maintenance and new API v1

27 files changed, 1057 insertions, 1013 deletions

diff --git a/Makefile b/Makefile
index d25b3c49..a4180ac4 100644
--- a/Makefile
+++ b/Makefile
@@ -47,7 +47,7 @@ appstore: clean lint build-js-production
 
 ### from vueexample
 
-all: dev-setup lint build-js-production test
+all: dev-setup build-js-production
 
 # Dev env management
 dev-setup: clean clean-dev init
diff --git a/appinfo/routes.php b/appinfo/routes.php
index 59af979a..1c43732b 100644
--- a/appinfo/routes.php
+++ b/appinfo/routes.php
@@ -1,16 +1,6 @@
 <?php
-/**
- * Nextcloud - Notes
- *
- * This file is licensed under the Affero General Public License version 3 or
- * later. See the COPYING file.
- *
- * @author Bernhard Posselt <dev@bernhard-posselt.com>
- * @copyright Bernhard Posselt 2012, 2014
- */
-
 return ['routes' => [
-	// page
+	//////////  P A G E  //////////
 	[
 		'name' => 'page#index',
 		'url' => '/',
@@ -30,7 +20,8 @@ return ['routes' => [
 		'requirements' => ['id' => '\d+'],
 	],
 
-	// notes
+
+	//////////  N O T E S  //////////
 	[
 		'name' => 'notes#index',
 		'url' => '/notes',
@@ -59,22 +50,13 @@ return ['routes' => [
 		'requirements' => ['id' => '\d+'],
 	],
 	[
-		'name' => 'notes#category',
-		'url' => '/notes/{id}/category',
-		'verb' => 'PUT',
-		'requirements' => ['id' => '\d+'],
-	],
-	[
-		'name' => 'notes#title',
-		'url' => '/notes/{id}/title',
-		'verb' => 'PUT',
-		'requirements' => ['id' => '\d+'],
-	],
-	[
-		'name' => 'notes#favorite',
-		'url' => '/notes/{id}/favorite',
+		'name' => 'notes#updateProperty',
+		'url' => '/notes/{id}/{property}',
 		'verb' => 'PUT',
-		'requirements' => ['id' => '\d+'],
+		'requirements' => [
+			'id' => '\d+',
+			'property' => '(modified|title|category|favorite)',
+		],
 	],
 	[
 		'name' => 'notes#destroy',
@@ -83,43 +65,88 @@ return ['routes' => [
 		'requirements' => ['id' => '\d+'],
 	],
 
-	// api
+
+	//////////  S E T T I N G S  //////////
+	['name' => 'settings#set', 'url' => '/settings', 'verb' => 'PUT'],
+	['name' => 'settings#get', 'url' => '/settings', 'verb' => 'GET'],
+
+
+	//////////  A P I  //////////
 	[
 		'name' => 'notes_api#index',
-		'url' => '/api/v0.2/notes',
+		'url' => '/api/{apiVersion}/notes',
 		'verb' => 'GET',
+		'requirements' => [
+			'apiVersion' => '(v0.2|v1)',
+		],
 	],
 	[
 		'name' => 'notes_api#get',
-		'url' => '/api/v0.2/notes/{id}',
+		'url' => '/api/{apiVersion}/notes/{id}',
 		'verb' => 'GET',
-		'requirements' => ['id' => '\d+'],
+		'requirements' => [
+			'apiVersion' => '(v0.2|v1)',
+			'id' => '\d+',
+		],
+	],
+	[
+		'name' => 'notes_api#createAutoTitle',
+		'url' => '/api/{apiVersion}/notes',
+		'verb' => 'POST',
+		'requirements' => [
+			'apiVersion' => '(v0.2)',
+		],
 	],
 	[
 		'name' => 'notes_api#create',
-		'url' => '/api/v0.2/notes',
+		'url' => '/api/{apiVersion}/notes',
 		'verb' => 'POST',
+		'requirements' => [
+			'apiVersion' => '(v1)',
+		],
+	],
+	[
+		'name' => 'notes_api#updateAutoTitle',
+		'url' => '/api/{apiVersion}/notes/{id}',
+		'verb' => 'PUT',
+		'requirements' => [
+			'apiVersion' => '(v0.2)',
+			'id' => '\d+',
+		],
 	],
 	[
 		'name' => 'notes_api#update',
-		'url' => '/api/v0.2/notes/{id}',
+		'url' => '/api/{apiVersion}/notes/{id}',
 		'verb' => 'PUT',
-		'requirements' => ['id' => '\d+'],
+		'requirements' => [
+			'apiVersion' => '(v1)',
+			'id' => '\d+',
+		],
 	],
 	[
 		'name' => 'notes_api#destroy',
-		'url' => '/api/v0.2/notes/{id}',
+		'url' => '/api/{apiVersion}/notes/{id}',
 		'verb' => 'DELETE',
-		'requirements' => ['id' => '\d+'],
+		'requirements' => [
+			'apiVersion' => '(v0.2|v1)',
+			'id' => '\d+',
+		],
+	],
+	[
+		'name' => 'notes_api#fail',
+		'url' => '/api/{catchAll}',
+		'verb' => 'GET',
+		'requirements' => [
+			'catchAll' => '.*',
+		],
 	],
 	[
 		'name' => 'notes_api#preflighted_cors',
-		'url' => '/api/v0.2/{path}',
+		'url' => '/api/{apiVersion}/{path}',
 		'verb' => 'OPTIONS',
-		'requirements' => ['path' => '.+'],
+		'requirements' => [
+			'apiVersion' => '(v0.2|v1)',
+			'path' => '.+',
+		],
 	],
-
-	// settings
-	['name' => 'settings#set', 'url' => '/settings', 'verb' => 'PUT'],
-	['name' => 'settings#get', 'url' => '/settings', 'verb' => 'GET'],
 ]];
diff --git a/lib/Application.php b/lib/Application.php
index 1f9010a6..a92bf5f7 100644
--- a/lib/Application.php
+++ b/lib/Application.php
@@ -6,6 +6,8 @@ use OCP\AppFramework\App;
 
 class Application extends App {
 
+	public static $API_VERSIONS = [ '0.2', '1.0' ];
+
 	public function __construct(array $urlParams = []) {
 		parent::__construct('notes', $urlParams);
 	}
diff --git a/lib/Capabilities.php b/lib/Capabilities.php
index 0f05aa78..8f4a0010 100644
--- a/lib/Capabilities.php
+++ b/lib/Capabilities.php
@@ -9,7 +9,7 @@ class Capabilities implements ICapability {
 	public function getCapabilities() {
 		return [
 			'notes' => [
-				'api_version' => [ '0.2' ],
+				'api_version' => Application::$API_VERSIONS,
 			],
 		];
 	}
diff --git a/lib/Controller/Errors.php b/lib/Controller/Errors.php
deleted file mode 100644
index 138f05d8..00000000
--- a/lib/Controller/Errors.php
+++ /dev/null
@@ -1,27 +0,0 @@
-<?php
-
-namespace OCA\Notes\Controller;
-
-use OCP\AppFramework\Http;
-use OCP\AppFramework\Http\DataResponse;
-
-use OCA\Notes\Service\NoteDoesNotExistException;
-
-/**
- * Class Errors
- *
- * @package OCA\Notes\Controller
- */
-trait Errors {
-	/**
-	 * @param $callback
-	 * @return DataResponse
-	 */
-	protected function respond($callback) {
-		try {
-			return new DataResponse($callback());
-		} catch (NoteDoesNotExistException $ex) {
-			return new DataResponse([], Http::STATUS_NOT_FOUND);
-		}
-	}
-}
diff --git a/lib/Controller/Helper.php b/lib/Controller/Helper.php
new file mode 100644
index 00000000..7eaf1dbe
--- /dev/null
+++ b/lib/Controller/Helper.php
@@ -0,0 +1,43 @@
+<?php declare(strict_types=1);
+
+namespace OCA\Notes\Controller;
+
+use OCA\Notes\Application;
+use OCA\Notes\Service\InsufficientStorageException;
+use OCA\Notes\Service\NoteDoesNotExistException;
+
+use OCP\AppFramework\Http;
+use OCP\AppFramework\Http\DataResponse;
+use OCP\ILogger;
+
+class Helper {
+
+	private $logger;
+	private $appName;
+
+	public function __construct(
+		ILogger $logger,
+		string $appName
+	) {
+		$this->logger = $logger;
+		$this->appName = $appName;
+	}
+
+	public function handleErrorResponse(callable $respond) : DataResponse {
+		try {
+			$data = $respond();
+			$response = $data instanceof DataResponse ? $data : new DataResponse($data);
+		} catch (NoteDoesNotExistException $e) {
+			$this->logger->logException($e, [ 'app' => $this->appName ]);
+			$response = new DataResponse([], Http::STATUS_NOT_FOUND);
+		} catch (InsufficientStorageException $e) {
+			$this->logger->logException($e, [ 'app' => $this->appName ]);
+			$response = new DataResponse([], Http::STATUS_INSUFFICIENT_STORAGE);
+		} catch (\Throwable $e) {
+			$this->logger->logException($e, [ 'app' => $this->appName ]);
+			$response = new DataResponse([], Http::STATUS_INTERNAL_SERVER_ERROR);
+		}
+		$response->addHeader('X-Notes-API-Versions', implode(', ', Application::$API_VERSIONS));
+		return $response;
+	}
+}
diff --git a/lib/Controller/NotesApiController.php b/lib/Controller/NotesApiController.php
index 52b553e2..f8e62ef3 100644
--- a/lib/Controller/NotesApiController.php
+++ b/lib/Controller/NotesApiController.php
@@ -1,106 +1,74 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace OCA\Notes\Controller;
 
+use OCA\Notes\Service\NotesService;
+use OCA\Notes\Service\MetaService;
+
 use OCP\AppFramework\ApiController;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\DataResponse;
 use OCP\IRequest;
 use OCP\IUserSession;
 
-use OCA\Notes\Service\NotesService;
-use OCA\Notes\Service\MetaService;
-use OCA\Notes\Service\InsufficientStorageException;
-use OCA\Notes\Service\NoteDoesNotExistException;
-use OCA\Notes\Db\Note;
-
-/**
- * Class NotesApiController
- *
- * @package OCA\Notes\Controller
- */
 class NotesApiController extends ApiController {
 
-	use Errors;
-
 	/** @var NotesService */
 	private $service;
 	/** @var MetaService */
 	private $metaService;
+	/** @var Helper */
+	private $helper;
 	/** @var IUserSession */
 	private $userSession;
 
-	/**
-	 * @param string $AppName
-	 * @param IRequest $request
-	 * @param NotesService $service
-	 * @param IUserSession $userSession
-	 */
 	public function __construct(
-		$AppName,
+		string $AppName,
 		IRequest $request,
 		NotesService $service,
 		MetaService $metaService,
+		Helper $helper,
 		IUserSession $userSession
 	) {
 		parent::__construct($AppName, $request);
 		$this->service = $service;
 		$this->metaService = $metaService;
+		$this->helper = $helper;
 		$this->userSession = $userSession;
 	}
 
-	private function getUID() {
+	private function getUID() : string {
 		return $this->userSession->getUser()->getUID();
 	}
 
-	/**
-	 * @param Note $note
-	 * @param string[] $exclude the fields that should be removed from the
-	 * notes
-	 * @return Note
-	 */
-	private function excludeFields(Note &$note, array $exclude) {
-		if (count($exclude) > 0) {
-			foreach ($exclude as $field) {
-				if (property_exists($note, $field)) {
-					unset($note->$field);
-				}
-			}
-		}
-		return $note;
-	}
-
 
