fix(SecureView): hide disfunctional *download* files action

This is achieved by setting a specific DAV attribute. At the moment there
is one handler in dav-apps FilesPlugin and it could overwrite the value
with "false". We make sure not to downgrade here and prevent downgrade
from dav (possible race condition).

Signed-off-by: Arthur Schiwon <blizzz@arthur-schiwon.de>

lib/AppInfo/Application.php

@@ -8,6 +8,7 @@ declare(strict_types=1);
 
 namespace OCA\Richdocuments\AppInfo;
 
+use OCA\DAV\Events\SabrePluginAddEvent;
 use OCA\Files_Sharing\Event\ShareLinkAccessedEvent;
 use OCA\Richdocuments\AppConfig;
 use OCA\Richdocuments\Capabilities;
@@ -15,6 +16,7 @@ use OCA\Richdocuments\Conversion\ConversionProvider;
 use OCA\Richdocuments\Db\WopiMapper;
 use OCA\Richdocuments\Listener\AddContentSecurityPolicyListener;
 use OCA\Richdocuments\Listener\AddFeaturePolicyListener;
+use OCA\Richdocuments\Listener\AddSabrePluginListener;
 use OCA\Richdocuments\Listener\BeforeFetchPreviewListener;
 use OCA\Richdocuments\Listener\BeforeGetTemplatesListener;
 use OCA\Richdocuments\Listener\BeforeTemplateRenderedListener;
@@ -49,6 +51,7 @@ use OCP\AppFramework\Bootstrap\IBootContext;
 use OCP\AppFramework\Bootstrap\IBootstrap;
 use OCP\AppFramework\Bootstrap\IRegistrationContext;
 use OCP\AppFramework\Http\Events\BeforeTemplateRenderedEvent;
+use OCP\BeforeSabrePubliclyLoadedEvent;
 use OCP\Collaboration\Reference\RenderReferenceEvent;
 use OCP\Collaboration\Resources\LoadAdditionalScriptsEvent;
 use OCP\Files\Storage\IStorage;
@@ -86,6 +89,8 @@ class Application extends App implements IBootstrap {
 		$context->registerEventListener(BeforeTemplateRenderedEvent::class, BeforeTemplateRenderedListener::class);
 		$context->registerEventListener(BeforeGetTemplatesEvent::class, BeforeGetTemplatesListener::class);
 		$context->registerEventListener(OverwritePublicSharePropertiesEvent::class, OverwritePublicSharePropertiesListener::class);
+		$context->registerEventListener(SabrePluginAddEvent::class, AddSabrePluginListener::class);
+		$context->registerEventListener(BeforeSabrePubliclyLoadedEvent::class, AddSabrePluginListener::class);
 		$context->registerReferenceProvider(OfficeTargetReferenceProvider::class);
 		$context->registerSensitiveMethods(WopiMapper::class, [
 			'getPathForToken',

