feature(dav/connector): Add createSymlink to Directory node

apps/dav/lib/Connector/Sabre/Directory.php

@@ -196,6 +196,51 @@ public function createDirectory($name) {
 		}
 	}
 
+	/**
+	 * Creates a new symlink
+	 *
+	 * @param string $name
+	 * @param string target
+	 */
+	public function createSymlink($name, $target) {
+		try {
+			if (!$this->info->isCreatable()) {
+				throw new \Sabre\DAV\Exception\Forbidden();
+			}
+
+			// TODO: check if symlink target leaves data dir
+			$this->fileView->verifyPath($this->path, $name);
+
+			[$storage, $internalPath] = $this->fileView->resolvePath($this->path);
+			if (!$storage->instanceOfStorage(\OC\Files\Storage\Local::class)) {
+				throw new \Sabre\DAV\Exception\NotImplemented("Symlinks currently not supported on non-local storages - failed to create '$name'!");
+			}
+
+			$internalPath = $internalPath . '/' . $name;
+			$storage->unlink($internalPath);
+			if (!$storage->symlink($target, $internalPath)) {
+				throw new \Sabre\DAV\Exception\Forbidden("Could not create symlink '$name'!");
+			}
+			$storage->getUpdater()->update($internalPath);
+			$newEtag = $storage->getETag($internalPath);
+			$infoData = [
+				'type' => FileInfo::TYPE_FILE,
+				'etag' => $newEtag,
+			];
+			$path = \OC\Files\Filesystem::normalizePath($this->path . '/' . $name);
+			$this->fileView->putFileInfo($path, $infoData);
+			return '"' . $newEtag . '"';
+		} catch (\OCP\Files\StorageNotAvailableException $e) {
+			throw new ServiceUnavailable($e->getMessage(), $e->getCode(), $e);
+		} catch (InvalidPathException $ex) {
+			throw new InvalidPath($ex->getMessage(), false, $ex);
+		} catch (ForbiddenException $ex) {
+			throw new Forbidden($ex->getMessage(), $ex->getRetry(), $ex);
+		} catch (LockedException $e) {
+			throw new FileLocked($e->getMessage(), $e->getCode(), $e);
+		}
+	}
+
 	/**
 	 * Returns a specific child node, referenced by its name
 	 *