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

Add well known handlers API

.htaccess

@@ -61,10 +61,6 @@
   RewriteCond %{HTTP_USER_AGENT} DavClnt
   RewriteRule ^$ /remote.php/webdav/ [L,R=302]
   RewriteRule .* - [env=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
-  RewriteRule ^\.well-known/host-meta /public.php?service=host-meta [QSA,L]
-  RewriteRule ^\.well-known/host-meta\.json /public.php?service=host-meta-json [QSA,L]
-  RewriteRule ^\.well-known/webfinger /public.php?service=webfinger [QSA,L]
-  RewriteRule ^\.well-known/nodeinfo /public.php?service=nodeinfo [QSA,L]
   RewriteRule ^\.well-known/carddav /remote.php/dav/ [R=301,L]
   RewriteRule ^\.well-known/caldav /remote.php/dav/ [R=301,L]
   RewriteRule ^remote/(.*) remote.php [QSA,L]

apps/settings/js/admin.js

@@ -256,10 +256,10 @@ window.addEventListener('DOMContentLoaded', function(){
 		// run setup checks then gather error messages
 		$.when(
 			OC.SetupChecks.checkWebDAV(),
-			OC.SetupChecks.checkWellKnownUrl('/.well-known/webfinger', OC.theme.docPlaceholderUrl, $('#postsetupchecks').data('check-wellknown') === true && !!OC.appConfig.core.public_webfinger, [200, 404]),
-			OC.SetupChecks.checkWellKnownUrl('/.well-known/nodeinfo', OC.theme.docPlaceholderUrl, $('#postsetupchecks').data('check-wellknown') === true && !!OC.appConfig.core.public_nodeinfo, [200, 404]),
-			OC.SetupChecks.checkWellKnownUrl('/.well-known/caldav', OC.theme.docPlaceholderUrl, $('#postsetupchecks').data('check-wellknown') === true),
-			OC.SetupChecks.checkWellKnownUrl('/.well-known/carddav', OC.theme.docPlaceholderUrl, $('#postsetupchecks').data('check-wellknown') === true),
+			OC.SetupChecks.checkWellKnownUrl('GET', '/.well-known/webfinger', OC.theme.docPlaceholderUrl, $('#postsetupchecks').data('check-wellknown') === true, [200, 404], true),
+			OC.SetupChecks.checkWellKnownUrl('GET', '/.well-known/nodeinfo', OC.theme.docPlaceholderUrl, $('#postsetupchecks').data('check-wellknown') === true, [200, 404], true),
+			OC.SetupChecks.checkWellKnownUrl('PROPFIND', '/.well-known/caldav', OC.theme.docPlaceholderUrl, $('#postsetupchecks').data('check-wellknown') === true),
+			OC.SetupChecks.checkWellKnownUrl('PROPFIND', '/.well-known/carddav', OC.theme.docPlaceholderUrl, $('#postsetupchecks').data('check-wellknown') === true),
 			OC.SetupChecks.checkProviderUrl(OC.getRootPath() + '/ocm-provider/', OC.theme.docPlaceholderUrl, $('#postsetupchecks').data('check-wellknown') === true),
 			OC.SetupChecks.checkProviderUrl(OC.getRootPath() + '/ocs-provider/', OC.theme.docPlaceholderUrl, $('#postsetupchecks').data('check-wellknown') === true),
 			OC.SetupChecks.checkSetup(),

apps/settings/lib/AppInfo/Application.php

@@ -163,8 +163,6 @@ class Application extends App implements IBootstrap {
 			$groupManager->listen('\OC\Group', 'postRemoveUser',  [$this, 'removeUserFromGroup']);
 			$groupManager->listen('\OC\Group', 'postAddUser',  [$this, 'addUserToGroup']);
 		});
-
-		Util::connectHook('\OCP\Config', 'js', $this, 'extendJsConfig');
 	}
 
 	public function addUserToGroup(IGroup $group, IUser $user): void {
@@ -209,23 +207,4 @@ class Application extends App implements IBootstrap {
 		$hooks = $this->getContainer()->query(Hooks::class);
 		$hooks->onChangeEmail($parameters['user'], $parameters['old_value']);
 	}
-
-	/**
-	 * @param array $settings
-	 */
-	public function extendJsConfig(array $settings) {
-		$appConfig = json_decode($settings['array']['oc_appconfig'], true);
-
-		$publicWebFinger = \OC::$server->getConfig()->getAppValue('core', 'public_webfinger', '');
-		if (!empty($publicWebFinger)) {
-			$appConfig['core']['public_webfinger'] = $publicWebFinger;
-		}
-
-		$publicNodeInfo = \OC::$server->getConfig()->getAppValue('core', 'public_nodeinfo', '');
-		if (!empty($publicNodeInfo)) {
-			$appConfig['core']['public_nodeinfo'] = $publicNodeInfo;
-		}
-
-		$settings['array']['oc_appconfig'] = json_encode($appConfig);
-	}
 }

