feat: add validators to check values in services

Signed-off-by: Luka Trovic <luka@nextcloud.com>

13 files changed, 511 insertions, 272 deletions

diff --git a/lib/Service/AssignmentService.php b/lib/Service/AssignmentService.php
index 96965f01..3e69948f 100644
--- a/lib/Service/AssignmentService.php
+++ b/lib/Service/AssignmentService.php
@@ -35,6 +35,7 @@ use OCA\Deck\Event\CardUpdatedEvent;
 use OCA\Deck\NoPermissionException;
 use OCA\Deck\NotFoundException;
 use OCA\Deck\Notification\NotificationHelper;
+use OCA\Deck\Validators\AssignmentServiceValidator;
 use OCP\AppFramework\Db\DoesNotExistException;
 use OCP\AppFramework\Db\Entity;
 use OCP\AppFramework\Db\MultipleObjectsReturnedException;
@@ -76,6 +77,11 @@ class AssignmentService {
 	private $eventDispatcher;
 	/** @var string|null */
 	private $currentUser;
+	/**
+	 * @var AssignmentServiceValidator
+	 */
+	private $assignmentServiceValidator;
+
 
 	public function __construct(
 		PermissionService $permissionService,
@@ -86,8 +92,10 @@ class AssignmentService {
 		ActivityManager $activityManager,
 		ChangeHelper $changeHelper,
 		IEventDispatcher $eventDispatcher,
+		AssignmentServiceValidator $assignmentServiceValidator,
 		$userId
 	) {
+		$this->assignmentServiceValidator = $assignmentServiceValidator;
 		$this->permissionService = $permissionService;
 		$this->cardMapper = $cardMapper;
 		$this->assignedUsersMapper = $assignedUsersMapper;
@@ -96,6 +104,8 @@ class AssignmentService {
 		$this->changeHelper = $changeHelper;
 		$this->activityManager = $activityManager;
 		$this->eventDispatcher = $eventDispatcher;
+
+		$this->assignmentServiceValidator->check(compact('userId'));
 		$this->currentUser = $userId;
 	}
 
@@ -109,13 +119,7 @@ class AssignmentService {
 	 * @throws DoesNotExistException
 	 */
 	public function assignUser($cardId, $userId, int $type = Assignment::TYPE_USER) {
-		if (is_numeric($cardId) === false) {
-			throw new BadRequestException('card id must be a number');
-		}
-
-		if ($userId === false || $userId === null) {
-			throw new BadRequestException('user id must be provided');
-		}
+		$this->assignmentServiceValidator->check(compact('cardId', 'userId'));
 
 		if ($type !== Assignment::TYPE_USER && $type !== Assignment::TYPE_GROUP) {
 			throw new BadRequestException('Invalid type provided for assignemnt');
@@ -168,16 +172,9 @@ class AssignmentService {
 	 * @throws MultipleObjectsReturnedException
 	 */
 	public function unassignUser($cardId, $userId, $type = 0) {
+		$this->assignmentServiceValidator->check(compact('cardId', 'userId'));
 		$this->permissionService->checkPermission($this->cardMapper, $cardId, Acl::PERMISSION_EDIT);
 
-		if (is_numeric($cardId) === false) {
-			throw new BadRequestException('card id must be a number');
-		}
-
-		if ($userId === false || $userId === null) {
-			throw new BadRequestException('user must be provided');
-		}
-
 		$assignments = $this->assignedUsersMapper->findAll($cardId);
 		foreach ($assignments as $assignment) {
 			if ($assignment->getParticipant() === $userId && $assignment->getType() === $type) {
diff --git a/lib/Service/AttachmentService.php b/lib/Service/AttachmentService.php
index c7c4532a..f9eb9682 100644
--- a/lib/Service/AttachmentService.php
+++ b/lib/Service/AttachmentService.php
@@ -36,6 +36,7 @@ use OCA\Deck\NoPermissionException;
 use OCA\Deck\NotFoundException;
 use OCA\Deck\Cache\AttachmentCacheHelper;
 use OCA\Deck\StatusException;
+use OCA\Deck\Validators\AttachmentServiceValidator;
 use OCP\AppFramework\Db\IMapperException;
 use OCP\AppFramework\Http\Response;
 use OCP\IL10N;
@@ -60,17 +61,22 @@ class AttachmentService {
 	/** @var ChangeHelper */
 	private $changeHelper;
 	private IUserManager $userManager;
-
-	public function __construct(AttachmentMapper $attachmentMapper,
-								CardMapper $cardMapper,
-								IUserManager $userManager,
-								ChangeHelper $changeHelper,
-								PermissionService $permissionService,
-								Application $application,
-								AttachmentCacheHelper $attachmentCacheHelper,
-								$userId,
-								IL10N $l10n,
-								ActivityManager $activityManager) {
+	/** @var AttachmentServiceValidator */
+	private AttachmentServiceValidator $attachmentServiceValidator;
+
+	public function __construct(
+		AttachmentMapper $attachmentMapper,
+		CardMapper $cardMapper,
+		IUserManager $userManager,
+		ChangeHelper $changeHelper,
+		PermissionService $permissionService,
+		Application $application,
+		AttachmentCacheHelper $attachmentCacheHelper,
+		$userId,
+		IL10N $l10n,
+		ActivityManager $activityManager,
+		AttachmentServiceValidator $attachmentServiceValidator
+	) {
 		$this->attachmentMapper = $attachmentMapper;
 		$this->cardMapper = $cardMapper;
 		$this->permissionService = $permissionService;
@@ -81,6 +87,7 @@ class AttachmentService {
 		$this->activityManager = $activityManager;
 		$this->changeHelper = $changeHelper;
 		$this->userManager = $userManager;
+		$this->attachmentServiceValidator = $attachmentServiceValidator;
 
