###############################################################################
#
# The MIT License (MIT)
#
# Copyright (c) typedef int GmbH
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
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# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
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# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
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###############################################################################
import zlib
from autobahn.util import public
from autobahn.websocket.compress_base import (
PerMessageCompress,
PerMessageCompressOffer,
PerMessageCompressOfferAccept,
PerMessageCompressResponse,
PerMessageCompressResponseAccept,
)
__all__ = (
"PerMessageDeflate",
"PerMessageDeflateMixin",
"PerMessageDeflateOffer",
"PerMessageDeflateOfferAccept",
"PerMessageDeflateResponse",
"PerMessageDeflateResponseAccept",
)
[docs]
class PerMessageDeflateMixin:
"""
Mixin class for this extension.
"""
[docs]
EXTENSION_NAME = "permessage-deflate"
"""
Name of this WebSocket extension.
"""
[docs]
WINDOW_SIZE_PERMISSIBLE_VALUES = [9, 10, 11, 12, 13, 14, 15]
"""
Permissible value for window size parameter.
Higher values use more memory, but produce smaller output. The default is 15.
"""
[docs]
MEM_LEVEL_PERMISSIBLE_VALUES = [1, 2, 3, 4, 5, 6, 7, 8, 9]
"""
Permissible value for memory level parameter.
Higher values use more memory, but are faster and produce smaller output. The default is 8.
"""
@public
[docs]
class PerMessageDeflateOffer(PerMessageCompressOffer, PerMessageDeflateMixin):
"""
Set of extension parameters for `permessage-deflate` WebSocket extension
offered by a client to a server.
"""
@classmethod
[docs]
def parse(cls, params):
"""
Parses a WebSocket extension offer for `permessage-deflate` provided by a client to a server.
:param params: Output from :func:`autobahn.websocket.WebSocketProtocol._parseExtensionsHeader`.
:type params: list
:returns: A new instance of :class:`autobahn.compress.PerMessageDeflateOffer`.
:rtype: obj
"""
# extension parameter defaults
accept_max_window_bits = False
accept_no_context_takeover = True
# accept_no_context_takeover = False # FIXME: this may change in draft
request_max_window_bits = 0
request_no_context_takeover = False
# verify/parse client ("client-to-server direction") parameters of permessage-deflate offer
for p in params:
if len(params[p]) > 1:
raise Exception(
f"multiple occurrence of extension parameter '{p}' for extension '{cls.EXTENSION_NAME}'"
)
val = params[p][0]
if p == "client_max_window_bits":
#
# see: https://tools.ietf.org/html/draft-ietf-hybi-permessage-compression-18
# 8.1.2.2. client_max_window_bits
# ".. This parameter has no value or a decimal integer value without
# leading zeroes between 9 to 15 inclusive ..""
# noinspection PySimplifyBooleanCheck
if val is not True:
try:
val = int(val)
except:
raise Exception(
f"illegal extension parameter value '{val}' for parameter '{p}' of extension '{cls.EXTENSION_NAME}'"
)
else:
if (
val
not in PerMessageDeflateMixin.WINDOW_SIZE_PERMISSIBLE_VALUES
):
raise Exception(
f"illegal extension parameter value '{val}' for parameter '{p}' of extension '{cls.EXTENSION_NAME}'"
)
else:
# FIXME (maybe): possibly forward/process the client hint!
# accept_max_window_bits = val
accept_max_window_bits = True
else:
accept_max_window_bits = True
elif p == "client_no_context_takeover":
# noinspection PySimplifyBooleanCheck
if val is not True:
raise Exception(
f"illegal extension parameter value '{val}' for parameter '{p}' of extension '{cls.EXTENSION_NAME}'"
)
else:
accept_no_context_takeover = True
elif p == "server_max_window_bits":
try:
val = int(val)
except:
raise Exception(
f"illegal extension parameter value '{val}' for parameter '{p}' of extension '{cls.EXTENSION_NAME}'"
)
else:
if val not in PerMessageDeflateMixin.WINDOW_SIZE_PERMISSIBLE_VALUES:
raise Exception(
f"illegal extension parameter value '{val}' for parameter '{p}' of extension '{cls.EXTENSION_NAME}'"
)
else:
request_max_window_bits = val
elif p == "server_no_context_takeover":
# noinspection PySimplifyBooleanCheck
if val is not True:
raise Exception(
f"illegal extension parameter value '{val}' for parameter '{p}' of extension '{cls.EXTENSION_NAME}'"
)
else:
request_no_context_takeover = True
else:
raise Exception(
f"illegal extension parameter '{p}' for extension '{cls.EXTENSION_NAME}'"
)
offer = cls(
accept_no_context_takeover,
accept_max_window_bits,
request_no_context_takeover,
request_max_window_bits,
)
return offer
def __init__(
self,
accept_no_context_takeover=True,
accept_max_window_bits=True,
request_no_context_takeover=False,
request_max_window_bits=0,
):
"""
:param accept_no_context_takeover: When ``True``, the client accepts the "no context takeover" feature.
