diff --git a/apps/comments/js/commentmodel.js b/apps/comments/js/commentmodel.js
index e75c79b3f0..3711e53c9f 100644
--- a/apps/comments/js/commentmodel.js
+++ b/apps/comments/js/commentmodel.js
@@ -9,7 +9,20 @@
  */
 
 (function(OC, OCA) {
-	var NS_OWNCLOUD = 'http://owncloud.org/ns';
+
+	_.extend(OC.Files.Client, {
+		PROPERTY_FILEID:	'{' + OC.Files.Client.NS_OWNCLOUD + '}id',
+		PROPERTY_MESSAGE: 	'{' + OC.Files.Client.NS_OWNCLOUD + '}message',
+		PROPERTY_ACTORTYPE:	'{' + OC.Files.Client.NS_OWNCLOUD + '}actorType',
+		PROPERTY_ACTORID:	'{' + OC.Files.Client.NS_OWNCLOUD + '}actorId',
+		PROPERTY_ISUNREAD:	'{' + OC.Files.Client.NS_OWNCLOUD + '}isUnread',
+		PROPERTY_OBJECTID:	'{' + OC.Files.Client.NS_OWNCLOUD + '}objectId',
+		PROPERTY_OBJECTTYPE:	'{' + OC.Files.Client.NS_OWNCLOUD + '}objectType',
+		PROPERTY_ACTORDISPLAYNAME:	'{' + OC.Files.Client.NS_OWNCLOUD + '}actorDisplayName',
+		PROPERTY_CREATIONDATETIME:	'{' + OC.Files.Client.NS_OWNCLOUD + '}creationDateTime',
+		PROPERTY_MENTIONS: '{' + OC.Files.Client.NS_OWNCLOUD + '}mentions'
+	});
+
 	/**
 	 * @class OCA.Comments.CommentModel
 	 * @classdesc
@@ -27,16 +40,16 @@
 		},
 
 		davProperties: {
-			'id': '{' + NS_OWNCLOUD + '}id',
-			'message': '{' + NS_OWNCLOUD + '}message',
-			'actorType': '{' + NS_OWNCLOUD + '}actorType',
-			'actorId': '{' + NS_OWNCLOUD + '}actorId',
-			'actorDisplayName': '{' + NS_OWNCLOUD + '}actorDisplayName',
-			'creationDateTime': '{' + NS_OWNCLOUD + '}creationDateTime',
-			'objectType': '{' + NS_OWNCLOUD + '}objectType',
-			'objectId': '{' + NS_OWNCLOUD + '}objectId',
-			'isUnread': '{' + NS_OWNCLOUD + '}isUnread',
-			'mentions': '{' + NS_OWNCLOUD + '}mentions'
+			'id':	OC.Files.Client.PROPERTY_FILEID,
+			'message':	OC.Files.Client.PROPERTY_MESSAGE,
+			'actorType':	OC.Files.Client.PROPERTY_ACTORTYPE,
+			'actorId':	OC.Files.Client.PROPERTY_ACTORID,
+			'actorDisplayName':	OC.Files.Client.PROPERTY_ACTORDISPLAYNAME,
+			'creationDateTime':	OC.Files.Client.PROPERTY_CREATIONDATETIME,
+			'objectType':	OC.Files.Client.PROPERTY_OBJECTTYPE,
+			'objectId':	OC.Files.Client.PROPERTY_OBJECTID,
+			'isUnread':	OC.Files.Client.PROPERTY_ISUNREAD,
+			'mentions': OC.Files.Client.PROPERTY_MENTIONS
 		},
 
 		parse: function(data) {
@@ -78,4 +91,3 @@
 
 	OCA.Comments.CommentModel = CommentModel;
 })(OC, OCA);
-
diff --git a/apps/comments/js/commentsummarymodel.js b/apps/comments/js/commentsummarymodel.js
index d405315ca1..ffabbc30fb 100644
--- a/apps/comments/js/commentsummarymodel.js
+++ b/apps/comments/js/commentsummarymodel.js
@@ -9,13 +9,17 @@
  */
 
