You may use $_SERVER["REMOTE_ADDR"] too, this is the more secure value, but it is also possible to fake. This remote_addr is the address where Apache returns result to.
This function CACHES results because gethostbyname is a very slow function.
为了这个目的,我实现了这个函数:
function isIPWhitelisted($whitelist = false)
{
if ( isset($_SESSION) && isset($_SESSION['isipallowed']) )
{ return $_SESSION['isipallowed']; }
// This is the whitelist
$ipchecklist = array("localhost", "127.0.0.1", "::1");
if ($whitelist) $ipchecklist = $whitelist;
$iplist = false;
$isipallowed = false;
$filename = "resolved-ip-list.txt";
$filename = substr(md5($filename), 0, 8)."_".$filename; // Just a spoon of security or just remove this line
if (file_exists($filename))
{
// If cache file has less than 1 day old use it
if (time() - filemtime($filename) <= 60*60*24*1)
$iplist = explode(";", file_get_contents($filename)); // Read cached resolved ips
}
// If file was not loaded or found -> generate ip list
if (!$iplist)
{
$iplist = array(); $c=0;
foreach ( $ipchecklist as $k => $iptoresolve )
{
// gethostbyname: It's a VERY SLOW function. We really need to cache the resolved ip list
$ip = gethostbyname($iptoresolve);
if ($ip != "") $iplist[$c] = $ip;
$c++;
}
file_put_contents($filename, implode(";", $iplist));
}
if (in_array($_SERVER['REMOTE_ADDR'], $iplist)) // Check if the client ip is allowed
$isipallowed = true;
if (isset($_SESSION)) $_SESSION['isipallowed'] = $isipallowed;
return $isipallowed;
}
为了更好的可靠性,你可以替换 Get _ ip _ address ()的 $_ SERVER [‘ REMOTE _ ADDR’],这是@Pekka 在他的 post中提到的 “这个赏金问题”
if ( substr_compare(getcwd(),":",1,1) == 0)
{
echo '<script type="text/javascript">alert(" The working dir is at the local computer ")</script>';
$client_or_server = 'client';
}
else
{
echo '<script type="text/javascript">alert(" The working dir is at the server ")</script>';
$client_or_server = 'server';
}