Ns returnfile

ns_returnfile 200 "application/zip" $filepath

ns_returnfile 200 [ns_guesstype $file] $filepath

Caveat programmor

ns_returnfile uses fastpath internally, so care should be taken when using it to return dynamically generated files. A better practice if dealing with dynamic data in the filesystem would probably be to use ns_return instead. For example:

set fd [open $myfile]
ns_unlink $myfile; # So that nothing else can access the file from the filesystem
ns_return 200 [ns_guesstype $myfile] [read $fd]
close $fd

Want to name the file returned?

ns_set update [ns_conn outputheaders] content-disposition "attachment; filename=1.abc"