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Dart upgrade client Socket to WebSocket

By : Kosma Bieńkowski
Date : October 14 2020, 02:24 PM
like below fixes the issue Use the HttpClient to establish the initial http(s) connection and then detach the socket. Here's an example with http. You should be able to adapt to https. Note how the initial connection is made over http, but upgraded by adding the appropriate request headers. (You'll need to adapt the headers to the security scheme required by your websocket server.)
code :
  Random r = new Random();
  String key = base64.encode(List<int>.generate(8, (_) => r.nextInt(255)));

  HttpClient client = HttpClient(/* optional security context here */);
  HttpClientRequest request = await client.get('echo.websocket.org', 80,
      '/foo/ws?api_key=myapikey'); // form the correct url here
  request.headers.add('Connection', 'upgrade');
  request.headers.add('Upgrade', 'websocket');
  request.headers.add('sec-websocket-version', '13'); // insert the correct version here
  request.headers.add('sec-websocket-key', key);

  HttpClientResponse response = await request.close();
  // todo check the status code, key etc
  Socket socket = await response.detachSocket();

  WebSocket ws = WebSocket.fromUpgradedSocket(
    serverSide: false,

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Handling unsuccessful websocket upgrade requests in Javascript Client

By : user2847407
Date : March 29 2020, 07:55 AM
hop of those help? I am afraid there is no way from Javascript to know the HTTP status code of the negotiation.
There are defined closing codes, and 1006 only means that the connection is closed abruptly, but the protocol even allows to close the connection without providing a reason. That, together with the readyState API, are the only tools you have to diagnosed the reason of the problem.

INET socket (not websocket) client from client side JS

By : user3651672
Date : March 29 2020, 07:55 AM
Any of those help No, it's impossibile. The primitive you have is XMLHttpRequest, which is a specialized socket facade: you can customize the HTTP method, the URL (but you can't even change host!) and the HTTP body. You can set headers and cookies (which are headers), but it will alway look like a HTTP request. Maybe there are browser specific extensions, though.
However, unless you want to use an already existing protocol, there should be no problem in encapsulating your payload in HTTP. You should always design on your constraints: if the client must run in any standard browser, then it must use HTTP.

Sending / receiving WebSocket message over Python socket / WebSocket Client

By : Kewal
Date : March 29 2020, 07:55 AM
hope this fix your issue Accoding to https://tools.ietf.org/html/rfc6455#section-5.1:
You should mask the client frames. (And the server frames is not masked at all.)
code :
import os
import array
import six
import socket
import struct


    # If wsaccel is available we use compiled routines to mask data.
    from wsaccel.xormask import XorMaskerSimple

    def _mask(_m, _d):
        return XorMaskerSimple(_m).process(_d)

except ImportError:
    # wsaccel is not available, we rely on python implementations.
    def _mask(_m, _d):
        for i in range(len(_d)):
            _d[i] ^= _m[i % 4]

        if six.PY3:
            return _d.tobytes()
            return _d.tostring()

def get_masked(data):
    mask_key = os.urandom(4)
    if data is None:
        data = ""

    bin_mask_key = mask_key
    if isinstance(mask_key, six.text_type):
        bin_mask_key = six.b(mask_key)

    if isinstance(data, six.text_type):
        data = six.b(data)

    _m = array.array("B", bin_mask_key)
    _d = array.array("B", data)
    s = _mask(_m, _d)

    if isinstance(mask_key, six.text_type):
        mask_key = mask_key.encode('utf-8')
    return mask_key + s

def ws_encode(data="", opcode=OPCODE_TEXT, mask=1):
    if opcode == OPCODE_TEXT and isinstance(data, six.text_type):
        data = data.encode('utf-8')

    length = len(data)
    fin, rsv1, rsv2, rsv3, opcode = 1, 0, 0, 0, opcode

    frame_header = chr(fin << 7 | rsv1 << 6 | rsv2 << 5 | rsv3 << 4 | opcode)

    if length < 0x7e:
        frame_header += chr(mask << 7 | length)
        frame_header = six.b(frame_header)
    elif length < 1 << 16:
        frame_header += chr(mask << 7 | 0x7e)
        frame_header = six.b(frame_header)
        frame_header += struct.pack("!H", length)
        frame_header += chr(mask << 7 | 0x7f)
        frame_header = six.b(frame_header)
        frame_header += struct.pack("!Q", length)

    if not mask:
        return frame_header + data
    return frame_header + get_masked(data)

def ws_decode(data):
    ws frame decode.
    :param data:
    _data = [ord(character) for character in data]
    length = _data[1] & 127
    index = 2
    if length < 126:
        index = 2
    if length == 126:
        index = 4
    elif length == 127:
        index = 10
    return array.array('B', _data[index:]).tostring()

# connect
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((socket.gethostbyname('echo.websocket.org'), 80))

# handshake
handshake = 'GET / HTTP/1.1\r\nHost: echo.websocket.org\r\nUpgrade: websocket\r\nConnection: ' \
            'Upgrade\r\nSec-WebSocket-Key: gfhjgfhjfj\r\nOrigin: http://example.com\r\nSec-WebSocket-Protocol: ' \
            'echo\r\n' \
            'Sec-WebSocket-Version: 13\r\n\r\n'


sock.sendall(ws_encode(data='Hello, China!', opcode=OPCODE_TEXT))

# receive it back
response = ws_decode(sock.recv(1024))
print('--%s--' % response)


How to differentiate client TCP socket and client websocket using socket.io library?

By : user1997406
Date : March 29 2020, 07:55 AM
this one helps. This would take a bit of creative work because you'd have to wait until the first data arrives on a newly connected socket in order to discern what type of connection it must be. Both start with an incoming TCP connection.
The webSocket connections then follow the initial TCP connection with an http request that requests a protocol upgrade to the webSocket protocol. You can examine the first data that arrives on the newly connected TCP socket and check to see if the first data on the socket is indeed an http request of that form. If it is, then it's an incoming webSocket connection.

Does socket.io upgrade transport to websocket from polling ?

By : Vibha Rathi
Date : March 29 2020, 07:55 AM
I wish did fix the issue. Yes, it uses polling first and then upgrades to websocket. I'm sure if you connect with a browser or use wireshark you see the "HTTP/1.1 101 Switching Protocols" message from the server. Also you see in the logs "engine:ws" which implies the websocket is working. If you still are not sure you can also print out the type of transport (e.g. on disconnect). This is server side code (socket.io 1.1.0):
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