 		// Register shipped attachment services
 		// TODO: move this to a plugin based approach once we have different types of attachments
@@ -187,17 +194,7 @@ class AttachmentService {
 	 * @throws BadRequestException
 	 */
 	public function create($cardId, $type, $data) {
-		if (is_numeric($cardId) === false) {
-			throw new BadRequestException('card id must be a number');
-		}
-
-		if ($type === false || $type === null) {
-			throw new BadRequestException('type must be provided');
-		}
-
-		if ($data === false || $data === null) {
-			//throw new BadRequestException('data must be provided');
-		}
+		$this->attachmentServiceValidator->check(compact('cardId', 'type', 'data'));
 
 		$this->permissionService->checkPermission($this->cardMapper, $cardId, Acl::PERMISSION_EDIT);
 
@@ -283,6 +280,8 @@ class AttachmentService {
 	 * @throws NoPermissionException
 	 */
 	public function update($cardId, $attachmentId, $data, $type = 'deck_file') {
+		$this->attachmentServiceValidator->check(compact('cardId', 'type', 'data'));
+
 		try {
 			$service = $this->getService($type);
 		} catch (InvalidAttachmentType $e) {
@@ -304,9 +303,6 @@ class AttachmentService {
 			}
 		}
 
-		if ($data === false || $data === null) {
-			//throw new BadRequestException('data must be provided');
-		}
 		try {
 			$attachment = $this->attachmentMapper->find($attachmentId);
 		} catch (\Exception $e) {
diff --git a/lib/Service/BoardService.php b/lib/Service/BoardService.php
index 01c56010..b63b5775 100644
--- a/lib/Service/BoardService.php
+++ b/lib/Service/BoardService.php
@@ -54,6 +54,7 @@ use OCA\Deck\Db\BoardMapper;
 use OCA\Deck\Db\LabelMapper;
 use OCP\IUserManager;
 use OCA\Deck\BadRequestException;
+use OCA\Deck\Validators\BoardServiceValidator;
 use OCP\IURLGenerator;
 use OCP\Server;
 use Psr\Container\ContainerExceptionInterface;
@@ -79,6 +80,7 @@ class BoardService {
 	private ?array $boardsCache = null;
 	private IURLGenerator $urlGenerator;
 	private IDBConnection $connection;
+	private BoardServiceValidator $boardServiceValidator;
 
 	public function __construct(
 		BoardMapper $boardMapper,
@@ -98,6 +100,7 @@ class BoardService {
 		ChangeHelper $changeHelper,
 		IURLGenerator $urlGenerator,
 		IDBConnection $connection,
+		BoardServiceValidator $boardServiceValidator,
 		?string $userId
 	) {
 		$this->boardMapper = $boardMapper;
@@ -118,6 +121,7 @@ class BoardService {
 		$this->urlGenerator = $urlGenerator;
 		$this->cardMapper = $cardMapper;
 		$this->connection = $connection;
+		$this->boardServiceValidator = $boardServiceValidator;
 	}
 
 	/**
@@ -182,6 +186,7 @@ class BoardService {
 	 * @throws BadRequestException
 	 */
 	public function find($boardId) {
+		$this->boardServiceValidator->check(compact('boardId'));
 		if ($this->boardsCache && isset($this->boardsCache[$boardId])) {
 			return $this->boardsCache[$boardId];
 		}
@@ -236,9 +241,7 @@ class BoardService {
 	 * @throws BadRequestException
 	 */
 	public function isArchived($mapper, $id) {
-		if (is_numeric($id) === false) {
-			throw new BadRequestException('id must be a number');
-		}
+		$this->boardServiceValidator->check(compact('id'));
 
 		try {
 			$boardId = $id;
@@ -265,13 +268,7 @@ class BoardService {
 	 * @throws BadRequestException
 	 */
 	public function isDeleted($mapper, $id) {
-		if ($mapper === false || $mapper === null) {
-			throw new BadRequestException('mapper must be provided');
-		}
-
-		if (is_numeric($id) === false) {
-			throw new BadRequestException('id must be a number');
-		}
+		$this->boardServiceValidator->check(compact('mapper', 'id'));
 
 		try {
 			$boardId = $id;
@@ -297,17 +294,7 @@ class BoardService {
 	 * @throws BadRequestException
 	 */
 	public function create($title, $userId, $color) {
-		if ($title === false || $title === null) {
-			throw new BadRequestException('title must be provided');
-		}
-
-		if ($userId === false || $userId === null) {
-			throw new BadRequestException('userId must be provided');
-		}
-
-		if ($color === false || $color === null) {
-			throw new BadRequestException('color must be provided');
-		}
+		$this->boardServiceValidator->check(compact('title', 'userId', 'color'));
 
 		if (!$this->permissionService->canCreate()) {
 			throw new NoPermissionException('Creating boards has been disabled for your account.');
@@ -358,9 +345,7 @@ class BoardService {
 	 * @throws BadRequestException
 	 */
 	public function delete($id) {
-		if (is_numeric($id) === false) {
-			throw new BadRequestException('board id must be a number');
-		}
+		$this->boardServiceValidator->check(compact('id'));
 
