#!/usr/bin/perl

use HTTP::Daemon;
use HTTP::Status;
use HTTP::Response;
use LWP::UserAgent;
use Compress::Zlib;

our $DEBUG=0;
our $UA= LWP::UserAgent->new(
 'agent'=>'ProxyAgent (Mozilla 9.0; compatible)',
 'timeout' => 20,
);
$UA->env_proxy;
our $DAEMON = HTTP::Daemon->new(LocalPort => 8080) || die $!;
our $startGzipFromLength=512;
our $contentEncodingField='Content-Encoding';
#'Client-Transfer-Encoding'
#'Transfer-Encoding'

sub term {
 my $signame=shift;
 print STDERR "Signal $signame received. Terminating.\n";
 exit(0);
}

$SIG{INT} = \&term;
$SIG{BREAK} = \&term;

print STDERR "Contact proxy at: <URL:", $DAEMON->url, ">, press ^C to terminate\n";
while (my ($c, $peeraddr) = $DAEMON->accept) {
 my ($rport, $raddr) = sockaddr_in($peeraddr);
 print STDOUT 'From: ',inet_ntoa($raddr),":$rport\n";
 my $pid=fork();
 unless (defined($pid)){
  warn "can't fork: $!";
  last;
 }
 next if $pid; #parent
 while (my $r = $c->get_request){
  print STDOUT $r->as_string,"\n";
  my $resp=$UA->request($r);
  if (
   index($resp->protocol,'HTTP/1.1') >= 0 &&
   !$resp->header($contentEncodingField) &&
   $r->header('Accept-Encoding')=~m/gzip/io &&
   length($resp->content()) > $startGzipFromLength)
  {
   my $nresp=HTTP::Response->new(
    $resp->code,
    $resp->message,
    $resp->headers->clone
   );
   my $content=Compress::Zlib::memGzip($resp->content);
   $nresp->content($content);
   $nresp->header($contentEncodingField => 'gzip');
   $nresp->header('Content-Length' => length($content));
   print STDOUT $nresp->as_string,"\n\n" if $DEBUG;
   print STDOUT $nresp->content,"\n" if $DEBUG;
   $c->send_response($nresp);
  } else {
   $c->send_response($resp);
   print STDOUT $resp->as_string,"\n\n" if $DEBUG;
   print STDOUT $resp->content,"\n" if $DEBUG;
  }
 }
 $c->close;
 undef($c);
}

__END__

=head1 NAME

simple_proxy_gz - simple proxy compressing (gzip) HTTP traffic to save time and money

=head1 SYNOPSIS

perl simple_proxy_gz.pl >proxy.log &