create re-share by owner and propagate unshare and unshare-from self request

correctly accross share owner and share initiator

4 files changed, 591 insertions, 73 deletions

diff --git a/apps/federatedfilesharing/lib/BackgroundJob/UnShare.php b/apps/federatedfilesharing/lib/BackgroundJob/RetryJob.php
index b056db4eac7..109a607bff0 100644
--- a/apps/federatedfilesharing/lib/BackgroundJob/UnShare.php
+++ b/apps/federatedfilesharing/lib/BackgroundJob/RetryJob.php
@@ -32,26 +32,26 @@ use OCP\BackgroundJob\IJobList;
 use OCP\ILogger;
 
 /**
- * Class UnShare
+ * Class RetryJob
  *
- * Background job to re-send the un-share notification to the remote server in
+ * Background job to re-send update of federated re-shares to the remote server in
  * case the server was not available on the first try
  *
  * @package OCA\FederatedFileSharing\BackgroundJob
  */
-class UnShare extends Job {
+class RetryJob extends Job {
 
 	/** @var  bool */
 	private $retainJob = true;
-	
+
 	/** @var Notifications */
 	private $notifications;
 
-	/** @var int max number of attempts to send the un-share request */
-	private $maxTry = 10;
+	/** @var int max number of attempts to send the request */
+	private $maxTry = 20;
 
-	/** @var int how much time should be between two tries (12 hours) */
-	private $interval = 43200;
+	/** @var int how much time should be between two tries (10 minutes) */
+	private $interval = 600;
 
 	/**
 	 * UnShare constructor.
@@ -77,7 +77,7 @@ class UnShare extends Job {
 				\OC::$server->getJobList()
 			);
 		}
-		
+
 	}
 
 	/**
@@ -99,12 +99,14 @@ class UnShare extends Job {
 
 	protected function run($argument) {
 		$remote = $argument['remote'];
-		$id = (int)$argument['id'];
+		$remoteId = $argument['remoteId'];
 		$token = $argument['token'];
+		$action = $argument['action'];
+		$data = json_decode($argument['data'], true);
 		$try = (int)$argument['try'] + 1;
 
-		$result = $this->notifications->sendRemoteUnShare($remote, $id, $token, $try);
-
+		$result = $this->notifications->sendUpdateToRemote($remote, $remoteId, $token, $action, $data, $try);
+		
 		if ($result === true || $try > $this->maxTry) {
 			$this->retainJob = false;
 		}
@@ -117,11 +119,13 @@ class UnShare extends Job {
 	 * @param array $argument
 	 */
 	protected function reAddJob(IJobList $jobList, array $argument) {
-		$jobList->add('OCA\FederatedFileSharing\BackgroundJob\UnShare',
+		$jobList->add('OCA\FederatedFileSharing\BackgroundJob\RetryJob',
 			[
 				'remote' => $argument['remote'],
-				'id' => $argument['id'],
+				'remoteId' => $argument['remoteId'],
 				'token' => $argument['token'],
+				'data' => $argument['data'],
+				'action' => $argument['action'],
 				'try' => (int)$argument['try'] + 1,
 				'lastRun' => time()
 			]
diff --git a/apps/federatedfilesharing/lib/FederatedShareProvider.php b/apps/federatedfilesharing/lib/FederatedShareProvider.php
index d014a6219a3..590c61559bf 100644
--- a/apps/federatedfilesharing/lib/FederatedShareProvider.php
+++ b/apps/federatedfilesharing/lib/FederatedShareProvider.php
@@ -23,6 +23,7 @@
 
 namespace OCA\FederatedFileSharing;
 
+use OC\Files\View;
 use OC\Share20\Share;
 use OCP\Files\IRootFolder;
 use OCP\IAppConfig;
@@ -70,6 +71,9 @@ class FederatedShareProvider implements IShareProvider {
 	/** @var IConfig */
 	private $config;
 
+	/** @var string */
+	private $externalShareTable = 'share_external';
+
 	/**
 	 * DefaultShareProvider constructor.
 	 *
@@ -127,7 +131,7 @@ class FederatedShareProvider implements IShareProvider {
 		$uidOwner = $share->getShareOwner();
 		$permissions = $share->getPermissions();
 		$sharedBy = $share->getSharedBy();
-
+		
 		/*
 		 * Check if file is not already shared with the remote user
 		 */
@@ -151,19 +155,42 @@ class FederatedShareProvider implements IShareProvider {
 			throw new \Exception($message_t);
 		}
 