 	/**
 	 * @NoAdminRequired
 	 * @CORS
 	 * @NoCSRFRequired
-	 *
-	 * @param string $exclude
-	 * @return DataResponse
 	 */
-	public function index($exclude = '', $pruneBefore = 0) {
-		$exclude = explode(',', $exclude);
-		$now = new \DateTime(); // this must be before loading notes if there are concurrent changes possible
-		$notes = $this->service->getAll($this->getUID());
-		$metas = $this->metaService->updateAll($this->getUID(), $notes);
-		foreach ($notes as $note) {
-			$lastUpdate = $metas[$note->getId()]->getLastUpdate();
-			if ($pruneBefore && $lastUpdate<$pruneBefore) {
-				$vars = get_object_vars($note);
-				unset($vars['id']);
-				$this->excludeFields($note, array_keys($vars));
-			} else {
-				$this->excludeFields($note, $exclude);
+	public function index(string $exclude = '', int $pruneBefore = 0) : DataResponse {
+		return $this->helper->handleErrorResponse(function () use ($exclude, $pruneBefore) {
+			$exclude = explode(',', $exclude);
+			$now = new \DateTime(); // this must be before loading notes if there are concurrent changes possible
+			$notes = $this->service->getAll($this->getUID());
+			$metas = $this->metaService->updateAll($this->getUID(), $notes);
+			$notesData = array_map(function ($note) use ($metas, $pruneBefore, $exclude) {
+				$lastUpdate = $metas[$note->getId()]->getLastUpdate();
+				if ($pruneBefore && $lastUpdate<$pruneBefore) {
+					return [ 'id' => $note->getId() ];
+				} else {
+					return $note->getData($exclude);
+				}
+			}, $notes);
+			$etag = md5(json_encode($notesData));
+			if ($this->request->getHeader('If-None-Match') === '"'.$etag.'"') {
+				return new DataResponse([], Http::STATUS_NOT_MODIFIED);
 			}
-		}
-		$etag = md5(json_encode($notes));
-		if ($this->request->getHeader('If-None-Match') === '"'.$etag.'"') {
-			return new DataResponse([], Http::STATUS_NOT_MODIFIED);
-		}
-		return (new DataResponse($notes))
-			->setLastModified($now)
-			->setETag($etag);
+			return (new DataResponse($notesData))
+				->setLastModified($now)
+				->setETag($etag);
+		});
 	}
 
 
@@ -108,20 +76,13 @@ class NotesApiController extends ApiController {
 	 * @NoAdminRequired
 	 * @CORS
 	 * @NoCSRFRequired
-	 *
-	 * @param int $id
-	 * @param string $exclude
-	 * @return DataResponse
 	 */
-	public function get($id, $exclude = '') {
-		try {
+	public function get(int $id, string $exclude = '') : DataResponse {
+		return $this->helper->handleErrorResponse(function () use ($id, $exclude) {
 			$exclude = explode(',', $exclude);
-			$note = $this->service->get($id, $this->getUID());
-			$note = $this->excludeFields($note, $exclude);
-			return new DataResponse($note);
-		} catch (NoteDoesNotExistException $e) {
-			return new DataResponse([], Http::STATUS_NOT_FOUND);
-		}
+			$note = $this->service->get($this->getUID(), $id);
+			return $note->getData($exclude);
+		});
 	}
 
 
@@ -129,86 +90,134 @@ class NotesApiController extends ApiController {
 	 * @NoAdminRequired
 	 * @CORS
 	 * @NoCSRFRequired
-	 *
-	 * @param string $content
-	 * @param string $category
-	 * @param int $modified
-	 * @param boolean $favorite
-	 * @return DataResponse
 	 */
-	public function create($content, $category = null, $modified = 0, $favorite = null) {
-		try {
-			$note = $this->service->create($this->getUID());
+	public function create(
+		string $category = '',
+		string $title = '',
+		string $content = '',
+		int $modified = 0,
+		bool $favorite = false
+	) : DataResponse {
+		return $this->helper->handleErrorResponse(function () use ($category, $title, $content, $modified, $favorite) {
+			$note = $this->service->create($this->getUID(), $title, $category);
 			try {
-				$note = $this->updateData($note->getId(), $content, $category, $modified, $favorite);
+				$note->setContent($content);
+				if ($modified) {
+					$note->setModified($modified);
+				}
+				if ($favorite) {
+					$note->setFavorite($favorite);
+				}
 			} catch (\Throwable $e) {
 				// roll-back note creation
-				$this->service->delete($note->getId(), $this->getUID());
+				$this->service->delete($this->getUID(), $note->getId());
 				throw $e;
 			}
-			return new DataResponse($note);
-		} catch (InsufficientStorageException $e) {
-			return new DataResponse([], Http::STATUS_INSUFFICIENT_STORAGE);
-		}
+			return $note->getData();
+		});
 	}
 
+	/**
+	 * @NoAdminRequired
+	 * @CORS
+	 * @NoCSRFRequired
+	 * @deprecated this was used in API v0.2 only, use #create() instead
+	 */
+	public function createAutoTitle(
+		string $category = '',
+		string $content = '',
+		int $modified = 0,
+		bool $favorite = false
+	) : DataResponse {
+		return $this->helper->handleErrorResponse(function () use ($category, $content, $modified, $favorite) {
+			$title = $this->service->getTitleFromContent($content);
+			return $this->create($category, $title, $content, $modified, $favorite);
+		});
+	}
 
 	/**
 	 * @NoAdminRequired
 	 * @CORS
 	 * @NoCSRFRequired
-	 *
-	 * @param int $id
-	 * @param string $content
-	 * @param string $category
-	 * @param int $modified
-	 * @param boolean $favorite
-	 * @return DataResponse
 	 */
-	public function update($id, $content = null, $category = null, $modified = 0, $favorite = null) {
-		try {
-			$note = $this->updateData($id, $content, $category, $modified, $favorite);
-			return new DataResponse($note);
-		} catch (NoteDoesNotExistException $e) {
-			return new DataResponse([], Http::STATUS_NOT_FOUND);
-		} catch (InsufficientStorageException $e) {
-			return new DataResponse([], Http::STATUS_INSUFFICIENT_STORAGE);
-		}
+	public function update(
+		int $id,
+		?string $content = null,
+		?int $modified = null,
+		?string $title = null,
+		?string $category = null,
+		?bool $favorite = null
+	) : DataResponse {
+		return $this->helper->handleErrorResponse(function () use (
+			$id,
+			$content,
+			$modified,
+			$title,
+			$category,
+			$favorite
+		) {
+			$note = $this->service->get($this->getUID(), $id);
+			if ($content !== null) {
+				$note->setContent($content);
+			}
+			if ($modified !== null) {
+				$note->setModified($modified);
+			}
+			if ($title !== null) {
+				$note->setTitleCategory($title, $category);
+			} elseif ($category !== null) {
+				$note->setCategory($category);
+			}
+			if ($favorite !== null) {
+				$note->setFavorite($favorite);
+			}
+			return $note->getData();
+		});
 	}
 
 	/**
-	 * Updates a note, used by create and update
-	 * @param int $id
-	 * @param string|null $content
-	 * @param int $modified
-	 * @param boolean|null $favorite
-	 * @return Note
+	 * @NoAdminRequired
+	 * @CORS
+	 * @NoCSRFRequired
+	 * @deprecated this was used in API v0.2 only, use #update() instead
 	 */
-	private function updateData($id, $content, $category, $modified, $favorite) {
-		if ($favorite!==null) {
-			$this->service->favorite($id, $favorite, $this->getUID());
-		}
-		if ($content===null) {
-			return $this->service->get($id, $this->getUID());
-		} else {
-			return $this->service->update($id, $content, $this->getUID(), $category, $modified);
-		}
+	public function updateAutoTitle(
+		int $id,
+		?string $content = null,
+		?int $modified = null,
+		?string $category = null,
+		?bool $favorite = null
+	) : DataResponse {
+		return $this->helper->handleErrorResponse(function () use ($id, $content, $modified, $category, $favorite) {
+			if ($content === null) {
+				$note = $this->service->get($this->getUID(), $id);
+				$title = $this->service->getTitleFromContent($note->getContent());
+			} else {
+				$title = $this->service->getTitleFromContent($content);
+			}
+			return $this->update($id, $content, $modified, $title, $category, $favorite);
+		});
 	}
 
 	/**
 	 * @NoAdminRequired
 	 * @CORS
 	 * @NoCSRFRequired
-	 *
-	 * @param int $id
-	 * @return DataResponse
 	 */
-	public function destroy($id) {
-		try {
-			$this->service->delete($id, $this->getUID());
-			return new DataResponse([]);
-		} catch (NoteDoesNotExistException $e) {
-			return new DataResponse([], Http::STATUS_NOT_FOUND);
-		}
+	public function destroy(int $id) : DataResponse {
+		return $this->helper->handleErrorResponse(function () use ($id) {
+			$this->service->delete($this->getUID(), $id);
+			return [];
+		});
+	}
+
+	/**
+	 * @NoAdminRequired
+	 * @NoCSRFRequired
+	 */
+	public function fail() : DataResponse {
+		return $this->helper->handleErrorResponse(function () {
+			return new DataResponse([], Http::STATUS_BAD_REQUEST);
+		});
 	}
 }
diff --git a/lib/Controller/NotesController.php b/lib/Controller/NotesController.php
index 13d22697..c2be6e73 100644
--- a/lib/Controller/NotesController.php
+++ b/lib/Controller/NotesController.php
@@ -1,7 +1,10 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace OCA\Notes\Controller;
 
+use OCA\Notes\Service\NotesService;
+use OCA\Notes\Service\SettingsService;
+
 use OCP\AppFramework\Controller;
 use OCP\IRequest;
 use OCP\IConfig;
@@ -9,23 +12,14 @@ use OCP\IL10N;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\DataResponse;
 
-use OCA\Notes\Service\NotesService;
-use OCA\Notes\Service\SettingsService;
-use OCA\Notes\Service\InsufficientStorageException;
-
-/**
- * Class NotesController
- *
- * @package OCA\Notes\Controller
- */
 class NotesController extends Controller {
 
-	use Errors;
-
 	/** @var NotesService */
 	private $notesService;
 	/** @var SettingsService */
 	private $settingsService;
+	/** @var Helper */
+	private $helper;
 	/** @var IConfig */
 	private $settings;
 	/** @var string */
@@ -33,27 +27,20 @@ class NotesController extends Controller {
 	/** @var IL10N */
 	private $l10n;
 
-	/**
-	 * @param string $AppName
-	 * @param IRequest $request
-	 * @param NotesService $notesService
-	 * @param SettingsService $settingsService
-	 * @param IConfig $settings
-	 * @param IL10N $l10n
-	 * @param string $UserId
-	 */
 	public function __construct(
-		$AppName,
+		string $AppName,
 		IRequest $request,
 		NotesService $notesService,
 		SettingsService $settingsService,
+		Helper $helper,
 		IConfig $settings,
 		IL10N $l10n,
-		$UserId
+		string $UserId
 	) {
 		parent::__construct($AppName, $request);
 		$this->notesService = $notesService;
 		$this->settingsService = $settingsService;
+		$this->helper = $helper;
 		$this->settings = $settings;
 		$this->userId = $UserId;
 		$this->l10n = $l10n;
@@ -63,176 +50,199 @@ class NotesController extends Controller {
 	/**
 	 * @NoAdminRequired
 	 */
-	public function index() {
-		$settings = $this->settingsService->getAll($this->userId);
-
-		$errorMessage = null;
-		$lastViewedNote = (int) $this->settings->getUserValue(
-			$this->userId,
-			$this->appName,
-			'notesLastViewedNote'
-		);
-		// check if notes folder is accessible
-		$notes = null;
-		try {
-			$notes = $this->notesService->getAll($this->userId, true);
-			if ($lastViewedNote) {
-				// check if note exists
-				try {
-					$this->notesService->get($lastViewedNote, $this->userId);
-				} catch (\Exception $ex) {
-					$this->settings->deleteUserValue($this->userId, $this->appName, 'notesLastViewedNote');
-					$lastViewedNote = 0;
-					$errorMessage = $this->l10n->t('The last viewed note cannot be accessed. ').$ex->getMessage();
+	public function index() : DataResponse {
+		return $this->helper->handleErrorResponse(function () {
+			$settings = $this->settingsService->getAll($this->userId);
+
+			$errorMessage = null;
+			$lastViewedNote = (int) $this->settings->getUserValue(
+				$this->userId,
+				$this->appName,
+				'notesLastViewedNote'
+			);
+			// check if notes folder is accessible
+			$notes = null;
+			try {
+				$notes = $this->notesService->getAll($this->userId);
+				$notesData = array_map(function ($note) {
+					return $note->getData([ 'content' ]);
+				}, $notes);
+				if ($lastViewedNote) {
+					// check if note exists
+					try {
+						$this->notesService->get($this->userId, $lastViewedNote);
+					} catch (\Exception $ex) {
+						$this->settings->deleteUserValue($this->userId, $this->appName, 'notesLastViewedNote');
+						$lastViewedNote = 0;
+						$errorMessage = $this->l10n->t('The last viewed note cannot be accessed. ').$ex->getMessage();
+					}
 				}
+			} catch (\Exception $e) {
+				$errorMessage = $this->l10n->t('The notes folder is not accessible: %s', $e->getMessage());
 			}
-		} catch (\Exception $e) {
-			$errorMessage = $this->l10n->t('The notes folder is not accessible: %s', $e->getMessage());
-		}
-
-		return new DataResponse([
-			'notes' => $notes,
-			'settings' => $settings,
-			'lastViewedNote' => $lastViewedNote,
-			'errorMessage' => $errorMessage,
-		]);
-	}
-
 