core/Controller/WellKnownController.php

@@ -0,0 +1,67 @@
+<?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\Core\Controller;
+
+use OC\Http\WellKnown\RequestManager;
+use OCP\AppFramework\Controller;
+use OCP\AppFramework\Http;
+use OCP\AppFramework\Http\JSONResponse;
+use OCP\AppFramework\Http\Response;
+use OCP\IRequest;
+
+class WellKnownController extends Controller {
+
+	/** @var RequestManager */
+	private $requestManager;
+
+	public function __construct(IRequest $request,
+								RequestManager $wellKnownManager) {
+		parent::__construct('core', $request);
+		$this->requestManager = $wellKnownManager;
+	}
+
+	/**
+	 * @PublicPage
+	 * @NoCSRFRequired
+	 *
+	 * @return Response
+	 */
+	public function handle(string $service): Response {
+		$response = $this->requestManager->process(
+			$service,
+			$this->request
+		);
+
+		if ($response === null) {
+			$httpResponse = new JSONResponse(["message" => "$service not supported"], Http::STATUS_NOT_FOUND);
+		} else {
+			$httpResponse = $response->toHttpResponse();
+		}
+
+		// We add a custom header so that setup checks can detect if their requests are answered by this controller
+		return $httpResponse->addHeader('X-NEXTCLOUD-WELL-KNOWN', '1');
+	}
+}

core/js/setupchecks.js

@@ -56,7 +56,7 @@
 		 * @param {int|int[]} expectedStatus the expected HTTP status to be returned by the URL, 207 by default
 		 * @return $.Deferred object resolved with an array of error messages
 		 */
-		checkWellKnownUrl: function(url, placeholderUrl, runCheck, expectedStatus) {
+		checkWellKnownUrl: function(verb, url, placeholderUrl, runCheck, expectedStatus, checkCustomHeader) {
 			if (expectedStatus === undefined) {
 				expectedStatus = [207];
 			}
@@ -73,7 +73,8 @@
 			}
 			var afterCall = function(xhr) {
 				var messages = [];
-				if (expectedStatus.indexOf(xhr.status) === -1) {
+				var customWellKnown = xhr.getResponseHeader('X-NEXTCLOUD-WELL-KNOWN')
+				if (expectedStatus.indexOf(xhr.status) === -1 || (checkCustomHeader && !customWellKnown)) {
 					var docUrl = placeholderUrl.replace('PLACEHOLDER', 'admin-setup-well-known-URL');
 					messages.push({
 						msg: t('core', 'Your web server is not properly set up to resolve "{url}". Further information can be found in the <a target="_blank" rel="noreferrer noopener" href="{docLink}">documentation</a>.', { docLink: docUrl, url: url }),
@@ -84,7 +85,7 @@
 			};
 
 			$.ajax({
-				type: 'PROPFIND',
+				type: verb,
 				url: url,
 				complete: afterCall,
 				allowAuthErrors: true

core/js/tests/specs/setupchecksSpec.js

@@ -62,7 +62,7 @@ describe('OC.SetupChecks tests', function() {
 
 	describe('checkWellKnownUrl', function() {
 		it('should fail with another response status code than the expected one', function(done) {
-			var async = OC.SetupChecks.checkWellKnownUrl('/.well-known/caldav', 'http://example.org/PLACEHOLDER', true, 207);
+			var async = OC.SetupChecks.checkWellKnownUrl('PROPFIND', '/.well-known/caldav', 'http://example.org/PLACEHOLDER', true, 207);
 
 			suite.server.requests[0].respond(200);
 
@@ -76,7 +76,7 @@ describe('OC.SetupChecks tests', function() {
 		});
 
 		it('should return no error with the expected response status code', function(done) {
-			var async = OC.SetupChecks.checkWellKnownUrl('/.well-known/caldav', 'http://example.org/PLACEHOLDER', true, 207);
+			var async = OC.SetupChecks.checkWellKnownUrl('PROPFIND', '/.well-known/caldav', 'http://example.org/PLACEHOLDER', true, 207);
 
 			suite.server.requests[0].respond(207);
 
