parse xml dvrs

#!/usr/bin/perl
# Read from: nmap -n -iL ips -p80 -sT -Pn --script getdvrcfg
# --min-rate=5000 -m 256 -v --min-hostgroup=1000 --script getdvrcfg -oA getDVR
use Nmap::Parser;
use Data::Dumper;
use JSON::XS;
use Geo::IP;
use strict;

my $gi = Geo::IP->open("./GeoLiteCity.dat", GEOIP_STANDARD);
my $xmlfile = $ARGV[0];
my $all;

print "# Reading from NMAP XML File '$xmlfile'.\n";
my $i=0;

my $np = new Nmap::Parser;
$np->parsefile("$xmlfile"); # $name
my $session = $np->get_session();
my $nmapv   = $session->nmap_version();
my $xmlv    = $session->xml_version();
for my $host ($np->all_hosts()) {
   my $os_sig = $host->os_sig();
   my $ipv4  = $host->ipv4_addr();
   my $hostn  = $host->hostname();
   for my $tcp ($host->tcp_ports()){
                my $service = $host->tcp_service($tcp);
        my $exinf = $service->extrainfo();
        if ($service->scripts('getdvrcfg')) {
                my $htmlindex = $service->scripts('getdvrcfg')->{output};
                if ($htmlindex =~ /_NAME=/) {
                        $i++;
                        my $record = $gi->record_by_addr($ipv4);
                        push @$all, {
                                 ip => $ipv4,
                         lat => $record->latitude,
                         lon => $record->longitude,
                         city => $record->city || $record->country_name
                       };
                         }
        }

   }
}

open J, ">cams.json" or die "No puedo abrir cams.json\n";
print J "var cams=";
print J encode_json( $all );
close J;
print "Records: $i\n";