-	/**
-	 * @NoAdminRequired
-	 *
-	 * @param int $id
-	 * @return DataResponse
-	 */
-	public function get($id) {
-		// save the last viewed note
-		$this->settings->setUserValue(
-			$this->userId,
-			$this->appName,
-			'notesLastViewedNote',
-			strval($id)
-		);
-
-		$note = $this->notesService->get($id, $this->userId);
-		return new DataResponse($note);
+			return [
+				'notes' => $notesData,
+				'settings' => $settings,
+				'lastViewedNote' => $lastViewedNote,
+				'errorMessage' => $errorMessage,
+			];
+		});
 	}
 
 
 	/**
 	 * @NoAdminRequired
-	 *
-	 * @param string $content
 	 */
-	public function create($content = '', $category = null) {
-		try {
-			$note = $this->notesService->create($this->userId);
-			$note = $this->notesService->update(
-				$note->getId(),
-				$content,
-				$this->userId,
-				$category
-			);
-			return new DataResponse($note);
-		} catch (InsufficientStorageException $e) {
-			return new DataResponse([], Http::STATUS_INSUFFICIENT_STORAGE);
-		}
-	}
-
+	public function get(int $id) : DataResponse {
+		return $this->helper->handleErrorResponse(function () use ($id) {
+			$note = $this->notesService->get($this->userId, $id);
 
-	/**
-	 * @NoAdminRequired
-	 *
-	 * @param string $content
-	 */
-	public function undo($id, $content, $category, $modified, $favorite) {
-		try {
-			// check if note still exists
-			$note = $this->notesService->get($id, $this->userId);
-			if ($note->getError()) {
-				throw new \Exception();
-			}
-		} catch (\Throwable $e) {
-			// re-create if note doesn't exit anymore
-			$note = $this->notesService->create($this->userId);
-			$note = $this->notesService->update(
-				$note->getId(),
-				$content,
+			// save the last viewed note
+			$this->settings->setUserValue(
 				$this->userId,
-				$category,
-				$modified
+				$this->appName,
+				'notesLastViewedNote',
+				strval($id)
 			);
-			$note->favorite = $this->notesService->favorite($note->getId(), $favorite, $this->userId);
-		}
-		return new DataResponse($note);
+
+			return $note->getData();
+		});
 	}
 
 
 	/**
 	 * @NoAdminRequired
 	 */
-	public function update(int $id, string $content, bool $autotitle) : DataResponse {
-		try {
-			if ($autotitle) {
-				$note = $this->notesService->update($id, $content, $this->userId);
-			} else {
-				$note = $this->notesService->setContent($this->userId, $id, $content);
-			}
-			return new DataResponse($note);
-		} catch (InsufficientStorageException $e) {
-			return new DataResponse([], Http::STATUS_INSUFFICIENT_STORAGE);
-		}
+	public function create(string $category) : DataResponse {
+		return $this->helper->handleErrorResponse(function () use ($category) {
+			$note = $this->notesService->create($this->userId, '', $category);
+			$note->setContent('');
+			return $note->getData();
+		});
 	}
 
 
-
 	/**
 	 * @NoAdminRequired
-	 *
-	 * @param int $id
-	 * @param string $category
-	 * @return DataResponse
 	 */
-	public function category($id, $category) {
-		$note = $this->notesService->setTitleCategory($this->userId, $id, null, $category);
-		return new DataResponse($note->getCategory()); // @phan-suppress-current-line PhanTypeMismatchArgument
+	public function undo(
+		int $id,
+		string $title,
+		string $content,
+		string $category,
+		int $modified,
+		bool $favorite
+	) : DataResponse {
+		return $this->helper->handleErrorResponse(function () use (
+			$id,
+			$title,
+			$content,
+			$category,
+			$modified,
+			$favorite
+		) {
+			try {
+				// check if note still exists
+				$note = $this->notesService->get($this->userId, $id);
+				$noteData = $note->getData();
+				if ($noteData['error']) {
+					throw new \Exception();
+				}
+				return $noteData;
+			} catch (\Throwable $e) {
+				// re-create if note doesn't exit anymore
+				$note = $this->notesService->create($this->userId, $title, $category);
+				$note->setContent($content);
+				$note->setModified($modified);
+				$note->setFavorite($favorite);
+				return $note->getData();
+			}
+		});
 	}
 
 
 	/**
 	 * @NoAdminRequired
-	 *
-	 * @param int $id
-	 * @param string $title
-	 * @return DataResponse
 	 */
-	public function title($id, $title) {
-		$note = $this->notesService->setTitleCategory($this->userId, $id, $title, null);
-		return new DataResponse($note->getTitle()); // @phan-suppress-current-line PhanTypeMismatchArgument
+	public function update(int $id, string $content, bool $autotitle) : DataResponse {
+		return $this->helper->handleErrorResponse(function () use ($id, $content, $autotitle) {
+			$note = $this->notesService->get($this->userId, $id);
+			$note->setContent($content);
+			if ($autotitle) {
+				$title = $this->notesService->getTitleFromContent($content);
+				$note->setTitle($title);
+			}
+			return $note->getData();
+		});
 	}
 
 
 	/**
 	 * @NoAdminRequired
-	 *
-	 * @param int $id
-	 * @param boolean $favorite
-	 * @return DataResponse
 	 */
-	public function favorite($id, $favorite) {
-		$result = $this->notesService->favorite($id, $favorite, $this->userId);
-		return new DataResponse($result); // @phan-suppress-current-line PhanTypeMismatchArgument
+	public function updateProperty(
+		int $id,
+		string $property,
+		?int $modified = null,
+		?string $title = null,
+		?string $category = null,
+		?bool $favorite = null
+	) : DataResponse {
+		return $this->helper->handleErrorResponse(function () use (
+			$id,
+			$property,
+			$modified,
+			$title,
+			$category,
+			$favorite
+		) {
+			$note = $this->notesService->get($this->userId, $id);
+			$result = null;
+			switch ($property) {
+				case 'modified':
+					if ($modified !== null) {
+						$note->setModified($modified);
+					}
+					$result = $note->getModified();
+					break;
+
+				case 'title':
+					if ($title !== null) {
+						$note->setTitle($title);
+					}
+					$result = $note->getTitle();
+					break;
+
+				case 'category':
+					if ($category !== null) {
+						$note->setCategory($category);
+					}
+					$result = $note->getCategory();
+					break;
+
+				case 'favorite':
+					if ($favorite !== null) {
+						$note->setFavorite($favorite);
+					}
+					$result = $note->getFavorite();
+					break;
+
+				default:
+					return new DataResponse([], Http::STATUS_BAD_REQUEST);
+			}
+			return $result;
+		});
 	}
 
 
 	/**
 	 * @NoAdminRequired
-	 *
-	 * @param int $id
-	 * @return DataResponse
 	 */
-	public function destroy($id) {
-		$this->notesService->delete($id, $this->userId);
-		return new DataResponse([]);
+	public function destroy(int $id) : DataResponse {
+		return $this->helper->handleErrorResponse(function () use ($id) {
+			$this->notesService->delete($this->userId, $id);
+			return [];
+		});
 	}
 }
diff --git a/lib/Controller/PageController.php b/lib/Controller/PageController.php
index e595116e..03fe7896 100644
--- a/lib/Controller/PageController.php
+++ b/lib/Controller/PageController.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace OCA\Notes\Controller;
 
@@ -7,18 +7,9 @@ use OCP\AppFramework\Http\TemplateResponse;
 use OCP\AppFramework\Http\ContentSecurityPolicy;
 use OCP\IRequest;
 
-/**
- * Class PageController
- *
- * @package OCA\Notes\Controller
- */
 class PageController extends Controller {
 
-	/**
-	 * @param string $AppName
-	 * @param IRequest $request
-	 */
-	public function __construct($AppName, IRequest $request) {
+	public function __construct(string $AppName, IRequest $request) {
 		parent::__construct($AppName, $request);
 	}
 
@@ -29,7 +20,7 @@ class PageController extends Controller {
 	 *
 	 * @return TemplateResponse
 	 */
-	public function index() {
+	public function index() : TemplateResponse {
 		$devMode = !is_file(dirname(__FILE__).'/../../js/notes.js');
 		$response = new TemplateResponse(
 			$this->appName,
diff --git a/lib/Controller/SettingsController.php b/lib/Controller/SettingsController.php
index 19b00b79..681e7763 100644
--- a/lib/Controller/SettingsController.php
+++ b/lib/Controller/SettingsController.php
@@ -1,12 +1,13 @@
-<?php
+<?php declare(strict_types=1);
+
 namespace OCA\Notes\Controller;
 
-use OCP\AppFramework\Controller;
+use OCA\Notes\Service\SettingsService;
 
+use OCP\AppFramework\Controller;
+use OCP\AppFramework\Http\JSONResponse;
 use OCP\IRequest;
 use OCP\IUserSession;
-use OCP\AppFramework\Http\JSONResponse;
-use OCA\Notes\Service\SettingsService;
 
 class SettingsController extends Controller {
 
@@ -14,7 +15,7 @@ class SettingsController extends Controller {
 	private $userSession;
 
 	public function __construct(
-		$appName,
+		string $appName,
 		IRequest $request,
 		SettingsService $service,
 		IUserSession $userSession
diff --git a/lib/Db/Meta.php b/lib/Db/Meta.php
index e970ed00..9144bea8 100644
--- a/lib/Db/Meta.php
+++ b/lib/Db/Meta.php
@@ -2,6 +2,8 @@
 
 namespace OCA\Notes\Db;
 
+use OCA\Notes\Service\Note;
+
 use OCP\AppFramework\Db\Entity;
 