@@ -87,7 +87,7 @@ describe('OC.SetupChecks tests', function() {
 		});
 
 		it('should return no error with the default expected response status code', function(done) {
-			var async = OC.SetupChecks.checkWellKnownUrl('/.well-known/caldav', 'http://example.org/PLACEHOLDER', true);
+			var async = OC.SetupChecks.checkWellKnownUrl('PROPFIND', '/.well-known/caldav', 'http://example.org/PLACEHOLDER', true);
 
 			suite.server.requests[0].respond(207);
 
@@ -98,7 +98,7 @@ describe('OC.SetupChecks tests', function() {
 		});
 
 		it('should return no error when no check should be run', function(done) {
-			var async = OC.SetupChecks.checkWellKnownUrl('/.well-known/caldav', 'http://example.org/PLACEHOLDER', false);
+			var async = OC.SetupChecks.checkWellKnownUrl('PROPFIND', '/.well-known/caldav', 'http://example.org/PLACEHOLDER', false);
 
 			async.done(function( data, s, x ){
 				expect(data).toEqual([]);

core/routes.php

@@ -89,6 +89,9 @@ $application->registerRoutes($this, [
 		// Logins for passwordless auth
 		['name' => 'WebAuthn#startAuthentication', 'url' => 'login/webauthn/start', 'verb' => 'POST'],
 		['name' => 'WebAuthn#finishAuthentication', 'url' => 'login/webauthn/finish', 'verb' => 'POST'],
+
+		// Well known requests https://tools.ietf.org/html/rfc5785
+		['name' => 'WellKnown#handle', 'url' => '.well-known/{service}'],
 	],
 	'ocs' => [
 		['root' => '/cloud', 'name' => 'OCS#getCapabilities', 'url' => '/capabilities', 'verb' => 'GET'],

lib/composer/composer/autoload_classmap.php

@@ -359,6 +359,11 @@ return array(
     'OCP\\Http\\Client\\IClientService' => $baseDir . '/lib/public/Http/Client/IClientService.php',
     'OCP\\Http\\Client\\IResponse' => $baseDir . '/lib/public/Http/Client/IResponse.php',
     'OCP\\Http\\Client\\LocalServerException' => $baseDir . '/lib/public/Http/Client/LocalServerException.php',
+    'OCP\\Http\\WellKnown\\GenericResponse' => $baseDir . '/lib/public/Http/WellKnown/GenericResponse.php',
+    'OCP\\Http\\WellKnown\\IHandler' => $baseDir . '/lib/public/Http/WellKnown/IHandler.php',
+    'OCP\\Http\\WellKnown\\IRequestContext' => $baseDir . '/lib/public/Http/WellKnown/IRequestContext.php',
+    'OCP\\Http\\WellKnown\\IResponse' => $baseDir . '/lib/public/Http/WellKnown/IResponse.php',
+    'OCP\\Http\\WellKnown\\JrdResponse' => $baseDir . '/lib/public/Http/WellKnown/JrdResponse.php',
     'OCP\\IAddressBook' => $baseDir . '/lib/public/IAddressBook.php',
     'OCP\\IAppConfig' => $baseDir . '/lib/public/IAppConfig.php',
     'OCP\\IAvatar' => $baseDir . '/lib/public/IAvatar.php',
@@ -892,6 +897,7 @@ return array(
     'OC\\Core\\Controller\\UserController' => $baseDir . '/core/Controller/UserController.php',
     'OC\\Core\\Controller\\WalledGardenController' => $baseDir . '/core/Controller/WalledGardenController.php',
     'OC\\Core\\Controller\\WebAuthnController' => $baseDir . '/core/Controller/WebAuthnController.php',
+    'OC\\Core\\Controller\\WellKnownController' => $baseDir . '/core/Controller/WellKnownController.php',
     'OC\\Core\\Controller\\WhatsNewController' => $baseDir . '/core/Controller/WhatsNewController.php',
     'OC\\Core\\Controller\\WipeController' => $baseDir . '/core/Controller/WipeController.php',
     'OC\\Core\\Data\\LoginFlowV2Credentials' => $baseDir . '/core/Data/LoginFlowV2Credentials.php',
@@ -1136,6 +1142,7 @@ return array(
     'OC\\Http\\Client\\ClientService' => $baseDir . '/lib/private/Http/Client/ClientService.php',
     'OC\\Http\\Client\\Response' => $baseDir . '/lib/private/Http/Client/Response.php',
     'OC\\Http\\CookieHelper' => $baseDir . '/lib/private/Http/CookieHelper.php',
+    'OC\\Http\\WellKnown\\RequestManager' => $baseDir . '/lib/private/Http/WellKnown/RequestManager.php',
     'OC\\InitialStateService' => $baseDir . '/lib/private/InitialStateService.php',
     'OC\\Installer' => $baseDir . '/lib/private/Installer.php',
     'OC\\IntegrityCheck\\Checker' => $baseDir . '/lib/private/IntegrityCheck/Checker.php',

