Upload a file from system directory to dropbox web account

Question

I have a script with create a file on server directory (in testing on system xampp server directory). I want to upload or move that file from system directory to dropbox account on web directly. I don't want to place on default Dropbox root folder on my system to sync.

$pat=getcwd();
$fd = fopen($pat."\\"."filename.txt", "w");
$md1 = $client->uploadFile($pat."\\"."filename.txt",dbx\WriteMode::add(), $fd);
 fclose($fd);
print_r($md1);
$rev = $md1["rev"];