 (function(OC, OCA) {
-	var NS_OWNCLOUD = 'http://owncloud.org/ns';
+
+	_.extend(OC.Files.Client, {
+		PROPERTY_READMARKER:	'{' + OC.Files.Client.NS_OWNCLOUD + '}readMarker'
+	});
+
 	/**
 	 * @class OCA.Comments.CommentSummaryModel
 	 * @classdesc
 	 *
 	 * Model containing summary information related to comments
-	 * like the read marker. 
+	 * like the read marker.
 	 *
 	 */
 	var CommentSummaryModel = OC.Backbone.Model.extend(
@@ -37,7 +41,7 @@
 		_objectId: null,
 
 		davProperties: {
-			'readMarker': '{' + NS_OWNCLOUD + '}readMarker'
+			'readMarker': OC.Files.Client.PROPERTY_READMARKER
 		},
 
 		/**
@@ -62,4 +66,3 @@
 
 	OCA.Comments.CommentSummaryModel = CommentSummaryModel;
 })(OC, OCA);
-
diff --git a/apps/comments/js/filesplugin.js b/apps/comments/js/filesplugin.js
index cc419c18dd..8c5762065a 100644
--- a/apps/comments/js/filesplugin.js
+++ b/apps/comments/js/filesplugin.js
@@ -11,6 +11,11 @@
 /* global Handlebars */
 
 (function() {
+
+	_.extend(OC.Files.Client, {
+		PROPERTY_COMMENTS_UNREAD:	'{' + OC.Files.Client.NS_OWNCLOUD + '}comments-unread'
+	});
+
 	var TEMPLATE_COMMENTS_UNREAD =
 		'<a class="action action-comment permanent" title="{{countMessage}}" href="#">' +
 		'<img class="svg" src="{{iconUrl}}"/>' +
@@ -52,19 +57,17 @@
 
 			fileList.registerTabView(new OCA.Comments.CommentsTabView('commentsTabView'));
 
-			var NS_OC = 'http://owncloud.org/ns';
-
 			var oldGetWebdavProperties = fileList._getWebdavProperties;
 			fileList._getWebdavProperties = function() {
 				var props = oldGetWebdavProperties.apply(this, arguments);
-				props.push('{' + NS_OC + '}comments-unread');
+				props.push(OC.Files.Client.PROPERTY_COMMENTS_UNREAD);
 				return props;
 			};
 
 			fileList.filesClient.addFileInfoParser(function(response) {
 				var data = {};
 				var props = response.propStat[0].properties;
-				var commentsUnread = props['{' + NS_OC + '}comments-unread'];
+				var commentsUnread = props[OC.Files.Client.PROPERTY_COMMENTS_UNREAD];
 				if (!_.isUndefined(commentsUnread) && commentsUnread !== '') {
 					data.commentsUnread = parseInt(commentsUnread, 10);
 				}
diff --git a/apps/dav/lib/Connector/Sabre/FilesPlugin.php b/apps/dav/lib/Connector/Sabre/FilesPlugin.php
index 54d91db5c0..5e401b8848 100644
--- a/apps/dav/lib/Connector/Sabre/FilesPlugin.php
+++ b/apps/dav/lib/Connector/Sabre/FilesPlugin.php
@@ -328,6 +328,9 @@ class FilesPlugin extends ServerPlugin {
 			$propFind->handle(self::HAS_PREVIEW_PROPERTYNAME, function () use ($node) {
 				return json_encode($this->previewManager->isAvailable($node->getFileInfo()));
 			});
+			$propFind->handle(self::SIZE_PROPERTYNAME, function() use ($node) {
+				return $node->getSize();
+			});
 		}
 
 		if ($node instanceof \OCA\DAV\Connector\Sabre\Node) {
diff --git a/apps/dav/tests/unit/Connector/Sabre/FilesPluginTest.php b/apps/dav/tests/unit/Connector/Sabre/FilesPluginTest.php
index c6e833033d..1c9ebdd09b 100644
--- a/apps/dav/tests/unit/Connector/Sabre/FilesPluginTest.php
+++ b/apps/dav/tests/unit/Connector/Sabre/FilesPluginTest.php
@@ -188,8 +188,6 @@ class FilesPluginTest extends TestCase {
 		$node->expects($this->exactly(2))
 			->method('getOwner')
 			->will($this->returnValue($user));
-		$node->expects($this->never())
-			->method('getSize');
 
 		$this->plugin->handleGetProperties(
 			$propFind,
diff --git a/apps/files/js/fileinfomodel.js b/apps/files/js/fileinfomodel.js
index de1b143a16..9d1eac3194 100644
--- a/apps/files/js/fileinfomodel.js
+++ b/apps/files/js/fileinfomodel.js
@@ -36,10 +36,18 @@
 			path: ''
 		},
 
