1 files changed, 199 insertions, 0 deletions
diff --git a/apps/dav/lib/Files/Sharing/FilesDropPlugin.php b/apps/dav/lib/Files/Sharing/FilesDropPlugin.php
new file mode 100644
index 00000000000..a3dbd32ce6b
--- /dev/null
+++ b/apps/dav/lib/Files/Sharing/FilesDropPlugin.php
@@ -0,0 +1,199 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2016 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCA\DAV\Files\Sharing;
+
+use OCP\Files\Folder;
+use OCP\Files\NotFoundException;
+use OCP\Share\IShare;
+use Sabre\DAV\Exception\BadRequest;
+use Sabre\DAV\Exception\MethodNotAllowed;
+use Sabre\DAV\ServerPlugin;
+use Sabre\HTTP\RequestInterface;
+use Sabre\HTTP\ResponseInterface;
+
+/**
+ * Make sure that the destination is writable
+ */
+class FilesDropPlugin extends ServerPlugin {
+
+	private ?IShare $share = null;
+	private bool $enabled = false;
+
+	public function setShare(IShare $share): void {
+		$this->share = $share;
+	}
+
+	public function enable(): void {
+		$this->enabled = true;
+	}
+
+	/**
+	 * This initializes the plugin.
+	 * It is ONLY initialized by the server on a file drop request.
+	 */
+	public function initialize(\Sabre\DAV\Server $server): void {
+		$server->on('beforeMethod:*', [$this, 'beforeMethod'], 999);
+		$server->on('method:MKCOL', [$this, 'onMkcol']);
+		$this->enabled = false;
+	}
+
+	public function onMkcol(RequestInterface $request, ResponseInterface $response) {
+		if (!$this->enabled || $this->share === null) {
+			return;
+		}
+
+		$node = $this->share->getNode();
+		if (!($node instanceof Folder)) {
+			return;
+		}
+
+		// If this is a folder creation request we need
+		// to fake a success so we can pretend every
+		// folder now exists.
+		$response->setStatus(201);
+		return false;
+	}
+
+	public function beforeMethod(RequestInterface $request, ResponseInterface $response) {
+		if (!$this->enabled || $this->share === null) {
+			return;
+		}
+
+		$node = $this->share->getNode();
+		if (!($node instanceof Folder)) {
+			return;
+		}
+
+		// Retrieve the nickname from the request
+		$nickname = $request->hasHeader('X-NC-Nickname')
+			? trim(urldecode($request->getHeader('X-NC-Nickname')))
+			: null;
+
+		if ($request->getMethod() !== 'PUT') {
+			// If uploading subfolders we need to ensure they get created
+			// within the nickname folder
+			if ($request->getMethod() === 'MKCOL') {
+				if (!$nickname) {
+					throw new BadRequest('A nickname header is required when uploading subfolders');
+				}
+			} else {
+				throw new MethodNotAllowed('Only PUT is allowed on files drop');
+			}
+		}
+
+		// If this is a folder creation request
+		// let's stop there and let the onMkcol handle it
+		if ($request->getMethod() === 'MKCOL') {
+			return;
+		}
+
+		// Now if we create a file, we need to create the
+		// full path along the way. We'll only handle conflict
+		// resolution on file conflicts, but not on folders.
+
+		// e.g files/dCP8yn3N86EK9sL/Folder/image.jpg
+		$path = $request->getPath();
+		$token = $this->share->getToken();
+
+		// e.g files/dCP8yn3N86EK9sL
+		$rootPath = substr($path, 0, strpos($path, $token) + strlen($token));
+		// e.g /Folder/image.jpg
+		$relativePath = substr($path, strlen($rootPath));
+		$isRootUpload = substr_count($relativePath, '/') === 1;
+
+		// Extract the attributes for the file request
+		$isFileRequest = false;
+		$attributes = $this->share->getAttributes();
+		if ($attributes !== null) {
+			$isFileRequest = $attributes->getAttribute('fileRequest', 'enabled') === true;
+		}
+
+		// We need a valid nickname for file requests
+		if ($isFileRequest && !$nickname) {
+			throw new BadRequest('A nickname header is required for file requests');
+		}
+
+		// We're only allowing the upload of
+		// long path with subfolders if a nickname is set.
+		// This prevents confusion when uploading files and help
+		// classify them by uploaders.
+		if (!$nickname && !$isRootUpload) {
+			throw new BadRequest('A nickname header is required when uploading subfolders');
+		}
+
+		if ($nickname) {
+			try {
+				$node->verifyPath($nickname);
+			} catch (\Exception $e) {
+				// If the path is not valid, we throw an exception
+				throw new BadRequest('Invalid nickname: ' . $nickname);
+			}
+
+			// Forbid nicknames starting with a dot
+			if (str_starts_with($nickname, '.')) {
+				throw new BadRequest('Invalid nickname: ' . $nickname);
+			}
+
+			// If we have a nickname, let's put
+			// all files in the subfolder
+			$relativePath = '/' . $nickname . '/' . $relativePath;
+			$relativePath = str_replace('//', '/', $relativePath);
+		}
+
+		// Create the folders along the way
+		$folder = $node;
+		$pathSegments = $this->getPathSegments(dirname($relativePath));
+		foreach ($pathSegments as $pathSegment) {
+			if ($pathSegment === '') {
+				continue;
+			}
+
+			try {
+				// get the current folder
+				$currentFolder = $folder->get($pathSegment);
+				// check target is a folder
+				if ($currentFolder instanceof Folder) {
+					$folder = $currentFolder;
+				} else {
+					// otherwise look in the parent folder if we already create an unique folder name
+					foreach ($folder->getDirectoryListing() as $child) {
+						// we look for folders which match "NAME (SUFFIX)"
+						if ($child instanceof Folder && str_starts_with($child->getName(), $pathSegment)) {
+							$suffix = substr($child->getName(), strlen($pathSegment));
+							if (preg_match('/^ \(\d+\)$/', $suffix)) {
+								// we found the unique folder name and can use it
+								$folder = $child;
+								break;
+							}
+						}
+					}
+					// no folder found so we need to create a new unique folder name
+					if (!isset($child) || $child !== $folder) {
+						$folder = $folder->newFolder($folder->getNonExistingName($pathSegment));
+					}
+				}
+			} catch (NotFoundException) {
+				// the folder does simply not exist so we create it
+				$folder = $folder->newFolder($pathSegment);
+			}
+		}
+
+		// Finally handle conflicts on the end files
+		$uniqueName = $folder->getNonExistingName(basename($relativePath));
+		$relativePath = substr($folder->getPath(), strlen($node->getPath()));
+		$path = '/files/' . $token . '/' . $relativePath . '/' . $uniqueName;
+		$url = rtrim($request->getBaseUrl(), '/') . str_replace('//', '/', $path);
+		$request->setUrl($url);
+	}
+
+	private function getPathSegments(string $path): array {
+		// Normalize slashes and remove trailing slash
+		$path = trim(str_replace('\\', '/', $path), '/');
+
+		return explode('/', $path);
+	}
+}