def _handShake()

in AWSIoTPythonSDK/core/protocol/connection/cores.py [0:0]

• 36 lines of code
• 9 McCabe index (conditional complexity)

    def _handShake(self, hostAddress, portNumber):
        CRLF = "\r\n"
        IOT_ENDPOINT_PATTERN = r"^[0-9a-zA-Z]+(\.ats|-ats)?\.iot\.(.*)\.amazonaws\..*"
        matched = re.compile(IOT_ENDPOINT_PATTERN, re.IGNORECASE).match(hostAddress)
        if not matched:
            raise ClientError("Invalid endpoint pattern for wss: %s" % hostAddress)
        region = matched.group(2)
        signedURL = self._sigV4Handler.createWebsocketEndpoint(hostAddress, portNumber, region, "GET", "iotdata", "/mqtt")
        # Now we got a signedURL
        path = signedURL[signedURL.index("/mqtt"):]
        # Assemble HTTP request headers
        Method = "GET " + path + " HTTP/1.1" + CRLF
        Host = "Host: " + hostAddress + CRLF
        Connection = "Connection: " + "Upgrade" + CRLF
        Upgrade = "Upgrade: " + "websocket" + CRLF
        secWebSocketVersion = "Sec-WebSocket-Version: " + "13" + CRLF
        rawSecWebSocketKey = self._generateWSSKey()  # Bytes
        secWebSocketKey = "sec-websocket-key: " + rawSecWebSocketKey.decode('utf-8') + CRLF  # Should be randomly generated...
        secWebSocketProtocol = "Sec-WebSocket-Protocol: " + "mqttv3.1" + CRLF
        secWebSocketExtensions = "Sec-WebSocket-Extensions: " + "permessage-deflate; client_max_window_bits" + CRLF
        # Send the HTTP request
        # Ensure that we are sending bytes, not by any chance unicode string
        handshakeBytes = Method + Host + Connection + Upgrade + secWebSocketVersion + secWebSocketProtocol + secWebSocketExtensions + secWebSocketKey + CRLF
        handshakeBytes = handshakeBytes.encode('utf-8')
        self._sslSocket.write(handshakeBytes)
        # Read it back (Non-blocking socket)
        timeStart = time.time()
        wssHandshakeResponse = bytearray()
        while len(wssHandshakeResponse) == 0:
            try:
                wssHandshakeResponse += self._sslSocket.read(1024)  # Response is always less than 1024 bytes
            except socket.error as err:
                if err.errno == ssl.SSL_ERROR_WANT_READ or err.errno == ssl.SSL_ERROR_WANT_WRITE:
                    if time.time() - timeStart > self._getTimeoutSec():
                        raise err  # We make sure that reconnect gets retried in Paho upon a wss reconnect response timeout
                else:
                    raise err
        # Verify response
        # Now both wssHandshakeResponse and rawSecWebSocketKey are byte strings
        if not self._verifyWSSResponse(wssHandshakeResponse, rawSecWebSocketKey):
            raise wssHandShakeError()
        else:
            pass