map $http_upgrade $connection_upgrade {
    default upgrade;
    ''      close;
}

server {
    listen       80;
    server_name  localhost;  # your domain here
    client_max_body_size 128M;  # maximum upload size

    location / {
        proxy_set_header Host $host;
        proxy_set_header   X-Real-IP            $remote_addr;
        proxy_set_header   X-Forwarded-For      $proxy_add_x_forwarded_for;
        proxy_set_header   X-Forwarded-Proto    $scheme;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection $connection_upgrade;
        proxy_pass http://127.0.0.1:9000/;
    }
}