-		$token = $this->tokenHandler->generateToken();
-
 		$shareWith = $user . '@' . $remote;
 
-		$shareId = $this->addShareToDB($itemSource, $itemType, $shareWith, $sharedBy, $uidOwner, $permissions, $token);
+		try {
+			$remoteShare = $this->getShareFromExternalShareTable($share);
+		} catch (ShareNotFound $e) {
+			$remoteShare = null;
+		}
 
-		$send = $this->notifications->sendRemoteShare(
-			$token,
-			$shareWith,
-			$share->getNode()->getName(),
-			$shareId,
-			$share->getSharedBy()
-		);
+		if ($remoteShare) {
+			$uidOwner = $remoteShare['owner'] . '@' . $remoteShare['remote'];
+			$shareId = $this->addShareToDB($itemSource, $itemType, $shareWith, $sharedBy, $uidOwner, $permissions, 'tmp_token_' . time());
+			list($token, $remoteId) = $this->askOwnerToReShare($shareWith, $share, $shareId);
+			// remote share was create successfully if we get a valid token as return
+			$send = is_string($token) && $token !== '';
+			if ($send) {
+				$this->updateSuccessfulReshare($shareId, $token);
+				$this->storeRemoteId($shareId, $remoteId);
+			}
+		} else {
+			$token = $this->tokenHandler->generateToken();
+			$shareId = $this->addShareToDB($itemSource, $itemType, $shareWith, $sharedBy, $uidOwner, $permissions, $token);
+			$sharedByFederatedId = $share->getSharedBy();
+			if ($this->userManager->userExists($sharedByFederatedId)) {
+				$sharedByFederatedId = $sharedByFederatedId . '@' . $this->addressHandler->generateRemoteURL();
+			}
+			$send = $this->notifications->sendRemoteShare(
+				$token,
+				$shareWith,
+				$share->getNode()->getName(),
+				$shareId,
+				$share->getShareOwner(),
+				$share->getShareOwner() . '@' . $this->addressHandler->generateRemoteURL(),
+				$share->getSharedBy(),
+				$sharedByFederatedId
+			);
+		}
 
 		$data = $this->getRawShare($shareId);
 		$share = $this->createShare($data);
@@ -179,6 +206,53 @@ class FederatedShareProvider implements IShareProvider {
 	}
 
 	/**
+	 * @param string $shareWith
+	 * @param IShare $share
+	 * @param string $shareId internal share Id
+	 * @return array
+	 * @throws \Exception
+	 */
+	protected function askOwnerToReShare($shareWith, IShare $share, $shareId) {
+
+		$remoteShare = $this->getShareFromExternalShareTable($share);
+		$token = $remoteShare['share_token'];
+		$remoteId = $remoteShare['remote_id'];
+		$remote = $remoteShare['remote'];
+
+		list($token, $remoteId) = $this->notifications->requestReShare(
+			$token,
+			$remoteId,
+			$shareId,
+			$remote,
+			$shareWith,
+			$share->getPermissions()
+		);
+
+		return [$token, $remoteId];
+	}
+
+	/**
+	 * get federated share from the share_external table but exclude mounted link shares
+	 *
+	 * @param IShare $share
+	 * @return array
+	 * @throws ShareNotFound
+	 */
+	protected function getShareFromExternalShareTable(IShare $share) {
+		$query = $this->dbConnection->getQueryBuilder();
+		$query->select('*')->from($this->externalShareTable)
+			->where($query->expr()->eq('user', $query->createNamedParameter($share->getShareOwner())))
+			->andWhere($query->expr()->eq('mountpoint', $query->createNamedParameter($share->getTarget())));
+		$result = $query->execute()->fetchAll();
+
+		if (isset($result[0]) && (int)$result[0]['remote_id'] > 0) {
+			return $result[0];
+		}
+
+		throw new ShareNotFound('share not found in share_external table');
+	}
+
+	/**
 	 * add share to the database and return the ID
 	 *
 	 * @param int $itemSource
@@ -238,6 +312,58 @@ class FederatedShareProvider implements IShareProvider {
 	}
 