:type accept_no_context_takeover: bool
:param accept_max_window_bits: When ``True``, the client accepts setting "max window size".
:type accept_max_window_bits: bool
:param request_no_context_takeover: When ``True``, the client request the "no context takeover" feature.
:type request_no_context_takeover: bool
:param request_max_window_bits: When non-zero, the client requests the given "max window size" (must be
and integer from the interval ``[9..15]``).
:type request_max_window_bits: int
"""
if type(accept_no_context_takeover) != bool:
raise Exception(
f"invalid type {type(accept_no_context_takeover)} for accept_no_context_takeover"
)
[docs]
self.accept_no_context_takeover = accept_no_context_takeover
if type(accept_max_window_bits) != bool:
raise Exception(
f"invalid type {type(accept_max_window_bits)} for accept_max_window_bits"
)
[docs]
self.accept_max_window_bits = accept_max_window_bits
if type(request_no_context_takeover) != bool:
raise Exception(
f"invalid type {type(request_no_context_takeover)} for request_no_context_takeover"
)
[docs]
self.request_no_context_takeover = request_no_context_takeover
if (
request_max_window_bits != 0
and request_max_window_bits not in self.WINDOW_SIZE_PERMISSIBLE_VALUES
):
raise Exception(
f"invalid value {request_max_window_bits} for request_max_window_bits - permissible values {self.WINDOW_SIZE_PERMISSIBLE_VALUES}"
)
[docs]
self.request_max_window_bits = request_max_window_bits
[docs]
def get_extension_string(self):
"""
Returns the WebSocket extension configuration string as sent to the server.
:returns: PMCE configuration string.
:rtype: str
"""
pmce_string = self.EXTENSION_NAME
if self.accept_no_context_takeover:
pmce_string += "; client_no_context_takeover"
if self.accept_max_window_bits:
pmce_string += "; client_max_window_bits"
if self.request_no_context_takeover:
pmce_string += "; server_no_context_takeover"
if self.request_max_window_bits != 0:
pmce_string += f"; server_max_window_bits={self.request_max_window_bits}"
return pmce_string
[docs]
def __json__(self):
"""
Returns a JSON serializable object representation.
:returns: JSON serializable representation.
:rtype: dict
"""
return {
"extension": self.EXTENSION_NAME,
"accept_no_context_takeover": self.accept_no_context_takeover,
"accept_max_window_bits": self.accept_max_window_bits,
"request_no_context_takeover": self.request_no_context_takeover,
"request_max_window_bits": self.request_max_window_bits,
}
[docs]
def __repr__(self):
"""
Returns Python object representation that can be eval'ed to reconstruct the object.
:returns: Python string representation.
:rtype: str
"""
return (
f"PerMessageDeflateOffer(accept_no_context_takeover = {self.accept_no_context_takeover}, accept_max_window_bits = {self.accept_max_window_bits}, request_no_context_takeover = {self.request_no_context_takeover}, request_max_window_bits = {self.request_max_window_bits})"
)
@public
[docs]
class PerMessageDeflateOfferAccept(
PerMessageCompressOfferAccept, PerMessageDeflateMixin
):
"""
Set of parameters with which to accept an `permessage-deflate` offer
from a client by a server.
"""
def __init__(
self,
offer,
request_no_context_takeover=False,
request_max_window_bits=0,
no_context_takeover=None,
window_bits=None,
mem_level=None,
max_message_size=None,
):
"""
:param offer: The offer being accepted.