 		$this->permissionService->checkPermission($this->boardMapper, $id, Acl::PERMISSION_MANAGE);
 		$board = $this->find($id);
@@ -383,9 +368,7 @@ class BoardService {
 	 * @throws \OCP\AppFramework\Db\MultipleObjectsReturnedException
 	 */
 	public function deleteUndo($id) {
-		if (is_numeric($id) === false) {
-			throw new BadRequestException('board id must be a number');
-		}
+		$this->boardServiceValidator->check(compact('id'));
 
 		$this->permissionService->checkPermission($this->boardMapper, $id, Acl::PERMISSION_MANAGE);
 		$board = $this->find($id);
@@ -406,9 +389,7 @@ class BoardService {
 	 * @throws BadRequestException
 	 */
 	public function deleteForce($id) {
-		if (is_numeric($id) === false) {
-			throw new BadRequestException('id must be a number');
-		}
+		$this->boardServiceValidator->check(compact('id'));
 
 		$this->permissionService->checkPermission($this->boardMapper, $id, Acl::PERMISSION_MANAGE);
 		$board = $this->find($id);
@@ -429,21 +410,7 @@ class BoardService {
 	 * @throws BadRequestException
 	 */
 	public function update($id, $title, $color, $archived) {
-		if (is_numeric($id) === false) {
-			throw new BadRequestException('board id must be a number');
-		}
-
-		if ($title === false || $title === null) {
-			throw new BadRequestException('title must be provided');
-		}
-
-		if ($color === false || $color === null) {
-			throw new BadRequestException('color must be provided');
-		}
-
-		if (is_bool($archived) === false) {
-			throw new BadRequestException('archived must be a boolean');
-		}
+		$this->boardServiceValidator->check(compact('id', 'title', 'color', 'archived'));
 
 		$this->permissionService->checkPermission($this->boardMapper, $id, Acl::PERMISSION_MANAGE);
 		$board = $this->find($id);
@@ -493,29 +460,7 @@ class BoardService {
 	 * @throws \OCA\Deck\NoPermissionException
 	 */
 	public function addAcl($boardId, $type, $participant, $edit, $share, $manage) {
-		if (is_numeric($boardId) === false) {
-			throw new BadRequestException('board id must be a number');
-		}
-
-		if ($type === false || $type === null) {
-			throw new BadRequestException('type must be provided');
-		}
-
-		if ($participant === false || $participant === null) {
-			throw new BadRequestException('participant must be provided');
-		}
-
-		if ($edit === null) {
-			throw new BadRequestException('edit must be provided');
-		}
-
-		if ($share === null) {
-			throw new BadRequestException('share must be provided');
-		}
-
-		if ($manage === null) {
-			throw new BadRequestException('manage must be provided');
-		}
+		$this->boardServiceValidator->check(compact('boardId', 'type', 'participant', 'edit', 'share', 'manage'));
 
 		$this->permissionService->checkPermission($this->boardMapper, $boardId, Acl::PERMISSION_SHARE);
 		[$edit, $share, $manage] = $this->applyPermissions($boardId, $edit, $share, $manage);
@@ -561,21 +506,7 @@ class BoardService {
 	 * @throws BadRequestException
 	 */
 	public function updateAcl($id, $edit, $share, $manage) {
-		if (is_numeric($id) === false) {
-			throw new BadRequestException('id must be a number');
-		}
-
-		if ($edit === null) {
-			throw new BadRequestException('edit must be provided');
-		}
-
-		if ($share === null) {
-			throw new BadRequestException('share must be provided');
-		}
-
-		if ($manage === null) {
-			throw new BadRequestException('manage must be provided');
-		}
+		$this->boardServiceValidator->check(compact('id', 'edit', 'share', 'manage'));
 
 		$this->permissionService->checkPermission($this->aclMapper, $id, Acl::PERMISSION_SHARE);
 
@@ -643,9 +574,7 @@ class BoardService {
 	 * @throws BadRequestException
 	 */
 	public function clone($id, $userId) {
-		if (is_numeric($id) === false) {
-			throw new BadRequestException('board id must be a number');
-		}
+		$this->boardServiceValidator->check(compact('id', 'userId'));
 
 		$this->permissionService->checkPermission($this->boardMapper, $id, Acl::PERMISSION_READ);
 
diff --git a/lib/Service/CardService.php b/lib/Service/CardService.php
index af0eb010..95dbcf59 100644
--- a/lib/Service/CardService.php
+++ b/lib/Service/CardService.php
@@ -43,6 +43,7 @@ use OCA\Deck\Db\BoardMapper;
 use OCA\Deck\Db\LabelMapper;
 use OCA\Deck\StatusException;
 use OCA\Deck\BadRequestException;
+use OCA\Deck\Validators\CardServiceValidator;
 use OCP\Comments\ICommentsManager;
 use OCP\EventDispatcher\IEventDispatcher;
 use OCP\IRequest;
@@ -69,6 +70,7 @@ class CardService {
 	private IURLGenerator $urlGenerator;
 	private LoggerInterface $logger;
 	private IRequest $request;
+	private CardServiceValidator $cardServiceValidator;
 