 	/**
+	 * update successful reShare with the correct token
+	 *
+	 * @param int $shareId
+	 * @param string $token
+	 */
+	protected function updateSuccessfulReShare($shareId, $token) {
+		$query = $this->dbConnection->getQueryBuilder();
+		$query->update('share')
+			->where($query->expr()->eq('id', $query->createNamedParameter($shareId)))
+			->set('token', $query->createNamedParameter($token))
+			->execute();
+	}
+
+	/**
+	 * store remote ID in federated reShare table
+	 *
+	 * @param $shareId
+	 * @param $remoteId
+	 */
+	public function storeRemoteId($shareId, $remoteId) {
+		$query = $this->dbConnection->getQueryBuilder();
+		$query->insert('federated_reshares')
+			->values(
+				[
+					'share_id' =>  $query->createNamedParameter($shareId),
+					'remote_id' => $query->createNamedParameter($remoteId),
+				]
+			);
+		$query->execute();
+	}
+
+	/**
+	 * get share ID on remote server for federated re-shares
+	 *
+	 * @param IShare $share
+	 * @return int
+	 * @throws ShareNotFound
+	 */
+	public function getRemoteId(IShare $share) {
+		$query = $this->dbConnection->getQueryBuilder();
+		$query->select('remote_id')->from('federated_reshares')
+			->where($query->expr()->eq('share_id', $query->createNamedParameter((int)$share->getId())));
+		$data = $query->execute()->fetch();
+
+		if (!is_array($data) || !isset($data['remote_id'])) {
+			throw new ShareNotFound();
+		}
+
+		return (int)$data['remote_id'];
+	}
+
+	/**
 	 * @inheritdoc
 	 */
 	public function move(IShare $share, $recipient) {
@@ -274,18 +400,77 @@ class FederatedShareProvider implements IShareProvider {
 	}
 
 	/**
-	 * Delete a share
+	 * Delete a share (owner unShares the file)
 	 *
 	 * @param IShare $share
 	 */
 	public function delete(IShare $share) {
+
+		list(, $remote) = $this->addressHandler->splitUserRemote($share->getSharedWith());
+
+		$isOwner = false;
+
+		// if the local user is the owner we can send the unShare request directly...
+		if ($this->userManager->userExists($share->getShareOwner())) {
+			$this->notifications->sendRemoteUnShare($remote, $share->getId(), $share->getToken());
+			$this->revokeShare($share, true);
+			$isOwner = true;
+		} else { // ... if not we need to correct ID for the unShare request
+			$remoteId = $this->getRemoteId($share);
+			$this->notifications->sendRemoteUnShare($remote, $remoteId, $share->getToken());
+			$this->revokeShare($share, false);
+		}
+
+		// send revoke notification to the other user, if initiator and owner are not the same user
+		if ($share->getShareOwner() !== $share->getSharedBy()) {
+			$remoteId = $this->getRemoteId($share);
+			if ($isOwner) {
+				list(, $remote) = $this->addressHandler->splitUserRemote($share->getSharedBy());
+			} else {
+				list(, $remote) = $this->addressHandler->splitUserRemote($share->getShareOwner());
+			}
+			$this->notifications->sendRevokeShare($remote, $remoteId, $share->getToken());
+		}
+
+		$this->removeShareFromTable($share);
+	}
+
+	/**
+	 * in case of a re-share we need to send the other use (initiator or owner)
+	 * a message that the file was unshared
+	 *
+	 * @param IShare $share
+	 * @param bool $isOwner the user can either be the owner or the user who re-sahred it
+	 * @throws ShareNotFound
+	 * @throws \OC\HintException
+	 */
+	protected function revokeShare($share, $isOwner) {
+		// also send a unShare request to the initiator, if this is a different user than the owner
+		if ($share->getShareOwner() !== $share->getSharedBy()) {
+			if ($isOwner) {
+				list(, $remote) = $this->addressHandler->splitUserRemote($share->getSharedBy());
+			} else {
+				list(, $remote) = $this->addressHandler->splitUserRemote($share->getShareOwner());
+			}
+			$remoteId = $this->getRemoteId($share);
+			$this->notifications->sendRevokeShare($remote, $remoteId, $share->getToken());
+		}
+	}
+
+	/**
+	 * remove share from table
+	 *
+	 * @param IShare $share
+	 */
+	public function removeShareFromTable(IShare $share) {
 		$qb = $this->dbConnection->getQueryBuilder();
 		$qb->delete('share')
 			->where($qb->expr()->eq('id', $qb->createNamedParameter($share->getId())));
 		$qb->execute();
 
-		list(, $remote) = $this->addressHandler->splitUserRemote($share->getSharedWith());
-		$this->notifications->sendRemoteUnShare($remote, $share->getId(), $share->getToken());
+		$qb->delete('federated_reshares')
+			->where($qb->expr()->eq('share_id', $qb->createNamedParameter($share->getId())));
+		$qb->execute();
 	}
 
