一个简单的方法实现 获取真实ip

if(!function_exists('getIP')){

    function getIP()
    {
        if(isset($_SERVER)){
            if(isset($_SERVER['HTTP_X_FORWARDED_FOR'])){
                $realip = $_SERVER['HTTP_X_FORWARDED_FOR'];
            }elseif(isset($_SERVER['HTTP_CLIENT_IP'])) {
                $realip = $_SERVER['HTTP_CLIENT_IP'];
            }else{
                $realip = $_SERVER['REMOTE_ADDR'];
            }
        }else{
            //不允许就使用getenv获取
            if(getenv("HTTP_X_FORWARDED_FOR")){
                $realip = getenv( "HTTP_X_FORWARDED_FOR");
            }elseif(getenv("HTTP_CLIENT_IP")) {
                $realip = getenv("HTTP_CLIENT_IP");
            }else{
                $realip = getenv("REMOTE_ADDR");
            }
        }

        return $realip;
    }
}