 	public function __construct(
 		CardMapper $cardMapper,
@@ -88,6 +90,7 @@ class CardService {
 		IURLGenerator $urlGenerator,
 		LoggerInterface $logger,
 		IRequest $request,
+		CardServiceValidator $cardServiceValidator,
 		?string $userId
 	) {
 		$this->cardMapper = $cardMapper;
@@ -108,6 +111,7 @@ class CardService {
 		$this->urlGenerator = $urlGenerator;
 		$this->logger = $logger;
 		$this->request = $request;
+		$this->cardServiceValidator = $cardServiceValidator;
 	}
 
 	public function enrich($card) {
@@ -130,6 +134,7 @@ class CardService {
 	}
 
 	public function fetchDeleted($boardId) {
+		$this->cardServiceValidator->check(compact('boardId'));
 		$this->permissionService->checkPermission($this->boardMapper, $boardId, Acl::PERMISSION_READ);
 		$cards = $this->cardMapper->findDeleted($boardId);
 		foreach ($cards as $card) {
@@ -190,29 +195,7 @@ class CardService {
 	 * @throws BadrequestException
 	 */
 	public function create($title, $stackId, $type, $order, $owner, $description = '', $duedate = null) {
-		if ($title === 'false' || $title === null) {
-			throw new BadRequestException('title must be provided');
-		}
-
-		if (mb_strlen($title) > Card::TITLE_MAX_LENGTH) {
-			throw new BadRequestException('The title cannot exceed 255 characters');
-		}
-
-		if (is_numeric($stackId) === false) {
-			throw new BadRequestException('stack id must be a number');
-		}
-
-		if ($type === 'false' || $type === null) {
-			throw new BadRequestException('type must be provided');
-		}
-
-		if (is_numeric($order) === false) {
-			throw new BadRequestException('order must be a number');
-		}
-
-		if ($owner === false || $owner === null) {
-			throw new BadRequestException('owner must be provided');
-		}
+		$this->cardServiceValidator->check(compact('title', 'stackId', 'type', 'order', 'owner'));
 
 		$this->permissionService->checkPermission($this->stackMapper, $stackId, Acl::PERMISSION_EDIT);
 		if ($this->boardService->isArchived($this->stackMapper, $stackId)) {
@@ -282,29 +265,7 @@ class CardService {
 	 * @throws BadRequestException
 	 */
 	public function update($id, $title, $stackId, $type, $owner, $description = '', $order = 0, $duedate = null, $deletedAt = null, $archived = null) {
-		if (is_numeric($id) === false) {
-			throw new BadRequestException('card id must be a number');
-		}
-
-		if ($title === false || $title === null) {
-			throw new BadRequestException('title must be provided');
-		}
-
-		if (mb_strlen($title) > Card::TITLE_MAX_LENGTH) {
-			throw new BadRequestException('The title cannot exceed 255 characters');
-		}
-
-		if (is_numeric($stackId) === false) {
-			throw new BadRequestException('stack id must be a number $$$');
-		}
-
-		if ($type === false || $type === null) {
-			throw new BadRequestException('type must be provided');
-		}
-
-		if ($owner === false || $owner === null) {
-			throw new BadRequestException('owner must be provided');
-		}
+		$this->cardServiceValidator->check(compact('id', 'title', 'stackId', 'type', 'owner', 'order'));
 
 		$this->permissionService->checkPermission($this->cardMapper, $id, Acl::PERMISSION_EDIT);
 		$this->permissionService->checkPermission($this->stackMapper, $stackId, Acl::PERMISSION_EDIT);
@@ -387,17 +348,7 @@ class CardService {
 	 * @throws BadRequestException
 	 */
 	public function rename($id, $title) {
-		if (is_numeric($id) === false) {
-			throw new BadRequestException('id must be a number');
-		}
-
-		if ($title === false || $title === null) {
-			throw new BadRequestException('title must be provided');
-		}
-
-		if (mb_strlen($title) > Card::TITLE_MAX_LENGTH) {
-			throw new BadRequestException('The title cannot exceed 255 characters');
-		}
+		$this->cardServiceValidator->check(compact('id', 'title'));
 
 		$this->permissionService->checkPermission($this->cardMapper, $id, Acl::PERMISSION_EDIT);
 		if ($this->boardService->isArchived($this->cardMapper, $id)) {
@@ -428,17 +379,8 @@ class CardService {
 	 * @throws BadRequestException
 	 */
 	public function reorder($id, $stackId, $order) {
-		if (is_numeric($id) === false) {
-			throw new BadRequestException('card id must be a number');
-		}
+		$this->cardServiceValidator->check(compact('id', 'stackId', 'order'));
 
-		if (is_numeric($stackId) === false) {
-			throw new BadRequestException('stack id must be a number');
-		}
-
-		if (is_numeric($order) === false) {
-			throw new BadRequestException('order must be a number');
-		}
 
 		$this->permissionService->checkPermission($this->cardMapper, $id, Acl::PERMISSION_EDIT);
 		$this->permissionService->checkPermission($this->stackMapper, $stackId, Acl::PERMISSION_EDIT);
@@ -493,9 +435,8 @@ class CardService {
 	 * @throws BadRequestException
 	 */
 	public function archive($id) {
-		if (is_numeric($id) === false) {
-			throw new BadRequestException('id must be a number');
-		}
+		$this->cardServiceValidator->check(compact('id'));
+
 
