fix(dav): Emit `BeforeZipCreatedEvent` when creating folder zip archivefix/bring-back-zip-event

This is required to not break behavior on zip download (apps should be able to react to zip download especially for shares).

Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>

4 files changed, 71 insertions, 47 deletions

diff --git a/apps/dav/lib/Connector/Sabre/ServerFactory.php b/apps/dav/lib/Connector/Sabre/ServerFactory.php
index 4235a02831a..617ba60f80d 100644
--- a/apps/dav/lib/Connector/Sabre/ServerFactory.php
+++ b/apps/dav/lib/Connector/Sabre/ServerFactory.php
@@ -28,39 +28,19 @@ use Psr\Log\LoggerInterface;
 use Sabre\DAV\Auth\Plugin;
 
 class ServerFactory {
-	private IConfig $config;
-	private LoggerInterface $logger;
-	private IDBConnection $databaseConnection;
-	private IUserSession $userSession;
-	private IMountManager $mountManager;
-	private ITagManager $tagManager;
-	private IRequest $request;
-	private IPreview $previewManager;
-	private IEventDispatcher $eventDispatcher;
-	private IL10N $l10n;
 
 	public function __construct(
-		IConfig $config,
-		LoggerInterface $logger,
-		IDBConnection $databaseConnection,
-		IUserSession $userSession,
-		IMountManager $mountManager,
-		ITagManager $tagManager,
-		IRequest $request,
-		IPreview $previewManager,
-		IEventDispatcher $eventDispatcher,
-		IL10N $l10n,
+		private IConfig $config,
+		private LoggerInterface $logger,
+		private IDBConnection $databaseConnection,
+		private IUserSession $userSession,
+		private IMountManager $mountManager,
+		private ITagManager $tagManager,
+		private IRequest $request,
+		private IPreview $previewManager,
+		private IEventDispatcher $eventDispatcher,
+		private IL10N $l10n,
 	) {
-		$this->config = $config;
-		$this->logger = $logger;
-		$this->databaseConnection = $databaseConnection;
-		$this->userSession = $userSession;
-		$this->mountManager = $mountManager;
-		$this->tagManager = $tagManager;
-		$this->request = $request;
-		$this->previewManager = $previewManager;
-		$this->eventDispatcher = $eventDispatcher;
-		$this->l10n = $l10n;
 	}
 
 	/**
@@ -80,7 +60,7 @@ class ServerFactory {
 		// Load plugins
 		$server->addPlugin(new \OCA\DAV\Connector\Sabre\MaintenancePlugin($this->config, $this->l10n));
 		$server->addPlugin(new BlockLegacyClientPlugin(
-			\OCP\Server::get(IConfig::class),
+			$this->config,
 			\OCP\Server::get(ThemingDefaults::class),
 		));
 		$server->addPlugin(new \OCA\DAV\Connector\Sabre\AnonymousOptionsPlugin());
@@ -90,11 +70,12 @@ class ServerFactory {
 		$server->addPlugin(new \OCA\DAV\Connector\Sabre\ExceptionLoggerPlugin('webdav', $this->logger));
 		$server->addPlugin(new \OCA\DAV\Connector\Sabre\LockPlugin());
 
-		$server->addPlugin(new RequestIdHeaderPlugin(\OC::$server->get(IRequest::class)));
+		$server->addPlugin(new RequestIdHeaderPlugin($this->request));
 
 		$server->addPlugin(new ZipFolderPlugin(
 			$objectTree,
 			$this->logger,
+			$this->eventDispatcher,
 		));
 
 		// Some WebDAV clients do require Class 2 WebDAV support (locking), since
diff --git a/apps/dav/lib/Connector/Sabre/ZipFolderPlugin.php b/apps/dav/lib/Connector/Sabre/ZipFolderPlugin.php
index a5820f80538..8484dfa1935 100644
--- a/apps/dav/lib/Connector/Sabre/ZipFolderPlugin.php
+++ b/apps/dav/lib/Connector/Sabre/ZipFolderPlugin.php
@@ -9,6 +9,9 @@ declare(strict_types=1);
 namespace OCA\DAV\Connector\Sabre;
 
 use OC\Streamer;
+use OCA\DAV\Connector\Sabre\Exception\Forbidden;
+use OCP\EventDispatcher\IEventDispatcher;
+use OCP\Files\Events\BeforeZipCreatedEvent;
 use OCP\Files\File as NcFile;
 use OCP\Files\Folder as NcFolder;
 use OCP\Files\Node as NcNode;
@@ -37,6 +40,7 @@ class ZipFolderPlugin extends ServerPlugin {
 	public function __construct(
 		private Tree $tree,
 		private LoggerInterface $logger,
+		private IEventDispatcher $eventDispatcher,
 	) {
 	}
 
@@ -114,17 +118,33 @@ class ZipFolderPlugin extends ServerPlugin {
 		if ($filesParam !== '') {
 			$files = json_decode($filesParam);
 			if (!is_array($files)) {
-				if (!is_string($files)) {
+				$files = [$files];
+			}
+
+			foreach ($files as $file) {
+				if (!is_string($file)) {
+					// we log this as this means either we - or an app - have a bug somewhere or a user is trying invalid things
+					$this->logger->notice('Invalid files filter parameter for ZipFolderPlugin', ['filter' => $filesParam]);
 					// no valid parameter so continue with Sabre behavior
-					$this->logger->debug('Invalid files filter parameter for ZipFolderPlugin', ['filter' => $filesParam]);
 					return null;
 				}
-
-				$files = [$files];
 			}
 		}
 
