diff --git a/appinfo/app.php b/appinfo/app.php
index 788b4c78..b45c7211 100644
--- a/appinfo/app.php
+++ b/appinfo/app.php
@@ -21,19 +21,19 @@
 
     return [
         // The string under which your app will be referenced in owncloud
-        'id' => 'sciencemesh',
+        "id" => "sciencemesh",
 
         // The sorting weight for the navigation.
         // The higher the number, the higher will it be listed in the navigation
-        'order' => 10,
+        "order" => 10,
 
         // The route that will be shown on startup
-        'href' => $urlGenerator->linkToRoute('sciencemesh.app.contacts'),
+        "href" => $urlGenerator->linkToRoute("sciencemesh.app.contacts"),
 
         // The icon that will be shown in the navigation, located in img/
-        'icon' => $urlGenerator->imagePath('sciencemesh', 'app-white.svg'),
+        "icon" => $urlGenerator->imagePath("sciencemesh", "app-white.svg"),
 
         // The application's title, used in the navigation & the settings page of your app
-        'name' => OC::$server->getL10N('sciencemesh')->t('ScienceMesh'),
+        "name" => OC::$server->getL10N("sciencemesh")->t("ScienceMesh"),
     ];
 });
diff --git a/lib/Controller/AuthController.php b/lib/Controller/AuthController.php
index 725301c2..caef9518 100644
--- a/lib/Controller/AuthController.php
+++ b/lib/Controller/AuthController.php
@@ -16,6 +16,7 @@
 use OC\Config;
 use OCA\ScienceMesh\ServerConfig;
 use OCA\ScienceMesh\ShareProvider\ScienceMeshShareProvider;
+use OCA\ScienceMesh\Utils\Utils;
 use OCP\AppFramework\Controller;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\JSONResponse;
@@ -44,6 +45,9 @@ class AuthController extends Controller
     /** @var IUserManager */
     private IUserManager $userManager;
 
+    /** @var Utils */
+    private Utils $utils;
+
     /** @var ScienceMeshShareProvider */
     private ScienceMeshShareProvider $shareProvider;
 
@@ -79,22 +83,7 @@ public function __construct(
         $this->logger = $logger;
         $this->userManager = $userManager;
         $this->shareProvider = $shareProvider;
-    }
-
-    // TODO: @Mahdi Move to utils.
-
-    /**
-     * @throws NotPermittedException
-     * @throws Exception
-     */
-    private function checkRevadAuth()
-    {
-        error_log("checkRevadAuth");
-        $authHeader = $this->request->getHeader('X-Reva-Secret');
-
-        if ($authHeader != $this->config->getRevaSharedSecret()) {
-            throw new NotPermittedException('Please set an http request header "X-Reva-Secret: <your_shared_secret>"!');
-        }
+        $this->utils = new Utils($l10n, $logger, $shareProvider);
     }
 
     /**
@@ -111,7 +100,7 @@ public function Authenticate($userId): JSONResponse
     {
         error_log("Authenticate: " . $userId);
 
-        $this->checkRevadAuth();
+        $this->utils->checkRevadAuth($this->request, $this->config->getRevaSharedSecret());
 
         if ($this->userManager->userExists($userId)) {
             $userId = $this->request->getParam("clientID");
@@ -143,7 +132,7 @@ public function Authenticate($userId): JSONResponse
             //  "path": "some/file/path.txt"
             // }
             $result = [
-                "user" => $this->formatUser($user),
+                "user" => $this->utils->formatUser($user, $this->config->getIopIdp()),
                 "scopes" => [
                     "user" => [
                         "resource" => [
@@ -160,19 +149,4 @@ public function Authenticate($userId): JSONResponse
 
         return new JSONResponse("Username / password not recognized", Http::STATUS_UNAUTHORIZED);
     }
-
-    // TODO: @Mahdi Move to utils.
-    private function formatUser($user): array
-    {
-        return [
-            "id" => [
-                "idp" => $this->config->getIopIdp(),
-                "opaque_id" => $user->getUID(),
-            ],
-            "display_name" => $user->getDisplayName(),
-            "username" => $user->getUID(),
-            "email" => $user->getEmailAddress(),
-            "type" => 1,
-        ];
-    }
 }
diff --git a/lib/Controller/OcmController.php b/lib/Controller/OcmController.php
index a82052c4..8697806f 100644
--- a/lib/Controller/OcmController.php
+++ b/lib/Controller/OcmController.php
@@ -14,9 +14,11 @@
 use DateTime;
 use Exception;
 use OC\Config;
+use OC\HintException;
 use OCA\ScienceMesh\AppInfo\ScienceMeshApp;
 use OCA\ScienceMesh\ServerConfig;
 use OCA\ScienceMesh\ShareProvider\ScienceMeshShareProvider;
+use OCA\ScienceMesh\Utils\Utils;
 use OCP\AppFramework\Controller;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\DataResponse;
@@ -25,7 +27,6 @@
 use OCP\Files\Folder;
 use OCP\Files\InvalidPathException;
 use OCP\Files\IRootFolder;
-use OCP\Files\Node;
 use OCP\Files\NotFoundException;
 use OCP\Files\NotPermittedException;
 use OCP\IConfig;
@@ -33,18 +34,9 @@
 use OCP\ILogger;
 use OCP\IRequest;
 use OCP\IUserManager;
-use OCP\Lock\ILockingProvider;
-use OCP\Lock\LockedException;
 use OCP\Share\Exceptions\IllegalIDChangeException;
 use OCP\Share\Exceptions\ShareNotFound;
 use OCP\Share\IManager;
-use OCP\Share\IShare;
-
-define("RESTRICT_TO_SCIENCEMESH_FOLDER", false);
-define("EFSS_PREFIX", (RESTRICT_TO_SCIENCEMESH_FOLDER ? "sciencemesh/" : ""));
-
-// See https://github.com/pondersource/sciencemesh-php/issues/96#issuecomment-1298656896
-define("REVA_PREFIX", "/home/");
 
 class OcmController extends Controller
 {
@@ -60,9 +52,6 @@ class OcmController extends Controller
     /** @var IManager */
     private IManager $shareManager;
 
-    /** @var ScienceMeshShareProvider */
-    private ScienceMeshShareProvider $shareProvider;
-
     /** @var Folder */
     private Folder $userFolder;
 
@@ -72,6 +61,12 @@ class OcmController extends Controller
     /** @var ILogger */
     private ILogger $logger;
 
+    /** @var Utils */
+    private Utils $utils;
+
+    /** @var ScienceMeshShareProvider */
+    private ScienceMeshShareProvider $shareProvider;
+
     /**
      * Open Cloud Mesh (OCM) Controller.
      *
@@ -108,6 +103,7 @@ public function __construct(
         $this->l = $l10n;
         $this->logger = $logger;
         $this->shareProvider = $shareProvider;
+        $this->utils = new Utils($l10n, $logger, $shareProvider);
     }
 
     /**
@@ -117,7 +113,7 @@ public function __construct(
     private function init($userId)
     {
         error_log("RevaController init for user '$userId'");
-        $this->checkRevadAuth();
+        $this->utils->checkRevadAuth($this->request, $this->config->getRevaSharedSecret());
         if ($userId) {
             error_log("root folder absolute path '" . $this->rootFolder->getPath() . "'");
             if ($this->rootFolder->nodeExists($userId)) {
@@ -129,230 +125,6 @@ private function init($userId)
         }
     }
 
