#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11134663
use warnings;
use IO::Socket;
use IO::Select;

my %data;
my $listen = IO::Socket::INET->new( LocalPort => 8080,
  Listen => 256, Reuse => 1) or die $@;
my $sel = IO::Select->new($listen);

sub checkforrequests
  {
  for my $fh ( $sel->can_read(0) ) # 0 for poll
    {
    if( $fh == $listen )
      {
      my $socket = $listen->accept;
      $data{$socket} = '';
      $sel->add( $socket );
      print "new client $socket\n";
      }
    elsif( sysread $fh, $data{$fh}, 4096, length $data{$fh} )
      {
      if( $data{$fh} =~ s/^(.*?\n\r?\n)//s ) # any whole HTTP commands
        {
        my $command = $1;
        print $command =~ s/^/got HTTP packet: /gmr;
        # FIXME process request here
        print $fh "OK\n"; # FIXME sample response
        shutdown $fh, 1;
        $command =~ /quit/ and die "exiting on 'quit' command\n";
        }
      }
    else
      {
      delete $data{$fh};
      $sel->remove( $fh );
      print "client left $fh\n";
      }
    }
  }

while( 1 ) # your loop as I understand it
  {
  select undef, undef, undef, 0.2; # FIXME your non-network stuff
  checkforrequests(); # this is added to your loop
  }