php获取客户端ip的函数

public static function getIp() {
if (getenv ( “HTTP_CLIENT_IP” ) && strcasecmp ( getenv ( “HTTP_CLIENT_IP” ), “unknown” )) {
$ip = getenv ( “HTTP_CLIENT_IP” );
} elseif (getenv ( “HTTP_X_FORWARDED_FOR” ) && strcasecmp ( getenv ( “HTTP_X_FORWARDED_FOR” ), “unknown” )) {
$ip = getenv ( “HTTP_X_FORWARDED_FOR” );
} elseif (getenv ( “REMOTE_ADDR” ) && strcasecmp ( getenv ( “REMOTE_ADDR” ), “unknown” )) {
$ip = getenv ( “REMOTE_ADDR” );
} elseif (isset ( $_SERVER [‘REMOTE_ADDR’] ) && $_SERVER [‘REMOTE_ADDR’] && strcasecmp ( $_SERVER [‘REMOTE_ADDR’], “unknown” )) {
$ip = $_SERVER [‘REMOTE_ADDR’];
} else {
$ip = “unknown”;
}
return $ip;
}