-    // TODO: @Mahdi Move to utils.
-
-    /**
-     * @throws NotPermittedException
-     * @throws Exception
-     */
-    private function checkRevadAuth()
-    {
-        error_log("checkRevadAuth");
-        $authHeader = $this->request->getHeader('X-Reva-Secret');
-
-        if ($authHeader != $this->config->getRevaSharedSecret()) {
-            throw new NotPermittedException('Please set an http request header "X-Reva-Secret: <your_shared_secret>"!');
-        }
-    }
-
-    // TODO: @Mahdi Move to utils.
-    private function revaPathToEfssPath($revaPath): string
-    {
-        if ("$revaPath/" == REVA_PREFIX) {
-            error_log("revaPathToEfssPath: Interpreting special case $revaPath as ''");
-            return '';
-        }
-        $ret = EFSS_PREFIX . $this->removePrefix($revaPath, REVA_PREFIX);
-        error_log("revaPathToEfssPath: Interpreting $revaPath as $ret");
-        return $ret;
-    }
-
-    // TODO: @Mahdi Move to utils.
-    private function revaPathFromOpaqueId($opaqueId)
-    {
-        return $this->removePrefix($opaqueId, "fileid-");
-    }
-
-    // TODO: @Mahdi Move to utils.
-    private function removePrefix($string, $prefix)
-    {
-        // first check if string is actually prefixed or not.
-        $len = strlen($prefix);
-        if (substr($string, 0, $len) === $prefix) {
-            $ret = substr($string, $len);
-        } else {
-            $ret = $string;
-        }
-
-        return $ret;
-    }
-
-    // TODO: @Mahdi Move to utils.
-    private function getPermissionsCode(array $permissions): int
-    {
-        $permissionsCode = 0;
-        if (!empty($permissions["get_path"]) || !empty($permissions["get_quota"]) || !empty($permissions["initiate_file_download"]) || !empty($permissions["initiate_file_upload"]) || !empty($permissions["stat"])) {
-            $permissionsCode += Constants::PERMISSION_READ;
-        }
-        if (!empty($permissions["create_container"]) || !empty($permissions["move"]) || !empty($permissions["add_grant"]) || !empty($permissions["restore_file_version"]) || !empty($permissions["restore_recycle_item"])) {
-            $permissionsCode += Constants::PERMISSION_CREATE;
-        }
-        if (!empty($permissions["move"]) || !empty($permissions["delete"]) || !empty($permissions["remove_grant"])) {
-            $permissionsCode += Constants::PERMISSION_DELETE;
-        }
-        if (!empty($permissions["list_grants"]) || !empty($permissions["list_file_versions"]) || !empty($permissions["list_recycle"])) {
-            $permissionsCode += Constants::PERMISSION_SHARE;
-        }
-        if (!empty($permissions["update_grant"])) {
-            $permissionsCode += Constants::PERMISSION_UPDATE;
-        }
-        return $permissionsCode;
-    }
-
-    // TODO: @Mahdi Move to utils.
-
-    /**
-     * @param Node $node
-     * @return void
-     *
-     * @throws LockedException
-     */
-    private function lock(Node $node)
-    {
-        $node->lock(ILockingProvider::LOCK_SHARED);
-    }
-
-    // TODO: @Mahdi Move to utils.
-    // For ListReceivedShares, GetReceivedShare and UpdateReceivedShare we need to include "state:2"
-    // see:
-    // https://github.com/cs3org/cs3apis/blob/cfd1ad29fdf00c79c2a321de7b1a60d0725fe4e8/cs3/sharing/ocm/v1beta1/resources.proto#L160
-    /**
-     * @throws NotFoundException
-     * @throws InvalidPathException
-     */
-    private function shareInfoToCs3Share(IShare $share, string $direction, $token = ""): array
-    {
-        $shareId = $share->getId();
-
-        // TODO @Mahdi use enums!
-        if ($direction === "sent") {
-            $ocmShareData = $this->shareProvider->getSentOcmShareFromSciencemeshTable($shareId);
-            $ocmShareProtocols = $this->shareProvider->getSentOcmShareProtocolsFromSciencemeshTable($ocmShareData["id"]);
-        } elseif ($direction === "received") {
-            $ocmShareData = $this->shareProvider->getReceivedOcmShareFromSciencemeshTable($shareId);
-            $ocmShareProtocols = $this->shareProvider->getReceivedOcmShareProtocolsFromSciencemeshTable($ocmShareData["id"]);
-        }
-
-        // use ocm payload stored in sciencemesh table. if it fails, use native efss share data.
-        // in case of total failure use "unknown".
-
-        // this one is obvious right?
-        if (isset($ocmShareData["share_with"])) {
-            $granteeParts = explode("@", $ocmShareData["share_with"]);
-        } else {
-            $granteeParts = explode("@", $share->getSharedWith());
-        }
-
-        if (count($granteeParts) != 2) {
-            $granteeParts = ["unknown", "unknown"];
-        }
-
-        // the original share owner (who owns the path that is shared)
-        if (isset($ocmShareData["owner"])) {
-            $ownerParts = explode("@", $ocmShareData["owner"]);
-        } else {
-            $ownerParts = explode("@", $share->getShareOwner());
-        }
-
-        if (count($granteeParts) != 2) {
-            $ownerParts = ["unknown", "unknown"];
-        }
-
-        // NOTE: @Mahdi initiator/creator/sharedBy etc., whatever other names it has! means the share sharer!
-        // you can be owner and sharer, you can be someone who is re-sharing, in this case you are sharer but not owner
-        if (isset($ocmShareData["initiator"])) {
-            $creatorParts = explode("@", $ocmShareData["initiator"]);
-        } else {
-            $creatorParts = explode("@", $share->getSharedBy());
-        }
-
-        if (count($granteeParts) != 2) {
-            $creatorParts = ["unknown", "unknown"];
-        }
-
-        try {
-            $filePath = $share->getNode()->getPath();
-            // @Mahdi why is this hardcoded?
-            // @Giuseppe this should be something that doesn't change when file is moved!
-            $opaqueId = "fileid-" . $filePath;
-        } catch (NotFoundException $e) {
-            // @Mahdi why not just return status bad request or status not found?
-            // @Michiel sometimes you want to translate share object even if file doesn't exist.
-            $opaqueId = "unknown";
-        }
-
-        // TODO: @Mahdi update this comment to point at the Reva structure  mappings for this json.
-        // produces JSON that maps to reva
-        $payload = [
-            // use OCM name, if null use efss share native name, if null fall back to "unknown"
-            "name" => $ocmShareData["name"] ?? ($share->getName() ?? "unknown"),
-            "token" => $token ?? "unknown",
-            // TODO: @Mahdi what permissions is the correct one? share permissions has different value than the share->node permissions.
-            // maybe use the ocmData for this one? needs testing for different scenarios to see which is the best/correct one.
-            "permissions" => $share->getNode()->getPermissions() ?? 0,
-            "id" => [
-                // https://github.com/cs3org/go-cs3apis/blob/d297419/cs3/sharing/ocm/v1beta1/resources.pb.go#L423
-                "opaque_id" => $shareId ?? "unknown",
-            ],
-            "resource_id" => [
-                "opaque_id" => $opaqueId,
-            ],
-            // these three have been already handled and don't need "unknown" default values.
-            "grantee" => [
-                "id" => [
-                    "opaque_id" => $granteeParts[0],
-                    "idp" => $granteeParts[1],
-                ],
-            ],
-            "owner" => [
-                "id" => [
-                    "opaque_id" => $ownerParts[0],
-                    "idp" => $ownerParts[1],
-                ],
-            ],
-            "creator" => [
-                "id" => [
-                    "opaque_id" => $creatorParts[0],
-                    "idp" => $creatorParts[1],
-                ],
-            ],
-            // NOTE: make sure seconds type is int, otherwise Reva gives:
-            // error="json: cannot unmarshal string into Go struct field Timestamp.ctime.seconds of type uint64"
-            "ctime" => [
-                "seconds" => isset($ocmShareData["ctime"]) ? (int)$ocmShareData["ctime"] : ($share->getShareTime()->getTimestamp() ?? 0)
-            ],
-            "mtime" => [
-                "seconds" => isset($ocmShareData["mtime"]) ? (int)$ocmShareData["ctime"] : ($share->getShareTime()->getTimestamp() ?? 0)
-            ],
-            "access_methods" => [
-                "transfer" => [
-                    "source_uri" => $ocmShareProtocols["transfer"]["source_uri"] ?? "unknown",
-                    // TODO: @Mahdi this feels redundant, already included in top-level token and webdav shared_secret.
-                    "shared_secret" => $ocmShareProtocols["transfer"]["shared_secret"] ?? "unknown",
-                    // TODO: @Mahdi should the default value be an integer?
-                    "size" => $ocmShareProtocols["transfer"]["size"] ?? "unknown",
-                ],
-                "webapp" => [
-                    "uri_template" => $ocmShareProtocols["webapp"]["uri_template"] ?? "unknown",
-                    "view_mode" => $ocmShareProtocols["webapp"]["view_mode"] ?? "unknown",
-                ],
-                "webdav" => [
-                    // TODO: @Mahdi it is better to have sharedSecret and permissions in this part of code.
-                    "uri" => $ocmShareProtocols["webdav"]["uri"] ?? "unknown",
-                    // TODO: @Mahdi it is interesting this function accepts token as argument! is token different that the share secret?
-                    // why do we have to pass token while the share object already has the information about token?
-                    // $share->getToken();
-                    "shared_secret" => $ocmShareProtocols["webdav"]["shared_secret"] ?? "unknown",
-                    "permissions" => $ocmShareProtocols["webdav"]["permissions"] ?? "unknown",
-                ],
-            ]
-        ];
-
-        error_log("shareInfoToCs3Share " . var_export($payload, true));
-
-        return $payload;
-    }
-
     /**
      * add a received share.
      *
@@ -460,7 +232,7 @@ public function addReceivedShare($userId): JSONResponse
         }
 
