reverse proxy

nginx.conf

server {
  listen      80;
  server_name example.com;
  charset     UTF-8;

  auth_basic           "Login message";
  auth_basic_user_file /path/to/.htpasswd;

  location / {
    proxy_redirect                      off;
    proxy_set_header Host               $host;
    proxy_set_header X-Real-IP          $remote_addr;
    proxy_set_header X-Forwarded-Host   $host;
    proxy_set_header X-Forwarded-Server $host;
    proxy_set_header X-Forwarded-For    $proxy_add_x_forwarded_for;
    proxy_pass                          http://localhost:3000/;
  }
}