A quick proxy script to bridge between Scratch and Mirobot.

package.json

{
  "author": "Ben Pirt",
  "name": "mirobot-scratch-proxy",
  "description": "A simple Scratch to Mirobot proxy",
  "version": "0.0.1",
  "dependencies": {
    "ws": "0.4.31"
  }
}

proxy.js

#!/usr/bin/env node

var net = require('net');
var WebSocket = require('ws');

var Mirobot = function(ready){
  this.ready = ready;
  this.init();
};

Mirobot.prototype = {
  init: function(){
    var self = this;
    
    this.conn = net.connect({host: '192.168.1.82', port: 8899}, function() {
      console.log("Mirobot connected");
      if(self.ready){
        self.ready();
      }
    });
    this.conn.on('data', function(data){ self.handleData(data) });
    this.conn.on('end', function() {
      console.log('mirobot disconnected');
    });
    this.conn.on('error', function(e) {
      console.log(e);
    });
  },
  action: function(cmd, arg, cb){
    var msg = {cmd: cmd}
    if(arg){ msg.arg = arg }
    this.send(msg, cb);
  },
  handleData: function(data){
    lines = data.toString().trim().split("\r\n");
    for(var i in lines){
      line = lines[i];
      line = JSON.parse(line);
      if(line.status === 'complete' && this.cbs[line.id]){
        this.cbs[line.id]();
        delete this.cbs[line.id];
      }else{
        console.log("no callback");
      }
    }
  },
  cbs: [],
  send: function(msg, cb){
    msg.id = Math.random().toString(36).substr(2, 9)
    if(cb){
      this.cbs[msg.id] = cb;
    }
    console.log(JSON.stringify(msg));
    this.conn.write(JSON.stringify(msg) + "\r\n");
  }
}
var mirobotClient = new Mirobot(function(){
  mirobotClient.action('penup');
});

var scratchClient = net.connect({host: '192.168.1.81', port: 42001}, function() {
  var broadcast = function(msg){
    msg = 'broadcast "' + msg + '"'
    console.log("sending: " + msg);
    var len = msg.length;
    var buf = new Buffer(4);
    buf.writeUInt32BE(len, 0);
    buf = Buffer.concat([buf, new Buffer(msg)]);
    scratchClient.write(buf);
  }
  
  scratchClient.on('data', function(data) {
    var len = data.readUInt32BE(0);
    var msg = data.slice(4, len + 4).toString();
    console.log("received: " + msg);
    var match = msg.match(/broadcast \"mirobot-([^-]*)-?(.*)?"/)
    if(match){
      mirobotClient.action(match[1], match[2], function(){
        broadcast('mirobot-ready');
      });
    }
  });
});
scratchClient.on('end', function() {
  console.log('scratchClient disconnected');
});
scratchClient.on('error', function(e) {
  console.log(e);
});