exec() in PHP to create zip archives.

[scc123]

I have a user front end for a file hosting type website (not hosted here) and I need to be able to let my users create zip archives and download them on the fly of their areas.

$usnses=$_SESSION['username'];
exec('zip /users/'.$usnses.'/smwfiles.zip /users/'.$usnses.'/');

Is what I am using at the minute but every archive is just empty =/
Any help?
Thanks

EDIT:
Never mind I done it

exec("zip -r $f ./users/".$usnses."/*.html");

 

[lemon-tree]

PHP has a great Zip functionality already

 

[scc123]

Eh I managed to get it done on one line
Thanks anyway.

 

[misson]

Just be careful of injection attacks.

 

[scc123]

$f=escapeshellarg(escapeshellcmd(clean($f)));
$usnses=escapeshellarg(escapeshellcmd(clean($usnses)));

Not to take any chances

 

[xav0989]

I would not recommend using exec as some hosts might disable it.