	 * @since 28.0.0
+	 */
+	public function getShareTypes(): array;
+
+	/**
+	 * set available protocols
+	 *
+	 * @param array<string, string> $protocols
+	 *
+	 * @return self
+	 * @since 28.0.0
+	 */
+	public function setProtocols(array $protocols): self;
+
+	/**
+	 * get configured protocols
+	 *
+	 * @return array<string, string>
+	 * @since 28.0.0
+	 */
+	public function getProtocols(): array;
+
+	/**
+	 * import data from an array
+	 *
+	 * @param array $data
+	 *
+	 * @return self
+	 * @since 28.0.0
+	 */
+	public function import(array $data): self;
+}
--- a/ocm-provider/index.php
+++ b/ocm-provider/index.php
@ -1,40 +0,0 @@
-<?php
-/**
- * @copyright Copyright (c) 2018 Bjoern Schiessle <bjoern@schiessle.org>
- *
- * @license GNU AGPL version 3 or any later version
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as
- * published by the Free Software Foundation, either version 3 of the
- * License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- */
-
-
-require_once __DIR__ . '/../lib/base.php';
-
-header('Content-Type: application/json');
-
-$server = \OC::$server;
-
-$isEnabled = $server->getAppManager()->isEnabledForUser('cloud_federation_api');
-
-if ($isEnabled) {
-	// Make sure the routes are loaded
-	\OC_App::loadApp('cloud_federation_api');
-	$capabilities = new OCA\CloudFederationAPI\Capabilities($server->getURLGenerator());
-	header('Content-Type: application/json');
-	echo json_encode($capabilities->getCapabilities()['ocm']);
-} else {
-	header($_SERVER["SERVER_PROTOCOL"]." 501 Not Implemented", true, 501);
-	exit("501 Not Implemented");
-}
--- a/psalm.xml
+++ b/psalm.xml
@ -43,7 +43,6 @@
 		<directory name="apps/workflowengine"/>
 		<directory name="core"/>
 		<directory name="lib"/>
-		<directory name="ocm-provider"/>
 		<directory name="ocs"/>
 		<directory name="ocs-provider"/>
 		<file name="index.php"/>