 	/**
diff --git a/apps/federatedfilesharing/lib/Notifications.php b/apps/federatedfilesharing/lib/Notifications.php
index 9cdc7760361..c65da212aad 100644
--- a/apps/federatedfilesharing/lib/Notifications.php
+++ b/apps/federatedfilesharing/lib/Notifications.php
@@ -67,9 +67,14 @@ class Notifications {
 	 * @param string $name
 	 * @param int $remote_id
 	 * @param string $owner
+	 * @param string $ownerFederatedId
+	 * @param string $sharedBy
+	 * @param string $sharedByFederatedId
 	 * @return bool
+	 * @throws \OC\HintException
+	 * @throws \OC\ServerNotAvailableException
 	 */
-	public function sendRemoteShare($token, $shareWith, $name, $remote_id, $owner) {
+	public function sendRemoteShare($token, $shareWith, $name, $remote_id, $owner, $ownerFederatedId, $sharedBy, $sharedByFederatedId) {
 
 		list($user, $remote) = $this->addressHandler->splitUserRemote($shareWith);
 
@@ -83,6 +88,9 @@ class Notifications {
 				'name' => $name,
 				'remoteId' => $remote_id,
 				'owner' => $owner,
+				'ownerFederatedId' => $ownerFederatedId,
+				'sharedBy' => $sharedBy,
+				'sharedByFederatedId' => $sharedByFederatedId,
 				'remote' => $local,
 			);
 
@@ -101,34 +109,138 @@ class Notifications {
 	}
 
 	/**
+	 * ask owner to re-share the file with the given user
+	 *
+	 * @param string $token
+	 * @param int $id remote Id
+	 * @param int $shareId internal share Id
+	 * @param string $remote remote address of the owner
+	 * @param string $shareWith
+	 * @param int $permission
+	 * @return bool
+	 * @throws \OC\HintException
+	 * @throws \OC\ServerNotAvailableException
+	 */
+	public function requestReShare($token, $id, $shareId, $remote, $shareWith, $permission) {
+
+		$fields = array(
+			'shareWith' => $shareWith,
+			'token' => $token,
+			'permission' => $permission,
+			'remoteId' => $shareId
+		);
+
+		$url = $this->addressHandler->removeProtocolFromUrl($remote);
+		$result = $this->tryHttpPostToShareEndpoint(rtrim($url, '/'), '/' . $id . '/reshare', $fields);
+		$status = json_decode($result['result'], true);
+
+		$httpRequestSuccessful = $result['success'];
+		$ocsCallSuccessful = $status['ocs']['meta']['statuscode'] === 100 || $status['ocs']['meta']['statuscode'] === 200;
+		$validToken = isset($status['ocs']['data']['token']) && is_string($status['ocs']['data']['token']);
+		$validRemoteId = isset($status['ocs']['data']['remoteId']);
+
+		if ($httpRequestSuccessful && $ocsCallSuccessful && $validToken && $validRemoteId) {
+			return [
+				$status['ocs']['data']['token'],
+				(int)$status['ocs']['data']['remoteId']
+			];
+		}
+
+		return false;
+	}
+
+	/**
+	 * send server-to-server unshare to remote server
+	 *
+	 * @param string $remote url
+	 * @param int $id share id
+	 * @param string $token
+	 * @return bool
+	 */
+	public function sendRemoteUnShare($remote, $id, $token) {
+		$this->sendUpdateToRemote($remote, $id, $token, 'unshare');
+	}
+
+	/**
 	 * send server-to-server unshare to remote server
 	 *
 	 * @param string $remote url
 	 * @param int $id share id
 	 * @param string $token
-	 * @param int $try how often did we already tried to send the un-share request
 	 * @return bool
 	 */
-	public function sendRemoteUnShare($remote, $id, $token, $try = 0) {
-		$url = rtrim($remote, '/');
-		$fields = array('token' => $token, 'format' => 'json');
-		$url = $this->addressHandler->removeProtocolFromUrl($url);
-		$result = $this->tryHttpPostToShareEndpoint($url, '/'.$id.'/unshare', $fields);
+	public function sendRevokeShare($remote, $id, $token) {
+		$this->sendUpdateToRemote($remote, $id, $token, 'revoke');
+	}
+
+	/**
+	 * send notification to remote server if the permissions was changed
+	 *
+	 * @param string $remote
+	 * @param int $remoteId
+	 * @param string $token
+	 * @param int $permissions
+	 * @return bool
+	 */
+	public function sendPermissionChange($remote, $remoteId, $token, $permissions) {
+		$this->sendUpdateToRemote($remote, $remoteId, $token, ['permissions' => $permissions]);
+	}
+
+	/**
+	 * forward accept reShare to remote server
+	 * 
+	 * @param string $remote
+	 * @param int $remoteId
+	 * @param string $token
+	 */
+	public function sendAcceptShare($remote, $remoteId, $token) {
+		$this->sendUpdateToRemote($remote, $remoteId, $token, 'accept');
+	}
+
+	/**
+	 * forward decline reShare to remote server
+	 *
+	 * @param string $remote
+	 * @param int $remoteId
+	 * @param string $token
+	 */
+	public function sendDeclineShare($remote, $remoteId, $token) {
+		$this->sendUpdateToRemote($remote, $remoteId, $token, 'decline');
+	}
+
+	/**
+	 * inform remote server whether server-to-server share was accepted/declined
+	 *
+	 * @param string $remote
+	 * @param string $token
+	 * @param int $remoteId Share id on the remote host
+	 * @param string $action possible actions: accept, decline, unshare, revoke, permissions
+	 * @param array $data
+	 * @param int $try
+	 * @return boolean
+	 */
+	public function sendUpdateToRemote($remote, $remoteId, $token, $action, $data = [], $try = 0) {
+
+		$fields = array('token' => $token);
+		$url = $this->addressHandler->removeProtocolFromUrl($remote);
+		$result = $this->tryHttpPostToShareEndpoint(rtrim($url, '/'), '/' . $remoteId . '/' . $action, $fields);
 		$status = json_decode($result['result'], true);
 