-		initialize: function(data) {
+		_filesClient: null,
+
+		initialize: function(data, options) {
 			if (!_.isUndefined(data.id)) {
 				data.id = parseInt(data.id, 10);
 			}
+
+			if( options ){
+				if (options.filesClient) {
+					this._filesClient = options.filesClient;
+				}
+			}
 		},
 
 		/**
@@ -73,6 +81,42 @@
 		 */
 		getFullPath: function() {
 			return OC.joinPaths(this.get('path'), this.get('name'));
+		},
+
+		/**
+		 * Reloads missing properties from server and set them in the model.
+		 * @param properties array of properties to be reloaded
+		 * @return ajax call object
+		 */
+		reloadProperties: function(properties) {
+			if( !this._filesClient ){
+				return;
+			}
+
+			var self = this;
+			var deferred = $.Deferred();
+
+			var targetPath = OC.joinPaths(this.get('path') + '/', this.get('name'));
+
+			this._filesClient.getFileInfo(targetPath, {
+					properties: properties
+				})
+				.then(function(status, data) {
+					// the following lines should be extracted to a mapper
+
+					if( properties.indexOf(OC.Files.Client.PROPERTY_GETCONTENTLENGTH) !== -1
+					||  properties.indexOf(OC.Files.Client.PROPERTY_SIZE) !== -1 ) {
+						self.set('size', data.size);
+					}
+
+					deferred.resolve(status, data);
+				})
+				.fail(function(status) {
+					OC.Notification.showTemporary(t('files', 'Could not load info for file "{file}"', {file: self.get('name')}));
+					deferred.reject(status);
+				});
+
+			return deferred.promise();
 		}
 	});
 
@@ -82,4 +126,3 @@
 	OCA.Files.FileInfoModel = FileInfoModel;
 
 })(OC, OCA);
-
diff --git a/apps/files/js/filelist.js b/apps/files/js/filelist.js
index a8daeadfd2..cd0eb390ee 100644
--- a/apps/files/js/filelist.js
+++ b/apps/files/js/filelist.js
@@ -442,7 +442,9 @@
 			// In the future the FileList should work with Backbone.Collection
 			// and contain existing models that can be used.
 			// This method would in the future simply retrieve the matching model from the collection.
-			var model = new OCA.Files.FileInfoModel(this.elementToFile($tr));
+			var model = new OCA.Files.FileInfoModel(this.elementToFile($tr), {
+				filesClient: this.filesClient
+			});
 			if (!model.get('path')) {
 				model.set('path', this.getCurrentDirectory(), {silent: true});
 			}
@@ -891,11 +893,14 @@
 				mimetype: $el.attr('data-mime'),
 				mtime: parseInt($el.attr('data-mtime'), 10),
 				type: $el.attr('data-type'),
-				size: parseInt($el.attr('data-size'), 10),
 				etag: $el.attr('data-etag'),
 				permissions: parseInt($el.attr('data-permissions'), 10),
 				hasPreview: $el.attr('data-has-preview') === 'true'
 			};
+			var size = $el.attr('data-size');
+			if (size) {
+				data.size = parseInt(size, 10);
+			}
 			var icon = $el.attr('data-icon');
 			if (icon) {
 				data.icon = icon;
@@ -1029,7 +1034,7 @@
 		 * Returns whether the given file info must be hidden
 		 *
 		 * @param {OC.Files.FileInfo} fileInfo file info
-		 * 
+		 *
 		 * @return {boolean} true if the file is a hidden file, false otherwise
 		 */
 		_isHiddenFile: function(file) {
@@ -2828,7 +2833,6 @@
 			});
 			uploader.on('fail', function(e, data) {
 				self._uploader.log('filelist handle fileuploadfail', e, data);
-				
 				self._uploads = [];
 