lib/DAV/SecureViewPlugin.php

@@ -0,0 +1,85 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCA\Richdocuments\DAV;
+
+use OCA\DAV\Connector\Sabre\FilesPlugin;
+use OCA\DAV\Connector\Sabre\Node;
+use OCA\Richdocuments\Middleware\WOPIMiddleware;
+use OCA\Richdocuments\Service\SecureViewService;
+use OCA\Richdocuments\Storage\SecureViewWrapper;
+use OCP\Files\ForbiddenException;
+use OCP\Files\NotFoundException;
+use OCP\Files\StorageNotAvailableException;
+use OCP\IAppConfig;
+use Psr\Log\LoggerInterface;
+use Sabre\DAV\INode;
+use Sabre\DAV\PropFind;
+use Sabre\DAV\Server;
+use Sabre\DAV\ServerPlugin;
+
+class SecureViewPlugin extends ServerPlugin {
+	public function __construct(
+		protected WOPIMiddleware $wopiMiddleware,
+		protected IAppConfig $appConfig,
+		protected SecureViewService $secureViewService,
+		protected LoggerInterface $logger,
+	) {
+	}
+
+	public function initialize(Server $server) {
+		if (!$this->secureViewService->isEnabled()) {
+			return;
+		}
+		$server->on('propFind', $this->handleGetProperties(...));
+	}
+
+	private function handleGetProperties(PropFind $propFind, INode $node): void {
+		if (!$node instanceof Node) {
+			return;
+		}
+
+		$requestedProperties = $propFind->getRequestedProperties();
+		if (!in_array(FilesPlugin::SHARE_HIDE_DOWNLOAD_PROPERTYNAME, $requestedProperties, true)) {
+			return;
+		}
+		$currentValue = $propFind->get(FilesPlugin::SHARE_HIDE_DOWNLOAD_PROPERTYNAME);
+		if ($currentValue === 'true') {
+			// We won't unhide, hence can return early
+			return;
+		}
+
+		if (!$this->isDownloadable($node->getNode())) {
+			// FIXME: coordinate with Files how a better solution looks like. Maybe by setting it only to 'true' by any provider? To avoid overwriting. Or throwing a dedicated event in just this case?
+			$propFind->set(FilesPlugin::SHARE_HIDE_DOWNLOAD_PROPERTYNAME, 'true');
+			// avoid potential race condition with FilesPlugin that may set it to "false"
+			$propFind->handle(FilesPlugin::SHARE_HIDE_DOWNLOAD_PROPERTYNAME, 'true');
+		}
+	}
+
+	private function isDownloadable(\OCP\Files\Node $node): bool {
+		$storage = $node->getStorage();
+		if ($this->wopiMiddleware->isWOPIRequest()
+			|| $storage === null
+			|| !$storage->instanceOfStorage(SecureViewWrapper::class)
+		) {
+			return true;
+		}
+
+		try {
+			return !$this->secureViewService->shouldSecure($node->getInternalPath(), $storage);
+		} catch (StorageNotAvailableException|ForbiddenException|NotFoundException $e) {
+			// Exceptions cannot be nicely inferred.
+			return false;
+		} catch (\Throwable $e) {
+			$this->logger->warning('SecureViewPlugin caught an exception that likely is ignorable. Still preventing download.',
+				['exception' => $e,]
+			);
+			return false;
+		}
+	}
+}

lib/Listener/AddSabrePluginListener.php

@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCA\Richdocuments\Listener;
+
+use OCA\DAV\Events\SabrePluginAddEvent;
+use OCA\Richdocuments\DAV\SecureViewPlugin;
+use OCP\BeforeSabrePubliclyLoadedEvent;
+use OCP\EventDispatcher\Event;
+use OCP\EventDispatcher\IEventListener;
+use Psr\Container\ContainerInterface;
+
+/** @template-implements IEventListener<SabrePluginAddEvent|BeforeSabrePubliclyLoadedEvent> */
+class AddSabrePluginListener implements IEventListener {
+
+	public function __construct(
+		protected ContainerInterface $server,
+	) {
+	}
+
+	public function handle(Event $event): void {
+		if (
+			!$event instanceof SabrePluginAddEvent
+			&& !$event instanceof BeforeSabrePubliclyLoadedEvent
+		) {
+			return;
+		}
+		$davServer = $event->getServer();
+		$davServer->addPlugin($this->server->get(SecureViewPlugin::class));
+	}
+}