         // convert permissions from array to integer.
-        $integerPermissions = $this->getPermissionsCode($ocmProtocolWebdav["permissions"]["permissions"]);
+        $integerPermissions = $this->utils->getPermissionsCode($ocmProtocolWebdav["permissions"]["permissions"]);
         $ocmProtocolWebdav["permissions"] = $integerPermissions;
 
         $sharedSecret = $ocmProtocolWebdav["sharedSecret"];
@@ -577,8 +349,8 @@ public function addSentShare($userId)
 
         // chained path conversions to verify this file exists in our server.
         // "fileid-/home/test" -> "/home/test" -> "/test"
-        $revaPath = $this->revaPathFromOpaqueId($resourceId);
-        $efssPath = $this->revaPathToEfssPath($revaPath);
+        $revaPath = $this->utils->revaPathFromOpaqueId($resourceId);
+        $efssPath = $this->utils->revaPathToEfssPath($revaPath);
 
         try {
             $node = $this->userFolder->get($efssPath);
@@ -677,7 +449,7 @@ public function addSentShare($userId)
         }
 
         // convert permissions from array to integer.
-        $permissions = $this->getPermissionsCode($ocmProtocolWebdav["permissions"]);
+        $permissions = $this->utils->getPermissionsCode($ocmProtocolWebdav["permissions"]);
 
         // prepare data for adding to the native efss table.
         $share = $this->shareManager->newShare();
@@ -723,7 +495,7 @@ public function addSentShare($userId)
             return new JSONResponse($message_t, Http::STATUS_UNPROCESSABLE_ENTITY);
         }
 
-        $this->lock($share->getNode());
+        $this->utils->lock($share->getNode());
 
         // prepare share data for ocm
         $share = $this->shareProvider->createNativeEfssScienceMeshShare($share);
@@ -779,7 +551,7 @@ public function getReceivedShare($userId): JSONResponse
 
         try {
             $share = $this->shareProvider->getReceivedShareByToken($opaqueId);
-            $response = $this->shareInfoToCs3Share($share, "received", $opaqueId);
+            $response = $this->utils->shareInfoToCs3Share($share, "received", $opaqueId);
             $response["state"] = 2;
             return new JSONResponse($response, Http::STATUS_OK);
         } catch (Exception $e) {
@@ -813,7 +585,7 @@ public function getSentShare($userId): JSONResponse
         $share = $this->shareProvider->getSentShareByName($userId, $name);
 
         if ($share) {
-            $response = $this->shareInfoToCs3Share($share, "sent");
+            $response = $this->utils->shareInfoToCs3Share($share, "sent");
             return new JSONResponse($response, Http::STATUS_OK);
         }
 
@@ -828,11 +600,7 @@ public function getSentShare($userId): JSONResponse
      * @param $userId
      * @return JSONResponse
      *
-     * @throws InvalidPathException
-     * @throws NotFoundException
      * @throws NotPermittedException
-     * @throws ShareNotFound
-     * @throws IllegalIDChangeException
      */
     public function getSentShareByToken($userId): JSONResponse
     {
@@ -847,18 +615,30 @@ public function getSentShareByToken($userId): JSONResponse
             }
         }
 
+        // TODO: @Mahdi check for being null?
         $token = $this->request->getParam("Spec")["Token"];
         error_log("GetSentShareByToken: " . var_export($this->request->getParam("Spec"), true));
 
-        // TODO: @Mahdi handle in try catch block and send back correct responses.
-        $share = $this->shareProvider->getSentShareByToken($token);
+        try {
+            $share = $this->shareProvider->getSentShareByToken($token);
+        } catch (ShareNotFound|IllegalIDChangeException $e) {
+            // TODO: @Mahdi log it.
+            return new JSONResponse(
+                ["error" => "GetSentShareByToken failed! because: $e"],
+                Http::STATUS_BAD_REQUEST
+            );
+        }
 
-        if ($share) {
-            $response = $this->shareInfoToCs3Share($share, "sent", $token);
+        try {
+            $response = $this->utils->shareInfoToCs3Share($share, "sent", $token);
             return new JSONResponse($response, Http::STATUS_OK);
+        } catch (NotFoundException|InvalidPathException $e) {
+            // TODO: @Mahdi log it.
+            return new JSONResponse(
+                ["error" => "GetSentShareByToken failed! because: $e"],
+                Http::STATUS_BAD_REQUEST
+            );
         }
-
-        return new JSONResponse(["error" => "GetSentShare failed"], Http::STATUS_BAD_REQUEST);
     }
 
     /**
@@ -886,7 +666,7 @@ public function listReceivedShares($userId): JSONResponse
 
         if ($shares) {
             foreach ($shares as $share) {
-                $response = $this->shareInfoToCs3Share($share, "received");
+                $response = $this->utils->shareInfoToCs3Share($share, "received");
                 $responses[] = [
                     "share" => $response,
                     "state" => 2
@@ -924,7 +704,7 @@ public function listSentShares($userId): JSONResponse
 
         if ($shares) {
             foreach ($shares as $share) {
-                $responses[] = $this->shareInfoToCs3Share($share, "sent");
+                $responses[] = $this->utils->shareInfoToCs3Share($share, "sent");
             }
         }
         return new JSONResponse($responses, Http::STATUS_OK);
@@ -987,13 +767,13 @@ public function updateReceivedShare($userId): JSONResponse
 
         $resourceId = $this->request->getParam("received_share")["share"]["resource_id"];
         $permissions = $this->request->getParam("received_share")["share"]["permissions"];
-        $permissionsCode = $this->getPermissionsCode($permissions);
+        $permissionsCode = $this->utils->getPermissionsCode($permissions);
 
         try {
             $share = $this->shareProvider->getReceivedShareByToken($resourceId);
             $share->setPermissions($permissionsCode);
             $shareUpdate = $this->shareProvider->UpdateReceivedShare($share);
-            $response = $this->shareInfoToCs3Share($shareUpdate, "received", $resourceId);
+            $response = $this->utils->shareInfoToCs3Share($shareUpdate, "received", $resourceId);
             $response["state"] = 2;
             return new JSONResponse($response, Http::STATUS_OK);
         } catch (Exception $e) {
@@ -1011,6 +791,7 @@ public function updateReceivedShare($userId): JSONResponse
      * @throws InvalidPathException
      * @throws NotFoundException
      * @throws NotPermittedException
+     * @throws ShareNotFound|HintException
      */
     public function updateSentShare($userId): JSONResponse
     {
@@ -1023,7 +804,7 @@ public function updateSentShare($userId): JSONResponse
 