lib/composer/composer/autoload_static.php

@@ -388,6 +388,11 @@ class ComposerStaticInit53792487c5a8370acc0b06b1a864ff4c
         'OCP\\Http\\Client\\IClientService' => __DIR__ . '/../../..' . '/lib/public/Http/Client/IClientService.php',
         'OCP\\Http\\Client\\IResponse' => __DIR__ . '/../../..' . '/lib/public/Http/Client/IResponse.php',
         'OCP\\Http\\Client\\LocalServerException' => __DIR__ . '/../../..' . '/lib/public/Http/Client/LocalServerException.php',
+        'OCP\\Http\\WellKnown\\GenericResponse' => __DIR__ . '/../../..' . '/lib/public/Http/WellKnown/GenericResponse.php',
+        'OCP\\Http\\WellKnown\\IHandler' => __DIR__ . '/../../..' . '/lib/public/Http/WellKnown/IHandler.php',
+        'OCP\\Http\\WellKnown\\IRequestContext' => __DIR__ . '/../../..' . '/lib/public/Http/WellKnown/IRequestContext.php',
+        'OCP\\Http\\WellKnown\\IResponse' => __DIR__ . '/../../..' . '/lib/public/Http/WellKnown/IResponse.php',
+        'OCP\\Http\\WellKnown\\JrdResponse' => __DIR__ . '/../../..' . '/lib/public/Http/WellKnown/JrdResponse.php',
         'OCP\\IAddressBook' => __DIR__ . '/../../..' . '/lib/public/IAddressBook.php',
         'OCP\\IAppConfig' => __DIR__ . '/../../..' . '/lib/public/IAppConfig.php',
         'OCP\\IAvatar' => __DIR__ . '/../../..' . '/lib/public/IAvatar.php',
@@ -921,6 +926,7 @@ class ComposerStaticInit53792487c5a8370acc0b06b1a864ff4c
         'OC\\Core\\Controller\\UserController' => __DIR__ . '/../../..' . '/core/Controller/UserController.php',
         'OC\\Core\\Controller\\WalledGardenController' => __DIR__ . '/../../..' . '/core/Controller/WalledGardenController.php',
         'OC\\Core\\Controller\\WebAuthnController' => __DIR__ . '/../../..' . '/core/Controller/WebAuthnController.php',
+        'OC\\Core\\Controller\\WellKnownController' => __DIR__ . '/../../..' . '/core/Controller/WellKnownController.php',
         'OC\\Core\\Controller\\WhatsNewController' => __DIR__ . '/../../..' . '/core/Controller/WhatsNewController.php',
         'OC\\Core\\Controller\\WipeController' => __DIR__ . '/../../..' . '/core/Controller/WipeController.php',
         'OC\\Core\\Data\\LoginFlowV2Credentials' => __DIR__ . '/../../..' . '/core/Data/LoginFlowV2Credentials.php',
@@ -1165,6 +1171,7 @@ class ComposerStaticInit53792487c5a8370acc0b06b1a864ff4c
         'OC\\Http\\Client\\ClientService' => __DIR__ . '/../../..' . '/lib/private/Http/Client/ClientService.php',
         'OC\\Http\\Client\\Response' => __DIR__ . '/../../..' . '/lib/private/Http/Client/Response.php',
         'OC\\Http\\CookieHelper' => __DIR__ . '/../../..' . '/lib/private/Http/CookieHelper.php',
+        'OC\\Http\\WellKnown\\RequestManager' => __DIR__ . '/../../..' . '/lib/private/Http/WellKnown/RequestManager.php',
         'OC\\InitialStateService' => __DIR__ . '/../../..' . '/lib/private/InitialStateService.php',
         'OC\\Installer' => __DIR__ . '/../../..' . '/lib/private/Installer.php',
         'OC\\IntegrityCheck\\Checker' => __DIR__ . '/../../..' . '/lib/private/IntegrityCheck/Checker.php',

lib/private/AppFramework/Bootstrap/RegistrationContext.php

@@ -74,6 +74,9 @@ class RegistrationContext {
 	/** @var array[] */
 	private $initialStates = [];
 