-		if ($result['success'] && 
-			($status['ocs']['meta']['statuscode'] === 100 || 
+		if ($result['success'] &&
+			($status['ocs']['meta']['statuscode'] === 100 ||
 				$status['ocs']['meta']['statuscode'] === 200
 			)
 		) {
 			return true;
 		} elseif ($try === 0) {
 			// only add new job on first try
-			$this->jobList->add('OCA\FederatedFileSharing\BackgroundJob\UnShare',
+			$this->jobList->add('OCA\FederatedFileSharing\BackgroundJob\RetryJob',
 				[
 					'remote' => $remote,
-					'id' => $id,
+					'remoteId' => $remoteId,
 					'token' => $token,
+					'action' => $action,
+					'data' => json_encode($data),
 					'try' => $try,
 					'lastRun' => $this->getTimestamp()
 				]
@@ -138,6 +250,7 @@ class Notifications {
 		return false;
 	}
 
+
 	/**
 	 * return current timestamp
 	 *
diff --git a/apps/federatedfilesharing/lib/RequestHandler.php b/apps/federatedfilesharing/lib/RequestHandler.php
index 90621666b6a..b6630496dcb 100644
--- a/apps/federatedfilesharing/lib/RequestHandler.php
+++ b/apps/federatedfilesharing/lib/RequestHandler.php
@@ -25,11 +25,14 @@
 
 namespace OCA\FederatedFileSharing;
 
-use OCA\FederatedFileSharing\DiscoveryManager;
-use OCA\FederatedFileSharing\FederatedShareProvider;
 use OCA\Files_Sharing\Activity;
+use OCP\AppFramework\Http;
+use OCP\Constants;
 use OCP\Files\NotFoundException;
 use OCP\IDBConnection;
+use OCP\IRequest;
+use OCP\IUserManager;
+use OCP\Share;
 
 /**
  * Class RequestHandler
@@ -46,6 +49,21 @@ class RequestHandler {
 	/** @var IDBConnection */
 	private $connection;
 
+	/** @var Share\IManager */
+	private $shareManager;
+
+	/** @var IRequest */
+	private $request;
+
+	/** @var Notifications */
+	private $notifications;
+
+	/** @var AddressHandler */
+	private $addressHandler;
+
+	/** @var  IUserManager */
+	private $userManager;
+
 	/** @var string */
 	private $shareTable = 'share';
 
@@ -54,10 +72,27 @@ class RequestHandler {
 	 *
 	 * @param FederatedShareProvider $federatedShareProvider
 	 * @param IDBConnection $connection
+	 * @param Share\IManager $shareManager
+	 * @param IRequest $request
+	 * @param Notifications $notifications
+	 * @param AddressHandler $addressHandler
+	 * @param IUserManager $userManager
 	 */
-	public function __construct(FederatedShareProvider $federatedShareProvider, IDBConnection $connection) {
+	public function __construct(FederatedShareProvider $federatedShareProvider,
+								IDBConnection $connection,
+								Share\IManager $shareManager,
+								IRequest $request,
+								Notifications $notifications,
+								AddressHandler $addressHandler,
+								IUserManager $userManager
+	) {
 		$this->federatedShareProvider = $federatedShareProvider;
 		$this->connection = $connection;
+		$this->shareManager = $shareManager;
+		$this->request = $request;
+		$this->notifications = $notifications;
+		$this->addressHandler = $addressHandler;
+		$this->userManager = $userManager;
 	}
 