         $opaqueId = $this->request->getParam("ref")["Spec"]["Id"]["opaque_id"];
         $permissions = $this->request->getParam("p")["permissions"];
-        $permissionsCode = $this->getPermissionsCode($permissions);
+        $permissionsCode = $this->utils->getPermissionsCode($permissions);
         $name = $this->getNameByOpaqueId($opaqueId);
         if (!($share = $this->shareProvider->getSentShareByName($userId, $name))) {
             return new JSONResponse(["error" => "UpdateSentShare failed"], Http::STATUS_INTERNAL_SERVER_ERROR);
@@ -1031,7 +812,7 @@ public function updateSentShare($userId): JSONResponse
 
         $share->setPermissions($permissionsCode);
         $shareUpdated = $this->shareProvider->update($share);
-        $response = $this->shareInfoToCs3Share($shareUpdated, "sent");
+        $response = $this->utils->shareInfoToCs3Share($shareUpdated, "sent");
         return new JSONResponse($response, Http::STATUS_OK);
     }
 }
diff --git a/lib/Controller/StorageController.php b/lib/Controller/StorageController.php
index f7f19da2..b6f4a889 100644
--- a/lib/Controller/StorageController.php
+++ b/lib/Controller/StorageController.php
@@ -16,12 +16,13 @@
 use OC\Files\View;
 use OCA\DAV\TrashBin\TrashBinManager;
 use OCA\ScienceMesh\ServerConfig;
+use OCA\ScienceMesh\ShareProvider\ScienceMeshShareProvider;
+use OCA\ScienceMesh\Utils\Utils;
 use OCP\AppFramework\Controller;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\DataResponse;
 use OCP\AppFramework\Http\JSONResponse;
 use OCP\AppFramework\Http\StreamResponse;
-use OCP\Files\FileInfo;
 use OCP\Files\Folder;
 use OCP\Files\InvalidPathException;
 use OCP\Files\IRootFolder;
@@ -36,10 +37,6 @@
 use Symfony\Component\Filesystem\Exception\FileNotFoundException;
 
 define("RESTRICT_TO_SCIENCEMESH_FOLDER", false);
-define("EFSS_PREFIX", (RESTRICT_TO_SCIENCEMESH_FOLDER ? "sciencemesh/" : ""));
-
-// See https://github.com/pondersource/sciencemesh-php/issues/96#issuecomment-1298656896
-define("REVA_PREFIX", "/home/");
 
 class StorageController extends Controller
 {
@@ -67,6 +64,9 @@ class StorageController extends Controller
     /** @var ILogger */
     private ILogger $logger;
 
+    /** @var Utils */
+    private Utils $utils;
+
     /**
      * Storage Controller.
      *
@@ -78,16 +78,18 @@ class StorageController extends Controller
      * @param TrashBinManager $trashManager
      * @param IL10N $l10n
      * @param ILogger $logger
+     * @param ScienceMeshShareProvider $shareProvider
      */
     public function __construct(
-        string          $appName,
-        IRootFolder     $rootFolder,
-        IRequest        $request,
-        IUserManager    $userManager,
-        IConfig         $config,
-        TrashBinManager $trashManager,
-        IL10N           $l10n,
-        ILogger         $logger
+        string                   $appName,
+        IRootFolder              $rootFolder,
+        IRequest                 $request,
+        IUserManager             $userManager,
+        IConfig                  $config,
+        TrashBinManager          $trashManager,
+        IL10N                    $l10n,
+        ILogger                  $logger,
+        ScienceMeshShareProvider $shareProvider
     )
     {
         parent::__construct($appName, $request);
@@ -100,6 +102,7 @@ public function __construct(
         $this->trashManager = $trashManager;
         $this->l = $l10n;
         $this->logger = $logger;
+        $this->utils = new Utils($l10n, $logger, $shareProvider);
     }
 
     /**
@@ -110,7 +113,7 @@ private function init($userId)
     {
         error_log("RevaController init for user '$userId'");
         $this->userId = $userId;
-        $this->checkRevadAuth();
+        $this->utils->checkRevadAuth($this->request, $this->config->getRevaSharedSecret());
         if ($userId) {
             error_log("root folder absolute path '" . $this->rootFolder->getPath() . "'");
             if ($this->rootFolder->nodeExists($userId)) {
@@ -122,136 +125,6 @@ private function init($userId)
         }
     }
 
-    /**
-     * @throws NotPermittedException
-     * @throws Exception
-     */
-    private function checkRevadAuth()
-    {
-        error_log("checkRevadAuth");
-        $authHeader = $this->request->getHeader('X-Reva-Secret');
-
-        if ($authHeader != $this->config->getRevaSharedSecret()) {
-            throw new NotPermittedException('Please set an http request header "X-Reva-Secret: <your_shared_secret>"!');
-        }
-    }
-
-    private function efssFullPathToRelativePath($efssFullPath)
-    {
-
-        $ret = $this->removePrefix($efssFullPath, $this->userFolder->getPath());
-        error_log("efssFullPathToRelativePath: Interpreting $efssFullPath as $ret");
-        return $ret;
-    }
-
-    private function efssPathToRevaPath($efssPath): string
-    {
-        $ret = REVA_PREFIX . $this->removePrefix($efssPath, EFSS_PREFIX);
-        error_log("efssPathToRevaPath: Interpreting $efssPath as $ret");
-        return $ret;
-    }
-
-    private function revaPathToEfssPath($revaPath): string
-    {
-        if ("$revaPath/" == REVA_PREFIX) {
-            error_log("revaPathToEfssPath: Interpreting special case $revaPath as ''");
-            return '';
-        }
-        $ret = EFSS_PREFIX . $this->removePrefix($revaPath, REVA_PREFIX);
-        error_log("revaPathToEfssPath: Interpreting $revaPath as $ret");
-        return $ret;
-    }
-
-    private function revaPathFromOpaqueId($opaqueId)
-    {
-        return $this->removePrefix($opaqueId, "fileid-");
-    }
-
-    private function removePrefix($string, $prefix)
-    {
-        // first check if string is actually prefixed or not.
-        $len = strlen($prefix);
-        if (substr($string, 0, $len) === $prefix) {
-            $ret = substr($string, $len);
-        } else {
-            $ret = $string;
-        }
-
-        return $ret;
-    }
-
-    private function getChecksum(Node $node, $checksumType = 4): string
-    {
-        $checksumTypes = array(
-            1 => "UNSET:",
-            2 => "ADLER32:",
-            3 => "MD5:",
-            4 => "SHA1:",
-        );
-
-        // checksum is in db table oc_filecache.
-        // folders do not have checksum
-        $checksums = explode(" ", $node->getFileInfo()->getChecksum());
-
-        foreach ($checksums as $checksum) {
-
-            // NOTE: that the use of !== false is deliberate (neither != false nor === true will return the desired result);
-            // strpos() returns either the offset at which the needle string begins in the haystack string, or the boolean
-            // false if the needle isn't found. Since 0 is a valid offset and 0 is "false", we can't use simpler constructs
-            //  like !strpos($a, 'are').
-            if (strpos($checksum, $checksumTypes[$checksumType]) !== false) {
-                return substr($checksum, strlen($checksumTypes[$checksumType]));
-            }
-        }
-
-        return "";
-    }
-
-    /**
-     * @throws InvalidPathException
-     * @throws NotFoundException
-     */
-    private function nodeToCS3ResourceInfo(Node $node): array
-    {
-        $isDirectory = ($node->getType() === FileInfo::TYPE_FOLDER);
-        $efssPath = substr($node->getPath(), strlen($this->userFolder->getPath()) + 1);
-        $revaPath = $this->efssPathToRevaPath($efssPath);
-
-        $payload = [
-            "type" => ($isDirectory ? 2 : 1),
-            "id" => [
-                "opaque_id" => "fileid-" . $revaPath,
-            ],
-            "checksum" => [
-                // checksum algorithms:
-                // 1 UNSET
-                // 2 ADLER32
-                // 3 MD5
-                // 4 SHA1
-
-                // NOTE: folders do not have checksum, their type should be unset.
-                "type" => $isDirectory ? 1 : 4,
-                "sum" => $this->getChecksum($node, $isDirectory ? 1 : 4),
-            ],
-            "etag" => $node->getEtag(),
-            "mime_type" => ($isDirectory ? "folder" : $node->getMimetype()),
-            "mtime" => [
-                "seconds" => $node->getMTime(),
-            ],
-            "path" => $revaPath,
-            "permissions" => $node->getPermissions(),
-            "size" => $node->getSize(),
-            "owner" => [
-                "opaque_id" => $this->userId,
-                "idp" => $this->config->getIopIdp(),
-            ]
-        ];
-
-        error_log("nodeToCS3ResourceInfo " . var_export($payload, true));
-
-        return $payload;
-    }
-
     /**
      * @PublicPage
      * @NoAdminRequired
@@ -269,7 +142,7 @@ public function addGrant($userId): JSONResponse
             return new JSONResponse("User not found", Http::STATUS_FORBIDDEN);
         }
 
