+function setValidAttributedTo (obj: any) {
+ if (Array.isArray(obj.attributedTo) === false) {
+ obj.attributedTo = []
+ return true
+ }
+
+ obj.attributedTo = obj.attributedTo.filter(a => {
+ return (a.type === 'Group' || a.type === 'Person') && isActivityPubUrlValid(a.id)
+ })
+
+ return true
+}
+
+function isActivityPubVideoDurationValid (value: string) {
+ // https://www.w3.org/TR/activitystreams-vocabulary/#dfn-duration
+ return exists(value) &&
+ typeof value === 'string' &&
+ value.startsWith('PT') &&
+ value.endsWith('S')
+}
+