http server & httpHandlers Object Question

[poppabear8883]

First, please forgive me as I am fairly new to the subject and am still learning about upnp and ssdp.

With that said, I am trying to "tap" into the http server request system so that I can handle additional requests however my method seems to give me

Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client

I suspect because of the way your http server is implemented. It looks like you define httpHandlers to handle requests, but obviously it does not appear that I can tap into that from the peer.

I will provide to you what I have that is giving me the above error in case its simpler then what I am seeing:

function onRequest(req, res) {

  switch (req.url) {
    case '/discover.json':
      if (req.method === 'GET') res.end(JSON.stringify(getDiscoverJson()));
      break;
    case '/lineup.json':
      if (req.method === 'GET') res.end(JSON.stringify(getLineupJson()));
      break;
    default:
      if (req.method === 'GET') res.end(JSON.stringify(getDiscoverJson()));
  }

}

const httpServer = http.createServer(onRequest).listen(PORT);
console.log(`Listening on ${PORT}`);

// ... methods that return an object for the json responses

// peer
const peer = upnp.createPeer({
  prefix: "/upnp",
  server: httpServer
}).on("ready", async (peer) => {
  console.log("Device Ready");
  device.advertise();
}).on("close", (peer) => {
  console.log("closed");
}).start();

const device = peer.createDevice({
  // all my options
});

Please advise A.S.A.P

Much appreciated in advance