that's what nix-channel expects.
UZENK33PYWZIWNJMLE2IIXKA6KOCGKGOWUMVBNXAYBOKT2H6ZT6AC
$c->response->content_type('text/plain');
$c->response->body($res);
my $tar = Archive::Tar->new;
$tar->add_data("channel/default.nix", $res);
my $tardata = $tar->write;
my $bzip2data;
bzip2(\$tardata => \$bzip2data);
$c->response->content_type('application/x-bzip2');
$c->response->body($bzip2data);