lib/Service/SecureViewService.php

@@ -0,0 +1,60 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCA\Richdocuments\Service;
+
+use OCA\Richdocuments\AppConfig;
+use OCA\Richdocuments\PermissionManager;
+use OCP\Files\NotFoundException;
+use OCP\Files\Storage\ISharedStorage;
+use OCP\Files\Storage\IStorage;
+use OCP\IAppConfig;
+use OCP\IUserSession;
+
+class SecureViewService {
+	public function __construct(
+		protected IUserSession $userSession,
+		protected PermissionManager $permissionManager,
+		protected IAppConfig $appConfig,
+	) {
+	}
+
+	public function isEnabled(): bool {
+		return $this->appConfig->getValueString(AppConfig::WATERMARK_APP_NAMESPACE, 'watermark_enabled', 'no') !== 'no';
+	}
+
+	/**
+	 * @throws NotFoundException
+	 */
+	public function shouldSecure(string $path, IStorage $storage, bool $tryOpen = true): bool {
+		if ($tryOpen) {
+			// pity… fopen() does not document any possible Exceptions
+			$fp = $storage->fopen($path, 'r');
+			fclose($fp);
+		}
+
+		$cacheEntry = $storage->getCache()->get($path);
+		if (!$cacheEntry) {
+			$parent = dirname($path);
+			if ($parent === '.') {
+				$parent = '';
+			}
+			$cacheEntry = $storage->getCache()->get($parent);
+			if (!$cacheEntry) {
+				throw new NotFoundException(sprintf('Could not find cache entry for path and parent of %s within storage %s ', $path, $storage->getId()));
+			}
+		}
+
+		$isSharedStorage = $storage->instanceOfStorage(ISharedStorage::class);
+		/** @noinspection PhpPossiblePolymorphicInvocationInspection */
+		/** @psalm-suppress UndefinedMethod **/
+		$share = $isSharedStorage ? $storage->getShare() : null;
+		$userId = $this->userSession->getUser()?->getUID();
+
+		return $this->permissionManager->shouldWatermark($cacheEntry, $userId, $share, $storage->getOwner($path) ?: null);
+	}
+}

lib/Storage/SecureViewWrapper.php

@@ -11,10 +11,9 @@ namespace OCA\Richdocuments\Storage;
 use OC\Files\Storage\Wrapper\Wrapper;
 use OCA\Richdocuments\Middleware\WOPIMiddleware;
 use OCA\Richdocuments\PermissionManager;
+use OCA\Richdocuments\Service\SecureViewService;
 use OCP\Files\ForbiddenException;
 use OCP\Files\IRootFolder;
-use OCP\Files\NotFoundException;
-use OCP\Files\Storage\ISharedStorage;
 use OCP\Files\Storage\IStorage;
 use OCP\IUserSession;
 use OCP\Server;
@@ -24,6 +23,7 @@ class SecureViewWrapper extends Wrapper {
 	private WOPIMiddleware $wopiMiddleware;
 	private IRootFolder $rootFolder;
 	private IUserSession $userSession;
+	private SecureViewService $secureViewService;
 
 	private string $mountPoint;
 
@@ -34,6 +34,7 @@ class SecureViewWrapper extends Wrapper {
 		$this->wopiMiddleware = Server::get(WOPIMiddleware::class);
 		$this->rootFolder = Server::get(IRootFolder::class);
 		$this->userSession = Server::get(IUserSession::class);
+		$this->secureViewService = Server::get(SecureViewService::class);
 
 		$this->mountPoint = $parameters['mountPoint'];
 	}
@@ -78,41 +79,15 @@ class SecureViewWrapper extends Wrapper {
 	 * @throws ForbiddenException
 	 */
 	private function checkFileAccess(string $path): void {
-		if ($this->shouldSecure($path) && !$this->wopiMiddleware->isWOPIRequest()) {
+		if (!$this->wopiMiddleware->isWOPIRequest() && $this->secureViewService->shouldSecure($path, $this, false)) {
 			throw new ForbiddenException('Download blocked due the secure view policy', false);
 		}
 	}
 
-	private function shouldSecure(string $path, ?IStorage $sourceStorage = null): bool {
-		if ($sourceStorage !== $this && $sourceStorage !== null) {
-			$fp = $sourceStorage->fopen($path, 'r');
-			fclose($fp);
-		}
-
-		$storage = $sourceStorage ?? $this;
-		$cacheEntry = $storage->getCache()->get($path);
-		if (!$cacheEntry) {
-			$parent = dirname($path);
-			if ($parent === '.') {
-				$parent = '';
-			}
-			$cacheEntry = $storage->getCache()->get($parent);
-			if (!$cacheEntry) {
-				throw new NotFoundException(sprintf('Could not find cache entry for path and parent of %s within storage %s ', $path, $storage->getId()));
-			}
-		}
-
-		$isSharedStorage = $storage->instanceOfStorage(ISharedStorage::class);
-
-		$share = $isSharedStorage ? $storage->getShare() : null;
-		$userId = $this->userSession->getUser()?->getUID();
-
-		return $this->permissionManager->shouldWatermark($cacheEntry, $userId, $share, $storage->getOwner($path) ?: null);
-	}
-
-
 	private function checkSourceAndTarget(string $source, string $target, ?IStorage $sourceStorage = null): void {
-		if ($this->shouldSecure($source, $sourceStorage) && !$this->shouldSecure($target)) {
+		if ($this->secureViewService->shouldSecure($source, $sourceStorage ?? $this, $sourceStorage !== null)
+			&& !$this->secureViewService->shouldSecure($target, $this)
+		) {
 			throw new ForbiddenException('Download blocked due the secure view policy. The source requires secure view that the target cannot offer.', false);
 		}
 	}