 		$this->permissionService->checkPermission($this->cardMapper, $id, Acl::PERMISSION_EDIT);
 		if ($this->boardService->isArchived($this->cardMapper, $id)) {
@@ -523,9 +464,8 @@ class CardService {
 	 * @throws BadRequestException
 	 */
 	public function unarchive($id) {
-		if (is_numeric($id) === false) {
-			throw new BadRequestException('id must be a number');
-		}
+		$this->cardServiceValidator->check(compact('id'));
+
 
 		$this->permissionService->checkPermission($this->cardMapper, $id, Acl::PERMISSION_EDIT);
 		if ($this->boardService->isArchived($this->cardMapper, $id)) {
@@ -552,13 +492,8 @@ class CardService {
 	 * @throws BadRequestException
 	 */
 	public function assignLabel($cardId, $labelId) {
-		if (is_numeric($cardId) === false) {
-			throw new BadRequestException('card id must be a number');
-		}
+		$this->cardServiceValidator->check(compact('cardId', 'labelId'));
 
-		if (is_numeric($labelId) === false) {
-			throw new BadRequestException('label id must be a number');
-		}
 
 		$this->permissionService->checkPermission($this->cardMapper, $cardId, Acl::PERMISSION_EDIT);
 		if ($this->boardService->isArchived($this->cardMapper, $cardId)) {
@@ -586,13 +521,8 @@ class CardService {
 	 * @throws BadRequestException
 	 */
 	public function removeLabel($cardId, $labelId) {
-		if (is_numeric($cardId) === false) {
-			throw new BadRequestException('card id must be a number');
-		}
+		$this->cardServiceValidator->check(compact('cardId', 'labelId'));
 
-		if (is_numeric($labelId) === false) {
-			throw new BadRequestException('label id must be a number');
-		}
 
 		$this->permissionService->checkPermission($this->cardMapper, $cardId, Acl::PERMISSION_EDIT);
 		if ($this->boardService->isArchived($this->cardMapper, $cardId)) {
diff --git a/lib/Service/LabelService.php b/lib/Service/LabelService.php
index f4c95fb6..61ed58f0 100644
--- a/lib/Service/LabelService.php
+++ b/lib/Service/LabelService.php
@@ -29,6 +29,7 @@ use OCA\Deck\Db\Acl;
 use OCA\Deck\Db\LabelMapper;
 use OCA\Deck\StatusException;
 use OCA\Deck\BadRequestException;
+use OCA\Deck\Validators\LabelServiceValidator;
 
 class LabelService {
 
@@ -40,12 +41,21 @@ class LabelService {
 	private $boardService;
 	/** @var ChangeHelper */
 	private $changeHelper;
-
-	public function __construct(LabelMapper $labelMapper, PermissionService $permissionService, BoardService $boardService, ChangeHelper $changeHelper) {
+	/** @var LabelServiceValidator */
+	private LabelServiceValidator $labelServiceValidator;
+
+	public function __construct(
+		LabelMapper $labelMapper,
+		PermissionService $permissionService,
+		BoardService $boardService,
+		ChangeHelper $changeHelper,
+		LabelServiceValidator $labelServiceValidator
+		) {
 		$this->labelMapper = $labelMapper;
 		$this->permissionService = $permissionService;
 		$this->boardService = $boardService;
 		$this->changeHelper = $changeHelper;
+		$this->labelServiceValidator = $labelServiceValidator;
 	}
 
 	/**
@@ -76,17 +86,7 @@ class LabelService {
 	 * @throws BadRequestException
 	 */
 	public function create($title, $color, $boardId) {
-		if ($title === false || $title === null) {
-			throw new BadRequestException('title must be provided');
-		}
-
-		if ($color === false || $color === null) {
-			throw new BadRequestException('color must be provided');
-		}
-
-		if (is_numeric($boardId) === false) {
-			throw new BadRequestException('board id must be a number');
-		}
+		$this->labelServiceValidator->check(compact('title', 'color', 'boardId'));
 
 		$this->permissionService->checkPermission(null, $boardId, Acl::PERMISSION_MANAGE);
 
@@ -119,9 +119,7 @@ class LabelService {
 	 * @throws BadRequestException
 	 */
 	public function delete($id) {
-		if (is_numeric($id) === false) {
-			throw new BadRequestException('label id must be a number');
-		}
+		$this->labelServiceValidator->check(compact('id'));
 
 		$this->permissionService->checkPermission($this->labelMapper, $id, Acl::PERMISSION_MANAGE);
 		if ($this->boardService->isArchived($this->labelMapper, $id)) {
@@ -144,17 +142,7 @@ class LabelService {
 	 * @throws BadRequestException
 	 */
 	public function update($id, $title, $color) {
-		if (is_numeric($id) === false) {
-			throw new BadRequestException('label id must be a number');
-		}
-
-		if ($title === false || $title === null || $title === "") {
-			throw new BadRequestException('title must be provided');
-		}
-
-		if ($color === false || $color === null) {
-			throw new BadRequestException('color must be provided');
-		}
+		$this->labelServiceValidator->check(compact('title', 'color', 'id'));
 
