php获取用户IP

function getIp() {
    static $realip = NULL;
 
    if ($realip !== NULL) {
        return $realip;
    }
 
    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‘);
    }
 
    preg_match("/[\d\.]{7,15}/", $realip, $onlineip);
    $realip = !empty($onlineip[0]) ? $onlineip[0] : ‘0.0.0.0‘;
 
    return $realip;
}