simple proxy.js

var mc = require('minecraft-protocol');
var states = mc.states;

var srv = mc.createServer({
  'online-mode': false,
  port: 25566,
  keepAlive: false,
  version:'1.8'
});

srv.on('login', function(client) {
  client.on('packet', function(data, meta) {
          console.log("client->server:", client.state + " "+ meta.name + " :", JSON.stringify(data));
  });
  var addr = client.socket.remoteAddress;
  console.log('Incoming connection', '(' + addr + ')');

  client.on('end', function() {
    console.log('Connection closed', '(' + addr + ')');
  });

  client.on('error', function(error) {
    console.log('Error:', error);
  });

  // send init data so client will start rendering world
  client.write('login', {
    entityId: client.id,
    levelType: 'default',
    gameMode: 0,
    dimension: 0,
    difficulty: 2,
    maxPlayers: srv.maxPlayers,
    reducedDebugInfo: false
  });

  client.write('position', {
    x: 0,
    y: 1.62,
    z: 0,
    yaw: 0,
    pitch: 0,
    flags: 0x00
  });

  var msg = {
    translate: 'chat.type.announcement',
    "with": [
      'Server',
      'Hello, world!'
    ]
  };
  client.write('chat', {message: JSON.stringify(msg), position: 0});
});

srv.on('error', function(error) {
  console.log('Error:', error);
});

srv.on('listening', function() {
  console.log('Server listening on port', srv.socketServer.address().port);
});