 		$this->permissionService->checkPermission($this->labelMapper, $id, Acl::PERMISSION_MANAGE);
 
diff --git a/lib/Service/StackService.php b/lib/Service/StackService.php
index 1e8bfc56..d41c00de 100644
--- a/lib/Service/StackService.php
+++ b/lib/Service/StackService.php
@@ -39,6 +39,7 @@ use OCA\Deck\Db\StackMapper;
 use OCA\Deck\Model\CardDetails;
 use OCA\Deck\NoPermissionException;
 use OCA\Deck\StatusException;
+use OCA\Deck\Validators\StackServiceValidator;
 use Psr\Log\LoggerInterface;
 
 class StackService {
@@ -54,6 +55,7 @@ class StackService {
 	private ActivityManager $activityManager;
 	private ChangeHelper $changeHelper;
 	private LoggerInterface $logger;
+	private StackServiceValidator $stackServiceValidator;
 
 	public function __construct(
 		StackMapper $stackMapper,
@@ -67,7 +69,8 @@ class StackService {
 		AttachmentService $attachmentService,
 		ActivityManager $activityManager,
 		ChangeHelper $changeHelper,
-		LoggerInterface $logger
+		LoggerInterface $logger,
+		StackServiceValidator $stackServiceValidator
 	) {
 		$this->stackMapper = $stackMapper;
 		$this->boardMapper = $boardMapper;
@@ -81,6 +84,7 @@ class StackService {
 		$this->activityManager = $activityManager;
 		$this->changeHelper = $changeHelper;
 		$this->logger = $logger;
+		$this->stackServiceValidator = $stackServiceValidator;
 	}
 
 	private function enrichStackWithCards($stack, $since = -1) {
@@ -218,17 +222,7 @@ class StackService {
 	 * @throws BadRequestException
 	 */
 	public function create($title, $boardId, $order) {
-		if ($title === false || $title === null || mb_strlen($title) === 0) {
-			throw new BadRequestException('title must be provided');
-		}
-
-		if (is_numeric($order) === false) {
-			throw new BadRequestException('order must be a number');
-		}
-
-		if (is_numeric($boardId) === false) {
-			throw new BadRequestException('board id must be a number');
-		}
+		$this->stackServiceValidator->check(compact('title', 'boardId', 'order'));
 
 		$this->permissionService->checkPermission(null, $boardId, Acl::PERMISSION_MANAGE);
 		if ($this->boardService->isArchived(null, $boardId)) {
@@ -291,21 +285,7 @@ class StackService {
 	 * @throws BadRequestException
 	 */
 	public function update($id, $title, $boardId, $order, $deletedAt) {
-		if (is_numeric($id) === false) {
-			throw new BadRequestException('stack id must be a number');
-		}
-
-		if ($title === false || $title === null || mb_strlen($title) === 0) {
-			throw new BadRequestException('title must be provided');
-		}
-
-		if (is_numeric($boardId) === false) {
-			throw new BadRequestException('board id must be a number');
-		}
-
-		if (is_numeric($order) === false) {
-			throw new BadRequestException('order must be a number');
-		}
+		$this->stackServiceValidator->check(compact('id', 'title', 'boardId', 'order'));
 
 		$this->permissionService->checkPermission($this->stackMapper, $id, Acl::PERMISSION_MANAGE);
 		$this->permissionService->checkPermission($this->boardMapper, $boardId, Acl::PERMISSION_MANAGE);
@@ -341,13 +321,7 @@ class StackService {
 	 * @throws BadRequestException
 	 */
 	public function reorder($id, $order) {
-		if (is_numeric($id) === false) {
-			throw new BadRquestException('id must be a number');
-		}
-
-		if ($order === false || $order === null) {
-			throw new BadRequestException('order must be provided');
-		}
+		$this->stackServiceValidator->check(compact('id', 'order'));
 