 /**
diff --git a/lib/Db/Note.php b/lib/Db/Note.php
deleted file mode 100644
index 69411de1..00000000
--- a/lib/Db/Note.php
+++ /dev/null
@@ -1,123 +0,0 @@
-<?php
-
-namespace OCA\Notes\Db;
-
-use OCP\Files\File;
-use OCP\Files\Folder;
-use OCP\AppFramework\Db\Entity;
-
-/**
- * Class Note
- * @method integer getId()
- * @method void setId(integer $value)
- * @method string getEtag()
- * @method void setEtag(string $value)
- * @method integer getModified()
- * @method void setModified(integer $value)
- * @method string getTitle()
- * @method void setTitle(string $value)
- * @method string getCategory()
- * @method void setCategory(string $value)
- * @method string getContent()
- * @method void setContent(string $value)
- * @method boolean getFavorite()
- * @method void setFavorite(boolean $value)
- * @method boolean getError()
- * @method void setError(boolean $value)
- * @method string getErrorMessage()
- * @method void setErrorMessage(string $value)
- * @package OCA\Notes\Db
- */
-class Note extends Entity {
-	public $etag;
-	public $modified;
-	public $title;
-	public $category;
-	public $content = null;
-	public $favorite = false;
-	public $error = false;
-	public $errorMessage='';
-
-	public function __construct() {
-		$this->addType('modified', 'integer');
-		$this->addType('favorite', 'boolean');
-	}
-
-	/**
-	 * @param File $file
-	 * @return static
-	 */
-	public static function fromFile(File $file, Folder $notesFolder, $tags = [], $onlyMeta = false) {
-		$note = new static();
-		$note->initCommonBaseFields($file, $notesFolder, $tags);
-		if (!$onlyMeta) {
-			$fileContent=$file->getContent();
-			$note->setContent(self::convertEncoding($fileContent));
-		}
-		if (!$onlyMeta) {
-			$note->updateETag();
-		}
-		$note->resetUpdatedFields();
-		return $note;
-	}
-
-	/**
-	 * @param File $file
-	 * @return static
-	 */
-	public static function fromException($message, File $file, Folder $notesFolder, $tags = []) {
-		$note = new static();
-		$note->initCommonBaseFields($file, $notesFolder, $tags);
-		$note->setErrorMessage($message);
-		$note->setError(true);
-		$note->setContent($message);
-		$note->resetUpdatedFields();
-		return $note;
-	}
-
-	private static function convertEncoding($str) {
-		if (!mb_check_encoding($str, 'UTF-8')) {
-			$str = mb_convert_encoding($str, 'UTF-8');
-		}
-		return $str;
-	}
-
-	// TODO NC19: replace this by OCP\ITags::TAG_FAVORITE
-	// OCP\ITags::TAG_FAVORITE was introduced in NC19
-	// https://github.com/nextcloud/server/pull/19412
-	/**
-	 * @suppress PhanUndeclaredClassConstant
-	 * @suppress PhanUndeclaredConstant
-	 * @suppress PhanUndeclaredConstantOfClass
-	 */
-	private static function getTagFavorite() {
-		if (defined('OCP\ITags::TAG_FAVORITE')) {
-			return \OCP\ITags::TAG_FAVORITE;
-		} else {
-			return \OC\Tags::TAG_FAVORITE;
-		}
-	}
-
-	private function initCommonBaseFields(File $file, Folder $notesFolder, $tags) {
-		$this->setId($file->getId());
-		$this->setTitle(pathinfo($file->getName(), PATHINFO_FILENAME)); // remove extension
-		$this->setModified($file->getMTime());
-		$subdir = substr(dirname($file->getPath()), strlen($notesFolder->getPath())+1);
-		$this->setCategory($subdir ? $subdir : '');
-		if (is_array($tags) && in_array(self::getTagFavorite(), $tags)) {
-			$this->setFavorite(true);
-		}
-	}
-
-	private function updateETag() {
-		// collect all relevant attributes
-		$data = '';
-		foreach (get_object_vars($this) as $key => $val) {
-			if ($key!=='etag') {
-				$data .= $val;
-			}
-		}
-		$etag = md5($data);
-		$this->setEtag($etag);
-	}
-}
diff --git a/lib/Service/InsufficientStorageException.php b/lib/Service/InsufficientStorageException.php
index d62cd6a3..78821d3b 100644
--- a/lib/Service/InsufficientStorageException.php
+++ b/lib/Service/InsufficientStorageException.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace OCA\Notes\Service;
 
diff --git a/lib/Service/MetaService.php b/lib/Service/MetaService.php
index 337ea03d..e4da1333 100644
--- a/lib/Service/MetaService.php
+++ b/lib/Service/MetaService.php
@@ -1,15 +1,10 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace OCA\Notes\Service;
 
 use OCA\Notes\Db\Meta;
 use OCA\Notes\Db\MetaMapper;
 
-/**
- * Class MetaService
- *
- * @package OCA\Notes\Service
- */
 class MetaService {
 
 	private $metaMapper;
@@ -18,7 +13,7 @@ class MetaService {
 		$this->metaMapper = $metaMapper;
 	}
 
-	public function updateAll($userId, Array $notes) {
+	public function updateAll(string $userId, array $notes) : array {
 		$metas = $this->metaMapper->getAll($userId);
 		$metas = $this->getIndexedArray($metas, 'fileId');
 		$notes = $this->getIndexedArray($notes, 'id');
@@ -42,7 +37,7 @@ class MetaService {
 		return $metas;
 	}
 
-	private function getIndexedArray(array $data, $property) {
+	private function getIndexedArray(array $data, string $property) : array {
 		$property = ucfirst($property);
 		$getter = 'get'.$property;
 		$result = array();
@@ -52,13 +47,13 @@ class MetaService {
 		return $result;
 	}
 
-	private function create($userId, $note) {
+	private function create(string $userId, Note $note) : Meta {
 		$meta = Meta::fromNote($note, $userId);
 		$this->metaMapper->insert($meta);
 		return $meta;
 	}
 
-	private function updateIfNeeded(&$meta, $note) {
+	private function updateIfNeeded(Meta &$meta, Note $note) : void {
 		if ($note->getEtag()!==$meta->getEtag()) {
 			$meta->setEtag($note->getEtag());
 			$meta->setLastUpdate(time());
diff --git a/lib/Service/Note.php b/lib/Service/Note.php
new file mode 100644
index 00000000..1fa3192c
--- /dev/null
+++ b/lib/Service/Note.php
@@ -0,0 +1,141 @@
+<?php declare(strict_types=1);
+
+namespace OCA\Notes\Service;
+
+use OCP\Files\File;
+use OCP\Files\Folder;
+
+class Note {
+
+	private $file;
+	private $notesFolder;
+	private $noteUtil;
+
+	public function __construct(File $file, Folder $notesFolder, NoteUtil $noteUtil) {
+		$this->file = $file;
+		$this->notesFolder = $notesFolder;
+		$this->noteUtil = $noteUtil;
+	}
+
+
+	public function getId() : int {
+		return $this->file->getId();
+	}
+
+	public function getTitle() : string {
+		return pathinfo($this->file->getName(), PATHINFO_FILENAME);
+	}
+
+	public function getCategory() : string {
+		$subdir = substr(
+			dirname($this->file->getPath()),
+			strlen($this->notesFolder->getPath()) + 1
+		);
+		return $subdir === false ? '' : $subdir;
+	}
+
+	public function getContent() : string {
+		$content = $this->file->getContent();
+		if (!mb_check_encoding($content, 'UTF-8')) {
+			$content = mb_convert_encoding($content, 'UTF-8');
+		}
+		return $content;
+	}
+
+	public function getModified() : int {
+		return $this->file->getMTime();
+	}
+
+	public function getFavorite() : bool {
+		return $this->noteUtil->getTagService()->isFavorite($this->getId());
+	}
+
+
+	public function getData(array $exclude = []) : array {
+		$data = [];
+		if (!in_array('id', $exclude)) {
+			$data['id'] = $this->getId();
+		}
+		if (!in_array('title', $exclude)) {
+			$data['title'] = $this->getTitle();
+		}
+		if (!in_array('modified', $exclude)) {
+			$data['modified'] = $this->getModified();
+		}
+		if (!in_array('category', $exclude)) {
+			$data['category'] = $this->getCategory();
+		}
+		if (!in_array('favorite', $exclude)) {
+			$data['favorite'] = $this->getFavorite();
+		}
+		$data['error'] = false;
+		$data['errorMessage'] = '';
+		if (!in_array('content', $exclude)) {
+			try {
+				$data['content'] = $this->getContent();
+			} catch (\Throwable $e) {
+				$message = $this->noteUtil->getL10N()->t('Error').': ('.$this->file->getName().') '.$e->getMessage();
+				$data['content'] = $message;
+				$data['error'] = true;
+				$data['errorMessage'] = $message;
+			}
+		}
+		return $data;
+	}
+
+	public function getEtag() : string {
+		$data = $this->getData();
+		// collect all relevant attributes
+		$str = '';
+		foreach ($data as $key => $val) {
+			$str .= $val;
+		}
+		return md5($str);
+	}
+
+
+	public function setTitle(string $title) : void {
+		$this->setTitleCategory($title);
+	}
+
+	public function setCategory(string $category) : void {
+		$this->setTitleCategory($this->getTitle(), $category);
+	}
+
+	/**
+	 * @throws \OCP\Files\NotPermittedException
+	 */
+	public function setTitleCategory(string $title, ?string $category = null) : void {
+		if ($category===null) {
+			$category = $this->getCategory();
+		}
+		$oldParent = $this->file->getParent();
+		$currentFilePath = $this->noteUtil->getRoot()->getFullPath($this->file->getPath());
+		$fileSuffix = '.' . pathinfo($this->file->getName(), PATHINFO_EXTENSION);
+
+		$folder = $this->noteUtil->getCategoryFolder($this->notesFolder, $category);
+		$filename = $this->noteUtil->generateFileName($folder, $title, $fileSuffix, $this->getId());
+		$newFilePath = $folder->getPath() . '/' . $filename;
+
+		// if the current path is not the new path, the file has to be renamed
+		if ($currentFilePath !== $newFilePath) {
+			$this->file->move($newFilePath);
+		}
+		$this->noteUtil->deleteEmptyFolder($oldParent, $this->notesFolder);
+	}
+
+	public function setContent(string $content) : void {
+		$this->noteUtil->ensureSufficientStorage($this->file->getParent(), strlen($content));
+		$this->file->putContent($content);
+	}
+
+	public function setModified(int $modified) : void {
+		$this->file->touch($modified);
+	}
+
+	public function setFavorite(bool $favorite) : void {
+		if ($favorite !== $this->getFavorite()) {
+			$this->noteUtil->getTagService()->setFavorite($this->getId(), $favorite);
+		}
+	}
+}
diff --git a/lib/Service/NoteDoesNotExistException.php b/lib/Service/NoteDoesNotExistException.php
index fc904e5a..25362ac0 100644
--- a/lib/Service/NoteDoesNotExistException.php
+++ b/lib/Service/NoteDoesNotExistException.php
@@ -1,13 +1,8 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace OCA\Notes\Service;
 
 use Exception;
 
-/**
- * Class NoteDoesNotExistException
- *
- * @package OCA\Notes\Service
- */
 class NoteDoesNotExistException extends Exception {
 }
diff --git a/lib/Service/NoteUtil.php b/lib/Service/NoteUtil.php
index 6f6bf99f..51d34a0a 100644
--- a/lib/Service/NoteUtil.php
+++ b/lib/Service/NoteUtil.php
@@ -1,109 +1,65 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace OCA\Notes\Service;
 
+use OCP\Files\Folder;
+use OCP\Files\IRootFolder;
 use OCP\IDBConnection;
 use OCP\IL10N;
 use OCP\ILogger;
-use OCP\Files\IRootFolder;
-use OCP\Files\FileInfo;
-use OCP\Files\File;
-use OCP\Files\Folder;
 
 class NoteUtil {
 
 	private $db;
 	private $l10n;
 	private $root;
+	private $tagService;
+	private $cachedTags;
 	private $logger;
 	private $appName;
 
-	/**
-	 * @param IDBConnection $db
-	 * @param IRootFolder $root
-	 * @param IL10N $l10n
-	 * @param ILogger $logger
-	 * @param String $appName
-	 */
 	public function __construct(
-		IDBConnection $db,
 		IRootFolder $root,
+		IDBConnection $db,
+		TagService $tagService,
 		IL10N $l10n,
 		ILogger $logger,
-		$appName
+		string $appName
 	) {
-		$this->db = $db;
 		$this->root = $root;
+		$this->db = $db;
+		$this->tagService = $tagService;
 		$this->l10n = $l10n;
 		$this->logger = $logger;
 		$this->appName = $appName;
 	}
 
-	/**
-	 * gather note files in given directory and all subdirectories
-	 */
-	public function gatherNoteFiles(Folder $folder) : array {
-		$notes = [];
-		$nodes = $folder->getDirectoryListing();
-		foreach ($nodes as $node) {
-			if ($node->getType() === FileInfo::TYPE_FOLDER && $node instanceof Folder) {
-				$notes = array_merge($notes, $this->gatherNoteFiles($node));
-				continue;
-			}
-			if ($this->isNote($node)) {
-				$notes[] = $node;
-			}
-		}
-		return $notes;
+	public function getRoot() : IRootFolder {
+		return $this->root;
 	}
 
