PHP源码学习：探测httpheader头！

<?php /****************************************************  
program : Spr2[detect_httpheader]  
Author  : web   
E-mail  : 7713  
QQ      : 7713  
Date    : 2001-7-25 
****************************************************/ 
$host = "www.infojet.com.cn"; 
$port = "80"; $path = "/yuhu/"; 
$filename = "talk0.asp"; 
$datestream = "sdjahsdjkhaksjd"; 
$length = strlen($datestream); 
$header = "POST ${path}$filename HTTP/1.1\n"; 
$header.= "HOST: $host\n"; 
$header.= "Content-Type: application/x-www-form-urlencoded\n"; 
$header.= "Content-Length: $length\n\n"; 
$header.= "$datestream"; 
function sock() { global $host, $port, $header; 
$fsocket = @fsockopen($host, $port, &$errno, &$errstr); 
if(!$fsocket) { echo "$errstr ($errno)\n"; }else { fputs($fsocket, $header); 
while(!feof($fsocket)) { 
$res = fread($fsocket, 128); 
echo $res; } 
} 
fclose($fsocket); 
} 
set_time_limit(0); 
sock();  
?>