怎样通过nginx代理获取用户真实IP？

use Workerman\Worker;
use Workerman\Connection\TcpConnection;
require_once __DIR__ . '/vendor/autoload.php';

$worker = new Worker('websocket://0.0.0.0:7272');

$worker->onWebSocketConnect = function(TcpConnection $connection, $request){
    $connection->realIP = $request->header('x-real-ip'); // workerman v5 用法
};
$worker->onMessage = function(TcpConnection $connection, $data)
{
    // 当使用客户端真实ip时，直接使用$connection->realIP即可
    $connection->send($connection->realIP);
};
Worker::runAll();