:type offer: Instance of :class:`autobahn.compress.PerMessageDeflateOffer`.
:param request_no_context_takeover: When ``True``, the server requests the "no context takeover" feature.
:type request_no_context_takeover: bool
:param request_max_window_bits: When non-zero, the server requests the given "max window size" (must be
and integer from the interval ``[9..15]``).
:param request_max_window_bits: int
:param no_context_takeover: Override server ("server-to-client direction") context takeover (this must
be compatible with the offer).
:type no_context_takeover: bool
:param window_bits: Override server ("server-to-client direction") window size (this must be
compatible with the offer).
:type window_bits: int
:param mem_level: Set server ("server-to-client direction") memory level.
:type mem_level: int
"""
if not isinstance(offer, PerMessageDeflateOffer):
raise Exception(f"invalid type {type(offer)} for offer")
if type(request_no_context_takeover) != bool:
raise Exception(
f"invalid type {type(request_no_context_takeover)} for request_no_context_takeover"
)
if request_no_context_takeover and not offer.accept_no_context_takeover:
raise Exception(
f"invalid value {request_no_context_takeover} for request_no_context_takeover - feature unsupported by client"
)
[docs]
self.request_no_context_takeover = request_no_context_takeover
if (
request_max_window_bits != 0
and request_max_window_bits not in self.WINDOW_SIZE_PERMISSIBLE_VALUES
):
raise Exception(
f"invalid value {request_max_window_bits} for request_max_window_bits - permissible values {self.WINDOW_SIZE_PERMISSIBLE_VALUES}"
)
if request_max_window_bits != 0 and not offer.accept_max_window_bits:
raise Exception(
f"invalid value {request_max_window_bits} for request_max_window_bits - feature unsupported by client"
)
[docs]
self.request_max_window_bits = request_max_window_bits
if no_context_takeover is not None:
if type(no_context_takeover) != bool:
raise Exception(
f"invalid type {type(no_context_takeover)} for no_context_takeover"
)
if offer.request_no_context_takeover and not no_context_takeover:
raise Exception(
f"invalid value {no_context_takeover} for no_context_takeover - client requested feature"
)
[docs]
self.no_context_takeover = no_context_takeover
if window_bits is not None:
if window_bits not in self.WINDOW_SIZE_PERMISSIBLE_VALUES:
raise Exception(
f"invalid value {window_bits} for window_bits - permissible values {self.WINDOW_SIZE_PERMISSIBLE_VALUES}"
)
if (
offer.request_max_window_bits != 0
and window_bits > offer.request_max_window_bits
):
raise Exception(
f"invalid value {window_bits} for window_bits - client requested lower maximum value"
)
[docs]
self.window_bits = window_bits
if mem_level is not None:
if mem_level not in self.MEM_LEVEL_PERMISSIBLE_VALUES:
raise Exception(
f"invalid value {mem_level} for mem_level - permissible values {self.MEM_LEVEL_PERMISSIBLE_VALUES}"
)
[docs]
self.mem_level = mem_level
[docs]
self.max_message_size = max_message_size # clamp/check values..?
[docs]
def get_extension_string(self):
"""
Returns the WebSocket extension configuration string as sent to the server.
:returns: PMCE configuration string.
:rtype: str
"""
pmce_string = self.EXTENSION_NAME
if self.offer.request_no_context_takeover:
pmce_string += "; server_no_context_takeover"
if self.offer.request_max_window_bits != 0:
pmce_string += (
f"; server_max_window_bits={self.offer.request_max_window_bits}"
)
if self.request_no_context_takeover:
pmce_string += "; client_no_context_takeover"
if self.request_max_window_bits != 0:
pmce_string += f"; client_max_window_bits={self.request_max_window_bits}"
return pmce_string
[docs]
def __json__(self):
"""
Returns a JSON serializable object representation.
:returns: JSON serializable representation.
:rtype: dict
"""
return {
"extension": self.EXTENSION_NAME,
"offer": self.offer.__json__(),
"request_no_context_takeover": self.request_no_context_takeover,
"request_max_window_bits": self.request_max_window_bits,
"no_context_takeover": self.no_context_takeover,
"window_bits": self.window_bits,
"mem_level": self.mem_level,
"max_message_size": self.max_message_size,
}
[docs]
def __repr__(self):
"""
Returns Python object representation that can be eval'ed to reconstruct the object.