 				//if user pressed cancel hide upload chrome
diff --git a/apps/files/js/mainfileinfodetailview.js b/apps/files/js/mainfileinfodetailview.js
index 1a69528fd1..e815fa70ec 100644
--- a/apps/files/js/mainfileinfodetailview.js
+++ b/apps/files/js/mainfileinfodetailview.js
@@ -130,6 +130,19 @@
 			if (this.model) {
 				this.model.on('change', this._onModelChanged, this);
 			}
+
+			if (this.model) {
+				var properties = [];
+				if( !this.model.has('size') ) {
+					properties.push(OC.Files.Client.PROPERTY_SIZE);
+					properties.push(OC.Files.Client.PROPERTY_GETCONTENTLENGTH);
+				}
+
+				if( properties.length > 0){
+					this.model.reloadProperties(properties);
+				}
+			}
+
 			this.render();
 		},
 
diff --git a/apps/files/js/tagsplugin.js b/apps/files/js/tagsplugin.js
index 3c0a231d00..9bb4ba3359 100644
--- a/apps/files/js/tagsplugin.js
+++ b/apps/files/js/tagsplugin.js
@@ -12,6 +12,11 @@
 
 (function(OCA) {
 
+	_.extend(OC.Files.Client, {
+		PROPERTY_TAGS:	'{' + OC.Files.Client.NS_OWNCLOUD + '}tags',
+		PROPERTY_FAVORITE:	'{' + OC.Files.Client.NS_OWNCLOUD + '}favorite'
+	});
+
 	var TEMPLATE_FAVORITE_ACTION =
 		'<a href="#" ' +
 		'class="action action-favorite {{#isFavorite}}permanent{{/isFavorite}}">' +
@@ -162,24 +167,22 @@
 				return fileInfo;
 			};
 
-			var NS_OC = 'http://owncloud.org/ns';
-
 			var oldGetWebdavProperties = fileList._getWebdavProperties;
 			fileList._getWebdavProperties = function() {
 				var props = oldGetWebdavProperties.apply(this, arguments);
-				props.push('{' + NS_OC + '}tags');
-				props.push('{' + NS_OC + '}favorite');
+				props.push(OC.Files.Client.PROPERTY_TAGS);
+				props.push(OC.Files.Client.PROPERTY_FAVORITE);
 				return props;
 			};
 
 			fileList.filesClient.addFileInfoParser(function(response) {
 				var data = {};
 				var props = response.propStat[0].properties;
-				var tags = props['{' + NS_OC + '}tags'];
-				var favorite = props['{' + NS_OC + '}favorite'];
+				var tags = props[OC.Files.Client.PROPERTY_TAGS];
+				var favorite = props[OC.Files.Client.PROPERTY_FAVORITE];
 				if (tags && tags.length) {
 					tags = _.chain(tags).filter(function(xmlvalue) {
-						return (xmlvalue.namespaceURI === NS_OC && xmlvalue.nodeName.split(':')[1] === 'tag');
+						return (xmlvalue.namespaceURI === OC.Files.Client.NS_OWNCLOUD && xmlvalue.nodeName.split(':')[1] === 'tag');
 					}).map(function(xmlvalue) {
 						return xmlvalue.textContent || xmlvalue.text;
 					}).value();
diff --git a/apps/files_sharing/js/share.js b/apps/files_sharing/js/share.js
index 01c2ccfb86..fcae7bc9a5 100644
--- a/apps/files_sharing/js/share.js
+++ b/apps/files_sharing/js/share.js
@@ -9,6 +9,12 @@
  */
 
 (function() {
+
+	_.extend(OC.Files.Client, {
+		PROPERTY_SHARE_TYPES:	'{' + OC.Files.Client.NS_OWNCLOUD + '}share-types',
+		PROPERTY_OWNER_DISPLAY_NAME:	'{' + OC.Files.Client.NS_OWNCLOUD + '}owner-display-name'
+	});
+
 	if (!OCA.Sharing) {
 		OCA.Sharing = {};
 	}
@@ -65,32 +71,38 @@
 					fileInfo.shareTypes = shareTypes;
 				}
 
+				if( $el.attr('data-expiration')){
+					var expirationTimestamp = parseInt($el.attr('data-expiration'));
+					fileInfo.shares = [];
+					fileInfo.shares.push({expiration: expirationTimestamp});
+				}
+
+				fileInfo.recipientsDisplayName = $el.attr('data-share-recipients') || undefined;
+
 				return fileInfo;
 			};
 
