192 lines
6 KiB
Python
192 lines
6 KiB
Python
"""
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websocket - WebSocket client library for Python
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Copyright (C) 2010 Hiroki Ohtani(liris)
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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"""
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import hashlib
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import hmac
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import os
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from base64 import encodebytes as base64encode
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from http import client as HTTPStatus
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from ._cookiejar import SimpleCookieJar
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from ._exceptions import *
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from ._http import *
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from ._logging import *
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from ._socket import *
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__all__ = ["handshake_response", "handshake", "SUPPORTED_REDIRECT_STATUSES"]
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# websocket supported version.
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VERSION = 13
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SUPPORTED_REDIRECT_STATUSES = (HTTPStatus.MOVED_PERMANENTLY, HTTPStatus.FOUND, HTTPStatus.SEE_OTHER,)
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SUCCESS_STATUSES = SUPPORTED_REDIRECT_STATUSES + (HTTPStatus.SWITCHING_PROTOCOLS,)
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CookieJar = SimpleCookieJar()
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class handshake_response(object):
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def __init__(self, status, headers, subprotocol):
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self.status = status
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self.headers = headers
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self.subprotocol = subprotocol
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CookieJar.add(headers.get("set-cookie"))
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def handshake(sock, hostname, port, resource, **options):
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headers, key = _get_handshake_headers(resource, hostname, port, options)
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header_str = "\r\n".join(headers)
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send(sock, header_str)
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dump("request header", header_str)
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status, resp = _get_resp_headers(sock)
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if status in SUPPORTED_REDIRECT_STATUSES:
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return handshake_response(status, resp, None)
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success, subproto = _validate(resp, key, options.get("subprotocols"))
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if not success:
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raise WebSocketException("Invalid WebSocket Header")
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return handshake_response(status, resp, subproto)
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def _pack_hostname(hostname):
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# IPv6 address
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if ':' in hostname:
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return '[' + hostname + ']'
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return hostname
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def _get_handshake_headers(resource, host, port, options):
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headers = [
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"GET %s HTTP/1.1" % resource,
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"Upgrade: websocket"
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]
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if port == 80 or port == 443:
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hostport = _pack_hostname(host)
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else:
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hostport = "%s:%d" % (_pack_hostname(host), port)
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if "host" in options and options["host"] is not None:
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headers.append("Host: %s" % options["host"])
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else:
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headers.append("Host: %s" % hostport)
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if "suppress_origin" not in options or not options["suppress_origin"]:
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if "origin" in options and options["origin"] is not None:
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headers.append("Origin: %s" % options["origin"])
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else:
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headers.append("Origin: http://%s" % hostport)
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key = _create_sec_websocket_key()
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# Append Sec-WebSocket-Key & Sec-WebSocket-Version if not manually specified
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if 'header' not in options or 'Sec-WebSocket-Key' not in options['header']:
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key = _create_sec_websocket_key()
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headers.append("Sec-WebSocket-Key: %s" % key)
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else:
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key = options['header']['Sec-WebSocket-Key']
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if 'header' not in options or 'Sec-WebSocket-Version' not in options['header']:
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headers.append("Sec-WebSocket-Version: %s" % VERSION)
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if 'connection' not in options or options['connection'] is None:
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headers.append('Connection: Upgrade')
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else:
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headers.append(options['connection'])
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subprotocols = options.get("subprotocols")
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if subprotocols:
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headers.append("Sec-WebSocket-Protocol: %s" % ",".join(subprotocols))
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if "header" in options:
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header = options["header"]
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if isinstance(header, dict):
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header = [
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": ".join([k, v])
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for k, v in header.items()
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if v is not None
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]
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headers.extend(header)
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server_cookie = CookieJar.get(host)
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client_cookie = options.get("cookie", None)
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cookie = "; ".join(filter(None, [server_cookie, client_cookie]))
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if cookie:
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headers.append("Cookie: %s" % cookie)
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headers.append("")
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headers.append("")
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return headers, key
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def _get_resp_headers(sock, success_statuses=SUCCESS_STATUSES):
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status, resp_headers, status_message = read_headers(sock)
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if status not in success_statuses:
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raise WebSocketBadStatusException("Handshake status %d %s", status, status_message, resp_headers)
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return status, resp_headers
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_HEADERS_TO_CHECK = {
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"upgrade": "websocket",
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"connection": "upgrade",
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}
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def _validate(headers, key, subprotocols):
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subproto = None
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for k, v in _HEADERS_TO_CHECK.items():
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r = headers.get(k, None)
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if not r:
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return False, None
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r = [x.strip().lower() for x in r.split(',')]
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if v not in r:
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return False, None
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if subprotocols:
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subproto = headers.get("sec-websocket-protocol", None)
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if not subproto or subproto.lower() not in [s.lower() for s in subprotocols]:
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error("Invalid subprotocol: " + str(subprotocols))
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return False, None
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subproto = subproto.lower()
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result = headers.get("sec-websocket-accept", None)
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if not result:
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return False, None
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result = result.lower()
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if isinstance(result, str):
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result = result.encode('utf-8')
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value = (key + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11").encode('utf-8')
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hashed = base64encode(hashlib.sha1(value).digest()).strip().lower()
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success = hmac.compare_digest(hashed, result)
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if success:
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return True, subproto
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else:
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return False, None
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def _create_sec_websocket_key():
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randomness = os.urandom(16)
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return base64encode(randomness).decode('utf-8').strip()
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