Question

I have a java-based server that allows client applications to connect via other programming languages (java, unity, obj-c). I would like to know how to add javascript to this list using node.js and socket.io. The server listens on a set port and accepts simple json data plus an int for length in bytes, it response in the same format. The format of the “packet” is like so:

first four bytes are the length
00 00 00 1c

remaining bytes are the data
7b 22 69 64 22 3a 31 2c 22 6e 61 6d 65 22 3a 22 73 6f 6d 65 77 69 64 67 65 74 22 7d

The data is sent over TCP and is encoded in little endian. The object in originating from Java is modeled like so:

public class Widget {
    private int id;
    private String name;
    public int getId() { return id; }
    public String getName() { return name; }
}

The JSON would be:

{"id":1,"name":"somewidget"}

Answer 1

So if you want just send request to server and get response you could do this:

var net = require('net');

var soc = net.Socket();
soc.connect(8088);

soc.on('connect', function(){
  var data, request, header;

  data = {request : true};
  data = JSON.stringify(data);

  request = new Buffer(Buffer.byteLength(data));
  request.write(data);

  header = new Buffer(4);
  header.write(request.length.toString());


  // send request  
  soc.end(header.toString('binary') + request.toString('binary'));
});

soc.on('data', function(buffer){
  // Crop length bytes
  var data = JSON.parse(buffer.slice(4).toString('utf-8'));
  soc.destroy();

  console.log(data);
});