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"""
websocket - WebSocket client library for Python
Copyright (C) 2010 Hiroki Ohtani(liris)
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1335 USA
"""
import hashlib
import hmac
import os
import six
from ._cookiejar import SimpleCookieJar
from ._exceptions import *
from ._http import *
from ._logging import *
from ._socket import *
if six.PY3:
from base64 import encodebytes as base64encode
else:
from base64 import encodestring as base64encode
__all__ = ["handshake_response", "handshake"]
if hasattr(hmac, "compare_digest"):
compare_digest = hmac.compare_digest
else:
def compare_digest(s1, s2):
return s1 == s2
# websocket supported version.
VERSION = 13
CookieJar = SimpleCookieJar()
class handshake_response(object):
def __init__(self, status, headers, subprotocol):
self.status = status
self.headers = headers
self.subprotocol = subprotocol
CookieJar.add(headers.get("set-cookie"))
def handshake(sock, hostname, port, resource, **options):
headers, key = _get_handshake_headers(resource, hostname, port, options)
header_str = "\r\n".join(headers)
send(sock, header_str)
dump("request header", header_str)
status, resp = _get_resp_headers(sock)
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):
# IPv6 address
if ':' in hostname:
return '[' + hostname + ']'
return hostname
def _get_handshake_headers(resource, host, port, options):
headers = [
"GET %s HTTP/1.1" % resource,
"Upgrade: websocket",
"Connection: Upgrade"
]
if port == 80 or port == 443:
hostport = _pack_hostname(host)
else:
hostport = "%s:%d" % (_pack_hostname(host), port)
if "host" in options and options["host"] is not None:
headers.append("Host: %s" % options["host"])
else:
headers.append("Host: %s" % hostport)
if "suppress_origin" not in options or not options["suppress_origin"]:
if "origin" in options and options["origin"] is not None:
headers.append("Origin: %s" % options["origin"])
else:
headers.append("Origin: http://%s" % hostport)
key = _create_sec_websocket_key()
headers.append("Sec-WebSocket-Key: %s" % key)
headers.append("Sec-WebSocket-Version: %s" % VERSION)
subprotocols = options.get("subprotocols")
if subprotocols:
headers.append("Sec-WebSocket-Protocol: %s" % ",".join(subprotocols))
if "header" in options:
header = options["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: %s" % cookie)
headers.append("")
headers.append("")
return headers, key
def _get_resp_headers(sock, success_status=101):
status, resp_headers, status_message = read_headers(sock)
if status != success_status:
raise WebSocketBadStatusException("Handshake status %d %s", status, status_message)
return status, resp_headers
_HEADERS_TO_CHECK = {
"upgrade": "websocket",
"connection": "upgrade",
}
def _validate(headers, key, subprotocols):
subproto = None
for k, v in _HEADERS_TO_CHECK.items():
r = headers.get(k, None)
if not r:
return False, None
r = r.lower()
if v != r:
return False, None
if subprotocols:
subproto = headers.get("sec-websocket-protocol", None).lower()
if not subproto or subproto not in [s.lower() for s in subprotocols]:
error("Invalid subprotocol: " + str(subprotocols))
return False, None
result = headers.get("sec-websocket-accept", None)
if not result:
return False, None
result = result.lower()
if isinstance(result, six.text_type):
result = result.encode('utf-8')
value = (key + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11").encode('utf-8')
hashed = base64encode(hashlib.sha1(value).digest()).strip().lower()
success = compare_digest(hashed, result)
if success:
return True, subproto
else:
return False, None
def _create_sec_websocket_key():
randomness = os.urandom(16)
return base64encode(randomness).decode('utf-8').strip()
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