def do_handshake(method, headers, transport):
"""Prepare WebSocket handshake. It return http response code,
response headers, websocket parser, websocket writer. It does not
perform any IO."""
# WebSocket accepts only GET
if method.upper() != 'GET':
raise errors.HttpErrorException(405, headers=(('Allow', 'GET'),))
headers = dict(((hdr, val) for hdr, val in headers if hdr in WS_HDRS))
if 'websocket' != headers.get('UPGRADE', '').lower().strip():
raise errors.HttpBadRequest(
'No WebSocket UPGRADE hdr: {}\n'
'Can "Upgrade" only to "WebSocket".'.format(
headers.get('UPGRADE')))
if 'upgrade' not in headers.get('CONNECTION', '').lower():
raise errors.HttpBadRequest(
'No CONNECTION upgrade hdr: {}'.format(
headers.get('CONNECTION')))
# check supported version
version = headers.get('SEC-WEBSOCKET-VERSION')
if version not in ('13', '8', '7'):
raise errors.HttpBadRequest(
'Unsupported version: {}'.format(version))
# check client handshake for validity
key = headers.get('SEC-WEBSOCKET-KEY')
try:
if not key or len(base64.b64decode(key)) != 16:
raise errors.HttpBadRequest(
'Handshake error: {!r}'.format(key))
except binascii.Error:
raise errors.HttpBadRequest(
'Handshake error: {!r}'.format(key)) from None
# response code, headers, parser, writer
return (101,
(('UPGRADE', 'websocket'),
('CONNECTION', 'upgrade'),
('TRANSFER-ENCODING', 'chunked'),
('SEC-WEBSOCKET-ACCEPT', base64.b64encode(
hashlib.sha1(key.encode() + WS_KEY).digest()).decode())),
WebSocketParser,
WebSocketWriter(transport))
def do_handshake(method,
headers,
transport,
protocols=(),
write_buffer_size=DEFAULT_LIMIT):
"""Prepare WebSocket handshake.
It return HTTP response code, response headers, websocket parser,
websocket writer. It does not perform any IO.
`protocols` is a sequence of known protocols. On successful handshake,
the returned response headers contain the first protocol in this list
which the server also knows.
`write_buffer_size` max size of write buffer before `drain()` get called.
"""
# WebSocket accepts only GET
if method.upper() != hdrs.METH_GET:
raise errors.HttpProcessingError(code=405,
headers=((hdrs.ALLOW,
hdrs.METH_GET), ))
if 'websocket' != headers.get(hdrs.UPGRADE, '').lower().strip():
raise errors.HttpBadRequest(
message='No WebSocket UPGRADE hdr: {}\n Can '
'"Upgrade" only to "WebSocket".'.format(headers.get(hdrs.UPGRADE)))
if 'upgrade' not in headers.get(hdrs.CONNECTION, '').lower():
raise errors.HttpBadRequest(
message='No CONNECTION upgrade hdr: {}'.format(
headers.get(hdrs.CONNECTION)))
# find common sub-protocol between client and server
protocol = None
if hdrs.SEC_WEBSOCKET_PROTOCOL in headers:
req_protocols = [
str(proto.strip())
for proto in headers[hdrs.SEC_WEBSOCKET_PROTOCOL].split(',')
]
for proto in req_protocols:
if proto in protocols:
protocol = proto
break
else:
# No overlap found: Return no protocol as per spec
ws_logger.warning(
'Client protocols %r don’t overlap server-known ones %r',
req_protocols, protocols)
# check supported version
version = headers.get(hdrs.SEC_WEBSOCKET_VERSION, '')
if version not in ('13', '8', '7'):
raise errors.HttpBadRequest(
message='Unsupported version: {}'.format(version),
headers=((hdrs.SEC_WEBSOCKET_VERSION, '13'), ))
# check client handshake for validity
key = headers.get(hdrs.SEC_WEBSOCKET_KEY)
try:
if not key or len(base64.b64decode(key)) != 16:
raise errors.HttpBadRequest(
message='Handshake error: {!r}'.format(key))
except binascii.Error:
raise errors.HttpBadRequest(
message='Handshake error: {!r}'.format(key)) from None
response_headers = [
(hdrs.UPGRADE, 'websocket'), (hdrs.CONNECTION, 'upgrade'),
(hdrs.TRANSFER_ENCODING, 'chunked'),
(hdrs.SEC_WEBSOCKET_ACCEPT,
base64.b64encode(hashlib.sha1(key.encode() +
WS_KEY).digest()).decode())
]
if protocol:
response_headers.append((hdrs.SEC_WEBSOCKET_PROTOCOL, protocol))
# response code, headers, parser, writer, protocol
return (101, response_headers, WebSocketParser,
WebSocketWriter(transport, limit=write_buffer_size), protocol)
def do_handshake(method, headers, transport, protocols=()):
"""Prepare WebSocket handshake. It return http response code,
response headers, websocket parser, websocket writer. It does not
perform any IO.
`protocols` is a sequence of known protocols. On successful handshake,
the returned response headers contain the first protocol in this list
which the server also knows."""
# WebSocket accepts only GET
if method.upper() != 'GET':
raise errors.HttpProcessingError(code=405,
headers=(('Allow', 'GET'), ))
if 'websocket' != headers.get('UPGRADE', '').lower().strip():
raise errors.HttpBadRequest(message='No WebSocket UPGRADE hdr: {}\n'
'Can "Upgrade" only to "WebSocket".'.
format(headers.get('UPGRADE')))
if 'upgrade' not in headers.get('CONNECTION', '').lower():
raise errors.HttpBadRequest(
message='No CONNECTION upgrade hdr: {}'.format(
headers.get('CONNECTION')))
# find common sub-protocol between client and server
protocol = None
if 'SEC-WEBSOCKET-PROTOCOL' in headers:
req_protocols = [
str(proto.strip())
for proto in headers['SEC-WEBSOCKET-PROTOCOL'].split(',')
]
for proto in req_protocols:
if proto in protocols:
protocol = proto
break
else:
# No overlap found: Return no protocol as per spec
ws_logger.warning(
'Client protocols %r don’t overlap server-known ones %r',
protocols, req_protocols)
# check supported version
version = headers.get('SEC-WEBSOCKET-VERSION')
if version not in ('13', '8', '7'):
raise errors.HttpBadRequest(
message='Unsupported version: {}'.format(version),
headers=(('Sec-WebSocket-Version', '13', '8', '7'), ))
# check client handshake for validity
key = headers.get('SEC-WEBSOCKET-KEY')
try:
if not key or len(base64.b64decode(key)) != 16:
raise errors.HttpBadRequest(
message='Handshake error: {!r}'.format(key))
except binascii.Error:
raise errors.HttpBadRequest(
message='Handshake error: {!r}'.format(key)) from None
response_headers = [
('UPGRADE', 'websocket'), ('CONNECTION', 'upgrade'),
('TRANSFER-ENCODING', 'chunked'),
('SEC-WEBSOCKET-ACCEPT',
base64.b64encode(hashlib.sha1(key.encode() +
WS_KEY).digest()).decode())
]
if protocol:
response_headers.append(('SEC-WEBSOCKET-PROTOCOL', protocol))
# response code, headers, parser, writer, protocol
return (101, response_headers, WebSocketParser, WebSocketWriter(transport),
protocol)