+	/** @var array[] */
+	private $wellKnownHandlers = [];
+
 	/** @var ILogger */
 	private $logger;
 
@@ -176,6 +179,13 @@ class RegistrationContext {
 					$class
 				);
 			}
+
+			public function registerWellKnownHandler(string $class): void {
+				$this->context->registerWellKnown(
+					$this->appId,
+					$class
+				);
+			}
 		};
 	}
 
@@ -262,6 +272,13 @@ class RegistrationContext {
 		];
 	}
 
+	public function registerWellKnown(string $appId, string $class): void {
+		$this->wellKnownHandlers[] = [
+			'appId' => $appId,
+			'class' => $class,
+		];
+	}
+
 	/**
 	 * @param App[] $apps
 	 */
@@ -439,4 +456,11 @@ class RegistrationContext {
 	public function getInitialStates(): array {
 		return $this->initialStates;
 	}
+
+	/**
+	 * @return array[]
+	 */
+	public function getWellKnownHandlers(): array {
+		return $this->wellKnownHandlers;
+	}
 }

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)
+		);
+	}
+}

lib/public/AppFramework/Bootstrap/IRegistrationContext.php

@@ -181,4 +181,18 @@ interface IRegistrationContext {
 	 * @since 21.0.0
 	 */
 	public function registerInitialStateProvider(string $class): void;
+
+	/**
+	 * Register a well known protocol handler
+	 *
+	 * It is allowed to register more than one handler per app.
+	 *
+	 * @param string $class
+	 * @psalm-param class-string<\OCP\Http\WellKnown\IHandler> $class
+	 *
+	 * @return void
+	 *
+	 * @since 21.0.0
+	 */
+	public function registerWellKnownHandler(string $class): void;
 }

lib/public/Http/WellKnown/GenericResponse.php

@@ -0,0 +1,51 @@
+<?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 OCP\Http\WellKnown;
+
+use OCP\AppFramework\Http\Response;
+
+/**
+ * @since 21.0.0
+ */
+final class GenericResponse implements IResponse {
+
+	/** @var Response */
+	private $response;
+
+	/**
+	 * @since 21.0.0
+	 */
+	public function __construct(Response $response) {
+		$this->response = $response;
+	}
+
+	/**
+	 * @since 21.0.0
+	 */
+	public function toHttpResponse(): Response {
+		return $this->response;
+	}
+}

lib/public/Http/WellKnown/IHandler.php

@@ -0,0 +1,48 @@
+<?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 OCP\Http\WellKnown;
+
+/**
+ * Interface for an app handler that reacts to requests to Nextcloud's well
+ * known URLs, e.g. to a WebFinger
+ *
+ * @ref https://tools.ietf.org/html/rfc5785
+ *
+ * @since 21.0.0
+ */
+interface IHandler {
+
+	/**
+	 * @param string $service the name of the well known service, e.g. 'webfinger'
+	 * @param IRequestContext $context
+	 * @param IResponse|null $previousResponse the response of the previous handler, if any
+	 *
+	 * @return IResponse|null a response object if the request could be handled, null otherwise
+	 *
+	 * @since 21.0.0
+	 */
+	public function handle(string $service, IRequestContext $context, ?IResponse $previousResponse): ?IResponse;
+}

lib/public/Http/WellKnown/IRequestContext.php

@@ -0,0 +1,46 @@
+<?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 OCP\Http\WellKnown;
+
+use OCP\IRequest;
+
+/**
+ * The context object for \OCP\Http\IWellKnownHandler::handle
+ *
+ * Objects of this type will transport any optional information, e.g. the request
+ * object through which the app well known handler can obtain URL parameters
+ *
+ * @since 21.0.0
+ */
+interface IRequestContext {
+
+	/**
+	 * @return IRequest
+	 *
+	 * @since 21.0.0
+	 */
+	public function getHttpRequest(): IRequest;
+}

lib/public/Http/WellKnown/IResponse.php

@@ -0,0 +1,39 @@
+<?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 OCP\Http\WellKnown;
+
+use OCP\AppFramework\Http\Response;
+
+/**
+ * @since 21.0.0
+ */
+interface IResponse {
+
+	/**
+	 * @since 21.0.0
+	 */
+	public function toHttpResponse(): Response;
+}