-        $path = $this->revaPathToEfssPath($this->request->getParam("path"));
+        $path = $this->utils->revaPathToEfssPath($this->request->getParam("path"));
         // FIXME: Expected a param with a grant to add here;
 
         return new JSONResponse("Not implemented", Http::STATUS_NOT_IMPLEMENTED);
@@ -293,7 +166,7 @@ public function createDir($userId): JSONResponse
         }
 
         $urlDecodedPath = urldecode($this->request->getParam("path"));
-        $path = $this->revaPathToEfssPath($urlDecodedPath);
+        $path = $this->utils->revaPathToEfssPath($urlDecodedPath);
 
         try {
             $this->userFolder->newFolder($path);
@@ -325,7 +198,10 @@ public function createHome($userId): JSONResponse
                 try {
                     $this->userFolder->newFolder("sciencemesh"); // Create the Sciencemesh directory for storage if it doesn't exist.
                 } catch (NotPermittedException $e) {
-                    return new JSONResponse(["error" => "Create home failed. Resource Path not founD"], Http::STATUS_INTERNAL_SERVER_ERROR);
+                    return new JSONResponse(
+                        ["error" => "Create home failed. Resource Path not found"],
+                        Http::STATUS_INTERNAL_SERVER_ERROR
+                    );
                 }
                 return new JSONResponse("CREATED", Http::STATUS_CREATED);
             }
@@ -349,7 +225,7 @@ public function createReference($userId): JSONResponse
         } else {
             return new JSONResponse("User not found", Http::STATUS_FORBIDDEN);
         }
-        $path = $this->revaPathToEfssPath($this->request->getParam("path"));
+        $path = $this->utils->revaPathToEfssPath($this->request->getParam("path"));
         return new JSONResponse("Not implemented", Http::STATUS_NOT_IMPLEMENTED);
     }
 
@@ -426,7 +302,7 @@ public function delete($userId): JSONResponse
             return new JSONResponse("User not found", Http::STATUS_FORBIDDEN);
         }
 
-        $path = $this->revaPathToEfssPath($this->request->getParam("path"));
+        $path = $this->utils->revaPathToEfssPath($this->request->getParam("path"));
 
         try {
             $node = $this->userFolder->get($path);
@@ -455,7 +331,7 @@ public function download($userId, $path)
 
         error_log("Download path: $path");
 
-        $efssPath = $this->removePrefix($path, "home/");
+        $efssPath = $this->utils->removePrefix($path, "home/");
         error_log("Download efss path: $efssPath");
 
         if ($this->userFolder->nodeExists($efssPath)) {
@@ -543,7 +419,7 @@ public function getMD($userId): JSONResponse
             //  },
             //  "mdKeys": null
             // }
-            $revaPath = $this->revaPathFromOpaqueId($ref["resource_id"]["opaque_id"]);
+            $revaPath = $this->utils->revaPathFromOpaqueId($ref["resource_id"]["opaque_id"]);
         } else {
             return new JSONResponse("ref not understood!", Http::STATUS_BAD_REQUEST);
         }
@@ -552,19 +428,24 @@ public function getMD($userId): JSONResponse
         // for example this converts "we%20have%20space" to "we have space"
         $revaPathDecoded = urldecode($revaPath);
 
-        $path = $this->revaPathToEfssPath($revaPathDecoded);
+        $path = $this->utils->revaPathToEfssPath($revaPathDecoded);
         error_log("Looking for EFSS path '$path' in user folder; reva path '$revaPathDecoded' ");
 
         // apparently nodeExists requires relative path to the user folder:
         // see https://github.com/owncloud/core/blob/b7bcbdd9edabf7d639b4bb42c4fb87862ddf4a80/lib/private/Files/Node/Folder.php#L45-L55;
         // another string manipulation is necessary to extract relative path from full path.
-        $relativePath = $this->efssFullPathToRelativePath($path);
+        $relativePath = $this->utils->efssFullPathToRelativePath($path, $this->userFolder->getPath());
 
         $success = $this->userFolder->nodeExists($relativePath);
         if ($success) {
             error_log("File found");
             $node = $this->userFolder->get($relativePath);
-            $resourceInfo = $this->nodeToCS3ResourceInfo($node);
+            $resourceInfo = $this->utils->nodeToCS3ResourceInfo(
+                $node,
+                $this->userFolder->getPath(),
+                $this->userId,
+                $this->config->getIopIdp()
+            );
             return new JSONResponse($resourceInfo, Http::STATUS_OK);
         }
 
@@ -609,7 +490,7 @@ public function getPathByID($userId)
     public function initiateUpload($userId): JSONResponse
     {
         $ref = $this->request->getParam("ref");
-        $path = $this->revaPathToEfssPath(($ref["path"] ?? ""));
+        $path = $this->utils->revaPathToEfssPath(($ref["path"] ?? ""));
 
         if ($this->userManager->userExists($userId)) {
             $this->init($userId);
@@ -646,7 +527,7 @@ public function listFolder($userId): JSONResponse
         // this path is url coded, we need to decode it
         // for example this converts "we%20have%20space" to "we have space"
         $pathDecoded = urldecode(($ref["path"] ?? ""));
-        $path = $this->revaPathToEfssPath($pathDecoded);
+        $path = $this->utils->revaPathToEfssPath($pathDecoded);
         $success = $this->userFolder->nodeExists($path);
         error_log("ListFolder: $path");
 
@@ -659,7 +540,12 @@ public function listFolder($userId): JSONResponse
         $node = $this->userFolder->get($path);
         $nodes = $node->getDirectoryListing();
         $resourceInfos = array_map(function (Node $node) {
-            return $this->nodeToCS3ResourceInfo($node);
+            return $this->utils->nodeToCS3ResourceInfo(
+                $node,
+                $this->userFolder->getPath(),
+                $this->userId,
+                $this->config->getIopIdp()
+            );
         }, $nodes);
 
         return new JSONResponse($resourceInfos, Http::STATUS_OK);
@@ -681,7 +567,7 @@ public function listGrants($userId): JSONResponse
             return new JSONResponse("User not found", Http::STATUS_FORBIDDEN);
         }
 
-        $path = $this->revaPathToEfssPath($this->request->getParam("path"));
+        $path = $this->utils->revaPathToEfssPath($this->request->getParam("path"));
 
         return new JSONResponse("Not implemented", Http::STATUS_NOT_IMPLEMENTED);
     }
@@ -708,7 +594,7 @@ public function listRecycle($userId): JSONResponse
 
         foreach ($trashItems as $node) {
             if (preg_match("/^sciencemesh/", $node->getOriginalLocation())) {
-                $path = $this->efssPathToRevaPath($node->getOriginalLocation());
+                $path = $this->utils->efssPathToRevaPath($node->getOriginalLocation());
                 $result = [
                     [
                         "opaque" => [
@@ -749,7 +635,7 @@ public function listRevisions($userId): JSONResponse
             return new JSONResponse("User not found", Http::STATUS_FORBIDDEN);
         }
 