-
-	/**
-	 * test if file is a note
-	 */
-	public function isNote(FileInfo $file) : bool {
-		$allowedExtensions = ['txt', 'org', 'markdown', 'md', 'note'];
-		$ext = strtolower(pathinfo($file->getName(), PATHINFO_EXTENSION));
-		return $file->getType() === 'file' && in_array($ext, $allowedExtensions);
+	public function getTagService() : TagService {
+		return $this->tagService;
 	}
 
-	public function moveNote(Folder $notesFolder, File $file, string $title, ?string $category = null) : void {
-		$id = $file->getId();
-		$title = $this->getSafeTitle($title);
-		$currentFilePath = $this->root->getFullPath($file->getPath());
-		$currentBasePath = pathinfo($currentFilePath, PATHINFO_DIRNAME);
-		$fileSuffix = '.' . pathinfo($file->getName(), PATHINFO_EXTENSION);
-
-		// detect (new) folder path based on category name
-		if ($category===null) {
-			$basePath = $currentBasePath;
-		} else {
-			$basePath = $notesFolder->getPath();
-			if (!empty($category)) {
-				// sanitise path
-				$cats = explode('/', $category);
-				$cats = array_map([$this, 'sanitisePath'], $cats);
-				$cats = array_filter($cats, function ($str) {
-					return !empty($str);
-				});
-				$basePath .= '/'.implode('/', $cats);
-			}
-		}
-		$folder = $this->getOrCreateFolder($basePath);
+	public function getL10N() : IL10N {
+		return $this->l10n;
+	}
 
-		// assemble new file path
-		$newFilePath = $basePath . '/' . $this->generateFileName($folder, $title, $fileSuffix, $id);
+	public function getLogger() : ILogger {
+		return $this->logger;
+	}
 
-		// if the current path is not the new path, the file has to be renamed
-		if ($currentFilePath !== $newFilePath) {
-			$file->move($newFilePath);
-		}
-		if ($currentBasePath !== $basePath) {
-			$fileBasePath = $this->root->get($currentBasePath);
-			if ($fileBasePath instanceof Folder) {
-				$this->deleteEmptyFolder($notesFolder, $fileBasePath);
-			}
-		}
+	public function getCategoryFolder(Folder $notesFolder, string $category) {
+		$path = $notesFolder->getPath();
+		// sanitise path
+		$cats = explode('/', $category);
+		$cats = array_map([$this, 'sanitisePath'], $cats);
+		$cats = array_filter($cats, function ($str) {
+			return $str !== '';
+		});
+		$path .= '/'.implode('/', $cats);
+		return $this->getOrCreateFolder($path);
 	}
 
 	/**
@@ -120,12 +76,13 @@ class NoteUtil {
 	 * files with the same title
 	 */
 	public function generateFileName(Folder $folder, string $title, string $suffix, int $id) : string {
-		$path = $title . $suffix;
+		$title = $this->getSafeTitle($title);
+		$filename = $title . $suffix;
 
 		// if file does not exist, that name has not been taken. Similar we don't
 		// need to handle file collisions if it is the filename did not change
-		if (!$folder->nodeExists($path) || $folder->get($path)->getId() === $id) {
-			return $path;
+		if (!$folder->nodeExists($filename) || $folder->get($filename)->getId() === $id) {
+			return $filename;
 		} else {
 			// increments name (2) to name (3)
 			$match = preg_match('/\((?P<id>\d+)\)$/u', $title, $matches);
@@ -143,15 +100,6 @@ class NoteUtil {
 		}
 	}
 
-	public function getSafeTitleFromContent(string $content) : string {
-		// prepare content: remove markdown characters and empty spaces
-		$content = preg_replace("/^\s*[*+-]\s+/mu", "", $content); // list item
-		$content = preg_replace("/^#+\s+(.*?)\s*#*$/mu", "$1", $content); // headline
-		$content = preg_replace("/^(=+|-+)$/mu", "", $content); // separate line for headline
-		$content = preg_replace("/(\*+|_+)(.*?)\\1/mu", "$2", $content); // emphasis
-		return $this->getSafeTitle($content);
-	}
-
 	public function getSafeTitle(string $content) : string {
 		// sanitize: prevent directory traversal, illegal characters and unintended file names
 		$content = $this->sanitisePath($content);
@@ -172,7 +120,7 @@ class NoteUtil {
 	}
 
 	/** removes characters that are illegal in a file or folder name on some operating systems */
-	public function sanitisePath(string $str) : string {
+	private function sanitisePath(string $str) : string {
 		// remove characters which are illegal on Windows (includes illegal characters on Unix/Linux)
 		// prevents also directory traversal by eliminiating slashes
 		// see also \OC\Files\Storage\Common::verifyPosixPath(...)
@@ -212,10 +160,10 @@ class NoteUtil {
 
 	/*
 	 * Delete a folder and it's parent(s) if it's/they're empty
-	 * @param Folder $notesFolder root folder for notes
 	 * @param Folder $folder folder to delete
+	 * @param Folder $notesFolder root notes folder
 	 */
-	public function deleteEmptyFolder(Folder $notesFolder, Folder $folder) : void {
+	public function deleteEmptyFolder(Folder $folder, Folder $notesFolder) : void {
 		$content = $folder->getDirectoryListing();
 		$isEmpty = !count($content);
 		$isNotesFolder = $folder->getPath()===$notesFolder->getPath();
@@ -223,7 +171,7 @@ class NoteUtil {
 			$this->logger->info('Deleting empty category folder '.$folder->getPath(), ['app' => $this->appName]);
 			$parent = $folder->getParent();
 			$folder->delete();
-			$this->deleteEmptyFolder($notesFolder, $parent);
+			$this->deleteEmptyFolder($parent, $notesFolder);
 		}
 	}
 
diff --git a/lib/Service/NotesFolderException.php b/lib/Service/NotesFolderException.php
index 8b98f3de..f6e9b6f8 100644
--- a/lib/Service/NotesFolderException.php
+++ b/lib/Service/NotesFolderException.php
@@ -1,13 +1,8 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace OCA\Notes\Service;
 
 use Exception;
 
-/**
- * Class NotesFolderException
- *
- * @package OCA\Notes\Service
- */
 class NotesFolderException extends Exception {
 }
diff --git a/lib/Service/NotesService.php b/lib/Service/NotesService.php
index 8d8050ea..3bfbf794 100644
--- a/lib/Service/NotesService.php
+++ b/lib/Service/NotesService.php
@@ -1,137 +1,61 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace OCA\Notes\Service;
 
-use OCP\Encryption\Exceptions\GenericEncryptionException;
+use OCA\Notes\Service\SettingsService;
+
 use OCP\Files\File;
+use OCP\Files\FileInfo;
 use OCP\Files\Folder;
-use OCP\Files\IRootFolder;
-use OCP\IConfig;
-use OCP\IL10N;
-use OCP\ILogger;
-use OCP\ITagManager;
 
-use OCA\Notes\Db\Note;
-use OCA\Notes\Service\SettingsService;
-
-/**
- * Class NotesService
- *
- * @package OCA\Notes\Service
- */
 class NotesService {
 
-	private $l10n;
-	private $root;
-	private $logger;
-	private $config;
-	private $tags;
 	private $settings;
 	private $noteUtil;
-	private $appName;
 
-	/**
-	 * @param IRootFolder $root
-	 * @param IL10N $l10n
-	 * @param ILogger $logger
-	 * @param IConfig $config
-	 * @param ITagManager $tagManager
-	 * @param SettingsService $settings
-	 * @param NoteUtil $noteUtil
-	 * @param String $appName
-	 */
 	public function __construct(
-		IRootFolder $root,
-		IL10N $l10n,
-		ILogger $logger,
-		IConfig $config,
-		ITagManager $tagManager,
 		SettingsService $settings,
-		NoteUtil $noteUtil,
-		$appName
+		NoteUtil $noteUtil
 	) {
-		$this->root = $root;
-		$this->l10n = $l10n;
-		$this->logger = $logger;
-		$this->config = $config;
-		$this->tags = $tagManager->load('files');
 		$this->settings = $settings;
 		$this->noteUtil = $noteUtil;
-		$this->appName = $appName;
 	}
 
-
-	/**
-	 * @param string $userId
-	 * @return array with all notes in the current directory
-	 */
-	public function getAll(string $userId, bool $onlyMeta = false) {
-		$notesFolder = $this->getFolderForUser($userId);
-		$notes = $this->noteUtil->gatherNoteFiles($notesFolder);
-		$filesById = [];
-		foreach ($notes as $note) {
-			$filesById[$note->getId()] = $note;
-		}
-		$tags = $this->tags->getTagsForObjects(array_keys($filesById));
-
-		$notes = [];
-		foreach ($filesById as $id => $file) {
-			$noteTags = is_array($tags) && array_key_exists($id, $tags) ? $tags[$id] : [];
-			$notes[] = $this->getNote($file, $notesFolder, $noteTags, $onlyMeta);
-		}
-
+	public function getAll(string $userId) {
+		$notesFolder = $this->getNotesFolder($userId);
+		$files = $this->gatherNoteFiles($notesFolder);
+		$fileIds = array_map(function (File $file) : int {
+			return $file->getId();
+		}, $files);
+		// pre-load tags for all notes (performance improvement)
+		$this->noteUtil->getTagService()->loadTags($fileIds);
+		$notes = array_map(function (File $file) use ($notesFolder) : Note {
+			return new Note($file, $notesFolder, $this->noteUtil);
+		}, $files);
 		return $notes;
 	}
 
-
-	/**
-	 * Used to get a single note by id
-	 * @param int $id the id of the note to get
-	 * @param string $userId
-	 * @throws NoteDoesNotExistException if note does not exist
-	 * @return Note
-	 */
-	public function get(int $id, string $userId, bool $onlyMeta = false) : Note {
-		$folder = $this->getFolderForUser($userId);
-		return $this->getNote($this->getFileById($folder, $id), $folder, $this->getTags($id), $onlyMeta);
-	}
-
-	private function getTags(int $id) {
-		$tags = $this->tags->getTagsForObjects([$id]);
-		return is_array($tags) && array_key_exists($id, $tags) ? $tags[$id] : [];
-	}
-
-	private function getNote(File $file, Folder $notesFolder, array $tags = [], bool $onlyMeta = false) : Note {
-		$id = $file->getId();
-		try {
-			$note = Note::fromFile($file, $notesFolder, $tags, $onlyMeta);
-		} catch (GenericEncryptionException $e) {
-			$message = $this->l10n->t('Encryption Error').': ('.$file->getName().') '.$e->getMessage();
-			$note = Note::fromException($message, $file, $notesFolder, array_key_exists($id, $tags) ? $tags[$id] : []);
-		} catch (\Exception $e) {
-			$message = $this->l10n->t('Error').': ('.$file->getName().') '.$e->getMessage();
-			$note = Note::fromException($message, $file, $notesFolder, array_key_exists($id, $tags) ? $tags[$id] : []);
-		}
-		return $note;
+	public function get(string $userId, int $id) : Note {
+		$notesFolder = $this->getNotesFolder($userId);
+		return new Note($this->getFileById($notesFolder, $id), $notesFolder, $this->noteUtil);
 	}
 
 
 	/**
-	 * Creates a note and returns the empty note
-	 * @param string $userId
-	 * @see update for setting note content
-	 * @return Note the newly created note
+	 * @throws \OCP\Files\NotPermittedException
 	 */
-	public function create(string $userId) : Note {
-		$title = $this->l10n->t('New note');
-		$folder = $this->getFolderForUser($userId);
+	public function create(string $userId, string $title, string $category) : Note {
+		// get folder based on category
+		$notesFolder = $this->getNotesFolder($userId);
+		$folder = $this->noteUtil->getCategoryFolder($notesFolder, $category);
 		$this->noteUtil->ensureSufficientStorage($folder, 1);
 
