PerlModule Apache::Filter \
  OurStuff::SessionFilter
<Directory "/www_doc_root/">
  PerlHandler OurStuff::SessionFilter
  SetHandler perl-script
</Directory>

##</code><code>##

package OurStuff::SessionFilter;
use Apache::Constants();
sub handler {
        my $r = shift;
        $r = $r->filter_register();
        my($fh, $status) = $r->filter_input();
    return $status unless $status == Apache::Constants::OK();
    my $session_id = OurStuff::Session->getCurrent()->id;
    # now the hard part: process the $fh filehandle and
    # find relative urls, and add &session=$session_id to
    # the query string.
    # keep in mind that urls can be embedded in javascript,
    # such as location.href='...' or window.open(...)
    return OK;
}
1;