-        $path = $this->revaPathToEfssPath($this->request->getParam("path"));
+        $path = $this->utils->revaPathToEfssPath($this->request->getParam("path"));
 
         return new JSONResponse("Not implemented", Http::STATUS_NOT_IMPLEMENTED);
     }
@@ -772,7 +658,7 @@ public function removeGrant($userId): JSONResponse
             return new JSONResponse("User not found", Http::STATUS_FORBIDDEN);
         }
 
-        $path = $this->revaPathToEfssPath($this->request->getParam("path"));
+        $path = $this->utils->revaPathToEfssPath($this->request->getParam("path"));
         // FIXME: Expected a grant to remove here;
 
         return new JSONResponse("Not implemented", Http::STATUS_NOT_IMPLEMENTED);
@@ -804,7 +690,7 @@ public function restoreRecycleItem($userId): JSONResponse
                 // unique key string, see:
                 // https://github.com/cs3org/cs3apis/blob/6eab4643f5113a54f4ce4cd8cb462685d0cdd2ef/cs3/storage/provider/v1beta1/resources.proto#L318
 
-                if ($this->revaPathToEfssPath($key) == $node->getOriginalLocation()) {
+                if ($this->utils->revaPathToEfssPath($key) == $node->getOriginalLocation()) {
                     $this->trashManager->restoreItem($node);
                     return new JSONResponse("OK", Http::STATUS_OK);
                 }
@@ -830,7 +716,7 @@ public function restoreRevision($userId): JSONResponse
             return new JSONResponse("User not found", Http::STATUS_FORBIDDEN);
         }
 
-        $path = $this->revaPathToEfssPath($this->request->getParam("path"));
+        $path = $this->utils->revaPathToEfssPath($this->request->getParam("path"));
         // FIXME: Expected a revision param here;
 
         return new JSONResponse("Not implemented", Http::STATUS_NOT_IMPLEMENTED);
@@ -852,7 +738,7 @@ public function setArbitraryMetadata($userId): JSONResponse
             return new JSONResponse("User not found", Http::STATUS_FORBIDDEN);
         }
 
-        $path = $this->revaPathToEfssPath($this->request->getParam("path"));
+        $path = $this->utils->revaPathToEfssPath($this->request->getParam("path"));
         $metadata = $this->request->getParam("metadata");
 
         // FIXME: this needs to be implemented for real, merging the incoming metadata with the existing ones.
@@ -876,7 +762,7 @@ public function unsetArbitraryMetadata($userId): JSONResponse
             return new JSONResponse("User not found", Http::STATUS_FORBIDDEN);
         }
 
-        $path = $this->revaPathToEfssPath($this->request->getParam("path"));
+        $path = $this->utils->revaPathToEfssPath($this->request->getParam("path"));
 
         // FIXME: this needs to be implemented for real
         return new JSONResponse("I'm cheating", Http::STATUS_OK);
@@ -898,7 +784,7 @@ public function updateGrant($userId): JSONResponse
             return new JSONResponse("User not found", Http::STATUS_FORBIDDEN);
         }
 
-        $path = $this->revaPathToEfssPath($this->request->getParam("path"));
+        $path = $this->utils->revaPathToEfssPath($this->request->getParam("path"));
 
         // FIXME: Expected a parameter with the grant(s)
         return new JSONResponse("Not implemented", Http::STATUS_NOT_IMPLEMENTED);
@@ -925,7 +811,7 @@ public function upload($userId, $path): JSONResponse
             }
 
             $contents = file_get_contents('php://input');
-            $efssPath = $this->revaPathToEfssPath($revaPath);
+            $efssPath = $this->utils->revaPathToEfssPath($revaPath);
 
             error_log("Uploading! reva path: $revaPath");
             error_log("Uploading! efss path $efssPath");
diff --git a/lib/Controller/UserController.php b/lib/Controller/UserController.php
index 8bc62b4b..5975d85b 100644
--- a/lib/Controller/UserController.php
+++ b/lib/Controller/UserController.php
@@ -14,10 +14,11 @@
 use Exception;
 use OC\Config;
 use OCA\ScienceMesh\ServerConfig;
+use OCA\ScienceMesh\ShareProvider\ScienceMeshShareProvider;
+use OCA\ScienceMesh\Utils\Utils;
 use OCP\AppFramework\Controller;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\JSONResponse;
-use OCP\Files\IRootFolder;
 use OCP\Files\NotPermittedException;
 use OCP\IConfig;
 use OCP\IL10N;
@@ -39,23 +40,28 @@ class UserController extends Controller
     /** @var IUserManager */
     private IUserManager $userManager;
 
+    /** @var Utils */
+    private Utils $utils;
+
     /**
      * User Controller.
      *
      * @param string $appName
      * @param IRequest $request
-     * @param IUserManager $userManager
      * @param IConfig $config
      * @param IL10N $l10n
      * @param ILogger $logger
+     * @param IUserManager $userManager
+     * @param ScienceMeshShareProvider $shareProvider
      */
     public function __construct(
-        string       $appName,
-        IRequest     $request,
-        IConfig      $config,
-        IL10N        $l10n,
-        ILogger      $logger,
-        IUserManager $userManager
+        string                   $appName,
+        IRequest                 $request,
+        IConfig                  $config,
+        IL10N                    $l10n,
+        ILogger                  $logger,
+        IUserManager             $userManager,
+        ScienceMeshShareProvider $shareProvider
     )
     {
         parent::__construct($appName, $request);
@@ -66,35 +72,7 @@ public function __construct(
         $this->l = $l10n;
         $this->logger = $logger;
         $this->userManager = $userManager;
-    }
-
-    /**
-     * @throws NotPermittedException
-     * @throws Exception
-     */
-    private function checkRevadAuth()
-    {
-        error_log("checkRevadAuth");
-        $authHeader = $this->request->getHeader("X-Reva-Secret");
-
-        if ($authHeader != $this->config->getRevaSharedSecret()) {
-            throw new NotPermittedException("Please set an http request header 'X-Reva-Secret: <your_shared_secret>'!");
-        }
-    }
-
-    // TODO: @Mahdi Move to utils.
-    private function formatUser($user): array
-    {
-        return [
-            "id" => [
-                "idp" => $this->config->getIopIdp(),
-                "opaque_id" => $user->getUID(),
-            ],
-            "display_name" => $user->getDisplayName(),
-            "username" => $user->getUID(),
-            "email" => $user->getEmailAddress(),
-            "type" => 1,
-        ];
+        $this->utils = new Utils($l10n, $logger, $shareProvider);
     }
 
     /**
@@ -104,16 +82,17 @@ private function formatUser($user): array
      * @NoCSRFRequired
      * @NoSameSiteCookieRequired
      * @throws NotPermittedException
+     * @throws Exception
      */
     public function getUser($dummy): JSONResponse
     {
-        $this->checkRevadAuth();
+        $this->utils->checkRevadAuth($this->request, $this->config->getRevaSharedSecret());
 
         $userToCheck = $this->request->getParam("opaque_id");
 
         if ($this->userManager->userExists($userToCheck)) {
             $user = $this->userManager->get($userToCheck);
-            $response = $this->formatUser($user);
+            $response = $this->utils->formatUser($user, $this->config->getIopIdp());
             return new JSONResponse($response, Http::STATUS_OK);
         }
 
@@ -128,10 +107,11 @@ public function getUser($dummy): JSONResponse
      * @NoSameSiteCookieRequired
      *
      * @throws NotPermittedException
+     * @throws Exception
      */
     public function getUserByClaim($dummy): JSONResponse
     {
-        $this->checkRevadAuth();
+        $this->utils->checkRevadAuth($this->request, $this->config->getRevaSharedSecret());
 
         $userToCheck = $this->request->getParam("value");
 