tests/features/bootstrap/RichDocumentsContext.php

@@ -30,6 +30,7 @@ class RichDocumentsContext implements Context {
 	private $fileIds = [];
 	/** @var array List of templates fetched for a given file type */
 	private $templates = [];
+	private array $directoryListing = [];
 
 	/** @BeforeScenario */
 	public function gatherContexts(BeforeScenarioScope $scope) {
@@ -75,6 +76,47 @@ class RichDocumentsContext implements Context {
 		Assert::assertNotEmpty($this->wopiToken);
 	}
 
+	/**
+	 * @When the download button for :path will be visible to :user
+	 */
+	public function downloadButtonIsVisible(string $path, string $user): void {
+		$this->downloadButtonIsNotVisibleOrNot($path, $user, true);
+	}
+
+	/**
+	 * @When the download button for :path will not be visible to :user
+	 */
+	public function downloadButtonIsNotVisible(string $path, string $user): void {
+		$this->downloadButtonIsNotVisibleOrNot($path, $user, false);
+	}
+
+	private function downloadButtonIsNotVisibleOrNot(string $path, string $user, bool $isVisible): void {
+		$hideDownloadProperty = '{http://nextcloud.org/ns}hide-download';
+		$this->serverContext->usingWebAsUser($user);
+		$fileInfo = $this->filesContext->listFolder($path, 0, [$hideDownloadProperty]);
+
+		if ($isVisible) {
+			Assert::assertTrue(!isset($fileInfo[$hideDownloadProperty]) || $fileInfo[$hideDownloadProperty] === 'false');
+		} else {
+			Assert::assertTrue(isset($fileInfo[$hideDownloadProperty]), 'property is not set');
+			Assert::assertTrue($fileInfo[$hideDownloadProperty] === 'true', 'property is not true');
+			Assert::assertTrue(isset($fileInfo[$hideDownloadProperty]) && $fileInfo[$hideDownloadProperty] === 'true');
+		}
+	}
+
+	/**
+	 * @When the download button for :path will not be visible in the last link share
+	 */
+	public function theDownloadButtonWillNotBeVisibleInLastLinkShare(string $path): void {
+		$hideDownloadProperty = '{http://nextcloud.org/ns}hide-download';
+		$this->serverContext->usingWebAsUser();
+		$shareToken = $this->sharingContext->getLastShareData()['token'];
+		$davClient = $this->filesContext->getPublicSabreClient($shareToken);
+		$result = $davClient->propFind($path, ['{http://nextcloud.org/ns}hide-download'], 1);
+		$fileInfo = $result[array_key_first($result)];
+		Assert::assertTrue(!isset($fileInfo[$hideDownloadProperty]) || $fileInfo[$hideDownloadProperty] === 'true');
+	}
+
 	public function generateTokenWithApi($user, $fileId, ?string $shareToken = null, ?string $path = null, ?string $guestName = null) {
 		$this->serverContext->usingWebAsUser($user);
 		$this->serverContext->sendJSONRequest('POST', '/index.php/apps/richdocuments/token', [
@@ -248,4 +290,26 @@ class RichDocumentsContext implements Context {
 