-			var NS_OC = 'http://owncloud.org/ns';
-
 			var oldGetWebdavProperties = fileList._getWebdavProperties;
 			fileList._getWebdavProperties = function() {
 				var props = oldGetWebdavProperties.apply(this, arguments);
-				props.push('{' + NS_OC + '}owner-display-name');
-				props.push('{' + NS_OC + '}share-types');
+				props.push(OC.Files.Client.PROPERTY_OWNER_DISPLAY_NAME);
+				props.push(OC.Files.Client.PROPERTY_SHARE_TYPES);
 				return props;
 			};
 
 			fileList.filesClient.addFileInfoParser(function(response) {
 				var data = {};
 				var props = response.propStat[0].properties;
-				var permissionsProp = props['{' + NS_OC + '}permissions'];
+				var permissionsProp = props[OC.Files.Client.PROPERTY_PERMISSIONS];
 
 				if (permissionsProp && permissionsProp.indexOf('S') >= 0) {
-					data.shareOwner = props['{' + NS_OC + '}owner-display-name'];
+					data.shareOwner = props[OC.Files.Client.PROPERTY_OWNER_DISPLAY_NAME];
 				}
 
-				var shareTypesProp = props['{' + NS_OC + '}share-types'];
+				var shareTypesProp = props[OC.Files.Client.PROPERTY_SHARE_TYPES];
 				if (shareTypesProp) {
 					data.shareTypes = _.chain(shareTypesProp).filter(function(xmlvalue) {
-						return (xmlvalue.namespaceURI === NS_OC && xmlvalue.nodeName.split(':')[1] === 'share-type');
+						return (xmlvalue.namespaceURI === OC.Files.Client.NS_OWNCLOUD && xmlvalue.nodeName.split(':')[1] === 'share-type');
 					}).map(function(xmlvalue) {
 						return parseInt(xmlvalue.textContent || xmlvalue.text, 10);
 					}).value();
diff --git a/core/js/files/client.js b/core/js/files/client.js
index 87559b2084..cde3afde9d 100644
--- a/core/js/files/client.js
+++ b/core/js/files/client.js
@@ -31,9 +31,9 @@
 			this._root = this._root.substr(0, this._root.length - 1);
 		}
 
-		var url = 'http://';
+		var url = Client.PROTOCOL_HTTP + '://';
 		if (options.useHTTPS) {
-			url = 'https://';
+			url = Client.PROTOCOL_HTTPS + '://';
 		}
 
 		url += options.host + this._root;
@@ -64,6 +64,19 @@
 	Client.NS_OWNCLOUD = 'http://owncloud.org/ns';
 	Client.NS_NEXTCLOUD = 'http://nextcloud.org/ns';
 	Client.NS_DAV = 'DAV:';
+
+	Client.PROPERTY_GETLASTMODIFIED	= '{' + Client.NS_DAV + '}getlastmodified';
+	Client.PROPERTY_GETETAG	= '{' + Client.NS_DAV + '}getetag';
+	Client.PROPERTY_GETCONTENTTYPE	= '{' + Client.NS_DAV + '}getcontenttype';
+	Client.PROPERTY_RESOURCETYPE	= '{' + Client.NS_DAV + '}resourcetype';
+	Client.PROPERTY_INTERNAL_FILEID	= '{' + Client.NS_OWNCLOUD + '}fileid';
+	Client.PROPERTY_PERMISSIONS	= '{' + Client.NS_OWNCLOUD + '}permissions';
+	Client.PROPERTY_SIZE	= '{' + Client.NS_OWNCLOUD + '}size';
+	Client.PROPERTY_GETCONTENTLENGTH	= '{' + Client.NS_DAV + '}getcontentlength';
+
+	Client.PROTOCOL_HTTP	= 'http';
+	Client.PROTOCOL_HTTPS	= 'https';
+
 	Client._PROPFIND_PROPERTIES = [
 		/**
 		 * Modified time
@@ -259,23 +272,23 @@
 			var props = response.propStat[0].properties;
 
 			var data = {
-				id: props['{' + Client.NS_OWNCLOUD + '}fileid'],
+				id: props[Client.PROPERTY_INTERNAL_FILEID],
 				path: OC.dirname(path) || '/',
 				name: OC.basename(path),
-				mtime: (new Date(props['{' + Client.NS_DAV + '}getlastmodified'])).getTime()
+				mtime: (new Date(props[Client.PROPERTY_GETLASTMODIFIED])).getTime()
 			};
 
-			var etagProp = props['{' + Client.NS_DAV + '}getetag'];
+			var etagProp = props[Client.PROPERTY_GETETAG];
 			if (!_.isUndefined(etagProp)) {
 				data.etag = this._parseEtag(etagProp);
 			}
 