:returns: Python string representation.
:rtype: str
"""
return (
f"PerMessageDeflateOfferAccept(offer = {self.offer.__repr__()}, request_no_context_takeover = {self.request_no_context_takeover}, request_max_window_bits = {self.request_max_window_bits}, no_context_takeover = {self.no_context_takeover}, window_bits = {self.window_bits}, mem_level = {self.mem_level}, max_message_size = {self.max_message_size})"
)
@public
[docs]
class PerMessageDeflateResponse(PerMessageCompressResponse, PerMessageDeflateMixin):
"""
Set of parameters for `permessage-deflate` responded by server.
"""
@classmethod
[docs]
def parse(cls, params):
"""
Parses a WebSocket extension response for `permessage-deflate` provided by a server to a client.
:param params: Output from :func:`autobahn.websocket.WebSocketProtocol._parseExtensionsHeader`.
:type params: list
:returns: A new instance of :class:`autobahn.compress.PerMessageDeflateResponse`.
:rtype: obj
"""
client_max_window_bits = 0
client_no_context_takeover = False
server_max_window_bits = 0
server_no_context_takeover = False
for p in params:
if len(params[p]) > 1:
raise Exception(
f"multiple occurrence of extension parameter '{p}' for extension '{cls.EXTENSION_NAME}'"
)
val = params[p][0]
if p == "client_max_window_bits":
try:
val = int(val)
except:
raise Exception(
f"illegal extension parameter value '{val}' for parameter '{p}' of extension '{cls.EXTENSION_NAME}'"
)
else:
if val not in PerMessageDeflateMixin.WINDOW_SIZE_PERMISSIBLE_VALUES:
raise Exception(
f"illegal extension parameter value '{val}' for parameter '{p}' of extension '{cls.EXTENSION_NAME}'"
)
else:
client_max_window_bits = val
elif p == "client_no_context_takeover":
# noinspection PySimplifyBooleanCheck
if val is not True:
raise Exception(
f"illegal extension parameter value '{val}' for parameter '{p}' of extension '{cls.EXTENSION_NAME}'"
)
else:
client_no_context_takeover = True
elif p == "server_max_window_bits":
try:
val = int(val)
except:
raise Exception(
f"illegal extension parameter value '{val}' for parameter '{p}' of extension '{cls.EXTENSION_NAME}'"
)
else:
if val not in PerMessageDeflateMixin.WINDOW_SIZE_PERMISSIBLE_VALUES:
raise Exception(
f"illegal extension parameter value '{val}' for parameter '{p}' of extension '{cls.EXTENSION_NAME}'"
)
else:
server_max_window_bits = val
elif p == "server_no_context_takeover":
# noinspection PySimplifyBooleanCheck
if val is not True:
raise Exception(
f"illegal extension parameter value '{val}' for parameter '{p}' of extension '{cls.EXTENSION_NAME}'"
)
else:
server_no_context_takeover = True
else:
raise Exception(
f"illegal extension parameter '{p}' for extension '{cls.EXTENSION_NAME}'"
)
response = cls(
client_max_window_bits,
client_no_context_takeover,
server_max_window_bits,
server_no_context_takeover,
)
return response
def __init__(
self,
client_max_window_bits,
client_no_context_takeover,
server_max_window_bits,
server_no_context_takeover,
):
"""
:param client_max_window_bits: FIXME
:type client_max_window_bits: int
:param client_no_context_takeover: FIXME
:type client_no_context_takeover: bool
:param server_max_window_bits: FIXME
:type server_max_window_bits: int
:param server_no_context_takeover: FIXME
:type server_no_context_takeover: bool
"""
[docs]
self.client_max_window_bits = client_max_window_bits
[docs]
self.client_no_context_takeover = client_no_context_takeover
[docs]
self.server_max_window_bits = server_max_window_bits
[docs]
self.server_no_context_takeover = server_no_context_takeover
[docs]
def __json__(self):
"""
Returns a JSON serializable object representation.