-		// check new note exists already and we need to number it
-		// pass -1 because no file has id -1 and that will ensure
-		// to only return filenames that dont yet exist
-		$path = $this->noteUtil->generateFileName($folder, $title, $this->settings->get($userId, 'fileSuffix'), -1);
-		$file = $folder->newFile($path);
+		// get file name
+		$fileSuffix = $this->settings->get($userId, 'fileSuffix');
+		$filename = $this->noteUtil->generateFileName($folder, $title, $fileSuffix, -1);
+
+		// create file
+		$file = $folder->newFile($filename);
 
 		// try to write some content
 		try {
@@ -141,142 +65,90 @@ class NotesService {
 			$file->putContent(' ');
 		} catch (\Throwable $e) {
 			// if writing the content fails, we have to roll back the note creation
-			$this->delete($file->getId(), $userId);
+			$this->delete($userId, $file->getId());
 			throw $e;
 		}
 
-		return $this->getNote($file, $folder);
+		return new Note($file, $notesFolder, $this->noteUtil);
 	}
 
 
 	/**
-	 * Updates a note. Be sure to check the returned note since the title is
-	 * dynamically generated and filename conflicts are resolved
-	 * @param int $id the id of the note used to update
-	 * @param string|null $content the content which will be written into the note
-	 * the title is generated from the first line of the content
-	 * @param string|null $category the category in which the note should be saved
-	 * @param int $mtime time of the note modification (optional)
 	 * @throws NoteDoesNotExistException if note does not exist
-	 * @return \OCA\Notes\Db\Note the updated note
 	 */
-	public function update(int $id, ?string $content, string $userId, ?string $category = null, int $mtime = 0) : Note {
-		$notesFolder = $this->getFolderForUser($userId);
+	public function delete(string $userId, int $id) {
+		$notesFolder = $this->getNotesFolder($userId);
 		$file = $this->getFileById($notesFolder, $id);
-		$title = $this->noteUtil->getSafeTitleFromContent($content===null ? $file->getContent() : $content);
+		$parent = $file->getParent();
+		$file->delete();
+		$this->noteUtil->deleteEmptyFolder($parent, $notesFolder);
+	}
 
-		// rename/move file with respect to title/category
-		// this can fail if access rights are not sufficient or category name is illegal
-		try {
-			$this->noteUtil->moveNote($notesFolder, $file, $title, $category);
-		} catch (\OCP\Files\NotPermittedException $e) {
-			$err = 'Moving note '.$file->getId().' ('.$title.') to the desired target is not allowed.'
-				.' Please check the note\'s target category ('.$category.').';
-			$this->logger->error($err, ['app' => $this->appName]);
-		} catch (\Exception $e) {
-			$err = 'Moving note '.$id.' ('.$title.') to the desired target has failed '
-				.'with a '.get_class($e).': '.$e->getMessage();
-			$this->logger->error($err, ['app' => $this->appName]);
-		}
+	public function getTitleFromContent(string $content) : string {
+		// prepare content: remove markdown characters and empty spaces
+		$content = preg_replace("/^\s*[*+-]\s+/mu", "", $content); // list item
+		$content = preg_replace("/^#+\s+(.*?)\s*#*$/mu", "$1", $content); // headline
+		$content = preg_replace("/^(=+|-+)$/mu", "", $content); // separate line for headline
+		$content = preg_replace("/(\*+|_+)(.*?)\\1/mu", "$2", $content); // emphasis
+		return $this->noteUtil->getSafeTitle($content);
+	}
 
-		if ($content !== null) {
-			$this->setContentForFile($file, $content);
-		}
 
-		if ($mtime) {
-			$file->touch($mtime);
-		}
 
-		return $this->getNote($file, $notesFolder, $this->getTags($id));
-	}
 
-	private function setContentForFile(File $file, $content) : void {
-		$this->noteUtil->ensureSufficientStorage($file->getParent(), strlen($content));
-		$file->putContent($content);
-	}
 
-	public function setContent(string $userId, int $id, string $content) : Note {
-		$notesFolder = $this->getFolderForUser($userId);
-		$file = $this->getFileById($notesFolder, $id);
-		$this->setContentForFile($file, $content);
-		return $this->getNote($file, $notesFolder, $this->getTags($id));
-	}
 
-	public function setTitleCategory(string $userId, int $id, ?string $title, ?string $category = null) : Note {
-		$notesFolder = $this->getFolderForUser($userId);
-		$file = $this->getFileById($notesFolder, $id);
-		if ($title === null) {
-			$note = $this->getNote($file, $notesFolder, [], true);
-			$title = $note->getTitle();
+	/**
+	 * @param string $userId the user id
+	 * @return Folder
+	 */
+	private function getNotesFolder(string $userId) : Folder {
+		$userPath = $this->noteUtil->getRoot()->getUserFolder($userId)->getPath();
+		$path = $userPath . '/' . $this->settings->get($userId, 'notesPath');
+		try {
+			$folder = $this->noteUtil->getOrCreateFolder($path);
+		} catch (\Exception $e) {
+			throw new NotesFolderException($path);
 		}
-		$this->noteUtil->moveNote($notesFolder, $file, $title, $category);
-
-		return $this->getNote($file, $notesFolder, $this->getTags($id));
+		return $folder;
 	}
 
 	/**
-	 * Set or unset a note as favorite.
-	 * @param int $id the id of the note used to update
-	 * @param boolean $favorite whether the note should be a favorite or not
-	 * @throws NoteDoesNotExistException if note does not exist
-	 * @return boolean the new favorite state of the note
+	 * gather note files in given directory and all subdirectories
 	 */
-	public function favorite(int $id, bool $favorite, string $userId) {
-		$note = $this->get($id, $userId, true);
-		if ($favorite !== $note->getFavorite()) {
-			if ($favorite) {
-				$this->tags->addToFavorites($id);
-			} else {
-				$this->tags->removeFromFavorites($id);
+	private static function gatherNoteFiles(Folder $folder) : array {
+		$files = [];
+		$nodes = $folder->getDirectoryListing();
+		foreach ($nodes as $node) {
+			if ($node->getType() === FileInfo::TYPE_FOLDER && $node instanceof Folder) {
+				$files = array_merge($files, self::gatherNoteFiles($node));
+				continue;
+			}
+			if (self::isNote($node)) {
+				$files[] = $node;
 			}
-			$note = $this->get($id, $userId, true);
 		}
-		return $note->getFavorite();
+		return $files;
 	}
 
-
 	/**
-	 * Deletes a note
-	 * @param int $id the id of the note which should be deleted
-	 * @param string $userId
-	 * @throws NoteDoesNotExistException if note does not
-	 * exist
+	 * test if file is a note
 	 */
-	public function delete(int $id, string $userId) {
-		$notesFolder = $this->getFolderForUser($userId);
-		$file = $this->getFileById($notesFolder, $id);
-		$parent = $file->getParent();
-		$file->delete();
-		$this->noteUtil->deleteEmptyFolder($notesFolder, $parent);
+	private static function isNote(FileInfo $file) : bool {
+		static $allowedExtensions = ['txt', 'org', 'markdown', 'md', 'note'];
+		$ext = strtolower(pathinfo($file->getName(), PATHINFO_EXTENSION));
+		return $file->getType() === 'file' && in_array($ext, $allowedExtensions);
 	}
 
 	/**
-	 * @param Folder $folder
-	 * @param int $id
 	 * @throws NoteDoesNotExistException
-	 * @return \OCP\Files\File
 	 */
-	private function getFileById(Folder $folder, int $id) : File {
+	private static function getFileById(Folder $folder, int $id) : File {
 		$file = $folder->getById($id);
 
-		if (count($file) <= 0 || !($file[0] instanceof File) || !$this->noteUtil->isNote($file[0])) {
+		if (count($file) <= 0 || !($file[0] instanceof File) || !self::isNote($file[0])) {
 			throw new NoteDoesNotExistException();
 		}
 		return $file[0];
 	}
-
-	/**
-	 * @param string $userId the user id
-	 * @return Folder
-	 */
-	private function getFolderForUser(string $userId) : Folder {
-		// TODO use IRootFolder->getUserFolder()  ?
-		$path = '/' . $userId . '/files/' . $this->settings->get($userId, 'notesPath');
-		try {
-			$folder = $this->noteUtil->getOrCreateFolder($path);
-		} catch (\Exception $e) {
-			throw new NotesFolderException($path);
-		}
-		return $folder;
-	}
 }
diff --git a/lib/Service/SettingsService.php b/lib/Service/SettingsService.php
index 1ce7add7..5c2308c3 100644
--- a/lib/Service/SettingsService.php
+++ b/lib/Service/SettingsService.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace OCA\Notes\Service;
 
@@ -24,7 +24,7 @@ class SettingsService {
 	/**
 	 * @throws \OCP\PreConditionNotMetException
 	 */
-	public function set($uid, $settings) {
+	public function set(string $uid, array $settings) : void {
 		// remove illegal, empty and default settings
 		foreach ($settings as $name => $value) {
 			if (!array_key_exists($name, $this->defaults)
@@ -37,7 +37,7 @@ class SettingsService {
 		$this->config->setUserValue($uid, 'notes', 'settings', json_encode($settings));
 	}
 
-	public function getAll($uid) {
+	public function getAll(string $uid) : \stdClass {
 		$settings = json_decode($this->config->getUserValue($uid, 'notes', 'settings'));
 		if (is_object($settings)) {
 			// use default for empty settings
@@ -55,7 +55,7 @@ class SettingsService {
 	/**
 	 * @throws \OCP\PreConditionNotMetException
 	 */
-	public function get($uid, $name) {
+	public function get(string $uid, string $name) : string {
 		$settings = $this->getAll($uid);
 		if (property_exists($settings, $name)) {
 			return $settings->{$name};
diff --git a/lib/Service/TagService.php b/lib/Service/TagService.php
new file mode 100644
index 00000000..5f3d5f2f
--- /dev/null
+++ b/lib/Service/TagService.php
@@ -0,0 +1,50 @@
+<?php declare(strict_types=1);
+
+namespace OCA\Notes\Service;
+
+use OCP\ITagManager;
+
+class TagService {
+	private $tagger;
+	private $cachedTags;
+
+	public function __construct(ITagManager $tagManager) {
+		$this->tagger = $tagManager->load('files');
+	}
+
+	public function loadTags(array $fileIds) : void {
+		$this->cachedTags = $this->tagger->getTagsForObjects($fileIds);
+	}
+
+	// TODO NC19: replace this by OCP\ITags::TAG_FAVORITE
+	// OCP\ITags::TAG_FAVORITE was introduced in NC19
+	// https://github.com/nextcloud/server/pull/19412
+	/**
+	 * @suppress PhanUndeclaredClassConstant
+	 * @suppress PhanUndeclaredConstant
+	 * @suppress PhanUndeclaredConstantOfClass
+	 */
+	private static function getTagFavorite() {
+		if (defined('OCP\ITags::TAG_FAVORITE')) {
+			return \OCP\ITags::TAG_FAVORITE;
+		} else {
+			return \OC\Tags::TAG_FAVORITE;
+		}
+	}
+
+	public function isFavorite($fileId) : bool {
+		$alltags = $this->cachedTags;
+		if (!is_array($alltags)) {
+			$alltags = $this->tagger->getTagsForObjects([$fileId]);
+		}
+		return array_key_exists($fileId, $alltags) && in_array(self::getTagFavorite(), $alltags[$fileId]);
+	}
+
+	public function setFavorite($fileId, $favorite) : void {
+		if ($favorite) {
+			$this->tagger->addToFavorites($fileId);
+		} else {
+			$this->tagger->removeFromFavorites($fileId);
+		}
+	}
+}
diff --git a/src/App.vue b/src/App.vue
index 0d9a5c61..fe1bbabf 100644
--- a/src/App.vue
+++ b/src/App.vue
@@ -198,7 +198,7 @@ export default {
 				return
 			}
 			this.loading.create = true
-			createNote(this.filter.category)
+			createNote(this.filter.category || '')
 				.then(note => {
 					this.routeToNote(note.id)
 				})
diff --git a/tests/api/APIv02Test.php b/tests/api/APIv02Test.php
index 93250eb8..cbca70de 100644
--- a/tests/api/APIv02Test.php
+++ b/tests/api/APIv02Test.php
@@ -2,199 +2,9 @@
 
 namespace OCA\Notes\Tests\API;
 