 	/**
@@ -76,8 +111,11 @@ class RequestHandler {
 		$token = isset($_POST['token']) ? $_POST['token'] : null;
 		$name = isset($_POST['name']) ? $_POST['name'] : null;
 		$owner = isset($_POST['owner']) ? $_POST['owner'] : null;
+		$sharedBy = isset($_POST['sharedBy']) ? $_POST['sharedBy'] : null;
 		$shareWith = isset($_POST['shareWith']) ? $_POST['shareWith'] : null;
 		$remoteId = isset($_POST['remoteId']) ? (int)$_POST['remoteId'] : null;
+		$sharedByFederatedId = isset($_POST['sharedByFederatedId']) ? $_POST['sharedByFederatedId'] : null;
+		$ownerFederatedId = isset($_POST['ownerFederatedId']) ? $_POST['ownerFederatedId'] : null;
 
 		if ($remote && $token && $name && $owner && $remoteId && $shareWith) {
 
@@ -118,10 +156,17 @@ class RequestHandler {
 				$externalManager->addShare($remote, $token, '', $name, $owner, false, $shareWith, $remoteId);
 				$shareId = \OC::$server->getDatabaseConnection()->lastInsertId('*PREFIX*share_external');
 
-				$user = $owner . '@' . $this->cleanupRemote($remote);
+				if ($ownerFederatedId === null) {
+					$ownerFederatedId = $owner . '@' . $this->cleanupRemote($remote);
+				}
+				// if the owner of the share and the initiator are the same user
+				// we also complete the federated share ID for the initiator
+				if ($sharedByFederatedId === null && $owner === $sharedBy) {
+					$sharedByFederatedId = $ownerFederatedId;
+				}
 
 				\OC::$server->getActivityManager()->publishActivity(
-					Activity::FILES_SHARING_APP, Activity::SUBJECT_REMOTE_SHARE_RECEIVED, array($user, trim($name, '/')), '', array(),
+					Activity::FILES_SHARING_APP, Activity::SUBJECT_REMOTE_SHARE_RECEIVED, array($ownerFederatedId, trim($name, '/')), '', array(),
 					'', '', $shareWith, Activity::TYPE_REMOTE_SHARE, Activity::PRIORITY_LOW);
 
 				$urlGenerator = \OC::$server->getURLGenerator();
@@ -132,7 +177,7 @@ class RequestHandler {
 					->setUser($shareWith)
 					->setDateTime(new \DateTime())
 					->setObject('remote_share', $shareId)
-					->setSubject('remote_share', [$user, trim($name, '/')]);
+					->setSubject('remote_share', [$ownerFederatedId, $sharedByFederatedId, trim($name, '/')]);
 
 				$declineAction = $notification->createAction();
 				$declineAction->setLabel('decline')
@@ -157,6 +202,66 @@ class RequestHandler {
 	}
 