 		$folder = $node->getNode();
+		$event = new BeforeZipCreatedEvent($folder, $files);
+		$this->eventDispatcher->dispatchTyped($event);
+		if ((!$event->isSuccessful()) || $event->getErrorMessage() !== null) {
+			$errorMessage = $event->getErrorMessage();
+			if ($errorMessage === null) {
+				// Not allowed to download but also no explaining error
+				// so we abort the ZIP creation and fall back to Sabre default behavior.
+				return null;
+			}
+			// Downloading was denied by an app
+			throw new Forbidden($errorMessage);
+		}
+
 		$content = empty($files) ? $folder->getDirectoryListing() : [];
 		foreach ($files as $path) {
 			$child = $node->getChild($path);
diff --git a/apps/dav/lib/Server.php b/apps/dav/lib/Server.php
index 69f05395cb5..4bfc8019218 100644
--- a/apps/dav/lib/Server.php
+++ b/apps/dav/lib/Server.php
@@ -86,9 +86,9 @@ class Server {
 
 		$this->request = $request;
 		$this->baseUri = $baseUri;
-		$logger = \OC::$server->get(LoggerInterface::class);
-		/** @var IEventDispatcher $dispatcher */
-		$dispatcher = \OC::$server->get(IEventDispatcher::class);
+
+		$logger = \OCP\Server::get(LoggerInterface::class);
+		$eventDispatcher = \OCP\Server::get(IEventDispatcher::class);
 
 		$root = new RootCollection();
 		$this->server = new \OCA\DAV\Connector\Sabre\Server(new CachingTree($root));
@@ -123,10 +123,10 @@ class Server {
 
 		// allow setup of additional auth backends
 		$event = new SabrePluginEvent($this->server);
-		$dispatcher->dispatch('OCA\DAV\Connector\Sabre::authInit', $event);
+		$eventDispatcher->dispatch('OCA\DAV\Connector\Sabre::authInit', $event);
 
 		$newAuthEvent = new SabrePluginAuthInitEvent($this->server);
-		$dispatcher->dispatchTyped($newAuthEvent);
+		$eventDispatcher->dispatchTyped($newAuthEvent);
 
 		$bearerAuthBackend = new BearerAuth(
 			\OC::$server->getUserSession(),
@@ -213,12 +213,13 @@ class Server {
 		$this->server->addPlugin(new ZipFolderPlugin(
 			$this->server->tree,
 			$logger,
+			$eventDispatcher,
 		));
 
 		// allow setup of additional plugins
-		$dispatcher->dispatch('OCA\DAV\Connector\Sabre::addPlugin', $event);
+		$eventDispatcher->dispatch('OCA\DAV\Connector\Sabre::addPlugin', $event);
 		$typedEvent = new SabrePluginAddEvent($this->server);
-		$dispatcher->dispatchTyped($typedEvent);
+		$eventDispatcher->dispatchTyped($typedEvent);
 
 		// Some WebDAV clients do require Class 2 WebDAV support (locking), since
 		// we do not provide locking we emulate it using a fake locking plugin.
diff --git a/lib/public/Files/Events/BeforeZipCreatedEvent.php b/lib/public/Files/Events/BeforeZipCreatedEvent.php
index b55b36d3968..0363d385d36 100644
--- a/lib/public/Files/Events/BeforeZipCreatedEvent.php
+++ b/lib/public/Files/Events/BeforeZipCreatedEvent.php
@@ -10,23 +10,45 @@ declare(strict_types=1);
 namespace OCP\Files\Events;
 
 use OCP\EventDispatcher\Event;
+use OCP\Files\Folder;
 
 /**
+ * This event is triggered before a archive is created when a user requested
+ * downloading a folder or multiple files.
+ *
+ * By setting `successful` to false the tar creation can be aborted and the download denied.
+ *
  * @since 25.0.0
  */
 class BeforeZipCreatedEvent extends Event {
 	private string $directory;
-	private array $files;
 	private bool $successful = true;
 	private ?string $errorMessage = null;
+	private ?Folder $folder = null;
 
 	/**
+	 * @param list<string> $files
 	 * @since 25.0.0
+	 * @since 31.0.0 support `OCP\Files\Folder` as `$directory` parameter - passing a string is deprecated now
 	 */
-	public function __construct(string $directory, array $files) {
+	public function __construct(
+		string|Folder $directory,
+		private array $files,
+	) {
 		parent::__construct();
-		$this->directory = $directory;
-		$this->files = $files;
+		if ($directory instanceof Folder) {
+			$this->directory = $directory->getPath();
+			$this->folder = $directory;
+		} else {
+			$this->directory = $directory;
+		}
+	}
+
+	/**
+	 * @since 31.0.0
+	 */
+	public function getFolder(): ?Folder {
+		return $this->folder;
 	}
 
 	/**