-class APIv02Test extends AbstractAPITest {
+class APIv02Test extends CommonAPITest {
 
 	public function __construct() {
-		parent::__construct('v0.2');
+		parent::__construct('0.2', true);
 	}
-
-	public function testCheckForReferenceNotes() : array {
-		$response = $this->http->request('GET', 'notes');
-		$this->checkResponse($response, 'Get existing notes', 200);
-		$notes = json_decode($response->getBody()->getContents());
-		$this->assertNotEmpty($notes, 'List of notes');
-		return $notes;
-	}
-
-	/** @depends testCheckForReferenceNotes */
-	public function testGetNotesWithExclude(array $refNotes) : void {
-		$this->checkGetReferenceNotes(
-			$refNotes,
-			'exclude content',
-			'?exclude=content',
-			false,
-			['content']
-		);
-		$this->checkGetReferenceNotes(
-			$refNotes,
-			'exclude content and category',
-			'?exclude=content,category',
-			false,
-			['content','category']
-		);
-	}
-
-	/** @depends testCheckForReferenceNotes */
-	public function testGetNotesWithEtag(array $refNotes) : void {
-		$response1 = $this->http->request('GET', 'notes');
-		$this->checkResponse($response1, 'Initial response', 200);
-		$this->assertTrue($response1->hasHeader('ETag'), 'Initial response has ETag header');
-		$etag = $response1->getHeaderLine('ETag');
-		$this->assertRegExp('/^"[[:alnum:]]{32}"$/', $etag, 'ETag format');
-
-		// Test If-None-Match with ETag
-		$response2 = $this->http->request('GET', 'notes', [ 'headers' => [ 'If-None-Match' => $etag ] ]);
-		$this->checkResponse($response2, 'ETag response', 304);
-		$this->assertEquals('', $response2->getBody(), 'ETag response body');
-	}
-
-	/** @depends testCheckForReferenceNotes */
-	public function testGetNotesWithPruneBefore(array $refNotes) : void {
-		sleep(1); // wait for 'Last-Modified' to be >= Last-change + 1
-		$response1 = $this->http->request('GET', 'notes');
-		$this->checkResponse($response1, 'Initial response', 200);
-		$this->assertTrue($response1->hasHeader('Last-Modified'), 'Initial response has Last-Modified header');
-		$lastModified = $response1->getHeaderLine('Last-Modified');
-		$dt = \DateTime::createFromFormat(\DateTime::RFC2822, $lastModified);
-		$this->assertInstanceOf(\DateTime::class, $dt);
-
-		$this->checkGetReferenceNotes(
-			$refNotes,
-			'pruneBefore with Last-Modified',
-			'?pruneBefore='.$dt->getTimestamp(),
-			true
-		);
-		$this->checkGetReferenceNotes(
-			$refNotes,
-			'pruneBefore with 1',
-			'?pruneBefore=1',
-			false
-		);
-		$this->checkGetReferenceNotes(
-			$refNotes,
-			'pruneBefore with PHP_INT_MAX (32bit)',
-			'?pruneBefore=2147483647', // 2038-01-19 03:14:07
-			true
-		);
-		$this->checkGetReferenceNotes(
-			$refNotes,
-			'pruneBefore with PHP_INT_MAX (64bit)',
-			'?pruneBefore=9223372036854775807',
-			true
-		);
-	}
-
-	/** @depends testCheckForReferenceNotes */
-	public function testCreateNotes(array $refNotes) : array {
-		$this->checkGetReferenceNotes($refNotes, 'Pre-condition');
-		$testNotes = [];
-		$testNotes[] = $this->createNote((object)[
-			'title' => 'This is not used',
-			'content' => '# *First* test/ note'.PHP_EOL.'This is some body content with some data.',
-			'favorite' => true,
-			'category' => 'Test/../New Category',
-			'modified' => mktime(8, 14, 30, 10, 2, 2020),
-		], (object)[
-			'title' => 'First test note',
-			'category' => 'Test/New Category',
-		]);
-		$testNotes[] = $this->createNote((object)[
-			'content' => 'Note with Defaults'.PHP_EOL.'This is some body content with some data.',
-		], (object)[
-			'title' => 'Note with Defaults',
-			'favorite' => false,
-			'category' => '',
-			'modified' => time(),
-		]);
-		$this->checkGetReferenceNotes(array_merge($refNotes, $testNotes), 'After creating notes');
-		return $testNotes;
-	}
-
-	/**
-	 * @depends testCheckForReferenceNotes
-	 * @depends testCreateNotes
-	 */
-	public function testGetSingleNote(array $refNotes, array $testNotes) : void {
-		foreach ($testNotes as $testNote) {
-			$response = $this->http->request('GET', 'notes/'.$testNote->id);
-			$this->checkResponse($response, 'Get note '.$testNote->title, 200);
-			$note = json_decode($response->getBody()->getContents());
-			$this->checkReferenceNote($testNote, $note, 'Get single note');
-		}
-		// test non-existing note
-		$response = $this->http->request('GET', 'notes/1');
-		$this->assertEquals(404, $response->getStatusCode());
-	}
-
-
-	/**
-	 * @depends testCheckForReferenceNotes
-	 * @depends testCreateNotes
-	 */
-	public function testUpdateNotes(array $refNotes, array $testNotes) : array {
-		$this->checkGetReferenceNotes(array_merge($refNotes, $testNotes), 'Pre-condition');
-		$note = $testNotes[0];
-		// test update note with all attributes
-		$this->updateNote($note, (object)[
-			'title' => 'This is not used',
-			'content' => '# *First* edited/ note'.PHP_EOL.'This is some body content with some data.',
-			'favorite' => false,
-			'category' => 'Test/Another Category',
-			'modified' => mktime(11, 46, 23, 4, 3, 2020),
-		], (object)[
-			'title' => 'First edited note',
-		]);
-		// test update note with single attributes
-		/* TODO this doesn't work (content is null)
-		$this->updateNote($note, (object)[
-			'category' => 'Test/Third Category',
-		], (object)[]);
-		 */
-		$this->updateNote($note, (object)[
-			'favorite' => true,
-		], (object)[]);
-		$this->updateNote($note, (object)[
-			'content' => '# First multi edited note'.PHP_EOL.'This is some body content with some data.',
-		], (object)[
-			'title' => 'First multi edited note',
-			'modified' => time(),
-		]);
-		$this->checkGetReferenceNotes(array_merge($refNotes, $testNotes), 'After updating notes');
-		return $testNotes;
-	}
-
-	/**
-	 * @depends testCheckForReferenceNotes
-	 * @depends testUpdateNotes
-	 */
-	public function testDeleteNotes(array $refNotes, array $testNotes) : void {
-		$this->checkGetReferenceNotes(array_merge($refNotes, $testNotes), 'Pre-condition');
-		foreach ($testNotes as $note) {
-			$response = $this->http->request('DELETE', 'notes/'.$note->id);
-			$this->checkResponse($response, 'Delete note '.$note->title, 200);
-		}
-		// test non-existing note
-		$response = $this->http->request('DELETE', 'notes/1');
-		$this->checkResponse($response, 'Delete non-existing note', 404);
-		$this->checkGetReferenceNotes($refNotes, 'After deletion');
-	}
-
-	public function testInsuficientStorage() {
-		$auth = ['quotatest', 'test'];
-		// get notes must still work
-		$response = $this->http->request('GET', 'notes', [ 'auth' => $auth ]);
-		$this->checkResponse($response, 'Get existing notes', 200);
-		$notes = json_decode($response->getBody()->getContents());
-		$this->assertNotEmpty($notes, 'List of notes');
-		$note = $notes[0]; // @phan-suppress-current-line PhanTypeArraySuspiciousNullable
-		$request = (object)[ 'content' => 'New test content' ];
-		// update will fail
-		$response1 = $this->http->request('PUT', 'notes/'.$note->id, [ 'auth' => $auth, 'json' =>  $request]);
-		$this->assertEquals(507, $response1->getStatusCode());
-		// craete will fail
-		$response2 = $this->http->request('POST', 'notes', [ 'auth' => $auth, 'json' =>  $request]);
-		$this->assertEquals(507, $response2->getStatusCode());
-	}
-
-	// TODO Test settings (switch to another notes folder)
 }
diff --git a/tests/api/APIv1Test.php b/tests/api/APIv1Test.php
new file mode 100644
index 00000000..acf8a03e
--- /dev/null
+++ b/tests/api/APIv1Test.php
@@ -0,0 +1,10 @@
+<?php declare(strict_types=1);
+
+namespace OCA\Notes\Tests\API;
+
+class APIv1Test extends CommonAPITest {
+
+	public function __construct() {
+		parent::__construct('1.0', false);
+	}
+}
diff --git a/tests/api/AbstractAPITest.php b/tests/api/AbstractAPITest.php
index 728b77f6..473c3af8 100644
--- a/tests/api/AbstractAPITest.php
+++ b/tests/api/AbstractAPITest.php
@@ -14,8 +14,13 @@ abstract class AbstractAPITest extends TestCase {
 	}
 
 	protected function setUp() : void {
+		if ($this->apiVersion === '0.2') {
+			$v = $this->apiVersion;
+		} else {
+			$v = intval($this->apiVersion);
+		}
 		$this->http = new \GuzzleHttp\Client([
-			'base_uri' => 'http://localhost:8080/index.php/apps/notes/api/'.$this->apiVersion.'/',
+			'base_uri' => 'http://localhost:8080/index.php/apps/notes/api/v'.$v.'/',
 			'auth' => ['test', 'test'],
 			'http_errors' => false,
 		]);
@@ -28,12 +33,24 @@ abstract class AbstractAPITest extends TestCase {
 		string $contentTypeExp = 'application/json; charset=utf-8'
 	) {
 		$this->assertEquals($statusExp, $response->getStatusCode(), $message.': Response status code');
-		$this->assertTrue($response->hasHeader('Content-Type'), $message.': Response has content-type header');
+		$this->assertTrue(
+			$response->hasHeader('Content-Type'),
+			$message.': Response has content-type header'
+		);
 		$this->assertEquals(
 			$contentTypeExp,
 			$response->getHeaderLine('Content-Type'),
 			$message.': Response content type'
 		);
+		$this->assertTrue(
+			$response->hasHeader('X-Notes-API-Versions'),
+			$message.': Response has Notes-API-Versions header'
+		);
+		$this->assertContains(
+			$this->apiVersion,
+			explode(', ', $response->getHeaderLine('X-Notes-API-Versions')),
+			$message.': Response Notes-API-Versions header'
+		);
 	}
 
 	protected function checkGetReferenceNotes(
@@ -47,7 +64,7 @@ abstract class AbstractAPITest extends TestCase {
 		$response = $this->http->request('GET', 'notes' . $param);
 		$this->checkResponse($response, $messagePrefix, 200);
 		$notes = json_decode($response->getBody()->getContents());
-		$notesMap = self::getNotesIdMap($notes);
+		$notesMap = $this->getNotesIdMap($notes, $messagePrefix);
 		$this->assertEquals(count($refNotes), count($notes), $messagePrefix.': Number of notes');
 		foreach ($refNotes as $refNote) {
 			$this->assertArrayHasKey(
@@ -140,9 +157,10 @@ abstract class AbstractAPITest extends TestCase {
 		);
 	}
 