 		$this->permissionService->checkPermission($this->stackMapper, $id, Acl::PERMISSION_MANAGE);
 		$stackToSort = $this->stackMapper->find($id);
diff --git a/lib/Validators/AssignmentServiceValidator.php b/lib/Validators/AssignmentServiceValidator.php
new file mode 100644
index 00000000..42980e16
--- /dev/null
+++ b/lib/Validators/AssignmentServiceValidator.php
@@ -0,0 +1,37 @@
+<?php
+/**
+ * @copyright Copyright (c) 2016 Julius Härtl <jus@bitgrid.net>
+ *
+ * @author Julius Härtl <jus@bitgrid.net>
+ * @author Maxence Lange <maxence@artificial-owl.com>
+ * @author Luka Trovic <luka.trovic@nextcloud.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Affero General Public License as
+ *  published by the Free Software Foundation, either version 3 of the
+ *  License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Affero General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Affero General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+declare(strict_types=1);
+
+namespace OCA\Deck\Validators;
+
+class AssignmentServiceValidator extends BaseValidator {
+	public function rules() {
+		return [
+			'cardId' => ['numeric'],
+			'userId' => ['not_empty', 'not_null', 'not_false', 'max:64'],
+		];
+	}
+}
diff --git a/lib/Validators/AttachmentServiceValidator.php b/lib/Validators/AttachmentServiceValidator.php
new file mode 100644
index 00000000..c3f6ae77
--- /dev/null
+++ b/lib/Validators/AttachmentServiceValidator.php
@@ -0,0 +1,37 @@
+<?php
+/**
+ * @copyright Copyright (c) 2016 Julius Härtl <jus@bitgrid.net>
+ *
+ * @author Julius Härtl <jus@bitgrid.net>
+ * @author Maxence Lange <maxence@artificial-owl.com>
+ * @author Luka Trovic <luka.trovic@nextcloud.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Affero General Public License as
+ *  published by the Free Software Foundation, either version 3 of the
+ *  License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Affero General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Affero General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+declare(strict_types=1);
+
+namespace OCA\Deck\Validators;
+
+class AttachmentServiceValidator extends BaseValidator {
+	public function rules() {
+		return [
+			'cardId' => ['numeric'],
+			'type' => ['not_empty', 'not_null', 'not_false'],
+			'data' => ['not_empty', 'not_null', 'not_false', 'max:255'],
+		];
+	}
+}
diff --git a/lib/Validators/BaseValidator.php b/lib/Validators/BaseValidator.php
new file mode 100644
index 00000000..5601a84a
--- /dev/null
+++ b/lib/Validators/BaseValidator.php
@@ -0,0 +1,182 @@
+<?php
+/**
+ * @copyright Copyright (c) 2016 Julius Härtl <jus@bitgrid.net>
+ *
+ * @author Julius Härtl <jus@bitgrid.net>
+ * @author Maxence Lange <maxence@artificial-owl.com>
+ * @author Luka Trovic <luka.trovic@nextcloud.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Affero General Public License as
+ *  published by the Free Software Foundation, either version 3 of the
+ *  License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Affero General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Affero General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+declare(strict_types=1);
+
+namespace OCA\Deck\Validators;
+
+use Exception;
+use OCA\Deck\BadRequestException;
+
+abstract class BaseValidator {
+
+	/**
+	 * @return array
+	 */
+	abstract public function rules();
+
+	/**
+	 * Validate given entries
+	 *
+	 * @param array $data
+	 * @return void
+	 * @throws BadRequestException
+	 */
+	private function validate($data) {
+		$rules = $this->rules();
+
+		foreach ($data as $field => $value) {
+			$field_rule = $rules[$field];
+
+			if (is_array($field_rule)) {
+				foreach ($field_rule as $rule) {
+					// The format for specifying validation rules and parameters follows an
+					// easy {rule}:{parameters} formatting convention. For instance the
+					// rule "Max:3" states that the value may only be three letters.
+					if (strpos($rule, ':') !== false) {
+						[$rule, $parameter] = explode(':', $rule, 2);
+						if (!$this->{$rule}($value, $parameter)) {
+							throw new BadRequestException(
+								$this->getErrorMessage($rule, $field, $parameter));
+						}
+					} else {
+						if (!$this->{$rule}($value)) {
+							throw new BadRequestException(
+								$field . ' must be provided and must be '. str_replace("_", " ", $rule));
+						}
+					}
+				}
+			}
+
+			if (is_callable($field_rule) && !$field_rule($value)) {
+				throw new BadRequestException($field . ' must be provided');
+			}
+		}
+	}
+
+	/**
+	 * @param array $data
+	 * @return void
+	 * @throws BadRequestException
+	 */
+	public function check(array $data) {
+		$this->validate($data);
+	}
+
+	/**
+	 * @param $value
+	 * @return bool
+	 */
+	private function numeric($value): bool {
+		return is_numeric($value);
+	}
+
+	/**
+	 * @param $value
+	 * @return bool
+	 */
+	private function bool($value): bool {
+		return is_bool($value);
+	}
+
+	/**
+	 * @param $value
+	 * @return bool
+	 */
+	private function not_false($value): bool {
+		return ($value !== false) && ($value !== 'false');
+	}
+
+	/**
+	 * @param $value
+	 * @return bool
+	 */
+	private function not_null($value): bool {
+		return !is_null($value);
+	}
+
+	/**
+	 * @param $value
+	 * @return bool
+	 */
+	private function not_empty($value): bool {
+		return !empty($value);
+	}
+
+	/**
+	 * @throws Exception
+	 */
+	private function max($value, $limit): bool {
+		if (!$limit || !is_numeric($limit)) {
+			throw new Exception("Validation rule max requires at least 1 parameter. " . json_encode($limit));
+		}
+		return $this->getSize($value) <= $limit;
+	}
+
+	/**
+	 * @throws Exception
+	 */
+	private function min($value, $limit): bool {
+		if (!$limit || !is_numeric($limit)) {
+			throw new Exception("Validation rule max requires at least 1 parameter.");
+		}
+		return $this->getSize($value) >= $limit;
+	}
+
+	/**
+	 * Get the size of an attribute.
+	 *
+	 * @param  mixed  $value
+	 * @return int
+	 */
