index.js

const io = require('socket.io')();
const middleware = require('socketio-wildcard')();

io.use(middleware);

const client = require('socket.io-client');

io.on('connection', function(socket) {
  console.log(`connection`);
  socket.upstream = client('http://127.0.0.1:8000');

  const patch = require('socketio-wildcard')(client.Manager);
  patch(socket.upstream);

  socket.on(`disconnect`, function() {
    console.log(`disconnec`);
    socket.upstream.disconnect();
  });

  socket.upstream.on('*', function(packet) {
    const [msg, content] = packet.data;
    socket.emit(msg, content);
    console.log(
      `replying`,
      msg,
      `content:`,
      JSON.stringify(content).substring(0, 90),
    );
  });

  socket.on('*', function(packet) {
    const [msg, content] = packet.data;
    console.log(`sending`, msg, `content:`, JSON.stringify(content));
    socket.upstream.send(msg, content);
  });
});

io.listen(8001);