use HTTP::Request;
use LWP::UserAgent;

my $html     = '';
my $request  = HTTP::Request->new(GET => "$url/$file" );
my $ua       = LWP::UserAgent->new;
my $response = $ua->request($request, \&cb);

sub cb {
    $html .= $_[0];
    die if length($html) > 4096;
}