Get remote filesize (HTTP HEAD) (See related posts)

function remote_file_size ($url){ 
	$head = ""; 
	$url_p = parse_url($url); 
	$host = $url_p["host"]; 
	if(!preg_match("/[0-9]*\.[0-9]*\.[0-9]*\.[0-9]*/",$host)){
		// a domain name was given, not an IP
		$ip=gethostbyname($host);
		if(!preg_match("/[0-9]*\.[0-9]*\.[0-9]*\.[0-9]*/",$ip)){
			//domain could not be resolved
			return -1;
		}
	}
	$port = intval($url_p["port"]); 
	if(!$port) $port=80;
	$path = $url_p["path"]; 
	//echo "Getting " . $host . ":" . $port . $path . " ...";

	$fp = fsockopen($host, $port, $errno, $errstr, 20); 
	if(!$fp) { 
		return false; 
		} else { 
		fputs($fp, "HEAD "  . $url  . " HTTP/1.1\r\n"); 
		fputs($fp, "HOST: " . $host . "\r\n"); 
		fputs($fp, "User-Agent: http://www.example.com/my_application\r\n");
		fputs($fp, "Connection: close\r\n\r\n"); 
		$headers = ""; 
		while (!feof($fp)) { 
			$headers .= fgets ($fp, 128); 
			} 
		} 
	fclose ($fp); 
	//echo $errno .": " . $errstr . "<br />";
	$return = -2; 
	$arr_headers = explode("\n", $headers); 
	// echo "HTTP headers for <a href='" . $url . "'>..." . substr($url,strlen($url)-20). "</a>:";
	// echo "<div class='http_headers'>";
	foreach($arr_headers as $header) { 
		// if (trim($header)) echo trim($header) . "<br />";
		$s1 = "HTTP/1.1"; 
		$s2 = "Content-Length: "; 
		$s3 = "Location: "; 
		if(substr(strtolower ($header), 0, strlen($s1)) == strtolower($s1)) $status = substr($header, strlen($s1)); 
		if(substr(strtolower ($header), 0, strlen($s2)) == strtolower($s2)) $size   = substr($header, strlen($s2));  
		if(substr(strtolower ($header), 0, strlen($s3)) == strtolower($s3)) $newurl = substr($header, strlen($s3));  
		} 
	// echo "</div>";
	if(intval($size) > 0) {
		$return=intval($size);
	} else {
		$return=$status;
	}
	// echo intval($status) .": [" . $newurl . "]<br />";
	if (intval($status)==302 && strlen($newurl) > 0) {
		// 302 redirect: get HTTP HEAD of new URL
		$return=remote_file_size($newurl);
	}
	return $return; 
}