lib/public/Http/WellKnown/JrdResponse.php

@@ -0,0 +1,170 @@
+<?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 OCP\Http\WellKnown;
+
+use OCP\AppFramework\Http\JSONResponse;
+use OCP\AppFramework\Http\Response;
+use function array_filter;
+
+/**
+ * A JSON Document Format (JDF) response to a well-known request
+ *
+ * @ref https://tools.ietf.org/html/rfc6415#appendix-A
+ * @ref https://tools.ietf.org/html/rfc7033#section-4.4
+ *
+ * @since 21.0.0
+ */
+final class JrdResponse implements IResponse {
+
+	/** @var string */
+	private $subject;
+
+	/** @var string|null */
+	private $expires;
+
+	/** @var string[] */
+	private $aliases = [];
+
+	/** @var (string|null)[] */
+	private $properties = [];
+
+	/** @var mixed[] */
+	private $links;
+
+	/**
+	 * @param string $subject https://tools.ietf.org/html/rfc7033#section-4.4.1
+	 *
+	 * @since 21.0.0
+	 */
+	public function __construct(string $subject) {
+		$this->subject = $subject;
+	}
+
+	/**
+	 * @param string $expires
+	 *
+	 * @return $this
+	 *
+	 * @since 21.0.0
+	 */
+	public function setExpires(string $expires): self {
+		$this->expires = $expires;
+
+		return $this;
+	}
+
+	/**
+	 * Add an alias
+	 *
+	 * @ref https://tools.ietf.org/html/rfc7033#section-4.4.2
+	 *
+	 * @param string $alias
+	 *
+	 * @return $this
+	 *
+	 * @since 21.0.0
+	 */
+	public function addAlias(string $alias): self {
+		$this->aliases[] = $alias;
+
+		return $this;
+	}
+
+	/**
+	 * Add a property
+	 *
+	 * @ref https://tools.ietf.org/html/rfc7033#section-4.4.3
+	 *
+	 * @param string $property
+	 * @param string|null $value
+	 *
+	 * @return $this
+	 *
+	 * @since 21.0.0
+	 */
+	public function addProperty(string $property, ?string $value): self {
+		$this->properties[$property] = $value;
+
+		return $this;
+	}
+
+	/**
+	 * Add a link
+	 *
+	 * @ref https://tools.ietf.org/html/rfc7033#section-8.4
+	 *
+	 * @param string $rel https://tools.ietf.org/html/rfc7033#section-4.4.4.1
+	 * @param string|null $type https://tools.ietf.org/html/rfc7033#section-4.4.4.2
+	 * @param string|null $href https://tools.ietf.org/html/rfc7033#section-4.4.4.3
+	 * @param string[]|null $titles https://tools.ietf.org/html/rfc7033#section-4.4.4.4
+	 * @param string|null $properties https://tools.ietf.org/html/rfc7033#section-4.4.4.5
+	 *
+	 * @psalm-param array<string,(string|null)>|null $properties https://tools.ietf.org/html/rfc7033#section-4.4.4.5
+	 *
+	 * @return JrdResponse
+	 * @since 21.0.0
+	 */
+	public function addLink(string $rel,
+							?string $type,
+							?string $href,
+							?array $titles = [],
+							?array $properties = []): self {
+		$this->links[] = array_filter([
+			'rel' => $rel,
+			'type' => $type,
+			'href' => $href,
+			'titles' => $titles,
+			'properties' => $properties,
+		]);
+
+		return $this;
+	}
+
+	/**
+	 * @since 21.0.0
+	 */
+	public function toHttpResponse(): Response {
+		return new JSONResponse(array_filter([
+			'subject' => $this->subject,
+			'expires' => $this->expires,
+			'aliases' => $this->aliases,
+			'properties' => $this->properties,
+			'links' => $this->links,
+		]));
+	}
+
+	/**
+	 * Does this response have any data attached to it?
+	 *
+	 * @since 21.0.0
+	 */
+	public function isEmpty(): bool {
+		return $this->expires === null
+			&& empty($this->aliases)
+			&& empty($this->properties)
+			&& empty($this->links);
+	}
+}