-			var sizeProp = props['{' + Client.NS_DAV + '}getcontentlength'];
+			var sizeProp = props[Client.PROPERTY_GETCONTENTLENGTH];
 			if (!_.isUndefined(sizeProp)) {
 				data.size = parseInt(sizeProp, 10);
 			}
 
-			sizeProp = props['{' + Client.NS_OWNCLOUD + '}size'];
+			sizeProp = props[Client.PROPERTY_SIZE];
 			if (!_.isUndefined(sizeProp)) {
 				data.size = parseInt(sizeProp, 10);
 			}
@@ -294,12 +307,12 @@
 				data.isFavorite = false;
 			}
 
-			var contentType = props['{' + Client.NS_DAV + '}getcontenttype'];
+			var contentType = props[Client.PROPERTY_GETCONTENTTYPE];
 			if (!_.isUndefined(contentType)) {
 				data.mimetype = contentType;
 			}
 
-			var resType = props['{' + Client.NS_DAV + '}resourcetype'];
+			var resType = props[Client.PROPERTY_RESOURCETYPE];
 			var isFile = true;
 			if (!data.mimetype && resType) {
 				var xmlvalue = resType[0];
@@ -310,7 +323,7 @@
 			}
 
 			data.permissions = OC.PERMISSION_READ;
-			var permissionProp = props['{' + Client.NS_OWNCLOUD + '}permissions'];
+			var permissionProp = props[Client.PROPERTY_PERMISSIONS];
 			if (!_.isUndefined(permissionProp)) {
 				var permString = permissionProp || '';
 				data.mountType = null;
@@ -752,7 +765,7 @@
 		},
 
 		/**
-		 * Returns the password 
+		 * Returns the password
 		 *
 		 * @since 11.0.0
 		 * @return {String} password
@@ -816,4 +829,3 @@
 
 	OC.Files.Client = Client;
 })(OC, OC.Files.FileInfo);
-
diff --git a/core/js/systemtags/systemtagmodel.js b/core/js/systemtags/systemtagmodel.js
index 89728357e2..72450a2abd 100644
--- a/core/js/systemtags/systemtagmodel.js
+++ b/core/js/systemtags/systemtagmodel.js
@@ -9,7 +9,15 @@
  */
 
 (function(OC) {
-	var NS_OWNCLOUD = 'http://owncloud.org/ns';
+
+	_.extend(OC.Files.Client, {
+		PROPERTY_FILEID:	'{' + OC.Files.Client.NS_OWNCLOUD + '}id',
+		PROPERTY_CAN_ASSIGN:'{' + OC.Files.Client.NS_OWNCLOUD + '}can-assign',
+		PROPERTY_DISPLAYNAME:	'{' + OC.Files.Client.NS_OWNCLOUD + '}display-name',
+		PROPERTY_USERVISIBLE:	'{' + OC.Files.Client.NS_OWNCLOUD + '}user-visible',
+		PROPERTY_USERASSIGNABLE:'{' + OC.Files.Client.NS_OWNCLOUD + '}user-assignable',
+	});
+
 	/**
 	 * @class OCA.SystemTags.SystemTagsCollection
 	 * @classdesc
@@ -28,12 +36,12 @@
 		},
 
 		davProperties: {
-			'id': '{' + NS_OWNCLOUD + '}id',
-			'name': '{' + NS_OWNCLOUD + '}display-name',
-			'userVisible': '{' + NS_OWNCLOUD + '}user-visible',
-			'userAssignable': '{' + NS_OWNCLOUD + '}user-assignable',
+			'id':	OC.Files.Client.PROPERTY_FILEID,
+			'name': OC.Files.Client.PROPERTY_DISPLAYNAME,
+			'userVisible': 	OC.Files.Client.PROPERTY_USERVISIBLE,
+			'userAssignable': 	OC.Files.Client.PROPERTY_USERASSIGNABLE,
 			// read-only, effective permissions computed by the server,
-			'canAssign': '{' + NS_OWNCLOUD + '}can-assign'
+			'canAssign': OC.Files.Client.PROPERTY_CAN_ASSIGN
 		},
 
 		parse: function(data) {
@@ -50,4 +58,3 @@
 	OC.SystemTags = OC.SystemTags || {};
 	OC.SystemTags.SystemTagModel = SystemTagModel;
 })(OC);
-