how can I make a separate upload_dir folder for each auth user?

[bytrix]

if the user id is 1, then it uploads to public/upload/files/1/xxx
if the user id is 2, then it uploads to public/upload/files/2/xxx
so how can i use Auth::user()->id in my project to do this?
I inject Auth::user()->id in the authority project of blueimp and it reports below error:

[Thu Dec 31 16:13:22 2015] PHP Parse error: syntax error, unexpected '(', expecting ',' or ';' in /home/ynl0zq/Desktop/witkey/Framework/public/upload/UploadHandler.php on line 18
[Thu Dec 31 16:13:22 2015] 127.0.0.1:33794 [200]: /upload - syntax error, unexpected '(', expecting ',' or ';' in /home/ynl0zq/Desktop/witkey/Framework/public/upload/UploadHandler.php on line 18