1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
|
"""
_handshake.py
websocket - WebSocket client library for Python
Copyright 2023 engn33r
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
"""
import hashlib
import hmac
import os
from base64 import encodebytes as base64encode
from http import client as HTTPStatus
from ._cookiejar import SimpleCookieJar
from ._exceptions import *
from ._http import *
from ._logging import *
from ._socket import *
__all__ = ["handshake_response", "handshake", "SUPPORTED_REDIRECT_STATUSES"]
# websocket supported version.
VERSION = 13
SUPPORTED_REDIRECT_STATUSES = (HTTPStatus.MOVED_PERMANENTLY, HTTPStatus.FOUND, HTTPStatus.SEE_OTHER, HTTPStatus.TEMPORARY_REDIRECT, HTTPStatus.PERMANENT_REDIRECT)
SUCCESS_STATUSES = SUPPORTED_REDIRECT_STATUSES + (HTTPStatus.SWITCHING_PROTOCOLS,)
CookieJar = SimpleCookieJar()
class handshake_response:
def __init__(self, status: int, headers: dict, subprotocol):
self.status = status
self.headers = headers
self.subprotocol = subprotocol
CookieJar.add(headers.get("set-cookie"))
def handshake(sock, url: str, hostname: str, port: int, resource: str, **options):
headers, key = _get_handshake_headers(resource, url, hostname, port, options)
header_str = "\r\n".join(headers)
send(sock, header_str)
dump("request header", header_str)
status, resp = _get_resp_headers(sock)
if status in SUPPORTED_REDIRECT_STATUSES:
return handshake_response(status, resp, None)
success, subproto = _validate(resp, key, options.get("subprotocols"))
if not success:
raise WebSocketException("Invalid WebSocket Header")
return handshake_response(status, resp, subproto)
def _pack_hostname(hostname: str) -> str:
# IPv6 address
if ':' in hostname:
return '[' + hostname + ']'
return hostname
def _get_handshake_headers(resource: str, url: str, host: str, port: int, options: dict):
headers = [
"GET {resource} HTTP/1.1".format(resource=resource),
"Upgrade: websocket"
]
if port == 80 or port == 443:
hostport = _pack_hostname(host)
else:
hostport = "{h}:{p}".format(h=_pack_hostname(host), p=port)
if options.get("host"):
headers.append("Host: {h}".format(h=options["host"]))
else:
headers.append("Host: {hp}".format(hp=hostport))
# scheme indicates whether http or https is used in Origin
# The same approach is used in parse_url of _url.py to set default port
scheme, url = url.split(":", 1)
if not options.get("suppress_origin"):
if "origin" in options and options["origin"] is not None:
headers.append("Origin: {origin}".format(origin=options["origin"]))
elif scheme == "wss":
headers.append("Origin: https://{hp}".format(hp=hostport))
else:
headers.append("Origin: http://{hp}".format(hp=hostport))
key = _create_sec_websocket_key()
# Append Sec-WebSocket-Key & Sec-WebSocket-Version if not manually specified
if not options.get('header') or 'Sec-WebSocket-Key' not in options['header']:
headers.append("Sec-WebSocket-Key: {key}".format(key=key))
else:
key = options['header']['Sec-WebSocket-Key']
if not options.get('header') or 'Sec-WebSocket-Version' not in options['header']:
headers.append("Sec-WebSocket-Version: {version}".format(version=VERSION))
if not options.get('connection'):
headers.append('Connection: Upgrade')
else:
headers.append(options['connection'])
subprotocols = options.get("subprotocols")
if subprotocols:
headers.append("Sec-WebSocket-Protocol: {protocols}".format(protocols=",".join(subprotocols)))
header = options.get("header")
if header:
if isinstance(header, dict):
header = [
": ".join([k, v])
for k, v in header.items()
if v is not None
]
headers.extend(header)
server_cookie = CookieJar.get(host)
client_cookie = options.get("cookie", None)
cookie = "; ".join(filter(None, [server_cookie, client_cookie]))
if cookie:
headers.append("Cookie: {cookie}".format(cookie=cookie))
headers.extend(("", ""))
return headers, key
def _get_resp_headers(sock, success_statuses: tuple = SUCCESS_STATUSES) -> tuple:
status, resp_headers, status_message = read_headers(sock)
if status not in success_statuses:
content_len = resp_headers.get('content-length')
if content_len:
response_body = sock.recv(int(content_len)) # read the body of the HTTP error message response and include it in the exception
else:
response_body = None
raise WebSocketBadStatusException("Handshake status {status} {message} -+-+- {headers} -+-+- {body}".format(status=status, message=status_message, headers=resp_headers, body=response_body), status, status_message, resp_headers, response_body)
return status, resp_headers
_HEADERS_TO_CHECK = {
"upgrade": "websocket",
"connection": "upgrade",
}
def _validate(headers, key: str, subprotocols):
subproto = None
for k, v in _HEADERS_TO_CHECK.items():
r = headers.get(k, None)
if not r:
return False, None
r = [x.strip().lower() for x in r.split(',')]
if v not in r:
return False, None
if subprotocols:
subproto = headers.get("sec-websocket-protocol", None)
if not subproto or subproto.lower() not in [s.lower() for s in subprotocols]:
error("Invalid subprotocol: " + str(subprotocols))
return False, None
subproto = subproto.lower()
result = headers.get("sec-websocket-accept", None)
if not result:
return False, None
result = result.lower()
if isinstance(result, str):
result = result.encode('utf-8')
value = (key + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11").encode('utf-8')
hashed = base64encode(hashlib.sha1(value).digest()).strip().lower()
success = hmac.compare_digest(hashed, result)
if success:
return True, subproto
else:
return False, None
def _create_sec_websocket_key() -> str:
randomness = os.urandom(16)
return base64encode(randomness).decode('utf-8').strip()
|
