static WebSocketHTTPD serveHttpWithWebsockets_server;
static int serveHttpWithWebsockets_port = 8888;

static new TreeSet<String> serveHttpWithWebsockets_peers;

// factory: func(NanoHTTPD.IHTTPSession) -> WebSocket
static int serveHttpWithWebsockets(int port, O factory) ctex {
  serveHttpWithWebsockets_port = port;
  serveHttpWithWebsockets_server = new WebSocketHTTPD(port, factory);
  serveHttpWithWebsockets_server.start();
  ret serveHttpWithWebsockets_port();
}

// serve on random port, return port number used
static int serveHttpWithWebsockets(O factory) {
  serveHttpWithWebsockets(0, factory);
  ret serveHttpWithWebsockets_port();
}

static int serveHttpWithWebsockets_port() {
  ret serveHttpWithWebsockets_server == null ? 0 : serveHttpWithWebsockets_server.getListeningPort();
}

static void cleanMeUp_serveHttpWithWebsockets() {
  if (serveHttpWithWebsockets_server != null) {
    serveHttpWithWebsockets_server.stop();
    serveHttpWithWebsockets_server = null;
  }
}

Began life as a copy of #1001648