@@ -143,7 +123,7 @@ public function getUserByClaim($dummy): JSONResponse
 
         if ($this->userManager->userExists($userToCheck)) {
             $user = $this->userManager->get($userToCheck);
-            $response = $this->formatUser($user);
+            $response = $this->utils->formatUser($user, $this->config->getIopIdp());
             return new JSONResponse($response, Http::STATUS_OK);
         }
 
diff --git a/lib/Utils/Utils.php b/lib/Utils/Utils.php
new file mode 100644
index 00000000..db63400f
--- /dev/null
+++ b/lib/Utils/Utils.php
@@ -0,0 +1,389 @@
+<?php
+
+/**
+ * ownCloud - sciencemesh
+ *
+ * This file is licensed under the MIT License. See the LICENCE file.
+ * @license MIT
+ * @copyright Sciencemesh 2020 - 2023
+ *
+ * @author Mohammad Mahdi Baghbani Pourvahid <mahdi-baghbani@azadehafzar.ir>
+ */
+
+namespace OCA\ScienceMesh\Utils;
+
+use OCA\ScienceMesh\ShareProvider\ScienceMeshShareProvider;
+use OCP\Constants;
+use OCP\Files\FileInfo;
+use OCP\Files\InvalidPathException;
+use OCP\Files\Node;
+use OCP\Files\NotFoundException;
+use OCP\Files\NotPermittedException;
+use OCP\IL10N;
+use OCP\ILogger;
+use OCP\IRequest;
+use OCP\IUser;
+use OCP\Lock\ILockingProvider;
+use OCP\Lock\LockedException;
+use OCP\Share\IShare;
+
+/**
+ * ownCloud - sciencemesh
+ *
+ * This file is licensed under the MIT License. See the LICENCE file.
+ * @license MIT
+ * @copyright Sciencemesh 2020 - 2023
+ *
+ * @author Mohammad Mahdi Baghbani Pourvahid <mahdi-baghbani@azadehafzar.ir>
+ */
+
+const RESTRICT_TO_SCIENCEMESH_FOLDER = false;
+const EFSS_PREFIX = (RESTRICT_TO_SCIENCEMESH_FOLDER ? "sciencemesh/" : "");
+
+// See https://github.com/pondersource/sciencemesh-php/issues/96#issuecomment-1298656896
+const REVA_PREFIX = "/home/";
+
+
+class Utils
+{
+    /** @var IL10N */
+    private IL10N $l;
+
+    /** @var ILogger */
+    private ILogger $logger;
+
+    /** @var ScienceMeshShareProvider */
+    private ScienceMeshShareProvider $shareProvider;
+
+    /**
+     * Utils class.
+     *
+     * @param IL10N $l10n
+     * @param ILogger $logger
+     * @param ScienceMeshShareProvider $shareProvider
+     */
+    public function __construct(
+        IL10N                    $l10n,
+        ILogger                  $logger,
+        ScienceMeshShareProvider $shareProvider
+    )
+    {
+        $this->l = $l10n;
+        $this->logger = $logger;
+        $this->shareProvider = $shareProvider;
+    }
+
+    public function removePrefix($string, $prefix)
+    {
+        // first check if string is actually prefixed or not.
+        $len = strlen($prefix);
+        if (substr($string, 0, $len) === $prefix) {
+            $ret = substr($string, $len);
+        } else {
+            $ret = $string;
+        }
+
+        return $ret;
+    }
+
+    public function revaPathToEfssPath($revaPath): string
+    {
+        if ("$revaPath/" == REVA_PREFIX) {
+            error_log("revaPathToEfssPath: Interpreting special case $revaPath as ''");
+            return '';
+        }
+        $ret = EFSS_PREFIX . $this->removePrefix($revaPath, REVA_PREFIX);
+        error_log("revaPathToEfssPath: Interpreting $revaPath as $ret");
+        return $ret;
+    }
+
+    public function revaPathFromOpaqueId($opaqueId)
+    {
+        return $this->removePrefix($opaqueId, "fileid-");
+    }
+
+    public function efssPathToRevaPath($efssPath): string
+    {
+        $ret = REVA_PREFIX . $this->removePrefix($efssPath, EFSS_PREFIX);
+        error_log("efssPathToRevaPath: Interpreting $efssPath as $ret");
+        return $ret;
+    }
+
+    public function efssFullPathToRelativePath($efssFullPath, string $userFolderPath)
+    {
+        $ret = $this->removePrefix($efssFullPath, $userFolderPath);
+        error_log("efssFullPathToRelativePath: Interpreting $efssFullPath as $ret");
+        return $ret;
+    }
+
+    public function getChecksum(Node $node, $checksumType = 4): string
+    {
+        $checksumTypes = array(
+            1 => "UNSET:",
+            2 => "ADLER32:",
+            3 => "MD5:",
+            4 => "SHA1:",
+        );
+
+        // checksum is in db table oc_filecache.
+        // folders do not have checksum
+        $checksums = explode(" ", $node->getFileInfo()->getChecksum());
+
+        foreach ($checksums as $checksum) {
+
+            // NOTE: that the use of !== false is deliberate (neither != false nor === true will return the desired result);
+            // strpos() returns either the offset at which the needle string begins in the haystack string, or the boolean
+            // false if the needle isn't found. Since 0 is a valid offset and 0 is "false", we can't use simpler constructs
+            //  like !strpos($a, 'are').
+            if (strpos($checksum, $checksumTypes[$checksumType]) !== false) {
+                return substr($checksum, strlen($checksumTypes[$checksumType]));
+            }
+        }
+
+        return "";
+    }
+
+    /**
+     * @throws NotPermittedException
+     */
+    public function checkRevadAuth(IRequest $request, string $revaSharedSecret)
+    {
+        error_log("checkRevadAuth");
+        $authHeader = $request->getHeader("X-Reva-Secret");
+
+        if ($authHeader != $revaSharedSecret) {
+            throw new NotPermittedException('Please set an http request header "X-Reva-Secret: <your_shared_secret>"!');
+        }
+    }
+
+    /**
+     * @param Node $node
+     * @return void
+     *
+     * @throws LockedException
+     */
+    public function lock(Node $node)
+    {
+        $node->lock(ILockingProvider::LOCK_SHARED);
+    }
+
+    public function getPermissionsCode(array $permissions): int
+    {
+        $permissionsCode = 0;
+        if (!empty($permissions["get_path"]) || !empty($permissions["get_quota"]) || !empty($permissions["initiate_file_download"]) || !empty($permissions["initiate_file_upload"]) || !empty($permissions["stat"])) {
+            $permissionsCode += Constants::PERMISSION_READ;
+        }
+        if (!empty($permissions["create_container"]) || !empty($permissions["move"]) || !empty($permissions["add_grant"]) || !empty($permissions["restore_file_version"]) || !empty($permissions["restore_recycle_item"])) {
+            $permissionsCode += Constants::PERMISSION_CREATE;
+        }
+        if (!empty($permissions["move"]) || !empty($permissions["delete"]) || !empty($permissions["remove_grant"])) {
+            $permissionsCode += Constants::PERMISSION_DELETE;
+        }
+        if (!empty($permissions["list_grants"]) || !empty($permissions["list_file_versions"]) || !empty($permissions["list_recycle"])) {
+            $permissionsCode += Constants::PERMISSION_SHARE;
+        }
+        if (!empty($permissions["update_grant"])) {
+            $permissionsCode += Constants::PERMISSION_UPDATE;
+        }
+        return $permissionsCode;
+    }
+
+    /**
+     * @throws InvalidPathException
+     * @throws NotFoundException
+     */
+    public function nodeToCS3ResourceInfo(Node $node, string $userFolderPath, string $userId, string $Idp): array
+    {
+        $isDirectory = ($node->getType() === FileInfo::TYPE_FOLDER);
+        $efssPath = substr($node->getPath(), strlen($userFolderPath) + 1);
+        $revaPath = $this->efssPathToRevaPath($efssPath);
+
+        $payload = [
+            "type" => ($isDirectory ? 2 : 1),
+            "id" => [
+                "opaque_id" => "fileid-" . $revaPath,
+            ],
+            "checksum" => [
+                // checksum algorithms:
+                // 1 UNSET
+                // 2 ADLER32
+                // 3 MD5
+                // 4 SHA1
+
+                // NOTE: folders do not have checksum, their type should be unset.
+                "type" => $isDirectory ? 1 : 4,
+                "sum" => $this->getChecksum($node, $isDirectory ? 1 : 4),
+            ],
+            "etag" => $node->getEtag(),