+	protected function getSize($value): int {
+		// This method will determine if the attribute is a number or string and
+		// return the proper size accordingly. If it is a number, then number itself
+		// is the size.
+		if (is_int($value)) {
+			return $value;
+		} elseif (is_array($value)) {
+			return count($value);
+		}
+
+		return mb_strlen($value ?? '');
+	}
+
+	/**
+	 * @param $rule
+	 * @param $field
+	 * @param $parameter
+	 * @return string
+	 */
+	protected function getErrorMessage($rule, $field, $parameter = null): string {
+		if (in_array($rule, ['max', 'min'])) {
+			return $rule === 'max'
+			? $field . ' cannot be longer than '. $parameter . ' characters '
+			: $field . ' must be at least '. $parameter . ' characters long ';
+		}
+
+		return $field . ' must be provided and must be '. str_replace("_", " ", $rule);
+	}
+}
diff --git a/lib/Validators/BoardServiceValidator.php b/lib/Validators/BoardServiceValidator.php
new file mode 100644
index 00000000..f5d58ecb
--- /dev/null
+++ b/lib/Validators/BoardServiceValidator.php
@@ -0,0 +1,47 @@
+<?php
+/**
+ * @copyright Copyright (c) 2016 Julius Härtl <jus@bitgrid.net>
+ *
+ * @author Julius Härtl <jus@bitgrid.net>
+ * @author Maxence Lange <maxence@artificial-owl.com>
+ * @author Luka Trovic <luka.trovic@nextcloud.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Affero General Public License as
+ *  published by the Free Software Foundation, either version 3 of the
+ *  License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Affero General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Affero General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+declare(strict_types=1);
+
+namespace OCA\Deck\Validators;
+
+class BoardServiceValidator extends BaseValidator {
+	public function rules() {
+		return [
+			'id' => ['numeric'],
+			'boardId' => ['numeric'],
+			'type' => ['numeric'],
+			'mapper' => ['not_empty', 'not_null', 'not_false'],
+			'title' => ['not_empty', 'not_null', 'not_false', 'max:100'],
+			'userId' => ['not_empty', 'not_null', 'not_false', 'max:64'],
+			'color' => ['not_empty', 'not_null', 'not_false', 'max:6'],
+			'participant' => ['not_empty', 'not_null', 'not_false', 'max:64'],
+			'edit' => ['not_null'],
+			'share' => ['not_null'],
+			'manage' => ['not_null'],
+			'archived' => ['bool']
+		];
+	}
+}
diff --git a/lib/Validators/CardServiceValidator.php b/lib/Validators/CardServiceValidator.php
new file mode 100644
index 00000000..0417d996
--- /dev/null
+++ b/lib/Validators/CardServiceValidator.php
@@ -0,0 +1,44 @@
+<?php
+/**
+ * @copyright Copyright (c) 2016 Julius Härtl <jus@bitgrid.net>
+ *
+ * @author Julius Härtl <jus@bitgrid.net>
+ * @author Maxence Lange <maxence@artificial-owl.com>
+ * @author Luka Trovic <luka.trovic@nextcloud.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Affero General Public License as
+ *  published by the Free Software Foundation, either version 3 of the
+ *  License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Affero General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Affero General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+declare(strict_types=1);
+
+namespace OCA\Deck\Validators;
+
+class CardServiceValidator extends BaseValidator {
+	public function rules() {
+		return [
+			'id' => ['numeric'],
+			'title' => ['not_empty', 'not_null', 'not_false', 'max:255'],
+			'cardId' => ['numeric'],
+			'stackId' => ['numeric'],
+			'boardId' => ['numeric'],
+			'labelId' => ['numeric'],
+			'type' => ['not_empty', 'not_null', 'not_false', 'max:64'],
+			'order' => ['numeric'],
+			'owner' => ['not_empty', 'not_null', 'not_false', 'max:64'],
+		];
+	}
+}
diff --git a/lib/Validators/LabelServiceValidator.php b/lib/Validators/LabelServiceValidator.php
new file mode 100644
index 00000000..c350cb76
--- /dev/null
+++ b/lib/Validators/LabelServiceValidator.php
@@ -0,0 +1,39 @@
+<?php
+/**
+ * @copyright Copyright (c) 2016 Julius Härtl <jus@bitgrid.net>
+ *
+ * @author Julius Härtl <jus@bitgrid.net>
+ * @author Maxence Lange <maxence@artificial-owl.com>
+ * @author Luka Trovic <luka.trovic@nextcloud.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Affero General Public License as
+ *  published by the Free Software Foundation, either version 3 of the
+ *  License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Affero General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Affero General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+ declare(strict_types=1);
+
+namespace OCA\Deck\Validators;
+
+class LabelServiceValidator extends BaseValidator {
+	public function rules() {
+		return [
+			'id' => ['numeric'],
+			'title' => ['not_empty', 'not_null', 'not_false', 'max:100'],
+			'boardId' => ['numeric', 'not_null'],
+			'color' => ['not_empty', 'not_null', 'not_false', 'max:6']
+		];
+	}
+}
diff --git a/lib/Validators/StackServiceValidator.php b/lib/Validators/StackServiceValidator.php
new file mode 100644
index 00000000..c32e7ac7
--- /dev/null
+++ b/lib/Validators/StackServiceValidator.php
@@ -0,0 +1,39 @@
+<?php
+/**
+ * @copyright Copyright (c) 2016 Julius Härtl <jus@bitgrid.net>
+ *
+ * @author Julius Härtl <jus@bitgrid.net>
+ * @author Maxence Lange <maxence@artificial-owl.com>
+ * @author Luka Trovic <luka.trovic@nextcloud.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Affero General Public License as
+ *  published by the Free Software Foundation, either version 3 of the
+ *  License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Affero General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Affero General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+declare(strict_types=1);
+
+namespace OCA\Deck\Validators;
+
+class StackServiceValidator extends BaseValidator {
+	public function rules() {
+		return [
+			'id' => ['numeric'],
+			'title' => ['not_empty', 'not_null', 'not_false', 'max:100'],
+			'boardId' => ['numeric', 'not_null'],
+			'order' => ['numeric', 'not_null']
+		];
+	}
+}