use strict;
use warnings;
require IO::Handle;	# let's us use sockets as objects.
require IO::Socket::IP;
# Implicitly included above, yet list it explicitly:
require Socket;

# When no arg1 is passed, the socket buffer section is skipped.
# Otherwise, this is the value to set as the SO_RCVBUF on the socket.
my $buf_size = shift;

# Notably, we cannot use IO::Socket::IP or related classes.
# Setting socket options (like SO_RCVBUF we do later) requires we do them on
# an otherwise *unconnected* socket. We handle this ourselves here:
my $host = "google.com";
my $port = 80;

socket(my $sock, Socket->AF_INET, Socket->SOCK_STREAM, Socket->IPPROTO_TCP);
defined $sock or die "no socket: $!";

# Set socket buffer, when requested:
my $size;
if ($buf_size) {
	my $rc;

	# Show current buf:
	$size = getsockopt($sock, Socket->SOL_SOCKET, Socket->SO_RCVBUF);
	die "No buf size??" unless defined $size;
	printf "Size of buffer before setting is: %s\n", unpack("i", $size);

	# Set new size:
	$rc = setsockopt($sock, Socket->SOL_SOCKET, Socket->SO_RCVBUF, pack("i", $buf_size));
	die "setsockopt() failed" unless ($rc);
}

# Regardless, show the current size:
$size = getsockopt($sock, Socket->SOL_SOCKET, Socket->SO_RCVBUF);
die "No buf size after set??" unless defined $size;
printf "Size of buffer is now: %s\n", unpack("i", $size);

print "Sleeping 2..\n";
sleep 2;

my $hints = {
	family => Socket->AF_INET,
	protocol => Socket->IPPROTO_TCP,
};
my ($err, @addrs) = Socket::getaddrinfo( $host, $port, $hints );
die "getaddrinfo error: $err ($!)" if ($err);
my $ai = shift @addrs or die "no addresses for the host!";
connect($sock, $ai->{addr}) or die "Connect failed: $!";

$sock->autoflush(1);

# Use Perl/IO (built on Standard I/O) to send a request for data:
$sock->print("GET /\n")
	or die "Socket error on write: $!";

# Read loop, printing out data from socket to STDOUT.
my $rc;
while (1) {
	$rc = $sock->read(my $buffer, 1024);
	
	# catch socket errors (excluding EOF):
	unless (defined $rc) {
		die "Socket error on read: $!";
	}

	# EOF returns 0, which exits the read loop:
	last if ($rc == 0);

	# Otherwise print the line, which may be a partial line.
	#printf "%s\n", $buffer;
}

print "\n";