+            "mime_type" => ($isDirectory ? "folder" : $node->getMimetype()),
+            "mtime" => [
+                "seconds" => $node->getMTime(),
+            ],
+            "path" => $revaPath,
+            "permissions" => $node->getPermissions(),
+            "size" => $node->getSize(),
+            "owner" => [
+                "opaque_id" => $userId,
+                "idp" => $Idp,
+            ]
+        ];
+
+        error_log("nodeToCS3ResourceInfo " . var_export($payload, true));
+
+        return $payload;
+    }
+
+    // For ListReceivedShares, GetReceivedShare and UpdateReceivedShare we need to include "state:2"
+    // see:
+    // https://github.com/cs3org/cs3apis/blob/cfd1ad29fdf00c79c2a321de7b1a60d0725fe4e8/cs3/sharing/ocm/v1beta1/resources.proto#L160
+    /**
+     * @throws NotFoundException
+     * @throws InvalidPathException
+     */
+    public function shareInfoToCs3Share(IShare $share, string $direction, string $token = ""): array
+    {
+        $shareId = $share->getId();
+
+        // TODO @Mahdi use enums!
+        if ($direction === "sent") {
+            $ocmShareData = $this->shareProvider->getSentOcmShareFromSciencemeshTable($shareId);
+            $ocmShareProtocols = $this->shareProvider->getSentOcmShareProtocolsFromSciencemeshTable($ocmShareData["id"]);
+        } elseif ($direction === "received") {
+            $ocmShareData = $this->shareProvider->getReceivedOcmShareFromSciencemeshTable($shareId);
+            $ocmShareProtocols = $this->shareProvider->getReceivedOcmShareProtocolsFromSciencemeshTable($ocmShareData["id"]);
+        }
+
+        // use ocm payload stored in sciencemesh table. if it fails, use native efss share data.
+        // in case of total failure use "unknown".
+
+        // this one is obvious right?
+        if (isset($ocmShareData["share_with"])) {
+            $granteeParts = explode("@", $ocmShareData["share_with"]);
+        } else {
+            $granteeParts = explode("@", $share->getSharedWith());
+        }
+
+        if (count($granteeParts) != 2) {
+            $granteeParts = ["unknown", "unknown"];
+        }
+
+        // the original share owner (who owns the path that is shared)
+        if (isset($ocmShareData["owner"])) {
+            $ownerParts = explode("@", $ocmShareData["owner"]);
+        } else {
+            $ownerParts = explode("@", $share->getShareOwner());
+        }
+
+        if (count($granteeParts) != 2) {
+            $ownerParts = ["unknown", "unknown"];
+        }
+
+        // NOTE: @Mahdi initiator/creator/sharedBy etc., whatever other names it has! means the share sharer!
+        // you can be owner and sharer, you can be someone who is re-sharing, in this case you are sharer but not owner
+        if (isset($ocmShareData["initiator"])) {
+            $creatorParts = explode("@", $ocmShareData["initiator"]);
+        } else {
+            $creatorParts = explode("@", $share->getSharedBy());
+        }
+
+        if (count($granteeParts) != 2) {
+            $creatorParts = ["unknown", "unknown"];
+        }
+
+        try {
+            $filePath = $share->getNode()->getPath();
+            // @Mahdi why is this hardcoded?
+            // @Giuseppe this should be something that doesn't change when file is moved!
+            $opaqueId = "fileid-" . $filePath;
+        } catch (NotFoundException $e) {
+            // @Mahdi why not just return status bad request or status not found?
+            // @Michiel sometimes you want to translate share object even if file doesn't exist.
+            $opaqueId = "unknown";
+        }
+
+        // TODO: @Mahdi update this comment to point at the Reva structure  mappings for this json.
+        // produces JSON that maps to reva
+        $payload = [
+            // use OCM name, if null use efss share native name, if null fall back to "unknown"
+            "name" => $ocmShareData["name"] ?? ($share->getName() ?? "unknown"),
+            "token" => $token ?? "unknown",
+            // TODO: @Mahdi what permissions is the correct one? share permissions has different value than the share->node permissions.
+            // maybe use the ocmData for this one? needs testing for different scenarios to see which is the best/correct one.
+            "permissions" => $share->getNode()->getPermissions() ?? 0,
+            "id" => [
+                // https://github.com/cs3org/go-cs3apis/blob/d297419/cs3/sharing/ocm/v1beta1/resources.pb.go#L423
+                "opaque_id" => $shareId ?? "unknown",
+            ],
+            "resource_id" => [
+                "opaque_id" => $opaqueId,
+            ],
+            // these three have been already handled and don't need "unknown" default values.
+            "grantee" => [
+                "id" => [
+                    "opaque_id" => $granteeParts[0],
+                    "idp" => $granteeParts[1],
+                ],
+            ],
+            "owner" => [
+                "id" => [
+                    "opaque_id" => $ownerParts[0],
+                    "idp" => $ownerParts[1],
+                ],
+            ],
+            "creator" => [
+                "id" => [
+                    "opaque_id" => $creatorParts[0],
+                    "idp" => $creatorParts[1],
+                ],
+            ],
+            // NOTE: make sure seconds type is int, otherwise Reva gives:
+            // error="json: cannot unmarshal string into Go struct field Timestamp.ctime.seconds of type uint64"
+            "ctime" => [
+                "seconds" => isset($ocmShareData["ctime"]) ? (int)$ocmShareData["ctime"] : ($share->getShareTime()->getTimestamp() ?? 0)
+            ],
+            "mtime" => [
+                "seconds" => isset($ocmShareData["mtime"]) ? (int)$ocmShareData["ctime"] : ($share->getShareTime()->getTimestamp() ?? 0)
+            ],
+            "access_methods" => [
+                "transfer" => [
+                    "source_uri" => $ocmShareProtocols["transfer"]["source_uri"] ?? "unknown",
+                    // TODO: @Mahdi this feels redundant, already included in top-level token and webdav shared_secret.
+                    "shared_secret" => $ocmShareProtocols["transfer"]["shared_secret"] ?? "unknown",
+                    // TODO: @Mahdi should the default value be an integer?
+                    "size" => $ocmShareProtocols["transfer"]["size"] ?? "unknown",
+                ],
+                "webapp" => [
+                    "uri_template" => $ocmShareProtocols["webapp"]["uri_template"] ?? "unknown",
+                    "view_mode" => $ocmShareProtocols["webapp"]["view_mode"] ?? "unknown",
+                ],
+                "webdav" => [
+                    // TODO: @Mahdi it is better to have sharedSecret and permissions in this part of code.
+                    "uri" => $ocmShareProtocols["webdav"]["uri"] ?? "unknown",
+                    // TODO: @Mahdi it is interesting this function accepts token as argument! is token different that the share secret?
+                    // why do we have to pass token while the share object already has the information about token?
+                    // $share->getToken();
+                    "shared_secret" => $ocmShareProtocols["webdav"]["shared_secret"] ?? "unknown",
+                    "permissions" => $ocmShareProtocols["webdav"]["permissions"] ?? "unknown",
+                ],
+            ]
+        ];
+
+        error_log("shareInfoToCs3Share " . var_export($payload, true));
+
+        return $payload;
+    }
+
+    public function formatUser(IUser $user, string $idp): array
+    {
+        return [
+            "id" => [
+                "idp" => $idp,
+                "opaque_id" => $user->getUID(),
+            ],
+            "display_name" => $user->getDisplayName(),
+            "username" => $user->getUID(),
+            "email" => $user->getEmailAddress(),
+            "type" => 1,
+        ];
+    }
+}