HTML5 WebSocket with hybi-17

Question

Update: I solved the decoding problem, thanks to pimvdb

Follows the solution (in PHP):

$len = $masks = $data = $decoded = null;

$len = ord ($buffer[1]) & 127;

if ($len === 126) {
  $masks = substr ($buffer, 4, 4);
  $data = substr ($buffer, 8);
}
else if ($len === 127) {
  $masks = substr ($buffer, 10, 4);
  $data = substr ($buffer, 14);
}
else {
  $masks = substr ($buffer, 2, 4);
  $data = substr ($buffer, 6);
}

for ($index = 0; $index < strlen ($data); $index++) {
  $decoded .= $data[$index] ^ $masks[$index % 4];
}

* Begin of the original topic *

I'm trying to develop HTML5 WebSocket for a personal application, using hybi-17 handshake.

I'm started with phpwebsocket and the only thing I changed is the handshake function, from the original to this:

function dohandshake($user,$buffer){
  $key = null;

  console("\nRequesting handshake...");
  console($buffer);
  console("Handshaking...");

  preg_match ("#Sec-WebSocket-Key: (.*?)\r\n#", $buffer, $match) && $key = $match[1];

  $key .= "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
  $key = sha1 ($key);
  $key = pack ('H*', $key);
  $key = base64_encode ($key);

  $upgrade = 
    "HTTP/1.1 101 Switching Protocols\r\n" .
    "Upgrade: websocket\r\n" .
    "Connection: Upgrade\r\n" .
    "Sec-WebSocket-Accept: {$key}\r\n\r\n";

  socket_write($user->socket,$upgrade.chr(0),strlen($upgrade.chr(0)));
  $user->handshake=true;
  console($upgrade);
  console("Done handshaking...");
  return true;
}

I used phpwebsocket source code, both for the client (http://code.google.com/p/phpwebsocket/source/browse/trunk/+phpwebsocket/client.html) and the server (http://code.google.com/p/phpwebsocket/source/browse/trunk/+phpwebsocket/server.php).

At this point, I tested the application. Follows the server debug:

Server Started : 2011-10-30 13:45:41
Master socket  : Resource id #4
Listening on   : localhost port 12345

Resource id #5 CONNECTED!

Requesting handshake...
GET /phpwebsocket/server.php HTTP/1.1
Upgrade: websocket
Connection: Upgrade
Host: localhost:12345
Sec-WebSocket-Origin: http://localhost
Sec-WebSocket-Key: +S/J2jcp/UKIS1HTW0n1/w==
Sec-WebSocket-Version: 8


Handshaking...
HTTP/1.1 101 Switching Protocols
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Accept: LEULWidwXDxY02iv3O+xksrxFz4=


Done handshaking...
< ��z�}p
> ��z�}p not understood
Resource id #5 DISCONNECTED!  

And this is the client debug:

WebSocket - status 0
Welcome - status 1
Sent: hello
Disconnected - status 3

What I did was simply connect the client and send the command 'Hello'. As you can see, server received encoded data and not plaintext: why?

I'm looking for someone who helps me to develop html5 websocket with hybi-17.

Cyaz

PS: this (http://stackoverflow.com/questions/7908306/implementing-handshake-for-hybi-17) topic and this one (http://stackoverflow.com/questions/7912772/decoding-network-chars-html5-websocket) might help.

PPS: I tested on Chromium 15.0.874.106~r107270-0ubuntu0.11.04.1

Answer 1

Decode solution (thanks to @pimvdb):

$len = $masks = $data = $decoded = null;

$len = ord ($buffer[1]) & 127;

if ($len === 126) {
  $masks = substr ($buffer, 4, 4);
  $data = substr ($buffer, 8);
}
else if ($len === 127) {
  $masks = substr ($buffer, 10, 4);
  $data = substr ($buffer, 14);
}
else {
  $masks = substr ($buffer, 2, 4);
  $data = substr ($buffer, 6);
}

for ($index = 0; $index < strlen ($data); $index++) {
  $decoded .= $data[$index] ^ $masks[$index % 4];
}

Answer 2

This encode function is great except that chrome 19 doesn't like the data being masked. I get this error after sending the first message to server: "A server must not mask any frames that it sends to the client."

I couldn't figure out how to not mask the data being sent to the server until I found a github example that works and has a flag you can set to not mask the data frames. https://github.com/lemmingzshadow/php-websocket

I had found this updated version of the phpwebsocket code: http://www.wilky.it/phpwebsocket-new-version/ One thing you need to fix in this to make it work is replace this line at line 234: preg_match ("#Sec-WebSocket-Origin: (.*?)\r\n#", $buffer, $match) && $origin = $match[1]; with preg_match ("#Origin: (.*?)\r\n#", $buffer, $match) && $origin = $match[1];

Then to fix the error in chrome: "A server must not mask any frames that it sends to the client." do the following: I fixed the replaced the encode function with the one in the connection.php file in lemmingzshadow's github and it started working. The function is called: hybi10Encode in the \server\lib\WebSocket\connection.php file. change this parameter in the function encode: $masked = true to $masked = false So we have 2 versions that work now in chrome and firefox 12!