-	protected static function getNotesIdMap(array $notes) : array {
+	protected function getNotesIdMap(array $notes, string $messagePrefix) : array {
 		$map = [];
 		foreach ($notes as $note) {
+			$this->assertObjectHasAttribute('id', $note, $messagePrefix.': Note has property id');
 			$map[$note->id] = $note;
 		}
 		return $map;
diff --git a/tests/api/CapabilitiesTest.php b/tests/api/CapabilitiesTest.php
new file mode 100644
index 00000000..2153a2e5
--- /dev/null
+++ b/tests/api/CapabilitiesTest.php
@@ -0,0 +1,58 @@
+<?php declare(strict_types=1);
+
+namespace OCA\Notes\Tests\API;
+
+use PHPUnit\Framework\TestCase;
+
+class CapabilitiesTest extends TestCase {
+	protected $http;
+
+	protected function setUp() : void {
+		$this->http = new \GuzzleHttp\Client([
+			'base_uri' => 'http://localhost:8080/',
+			'auth' => ['test', 'test'],
+			'http_errors' => false,
+		]);
+	}
+
+	public function testCapabilities() {
+		$response = $this->http->request('GET', 'ocs/v2.php/cloud/capabilities', [
+			'headers' => [
+				'OCS-APIRequest' => 'true',
+				'Accept' => 'application/json',
+			]
+		]);
+		$this->assertEquals(200, $response->getStatusCode(), 'Response status code');
+		$this->assertTrue(
+			$response->hasHeader('Content-Type'),
+			'Response has content-type header'
+		);
+		$this->assertEquals(
+			'application/json; charset=utf-8',
+			$response->getHeaderLine('Content-Type'),
+			'Response content type'
+		);
+		$ocs = json_decode($response->getBody()->getContents());
+		$capabilities = $ocs->ocs->data->capabilities;
+		$this->assertObjectHasAttribute('notes', $capabilities, 'Nextcloud provides capabilities');
+		$notesCapability = $capabilities->notes;
+		$this->assertObjectHasAttribute('api_version', $notesCapability, 'Notes API-Version capability exists');
+		$apiVersions = $notesCapability->api_version;
+		$this->assertIsArray($apiVersions, 'Notes API-Version capability is array');
+		$this->assertNotEmpty($apiVersions, 'Notes API-Version capability array');
+		foreach ($apiVersions as $apiVersion) {
+			$this->assertStringMatchesFormat('%d.%d', $apiVersion, 'API Version format');
+			$v = $apiVersion === '0.2' ? '02' : intval($apiVersion);
+			$path = dirname(__FILE__).'/APIv'.$v.'Test.php';
+			$this->assertFileExists($path, 'Test for API v'.$apiVersion.' exists');
+		}
+	}
+
+	public function testInvalidVersion() {
+		$v = 7;
+		$response1 = $this->http->request('GET', 'index.php/apps/notes/api/v'.$v.'/notes');
+		$this->assertEquals(400, $response1->getStatusCode(), 'First response status code');
+		$response2 = $this->http->request('GET', 'index.php/apps/notes/api/v'.$v.'/notes/1');
+		$this->assertEquals(400, $response2->getStatusCode(), 'Second response status code');
+	}
+}
diff --git a/tests/api/CommonAPITest.php b/tests/api/CommonAPITest.php
new file mode 100644
index 00000000..5f69e02a
--- /dev/null
+++ b/tests/api/CommonAPITest.php
@@ -0,0 +1,217 @@
+<?php declare(strict_types=1);
+
+namespace OCA\Notes\Tests\API;
+
+abstract class CommonAPITest extends AbstractAPITest {
+
+	private $requiredAttributes = [
+		'id' => 'integer',
+		'content' => 'string',
+		'title' => 'string',
+		'category' => 'string',
+		'modified' => 'integer',
+		'favorite' => 'boolean',
+	];
+
+	private $autotitle;
+
+	public function __construct(string $apiVersion, bool $autotitle) {
+		parent::__construct($apiVersion);
+		$this->autotitle = $autotitle;
+	}
+
+	public function testCheckForReferenceNotes() : array {
+		$response = $this->http->request('GET', 'notes');
+		$this->checkResponse($response, 'Get existing notes', 200);
+		$notes = json_decode($response->getBody()->getContents());
+		$this->assertNotEmpty($notes, 'List of notes');
+		foreach ($notes as $note) {
+			foreach ($this->requiredAttributes as $key => $type) {
+				$this->assertObjectHasAttribute($key, $note, 'Note has property '.$key);
+				$this->assertEquals($type, gettype($note->$key), 'Property type of '.$key);
+			}
+		}
+		return $notes;
+	}
+
+	/** @depends testCheckForReferenceNotes */
+	public function testGetNotesWithExclude(array $refNotes) : void {
+		$this->checkGetReferenceNotes(
+			$refNotes,
+			'exclude content',
+			'?exclude=content',
+			false,
+			['content']
+		);
+		$this->checkGetReferenceNotes(
+			$refNotes,
+			'exclude content and category',
+			'?exclude=content,category',
+			false,
+			['content','category']
+		);
+	}
+
+	/** @depends testCheckForReferenceNotes */
+	public function testGetNotesWithEtag(array $refNotes) : void {
+		$response1 = $this->http->request('GET', 'notes');
+		$this->checkResponse($response1, 'Initial response', 200);
+		$this->assertTrue($response1->hasHeader('ETag'), 'Initial response has ETag header');
+		$etag = $response1->getHeaderLine('ETag');
+		$this->assertRegExp('/^"[[:alnum:]]{32}"$/', $etag, 'ETag format');
+
+		// Test If-None-Match with ETag
+		$response2 = $this->http->request('GET', 'notes', [ 'headers' => [ 'If-None-Match' => $etag ] ]);
+		$this->checkResponse($response2, 'ETag response', 304);
+		$this->assertEquals('', $response2->getBody(), 'ETag response body');
+	}
+
+	/** @depends testCheckForReferenceNotes */
+	public function testGetNotesWithPruneBefore(array $refNotes) : void {
+		sleep(1); // wait for 'Last-Modified' to be >= Last-change + 1
+		$response1 = $this->http->request('GET', 'notes');
+		$this->checkResponse($response1, 'Initial response', 200);
+		$this->assertTrue($response1->hasHeader('Last-Modified'), 'Initial response has Last-Modified header');
+		$lastModified = $response1->getHeaderLine('Last-Modified');
+		$dt = \DateTime::createFromFormat(\DateTime::RFC2822, $lastModified);
+		$this->assertInstanceOf(\DateTime::class, $dt);
+
+		$this->checkGetReferenceNotes(
+			$refNotes,
+			'pruneBefore with Last-Modified',
+			'?pruneBefore='.$dt->getTimestamp(),
+			true
+		);
+		$this->checkGetReferenceNotes(
+			$refNotes,
+			'pruneBefore with 1',
+			'?pruneBefore=1',
+			false
+		);
+		$this->checkGetReferenceNotes(
+			$refNotes,
+			'pruneBefore with PHP_INT_MAX (32bit)',
+			'?pruneBefore=2147483647', // 2038-01-19 03:14:07
+			true
+		);
+		$this->checkGetReferenceNotes(
+			$refNotes,
+			'pruneBefore with PHP_INT_MAX (64bit)',
+			'?pruneBefore=9223372036854775807',
+			true
+		);
+	}
+
+	/** @depends testCheckForReferenceNotes */
+	public function testCreateNotes(array $refNotes) : array {
+		$this->checkGetReferenceNotes($refNotes, 'Pre-condition');
+		$testNotes = [];
+		$testNotes[] = $this->createNote((object)[
+			'title' => 'First *manual* title',
+			'content' => '# *First* test/ note'.PHP_EOL.'This is some body content with some data.',
+			'favorite' => true,
+			'category' => 'Test/../New Category',
+			'modified' => mktime(8, 14, 30, 10, 2, 2020),
+		], (object)[
+			'title' => $this->autotitle ? 'First test note' : 'First manual title',
+			'category' => 'Test/New Category',
+		]);
+		$testNotes[] = $this->createNote((object)[
+			'content' => 'Note with Defaults'.PHP_EOL.'This is some body content with some data.',
+		], (object)[
+			'title' => $this->autotitle ? 'Note with Defaults' : 'New note', // waring: requires lang=C
+			'favorite' => false,
+			'category' => '',
+			'modified' => time(),
+		]);
+		$this->checkGetReferenceNotes(array_merge($refNotes, $testNotes), 'After creating notes');
+		return $testNotes;
+	}
+
+	/**
+	 * @depends testCheckForReferenceNotes
+	 * @depends testCreateNotes
+	 */
+	public function testGetSingleNote(array $refNotes, array $testNotes) : void {
+		foreach ($testNotes as $testNote) {
+			$response = $this->http->request('GET', 'notes/'.$testNote->id);
+			$this->checkResponse($response, 'Get note '.$testNote->title, 200);
+			$note = json_decode($response->getBody()->getContents());
+			$this->checkReferenceNote($testNote, $note, 'Get single note');
+		}
+		// test non-existing note
+		$response = $this->http->request('GET', 'notes/1');
+		$this->assertEquals(404, $response->getStatusCode());
+	}
+
+
+	/**
+	 * @depends testCheckForReferenceNotes
+	 * @depends testCreateNotes
+	 */
+	public function testUpdateNotes(array $refNotes, array $testNotes) : array {
+		$this->checkGetReferenceNotes(array_merge($refNotes, $testNotes), 'Pre-condition');
+		$note = $testNotes[0];
+		// test update note with all attributes
+		$this->updateNote($note, (object)[
+			'title' => 'First *manual* edited title',
+			'content' => '# *First* edited/ note'.PHP_EOL.'This is some body content with some data.',
+			'favorite' => false,
+			'category' => 'Test/Another Category',
+			'modified' => mktime(11, 46, 23, 4, 3, 2020),
+		], (object)[
+			'title' => $this->autotitle ? 'First edited note' : 'First manual edited title',
+		]);
+		// test update note with single attributes
+		$this->updateNote($note, (object)[
+			'category' => 'Test/Third Category',
+		], (object)[]);
+		// TODO test update category with read-only folder (target category)
+		$this->updateNote($note, (object)[
+			'favorite' => true,
+		], (object)[]);
+		$this->updateNote($note, (object)[
+			'content' => '# First multi edited note'.PHP_EOL.'This is some body content with some data.',
+		], (object)[
+			'title' => $this->autotitle ? 'First multi edited note' : 'First manual edited title',
+			'modified' => time(),
+		]);
+		$this->checkGetReferenceNotes(array_merge($refNotes, $testNotes), 'After updating notes');
+		return $testNotes;
+	}
+
+	/**
+	 * @depends testCheckForReferenceNotes
+	 * @depends testUpdateNotes
+	 */
+	public function testDeleteNotes(array $refNotes, array $testNotes) : void {
+		$this->checkGetReferenceNotes(array_merge($refNotes, $testNotes), 'Pre-condition');
+		foreach ($testNotes as $note) {
+			$response = $this->http->request('DELETE', 'notes/'.$note->id);
+			$this->checkResponse($response, 'Delete note '.$note->title, 200);
+		}
+		// test non-existing note
+		$response = $this->http->request('DELETE', 'notes/1');
+		$this->checkResponse($response, 'Delete non-existing note', 404);
+		$this->checkGetReferenceNotes($refNotes, 'After deletion');
+	}
+
+	public function testInsuficientStorage() {
+		$auth = ['quotatest', 'test'];
+		// get notes must still work
+		$response = $this->http->request('GET', 'notes', [ 'auth' => $auth ]);
+		$this->checkResponse($response, 'Get existing notes', 200);
+		$notes = json_decode($response->getBody()->getContents());
+		$this->assertNotEmpty($notes, 'List of notes');
+		$note = $notes[0]; // @phan-suppress-current-line PhanTypeArraySuspiciousNullable
+		$request = (object)[ 'content' => 'New test content' ];
+		// update will fail
+		$response1 = $this->http->request('PUT', 'notes/'.$note->id, [ 'auth' => $auth, 'json' =>  $request]);
+		$this->assertEquals(507, $response1->getStatusCode());
+		// craete will fail
+		$response2 = $this->http->request('POST', 'notes', [ 'auth' => $auth, 'json' =>  $request]);
+		$this->assertEquals(507, $response2->getStatusCode());
+	}
+
+	// TODO Test settings (switch to another notes folder)
+}