sub handle_request {
        my $self = shift;
        my $cgi  = shift;
        my $json_string = $cgi->param('POSTDATA');
        # { "type":"cardCheck", "date":"1482307795601", "lang": "EN", "machineName":"PLUSMAKM", "cardNumber":"1234567890", "PIN": "1234" }
        print "json_string=$json_string\n";
        $json_dict = decode_json $json_string;
        print "json_dict=" . Dumper($json_dict) . "\n";
        my $response = $self->{kiosk}->process($json_dict);
        print "response=$response\n";
        return $response;
    }