securedWebsocketCore.py 文件源码

def _handShake(self, hostAddress, portNumber):
        CRLF = "\r\n"
        hostAddressChunks = hostAddress.split('.')  # <randomString>.iot.<region>.amazonaws.com
        region = hostAddressChunks[2]  # XXXX.<region>.beta
        signedURL = self._sigV4Handler.createWebsocketEndpoint(hostAddress, portNumber, region, "GET", "iotdata", "/mqtt")
        if signedURL == "":
            raise wssNoKeyInEnvironmentError()
        # 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()
        SecWebSocketKey = "sec-websocket-key: " + rawSecWebSocketKey + 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
        self._sslSocket.write(Method + Host + Connection + Upgrade + SecWebSocketVersion + SecWebSocketProtocol + SecWebSocketExtensions + SecWebSocketKey + CRLF)
        # Read it back (Non-blocking socket)
        # Do we need a timeout here?
        wssHandshakeResponse = ""
        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:
                    pass
        # Verify response
        if not self._verifyWSSResponse(wssHandshakeResponse, rawSecWebSocketKey):
            raise wssHandShakeError()
        else:
            pass

    # Used to create a single wss frame
    # Assume that the maximum length of a MQTT packet never exceeds the maximum length
    # for a wss frame. Therefore, the FIN bit for the encoded frame will always be 1.
    # Frames are encoded as BINARY frames.