126 lines
4.7 KiB
Python
126 lines
4.7 KiB
Python
import base64
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import hashlib
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import json
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import logging
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logger = logging.getLogger(__name__)
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class WebSocketConnection(object):
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def __init__(self, handler, messageHandler):
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self.handler = handler
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self.messageHandler = messageHandler
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my_headers = self.handler.headers.items()
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my_header_keys = list(map(lambda x: x[0], my_headers))
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h_key_exists = lambda x: my_header_keys.count(x)
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h_value = lambda x: my_headers[my_header_keys.index(x)][1]
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if (
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(not h_key_exists("Upgrade"))
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or not (h_value("Upgrade") == "websocket")
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or (not h_key_exists("Sec-WebSocket-Key"))
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):
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raise WebSocketException
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ws_key = h_value("Sec-WebSocket-Key")
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shakey = hashlib.sha1()
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shakey.update("{ws_key}258EAFA5-E914-47DA-95CA-C5AB0DC85B11".format(ws_key=ws_key).encode())
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ws_key_toreturn = base64.b64encode(shakey.digest())
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self.handler.wfile.write(
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"HTTP/1.1 101 Switching Protocols\r\nUpgrade: websocket\r\nConnection: Upgrade\r\nSec-WebSocket-Accept: {0}\r\nCQ-CQ-de: HA5KFU\r\n\r\n".format(
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ws_key_toreturn.decode()
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).encode()
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)
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def get_header(self, size, opcode):
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ws_first_byte = 0b10000000 | (opcode & 0x0F)
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if size > 2 ** 16 - 1:
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# frame size can be increased up to 2^64 by setting the size to 127
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# anything beyond that would need to be segmented into frames. i don't really think we'll need more.
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return bytes(
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[
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ws_first_byte,
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127,
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(size >> 56) & 0xFF,
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(size >> 48) & 0xFF,
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(size >> 40) & 0xFF,
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(size >> 32) & 0xFF,
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(size >> 24) & 0xFF,
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(size >> 16) & 0xFF,
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(size >> 8) & 0xFF,
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size & 0xFF,
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]
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)
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elif size > 125:
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# up to 2^16 can be sent using the extended payload size field by putting the size to 126
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return bytes([ws_first_byte, 126, (size >> 8) & 0xFF, size & 0xFF])
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else:
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# 125 bytes binary message in a single unmasked frame
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return bytes([ws_first_byte, size])
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def send(self, data):
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# convenience
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if type(data) == dict:
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# allow_nan = False disallows NaN and Infinty to be encoded. Browser JSON will not parse them anyway.
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data = json.dumps(data, allow_nan=False)
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# string-type messages are sent as text frames
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if type(data) == str:
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header = self.get_header(len(data), 1)
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data_to_send = header + data.encode("utf-8")
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# anything else as binary
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else:
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header = self.get_header(len(data), 2)
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data_to_send = header + data
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written = self.handler.wfile.write(data_to_send)
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if written != len(data_to_send):
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logger.error("incomplete write! closing socket!")
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self.close()
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else:
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self.handler.wfile.flush()
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def read_loop(self):
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open = True
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while open:
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header = self.handler.rfile.read(2)
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opcode = header[0] & 0x0F
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length = header[1] & 0x7F
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mask = (header[1] & 0x80) >> 7
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if length == 126:
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header = self.handler.rfile.read(2)
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length = (header[0] << 8) + header[1]
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if mask:
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masking_key = self.handler.rfile.read(4)
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data = self.handler.rfile.read(length)
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if mask:
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data = bytes([b ^ masking_key[index % 4] for (index, b) in enumerate(data)])
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if opcode == 1:
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message = data.decode("utf-8")
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self.messageHandler.handleTextMessage(self, message)
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elif opcode == 2:
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self.messageHandler.handleBinaryMessage(self, data)
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elif opcode == 8:
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open = False
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self.messageHandler.handleClose(self)
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else:
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logger.warning("unsupported opcode: {0}".format(opcode))
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def close(self):
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try:
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header = self.get_header(0, 8)
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self.handler.wfile.write(header)
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self.handler.wfile.flush()
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except ValueError:
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logger.exception("ValueError while writing close frame:")
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except OSError:
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logger.exception("OSError while writing close frame:")
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try:
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self.handler.finish()
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self.handler.connection.close()
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except Exception:
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logger.exception("while closing connection:")
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class WebSocketException(Exception):
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pass
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