:returns: JSON serializable representation.
:rtype: dict
"""
return {
"extension": self.EXTENSION_NAME,
"client_max_window_bits": self.client_max_window_bits,
"client_no_context_takeover": self.client_no_context_takeover,
"server_max_window_bits": self.server_max_window_bits,
"server_no_context_takeover": self.server_no_context_takeover,
}
[docs]
def __repr__(self):
"""
Returns Python object representation that can be eval'ed to reconstruct the object.
:returns: Python string representation.
:rtype: str
"""
return (
f"PerMessageDeflateResponse(client_max_window_bits = {self.client_max_window_bits}, client_no_context_takeover = {self.client_no_context_takeover}, server_max_window_bits = {self.server_max_window_bits}, server_no_context_takeover = {self.server_no_context_takeover})"
)
@public
[docs]
class PerMessageDeflateResponseAccept(
PerMessageCompressResponseAccept, PerMessageDeflateMixin
):
"""
Set of parameters with which to accept an `permessage-deflate` response
from a server by a client.
"""
def __init__(
self,
response,
no_context_takeover=None,
window_bits=None,
mem_level=None,
max_message_size=None,
):
"""
:param response: The response being accepted.
:type response: Instance of :class:`autobahn.compress.PerMessageDeflateResponse`.
:param no_context_takeover: Override client ("client-to-server direction") context takeover (this must be compatible with response).
:type no_context_takeover: bool
:param window_bits: Override client ("client-to-server direction") window size (this must be compatible with response).
:type window_bits: int
:param mem_level: Set client ("client-to-server direction") memory level.
:type mem_level: int
"""
if not isinstance(response, PerMessageDeflateResponse):
raise Exception(f"invalid type {type(response)} for response")
[docs]
self.response = response
if no_context_takeover is not None:
if type(no_context_takeover) != bool:
raise Exception(
f"invalid type {type(no_context_takeover)} for no_context_takeover"
)
if response.client_no_context_takeover and not no_context_takeover:
raise Exception(
f"invalid value {no_context_takeover} for no_context_takeover - server requested feature"
)
[docs]
self.no_context_takeover = no_context_takeover
if window_bits is not None:
if window_bits not in self.WINDOW_SIZE_PERMISSIBLE_VALUES:
raise Exception(
f"invalid value {window_bits} for window_bits - permissible values {self.WINDOW_SIZE_PERMISSIBLE_VALUES}"
)
if (
response.client_max_window_bits != 0
and window_bits > response.client_max_window_bits
):
raise Exception(
f"invalid value {window_bits} for window_bits - server requested lower maximum value"
)
[docs]
self.window_bits = window_bits
if mem_level is not None:
if mem_level not in self.MEM_LEVEL_PERMISSIBLE_VALUES:
raise Exception(
f"invalid value {mem_level} for mem_level - permissible values {self.MEM_LEVEL_PERMISSIBLE_VALUES}"
)
[docs]
self.mem_level = mem_level
[docs]
self.max_message_size = max_message_size
[docs]
def __json__(self):
"""
Returns a JSON serializable object representation.
:returns: JSON serializable representation.
:rtype: dict
"""
return {
"extension": self.EXTENSION_NAME,
"response": self.response.__json__(),
"no_context_takeover": self.no_context_takeover,
"window_bits": self.window_bits,
"mem_level": self.mem_level,
}
[docs]
def __repr__(self):
"""
Returns Python object representation that can be eval'ed to reconstruct the object.
:returns: Python string representation.
:rtype: str
"""
return (
f"PerMessageDeflateResponseAccept(response = {self.response.__repr__()}, no_context_takeover = {self.no_context_takeover}, window_bits = {self.window_bits}, mem_level = {self.mem_level})"
)
# noinspection PyArgumentList
[docs]
class PerMessageDeflate(PerMessageCompress, PerMessageDeflateMixin):
"""
`permessage-deflate` WebSocket extension processor.