 	/**
+	 * create re-share on behalf of another user
+	 *
+	 * @param $params
+	 * @return \OC_OCS_Result
+	 */
+	public function reShare($params) {
+
+		$id = isset($params['id']) ? (int)$params['id'] : null;
+		$token = $this->request->getParam('token', null);
+		$shareWith = $this->request->getParam('shareWith', null);
+		$permission = (int)$this->request->getParam('permission', null);
+		$remoteId = (int)$this->request->getParam('remoteId', null);
+
+		if ($id === null ||
+			$token === null ||
+			$shareWith === null ||
+			$permission === null ||
+			$remoteId === null
+		) {
+			return new \OC_OCS_Result(null, Http::STATUS_BAD_REQUEST);
+		}
+
+		try {
+			$share = $this->federatedShareProvider->getShareById($id);
+		} catch (Share\Exceptions\ShareNotFound $e) {
+			return new \OC_OCS_Result(null, Http::STATUS_NOT_FOUND);
+		}
+
+		// don't allow to share a file back to the owner
+		list($user, $remote) = $this->addressHandler->splitUserRemote($shareWith);
+		$owner = $share->getShareOwner();
+		$currentServer = $this->addressHandler->generateRemoteURL();
+		if ($this->addressHandler->compareAddresses($user, $remote,$owner , $currentServer)) {
+			return new \OC_OCS_Result(null, Http::STATUS_FORBIDDEN);
+		}
+
+		if ($this->verifyShare($share, $token)) {
+
+			// check if re-sharing is allowed
+			if ($share->getPermissions() | ~Constants::PERMISSION_SHARE) {
+				$share->setPermissions($share->getPermissions() & $permission);
+				// the recipient of the initial share is now the initiator for the re-share
+				$share->setSharedBy($share->getSharedWith());
+				$share->setSharedWith($shareWith);
+				try {
+					$result = $this->federatedShareProvider->create($share);
+					$this->federatedShareProvider->storeRemoteId((int)$result->getId(), $remoteId);
+					return new \OC_OCS_Result(['token' => $result->getToken(), 'remoteId' => $result->getId()]);
+				} catch (\Exception $e) {
+					return new \OC_OCS_Result(null, Http::STATUS_INTERNAL_SERVER_ERROR);
+				}
+			} else {
+				return new \OC_OCS_Result(null, Http::STATUS_FORBIDDEN);
+			}
+		}
+		return new \OC_OCS_Result(null, Http::STATUS_BAD_REQUEST);
+
+	}
+
+	/**
 	 * accept server-to-server share
 	 *
 	 * @param array $params
@@ -170,24 +275,38 @@ class RequestHandler {
 
 		$id = $params['id'];
 		$token = isset($_POST['token']) ? $_POST['token'] : null;
-		$share = $this->getShare($id, $token);
-
-		if ($share) {
-			list($file, $link) = $this->getFile($share['uid_owner'], $share['file_source']);
-
-			$event = \OC::$server->getActivityManager()->generateEvent();
-			$event->setApp(Activity::FILES_SHARING_APP)
-				->setType(Activity::TYPE_REMOTE_SHARE)
-				->setAffectedUser($share['uid_owner'])
-				->setSubject(Activity::SUBJECT_REMOTE_SHARE_ACCEPTED, [$share['share_with'], basename($file)])
-				->setObject('files', $share['file_source'], $file)
-				->setLink($link);
-			\OC::$server->getActivityManager()->publish($event);
+
+		try {
+			$share = $this->federatedShareProvider->getShareById($id);
+		} catch (Share\Exceptions\ShareNotFound $e) {
+			return new \OC_OCS_Result();
+		}
+
+		if ($this->verifyShare($share, $token)) {
+			$this->executeAcceptShare($share);
+			if ($share->getShareOwner() !== $share->getSharedBy()) {
+				list(, $remote) = $this->addressHandler->splitUserRemote($share->getSharedBy());
+				$remoteId = $this->federatedShareProvider->getRemoteId($share);
+				$this->notifications->sendAcceptShare($remote, $remoteId, $share->getToken());
+			}
 		}
 
 		return new \OC_OCS_Result();
 	}
 
+	protected function executeAcceptShare(Share\IShare $share) {
+		list($file, $link) = $this->getFile($this->getCorrectUid($share), $share->getNode()->getId());
+
+		$event = \OC::$server->getActivityManager()->generateEvent();
+		$event->setApp(Activity::FILES_SHARING_APP)
+			->setType(Activity::TYPE_REMOTE_SHARE)
+			->setAffectedUser($this->getCorrectUid($share))
+			->setSubject(Activity::SUBJECT_REMOTE_SHARE_ACCEPTED, [$share->getSharedWith(), basename($file)])
+			->setObject('files', $share->getNode()->getId(), $file)
+			->setLink($link);
+		\OC::$server->getActivityManager()->publish($event);
+	}
+
 	/**
 	 * decline server-to-server share
 	 *
@@ -200,28 +319,59 @@ class RequestHandler {
 			return new \OC_OCS_Result(null, 503, 'Server does not support federated cloud sharing');
 		}
 
-		$id = $params['id'];
+		$id = (int)$params['id'];
 		$token = isset($_POST['token']) ? $_POST['token'] : null;
 
-		$share = $this->getShare($id, $token);
+		try {
+			$share = $this->federatedShareProvider->getShareById($id);
+		} catch (Share\Exceptions\ShareNotFound $e) {
+			return new \OC_OCS_Result();
+		}
+
+		if($this->verifyShare($share, $token)) {
+			if ($share->getShareOwner() !== $share->getSharedBy()) {
+				list(, $remote) = $this->addressHandler->splitUserRemote($share->getSharedBy());
+				$remoteId = $this->federatedShareProvider->getRemoteId($share);
+				$this->notifications->sendDeclineShare($remote, $remoteId, $share->getToken());
+			}
+			$this->executeDeclineShare($share);
+		}
 
