#!/usr/bin/perl
use strict;
use warnings;

################################################################################
# Load hash from CSV at startup
################################################################################
open DATA, "mapping.csv";
my %hash;
while( <DATA> ) {
    chomp $_;
    my ($field1,$field2) = split /,/, $_;
    if( $field1 ne '' ) {
        $hash{$field1} = $field2;
    }
}
close DATA;
print "Readyn";

################################################################################
# Answer queries forever
################################################################################
use IO::Socket::INET;

# auto-flush on socket
$| = 1;
my $port=5000;

# creating a listening socket
my $socket = new IO::Socket::INET (
    LocalHost => '127.0.0.1',
    LocalPort => $port,
    Proto => 'tcp',
    Listen => 5,
    Reuse => 1
);
die "cannot create socket $!n" unless $socket;

while(1)
{
    # waiting for a new client connection
    my $client_socket = $socket->accept();

    my $data = "";
    $client_socket->recv($data, 1024);

    my $key=$data;
    chomp $key;
    my $reply = "ERROR: Not found $key";
    if (defined $hash{$key}){
       $reply=$hash{$key};
    }
    print "DEBUG: Received $key: Replying $replyn";

    $client_socket->send($reply);
    # notify client that response has been sent
    shutdown($client_socket, 1);
}

chmod +x go.pl

./go.pl

socat - TCP:127.0.0.1:5000 <<< "1350772177"
1347092335

START=$SECONDS; tail -1000 *csv | awk -F, '{print $1}' |
   while read a; do echo $a | socat - TCP:127.0.0.1:5000 ; echo; done; echo $START,$SECONDS