"""
[docs]
DEFAULT_WINDOW_BITS = zlib.MAX_WBITS
@classmethod
[docs]
def create_from_response_accept(cls, is_server, accept):
# accept: instance of PerMessageDeflateResponseAccept
pmce = cls(
is_server,
accept.response.server_no_context_takeover,
(
accept.no_context_takeover
if accept.no_context_takeover is not None
else accept.response.client_no_context_takeover
),
accept.response.server_max_window_bits,
(
accept.window_bits
if accept.window_bits is not None
else accept.response.client_max_window_bits
),
accept.mem_level,
accept.max_message_size,
)
return pmce
@classmethod
[docs]
def create_from_offer_accept(cls, is_server, accept):
# accept: instance of PerMessageDeflateOfferAccept
pmce = cls(
is_server,
(
accept.no_context_takeover
if accept.no_context_takeover is not None
else accept.offer.request_no_context_takeover
),
accept.request_no_context_takeover,
(
accept.window_bits
if accept.window_bits is not None
else accept.offer.request_max_window_bits
),
accept.request_max_window_bits,
accept.mem_level,
accept.max_message_size,
)
return pmce
def __init__(
self,
is_server,
server_no_context_takeover,
client_no_context_takeover,
server_max_window_bits,
client_max_window_bits,
mem_level,
max_message_size=None,
):
[docs]
self._is_server = is_server
[docs]
self.server_no_context_takeover = server_no_context_takeover
[docs]
self.client_no_context_takeover = client_no_context_takeover
[docs]
self.server_max_window_bits = (
server_max_window_bits
if server_max_window_bits != 0
else self.DEFAULT_WINDOW_BITS
)
[docs]
self.client_max_window_bits = (
client_max_window_bits
if client_max_window_bits != 0
else self.DEFAULT_WINDOW_BITS
)
[docs]
self.mem_level = mem_level if mem_level else self.DEFAULT_MEM_LEVEL
[docs]
self.max_message_size = max_message_size # None means "no limit"
[docs]
self._compressor = None
[docs]
self._decompressor = None
[docs]
def __json__(self):
return {
"extension": self.EXTENSION_NAME,
"is_server": self._is_server,
"server_no_context_takeover": self.server_no_context_takeover,
"client_no_context_takeover": self.client_no_context_takeover,
"server_max_window_bits": self.server_max_window_bits,
"client_max_window_bits": self.client_max_window_bits,
"mem_level": self.mem_level,
}
[docs]
def __repr__(self):
return (
f"PerMessageDeflate(is_server = {self._is_server}, server_no_context_takeover = {self.server_no_context_takeover}, client_no_context_takeover = {self.client_no_context_takeover}, server_max_window_bits = {self.server_max_window_bits}, client_max_window_bits = {self.client_max_window_bits}, mem_level = {self.mem_level})"
)
[docs]
def start_compress_message(self):
# compressobj([level[, method[, wbits[, mem_level[, strategy]]]]])
# http://bugs.python.org/issue19278
# http://hg.python.org/cpython/rev/c54c8e71b79a
if self._is_server:
if self._compressor is None or self.server_no_context_takeover:
self._compressor = zlib.compressobj(
zlib.Z_DEFAULT_COMPRESSION,
zlib.DEFLATED,
-self.server_max_window_bits,
self.mem_level,
)
else:
if self._compressor is None or self.client_no_context_takeover:
self._compressor = zlib.compressobj(
zlib.Z_DEFAULT_COMPRESSION,
zlib.DEFLATED,
-self.client_max_window_bits,
self.mem_level,
)
[docs]
def compress_message_data(self, data):
return self._compressor.compress(data)
[docs]
def end_compress_message(self):
data = self._compressor.flush(zlib.Z_SYNC_FLUSH)
return data[:-4]
[docs]
def start_decompress_message(self):
if self._is_server:
if self._decompressor is None or self.client_no_context_takeover:
self._decompressor = zlib.decompressobj(-self.client_max_window_bits)
else:
if self._decompressor is None or self.server_no_context_takeover:
self._decompressor = zlib.decompressobj(-self.server_max_window_bits)
[docs]
def decompress_message_data(self, data):
if self.max_message_size is not None:
return self._decompressor.decompress(data, self.max_message_size)
return self._decompressor.decompress(data)
[docs]
def end_decompress_message(self):
# Eat stripped LEN and NLEN field of a non-compressed block added
# for Z_SYNC_FLUSH.
self._decompressor.decompress(b"\x00\x00\xff\xff")