 		$this->wopiContext->collaboraRenamesTo($fileId, $newName);
 	}
+
+	/**
+	 * @When admin enables secure view
+	 */
+	public function enableSecureView(): void {
+		$this->serverContext->actAsAdmin(function () {
+			$watermarkKeysToEnable = [
+				'watermark_enabled',
+				'watermark_linkAll',
+				'watermark_shareRead',
+			];
+
+			foreach ($watermarkKeysToEnable as $configKey) {
+				$this->serverContext->sendOCSRequest(
+					'POST',
+					'apps/provisioning_api/api/v1/config/apps/files/' . $configKey,
+					['value' => 'yes'],
+				);
+				$this->serverContext->assertHttpStatusCode(200);
+			}
+		});
+	}
 }

tests/features/secure-view.feature

@@ -0,0 +1,38 @@
+Feature: API
+
+	Background:
+		Given user "user1" exists
+		And user "user2" exists
+		And admin enables secure view
+
+	Scenario: Download button is not shown in public shares
+		Given as user "user1"
+		And User "user1" creates a folder "NewFolder"
+		And User "user1" uploads file "./../emptyTemplates/template.odt" to "/NewFolder/file.odt"
+		And as "user1" create a share with
+			| path      | /NewFolder |
+			| shareType | 3          |
+		Then the download button for "/NewFolder/file.odt" will be visible to "user1"
+		And the download button for "file.odt" will not be visible in the last link share
+
+	Scenario: Download button is not shown in internal read-only shares
+		Given as user "user1"
+		And User "user1" creates a folder "NewFolder"
+		And User "user1" uploads file "./../emptyTemplates/template.odt" to "/NewFolder/file.odt"
+		And as "user1" create a share with
+			| path        | /NewFolder |
+			| shareType   | 0          |
+			| shareWith   | user2        |
+			| permissions | 1           |
+		Then the download button for "/NewFolder/file.odt" will not be visible to "user2"
+
+	Scenario: Download button is shown in internal shares
+		Given as user "user1"
+		And User "user1" creates a folder "NewFolder"
+		And User "user1" uploads file "./../emptyTemplates/template.odt" to "/NewFolder/file.odt"
+		And as "user1" create a share with
+			| path        | /NewFolder |
+			| shareType   | 0          |
+			| shareWith   | user2        |
+			| permissions | 31           |
+		Then the download button for "/NewFolder/file.odt" will be visible to "user2"

tests/psalm-baseline.xml

@@ -8,11 +8,6 @@
       <code><![CDATA[array_key_exists($key, self::APP_SETTING_TYPES) && self::APP_SETTING_TYPES[$key] === 'array']]></code>
     </RedundantCondition>
   </file>
-  <file src="lib/AppInfo/Application.php">
-    <MissingDependency>
-      <code><![CDATA[SecureViewWrapper|IStorage]]></code>
-    </MissingDependency>
-  </file>
   <file src="lib/Command/ActivateConfig.php">
     <UndefinedClass>
       <code><![CDATA[Command]]></code>

tests/run-integration.sh

@@ -55,7 +55,6 @@ $OCC config:system:set allow_local_remote_servers --value true --type bool
 $OCC config:system:set gs.trustedHosts 0 --value="localhost:$PORT_SERVERA"
 $OCC config:system:set gs.trustedHosts 1 --value="localhost:$PORT_SERVERB"
 
-
 vendor/bin/behat $SCENARIO_TO_RUN
 RESULT=$?
 

tests/stub.phpstub

@@ -10,6 +10,76 @@ class OC_User {
 	public static function setIncognitoMode($status) {}
 }
 
