It's very easy to implement a dispatching module based on the MIME type of the request—that is, for different content handlers to be called for different MIME types. Example A-5 shows such a dispatcher.

Example A-5. Book/MimeTypeDispatch.pm

package Book::MimeTypeDispatch;
use Apache::Constants qw(DECLINED);

my %mime_types = (
    'text/html'  => \&HTML::Template::handler,
    'text/plain' => \&Book::Text::handler,
);

sub handler {
    my $r = shift;
    if (my $h = $mime_types{$r->content_type}) {
        $r->push_handlers(PerlHandler => $h);
        $r->handler('perl-script');
    }
    return DECLINED;
}
1;
__END__

This should be done with PerlFixupHandler, so we add this line in httpd.conf:

PerlFixupHandler Book::MimeTypeDispatch

After declaring the package name and importing constants, we set a translation table of MIME types and the corresponding handlers to be called. Then comes the handler, where the request object is retrieved. If the request object's MIME type is found in our translation table, we set the handler that should handle this request; otherwise, we do nothing. At the end we return DECLINEDso another fixup handler can take over.