Unable to get the Name of logged in User #26908

Hi,

I am trying to get the user name who is currently logged in. For this I am trying following line of code in upload.php file.

echo OCP\User::getUser();

But

Actually I want that when I upload any file then before uploading I want
to show the name of the logged in user on top of page. But I m unable
to see.
How to fix this?