+namespace OC\Files\Storage\Wrapper {
+	class Wrapper implements \OCP\Files\Storage\IStorage{
+		protected $storage;
+
+		public function __construct(array $parameters) {}
+		public function copy(string $source, string $target): bool {}
+		public function copyFromStorage(\OCP\Files\Storage\IStorage $sourceStorage, string $sourceInternalPath, string $targetInternalPath): bool {}
+		public function moveFromStorage(\OCP\Files\Storage\IStorage $sourceStorage, string $sourceInternalPath, string $targetInternalPath): bool {}
+		public function rename(string $source, string $target): bool {}
+		public function getId(): string {};
+		public function mkdir(string $path): bool {};
+		public function rmdir(string $path): bool {};
+		public function opendir(string $path) {};
+		public function is_dir(string $path): bool {};
+		public function is_file(string $path): bool {};
+		public function is_file(string $path): bool {};
+        public function stat(string $path): array|false {};
+        public function filetype(string $path): string|false {};
+        public function filesize(string $path): int|float|false {};
+        public function isCreatable(string $path): bool {};
+        public function isReadable(string $path): bool {};
+        public function isUpdatable(string $path): bool {};
+        public function isDeletable(string $path): bool {};
+        public function isSharable(string $path): bool {};
+        public function getPermissions(string $path): int {};
+        public function file_exists(string $path): bool {};
+        public function filemtime(string $path): int|false {};
+        public function file_get_contents(string $path): string|false {};
+        public function file_put_contents(string $path, mixed $data): int|float|false {};
+        public function unlink(string $path): bool {};
+        public function rename(string $source, string $target): bool {};
+        public function copy(string $source, string $target): bool {};
+        public function fopen(string $path, string $mode) {};
+        public function getMimeType(string $path): string|false {};
+        public function hash(string $type, string $path, bool $raw = false): string|false {};
+        public function free_space(string $path): int|float|false {};
+        public function touch(string $path, ?int $mtime = null): bool {};
+        public function getLocalFile(string $path): string|false {};
+        public function hasUpdated(string $path, int $time): bool {};
+        public function getCache(string $path = , ?IStorage $storage = null): ICache {};
+        public function getScanner(string $path = , ?IStorage $storage = null): IScanner {};
+        public function getOwner(string $path): string|false {};
+        public function getWatcher(string $path = , ?IStorage $storage = null): IWatcher {};
+        public function getPropagator(?IStorage $storage = null): IPropagator {};
+        public function getUpdater(?IStorage $storage = null): IUpdater {};
+        public function getStorageCache(): OCFilesCacheStorage {};
+        public function getETag(string $path): string|false {};
+        public function test(): bool {};
+        public function isLocal(): bool {};
+        public function instanceOfStorage(string $class): bool {};
+        public function getInstanceOfStorage(string $class): ?IStorage {};
+        public function __call(string $method, array $args) {};
+        public function getDirectDownload(string $path): array|false {};
+        public function getAvailability(): array {};
+        public function setAvailability(bool $isAvailable): void {};
+        public function verifyPath(string $path, string $fileName): void {};
+        public function copyFromStorage(\OCP\Files\Storage\IStorage $sourceStorage, string $sourceInternalPath, string $targetInternalPath): bool {};
+        public function moveFromStorage(\OCP\Files\Storage\IStorage $sourceStorage, string $sourceInternalPath, string $targetInternalPath): bool {};
+        public function getMetaData(string $path): ?array {};
+        public function acquireLock(string $path, int $type, ILockingProvider $provider): void {};
+        public function releaseLock(string $path, int $type, ILockingProvider $provider): void {};
+        public function changeLock(string $path, int $type, ILockingProvider $provider): void {};
+        public function needsPartFile(): bool {};
+        public function writeStream(string $path, $stream, ?int $size = null): int {};
+        public function getDirectoryContent(string $directory): Traversable {};
+        public function isWrapperOf(IStorage $storage): bool {};
+        public function setOwner(?string $user): void {};
+	}
+}
+
 namespace OC\Hooks {
 	interface Emitter {
 		/**
@@ -32,6 +102,20 @@ namespace OC\Hooks {
 	}
 }
 
+namespace OCA\DAV\Connector\Sabre {
+	abstract class Node {
+		public function getNode(): \OCP\Files\Node;
+	}
+
+	class FilesPlugin {
+		public const SHARE_HIDE_DOWNLOAD_PROPERTYNAME = 'somePropertyName';
+	}
+}
+
+namespace OCA\DAV\Events {
+	class SabrePluginAddEvent extends \OCP\EventDispatcher\Event {}
+}
+
 namespace OCA\Federation {
 	class TrustedServers {
 		public function getServers() {
@@ -147,3 +231,30 @@ namespace OCA\Talk\Events {
 		}
 	}
 }
+
+namespace Sabre\DAV {
+	interface INode {}
+
+	class PropFind {
+		/**
+		 * @return string[]
+		 */
+		public function getRequestedProperties(): array {
+			return [];
+		}
+
+		public function get(string $key) {
+			return null;
+		}
+
+		public function set(string $key, $value) {}
+
+		public function handle(string $key, $valueOrCallable): void {}
+	}
+
+	class Server {
+		public function on(string $eventName, callable $callable): void {}
+	}
+
+    class ServerPlugin {}
+}