如何从websockets解析二进制数据？

Question

I'm trying to parse frames from Websockets. I did it with Fiddler, which shows me binary data from the frame. I need the same result but I need to get it via Javascript or Php (or any other language). I tried to do that with Js

var a = new WebSocket("ws://example.com");   
a.onopen = function() 
 { 
  console.log("open"); 
  a.send("test");
  var b = new Uint8Array([8,6,7,5,3,0,9]);
  a.send(b.buffer); };
a.onmessage = function(e) {  console.log(e.data.toString());};
a.onclose = function() { console.log("closed");};

But I didn't receive any data on "a.onmessage". At this moment I've stucked. To clarify my question one more time. I need simple code example which parses frames from websockets. Example of what I'm trying to parse

Thanks!

Answer 1

Using DataView:

var socket = new WebSocket('ws://127.0.0.1:8081');
socket.binaryType = 'arraybuffer';

socket.onmessage = function (e) {
  var data = e.data;
  var dv = new DataView(data);

  // reads an UInt16 at the beginning 
  var uint16= dv.getUint16(0);

  // reads next UInt16 (sets 2 bytes of offset, since previous UInt16 takes 2 bytes)  
  var another_uint16= dv.getUint16(0);
};