package myHandler;
use strict;

use Apache;
use Apache::Constants wq(:response);

sub handler {
        my $r = shift;
        my $uri = $r->uri();

        unless ($uri =~ /\.extension$/) {
                return DECLINED;
        }

        # rest of code

##</code><code>##

<Directory "/usr/local/apache/sites/test">
        SetHandler perl-script
        PerlHandler myHandler

        Options Indexes Includes FollowSymLinks
        AllowOverride None

        Order allow,deny
        Allow from all
</Directory>

##</code><code>##

[root@styx conf]# telnet localhost 80
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
GET /test/you_are_not_here HTTP/1.0

Connection closed by foreign host.