tests/Core/Controller/WellKnownControllerTest.php

@@ -0,0 +1,86 @@
+<?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 Tests\Core\Controller;
+
+use OC\Core\Controller\WellKnownController;
+use OC\Http\WellKnown\RequestManager;
+use OCP\AppFramework\Http\JSONResponse;
+use OCP\Http\WellKnown\IResponse;
+use OCP\IRequest;
+use PHPUnit\Framework\MockObject\MockObject;
+use Test\TestCase;
+
+class WellKnownControllerTest extends TestCase {
+
+	/** @var IRequest|MockObject */
+	private $request;
+
+	/** @var RequestManager|MockObject */
+	private $manager;
+
+	/** @var WellKnownController */
+	private $controller;
+
+	protected function setUp(): void {
+		parent::setUp();
+
+		$this->request = $this->createMock(IRequest::class);
+		$this->manager = $this->createMock(RequestManager::class);
+
+		$this->controller = new WellKnownController(
+			$this->request,
+			$this->manager,
+		);
+	}
+
+	public function testHandleNotProcessed(): void {
+		$httpResponse = $this->controller->handle("nodeinfo");
+
+		self::assertInstanceOf(JSONResponse::class, $httpResponse);
+		self::assertArrayHasKey('X-NEXTCLOUD-WELL-KNOWN', $httpResponse->getHeaders());
+	}
+
+	public function testHandle(): void {
+		$response = $this->createMock(IResponse::class);
+		$jsonResponse = $this->createMock(JSONResponse::class);
+		$response->expects(self::once())
+			->method('toHttpResponse')
+			->willReturn($jsonResponse);
+		$this->manager->expects(self::once())
+			->method('process')
+			->with(
+				"nodeinfo",
+				$this->request
+			)->willReturn($response);
+		$jsonResponse->expects(self::once())
+			->method('addHeader')
+			->willReturnSelf();
+
+		$httpResponse = $this->controller->handle("nodeinfo");
+
+		self::assertInstanceOf(JSONResponse::class, $httpResponse);
+	}
+}

tests/lib/Http/WellKnown/GenericResponseTest.php

@@ -0,0 +1,40 @@
+<?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 Tests\Http\WellKnown;
+
+use OCP\AppFramework\Http\JSONResponse;
+use OCP\Http\WellKnown\GenericResponse;
+use Test\TestCase;
+
+class GenericResponseTest extends TestCase {
+	public function testToHttpResponse(): void {
+		$httpResponse = $this->createMock(JSONResponse::class);
+
+		$response = new GenericResponse($httpResponse);
+
+		self::assertSame($httpResponse, $response->toHttpResponse());
+	}
+}

tests/lib/Http/WellKnown/JrdResponseTest.php

@@ -0,0 +1,108 @@
+<?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 Test\Http\WellKnown;
+
+use OCP\AppFramework\Http\JSONResponse;
+use OCP\Http\WellKnown\JrdResponse;
+use Test\TestCase;
+
+class JrdResponseTest extends TestCase {
+	public function testEmptyToHttpResponse(): void {
+		$response = new JrdResponse("subject");
+		$httpResponse = $response->toHttpResponse();
+
+		self::assertTrue($response->isEmpty());
+		self::assertInstanceOf(JSONResponse::class, $httpResponse);
+		/** @var JSONResponse $httpResponse */
+		self::assertEquals(
+			[
+				'subject' => 'subject',
+			],
+			$httpResponse->getData()
+		);
+	}
+
+	public function testComplexToHttpResponse(): void {
+		$response = new JrdResponse("subject");
+		$response->addAlias('alias');
+		$response->addAlias('blias');
+		$response->addProperty('propa', 'a');
+		$response->addProperty('propb', null);
+		$response->setExpires('tomorrow');
+		$response->addLink('rel', null, null);
+		$response->addLink('rel', 'type', null);
+		$response->addLink('rel', 'type', 'href', ['title' => 'titlevalue']);
+		$response->addLink('rel', 'type', 'href', ['title' => 'titlevalue'], ['propx' => 'valx']);
+		$httpResponse = $response->toHttpResponse();
+
+		self::assertFalse($response->isEmpty());
+		self::assertInstanceOf(JSONResponse::class, $httpResponse);
+		/** @var JSONResponse $httpResponse */
+		self::assertEquals(
+			[
+				'subject' => 'subject',
+				'aliases' => [
+					'alias',
+					'blias',
+				],
+				'properties' => [
+					'propa' => 'a',
+					'propb' => null,
+				],
+				'expires' => 'tomorrow',
+				'links' => [
+					[
+						'rel' => 'rel',
+					],
+					[
+						'rel' => 'rel',
+						'type' => 'type',
+					],
+					[
+						'rel' => 'rel',
+						'type' => 'type',
+						'href' => 'href',
+						'titles' => [
+							'title' => 'titlevalue',
+						],
+					],
+					[
+						'rel' => 'rel',
+						'type' => 'type',
+						'href' => 'href',
+						'titles' => [
+							'title' => 'titlevalue',
+						],
+						'properties' => [
+							'propx' => 'valx',
+						],
+					],
+				]
+			],
+			$httpResponse->getData()
+		);
+	}
+}