-		if ($share) {
-			// userId must be set to the user who unshares
-			\OCP\Share::unshare($share['item_type'], $share['item_source'], $share['share_type'], $share['share_with'], $share['uid_owner']);
+		return new \OC_OCS_Result();
+	}
 
-			list($file, $link) = $this->getFile($share['uid_owner'], $share['file_source']);
+	/**
+	 * delete declined share and create a activity
+	 *
+	 * @param Share\IShare $share
+	 */
+	protected function executeDeclineShare(Share\IShare $share) {
+		$this->federatedShareProvider->removeShareFromTable($share);
+		list($file, $link) = $this->getFile($this->getCorrectUid($share), $share->getNode()->getId());
+
+		$event = \OC::$server->getActivityManager()->generateEvent();
+		$event->setApp(Activity::FILES_SHARING_APP)
+			->setType(Activity::TYPE_REMOTE_SHARE)
+			->setAffectedUser($this->getCorrectUid($share))
+			->setSubject(Activity::SUBJECT_REMOTE_SHARE_DECLINED, [$share->getSharedWith(), basename($file)])
+			->setObject('files', $share->getNode()->getId(), $file)
+			->setLink($link);
+		\OC::$server->getActivityManager()->publish($event);
 
-			$event = \OC::$server->getActivityManager()->generateEvent();
-			$event->setApp(Activity::FILES_SHARING_APP)
-				->setType(Activity::TYPE_REMOTE_SHARE)
-				->setAffectedUser($share['uid_owner'])
-				->setSubject(Activity::SUBJECT_REMOTE_SHARE_DECLINED, [$share['share_with'], basename($file)])
-				->setObject('files', $share['file_source'], $file)
-				->setLink($link);
-			\OC::$server->getActivityManager()->publish($event);
+	}
+
+	/**
+	 * check if we are the initiator or the owner of a re-share and return the correct UID
+	 *
+	 * @param Share\IShare $share
+	 * @return string
+	 */
+	protected function getCorrectUid(Share\IShare $share) {
+		if($this->userManager->userExists($share->getShareOwner())) {
+			return $share->getShareOwner();
 		}
 
-		return new \OC_OCS_Result();
+		return $share->getSharedBy();
 	}
 
 	/**
@@ -281,6 +431,28 @@ class RequestHandler {
 		return rtrim($remote, '/');
 	}
 
+
+	/**
+	 * federated share was revoked, either by the owner or the re-sharer
+	 *
+	 * @param $params
+	 * @return \OC_OCS_Result
+	 */
+	public function revoke($params) {
+		$id = (int)$params['id'];
+		$token = $this->request->getParam('token');
+		
+		$share = $this->federatedShareProvider->getShareById($id);
+		
+		if ($this->verifyShare($share, $token)) {
+			$this->federatedShareProvider->removeShareFromTable($share);
+			return new \OC_OCS_Result();
+		}
+
+	return new \OC_OCS_Result(null, Http::STATUS_BAD_REQUEST);
+
+	}
+	
 	/**
 	 * get share
 	 *
@@ -345,4 +517,48 @@ class RequestHandler {
 		return $result;
 	}
 
+	/**
+	 * check if we got the right share
+	 *
+	 * @param Share\IShare $share
+	 * @param string $token
+	 * @return bool
+	 */
+	protected function verifyShare(Share\IShare $share, $token) {
+		if (
+			$share->getShareType() === FederatedShareProvider::SHARE_TYPE_REMOTE &&
+			$share->getToken() === $token
+		) {
+			return true;
+		}
+
+		return false;
+	}
+
+	/**
+	 * update share information to keep federated re-shares in sync
+	 */
+	public function update() {
+		$token = $this->request->getParam('token', null);
+		$data = $this->request->getParam('data', []);
+
+		$dataArray = json_decode($data, true);
+
+		try {
+			$share = $this->federatedShareProvider->getShareByToken($token);
+		} catch (Share\Exceptions\ShareNotFound $e) {
+			return new \OC_OCS_Result(null, Http::STATUS_BAD_REQUEST);
+		}
+
+		if (isset($dataArray['decline'])) {
+			$this->executeDeclineShare($share);
+		}
+
+		if (isset($dataArray['accept'])) {
+			$this->executeAcceptShare($share);
+		}
+
+		return new \OC_OCS_Result();
+	}
+
 }