tests/lib/Http/WellKnown/RequestManagerTest.php

@@ -0,0 +1,176 @@
+<?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 Test\Http\WellKnown;
+
+use OC\AppFramework\Bootstrap\Coordinator;
+use OC\AppFramework\Bootstrap\RegistrationContext;
+use OC\Http\WellKnown\RequestManager;
+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 PHPUnit\Framework\MockObject\MockObject;
+use Psr\Log\LoggerInterface;
+use RuntimeException;
+use Test\TestCase;
+use function get_class;
+
+class RequestManagerTest extends TestCase {
+
+	/** @var Coordinator|MockObject */
+	private $coordinator;
+
+	/** @var IServerContainer|MockObject */
+	private $container;
+
+	/** @var MockObject|LoggerInterface */
+	private $logger;
+
+	/** @var RequestManager */
+	private $manager;
+
+	protected function setUp(): void {
+		parent::setUp();
+
+		$this->coordinator = $this->createMock(Coordinator::class);
+		$this->container = $this->createMock(IServerContainer::class);
+		$this->logger = $this->createMock(LoggerInterface::class);
+
+		$this->manager = new RequestManager(
+			$this->coordinator,
+			$this->container,
+			$this->logger,
+		);
+	}
+
+	public function testProcessAppsNotRegistered(): void {
+		$request = $this->createMock(IRequest::class);
+		$this->expectException(RuntimeException::class);
+
+		$this->manager->process("webfinger", $request);
+	}
+
+	public function testProcessNoHandlersRegistered(): void {
+		$request = $this->createMock(IRequest::class);
+		$registrationContext = $this->createMock(RegistrationContext::class);
+		$this->coordinator->expects(self::once())
+			->method('getRegistrationContext')
+			->willReturn($registrationContext);
+		$registrationContext->expects(self::once())
+			->method('getWellKnownHandlers')
+			->willReturn([]);
+
+		$response = $this->manager->process("webfinger", $request);
+
+		self::assertNull($response);
+	}
+
+	public function testProcessHandlerNotLoadable(): void {
+		$request = $this->createMock(IRequest::class);
+		$registrationContext = $this->createMock(RegistrationContext::class);
+		$this->coordinator->expects(self::once())
+			->method('getRegistrationContext')
+			->willReturn($registrationContext);
+		$handler = new class {
+		};
+		$registrationContext->expects(self::once())
+			->method('getWellKnownHandlers')
+			->willReturn([
+				[
+					'class' => get_class($handler),
+				],
+			]);
+		$this->container->expects(self::once())
+			->method('get')
+			->with(get_class($handler))
+			->willThrowException(new QueryException(""));
+		$this->logger->expects(self::once())
+			->method('error');
+
+		$response = $this->manager->process("webfinger", $request);
+
+		self::assertNull($response);
+	}
+
+	public function testProcessHandlerOfWrongType(): void {
+		$request = $this->createMock(IRequest::class);
+		$registrationContext = $this->createMock(RegistrationContext::class);
+		$this->coordinator->expects(self::once())
+			->method('getRegistrationContext')
+			->willReturn($registrationContext);
+		$handler = new class {
+		};
+		$registrationContext->expects(self::once())
+			->method('getWellKnownHandlers')
+			->willReturn([
+				[
+					'class' => get_class($handler),
+				],
+			]);
+		$this->container->expects(self::once())
+			->method('get')
+			->with(get_class($handler))
+			->willReturn($handler);
+		$this->logger->expects(self::once())
+			->method('error');
+
+		$response = $this->manager->process("webfinger", $request);
+
+		self::assertNull($response);
+	}
+
+	public function testProcess(): void {
+		$request = $this->createMock(IRequest::class);
+		$registrationContext = $this->createMock(RegistrationContext::class);
+		$this->coordinator->expects(self::once())
+			->method('getRegistrationContext')
+			->willReturn($registrationContext);
+		$handler = new class implements IHandler {
+			public function handle(string $service, IRequestContext $context, ?IResponse $previousResponse): ?IResponse {
+				return (new JrdResponse($service))->addAlias('alias');
+			}
+		};
+		$registrationContext->expects(self::once())
+			->method('getWellKnownHandlers')
+			->willReturn([
+				[
+					'class' => get_class($handler),
+				],
+			]);
+		$this->container->expects(self::once())
+			->method('get')
+			->with(get_class($handler))
+			->willReturn($handler);
+
+		$response = $this->manager->process("webfinger", $request);
+
+		self::assertNotNull($response);
+		self::assertInstanceOf(JrdResponse::class, $response);
+	}
+}