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- ###############################################################################
- #
- # 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
- # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- # copies of the Software, and to permit persons to whom the Software is
- # furnished to do so, subject to the following conditions:
- #
- # The above copyright notice and this permission notice shall be included in
- # all copies or substantial portions of the Software.
- #
- # 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
- # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- # 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.
- #
- ###############################################################################
-
- import zlib
-
- from autobahn.util import public
- from autobahn.websocket.compress_base import PerMessageCompressOffer, \
- PerMessageCompressOfferAccept, \
- PerMessageCompressResponse, \
- PerMessageCompressResponseAccept, \
- PerMessageCompress
-
- __all__ = (
- 'PerMessageDeflateMixin',
- 'PerMessageDeflateOffer',
- 'PerMessageDeflateOfferAccept',
- 'PerMessageDeflateResponse',
- 'PerMessageDeflateResponseAccept',
- 'PerMessageDeflate',
- )
-
-
- class PerMessageDeflateMixin(object):
- """
- Mixin class for this extension.
- """
-
- EXTENSION_NAME = "permessage-deflate"
- """
- Name of this WebSocket extension.
- """
-
- 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.
- """
-
- 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
- class PerMessageDeflateOffer(PerMessageCompressOffer, PerMessageDeflateMixin):
- """
- Set of extension parameters for `permessage-deflate` WebSocket extension
- offered by a client to a server.
- """
-
- @classmethod
- 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("multiple occurrence of extension parameter '%s' for extension '%s'" % (p, 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("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
- else:
- if val not in PerMessageDeflateMixin.WINDOW_SIZE_PERMISSIBLE_VALUES:
- raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, 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("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
- else:
- accept_no_context_takeover = True
-
- elif p == 'server_max_window_bits':
- try:
- val = int(val)
- except:
- raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
- else:
- if val not in PerMessageDeflateMixin.WINDOW_SIZE_PERMISSIBLE_VALUES:
- raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
- else:
- request_max_window_bits = val
-
- elif p == 'server_no_context_takeover':
- # noinspection PySimplifyBooleanCheck
- if val is not True:
- raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
- else:
- request_no_context_takeover = True
-
- else:
- raise Exception("illegal extension parameter '%s' for extension '%s'" % (p, 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("invalid type %s for accept_no_context_takeover" % type(accept_no_context_takeover))
-
- self.accept_no_context_takeover = accept_no_context_takeover
-
- if type(accept_max_window_bits) != bool:
- raise Exception("invalid type %s for accept_max_window_bits" % type(accept_max_window_bits))
-
- self.accept_max_window_bits = accept_max_window_bits
-
- if type(request_no_context_takeover) != bool:
- raise Exception("invalid type %s for request_no_context_takeover" % type(request_no_context_takeover))
-
- 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("invalid value %s for request_max_window_bits - permissible values %s" % (request_max_window_bits, self.WINDOW_SIZE_PERMISSIBLE_VALUES))
-
- self.request_max_window_bits = request_max_window_bits
-
- 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 += "; server_max_window_bits=%d" % self.request_max_window_bits
- return pmce_string
-
- 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}
-
- def __repr__(self):
- """
- Returns Python object representation that can be eval'ed to reconstruct the object.
-
- :returns: Python string representation.
- :rtype: str
- """
- return "PerMessageDeflateOffer(accept_no_context_takeover = %s, accept_max_window_bits = %s, request_no_context_takeover = %s, request_max_window_bits = %s)" % (self.accept_no_context_takeover, self.accept_max_window_bits, self.request_no_context_takeover, self.request_max_window_bits)
-
-
- @public
- 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("invalid type %s for offer" % type(offer))
-
- self.offer = offer
-
- if type(request_no_context_takeover) != bool:
- raise Exception("invalid type %s for request_no_context_takeover" % type(request_no_context_takeover))
-
- if request_no_context_takeover and not offer.accept_no_context_takeover:
- raise Exception("invalid value %s for request_no_context_takeover - feature unsupported by client" % request_no_context_takeover)
-
- 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("invalid value %s for request_max_window_bits - permissible values %s" % (request_max_window_bits, self.WINDOW_SIZE_PERMISSIBLE_VALUES))
-
- if request_max_window_bits != 0 and not offer.accept_max_window_bits:
- raise Exception("invalid value %s for request_max_window_bits - feature unsupported by client" % request_max_window_bits)
-
- self.request_max_window_bits = request_max_window_bits
-
- if no_context_takeover is not None:
- if type(no_context_takeover) != bool:
- raise Exception("invalid type %s for no_context_takeover" % type(no_context_takeover))
-
- if offer.request_no_context_takeover and not no_context_takeover:
- raise Exception("invalid value %s for no_context_takeover - client requested feature" % no_context_takeover)
-
- 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("invalid value %s for window_bits - permissible values %s" % (window_bits, self.WINDOW_SIZE_PERMISSIBLE_VALUES))
-
- if offer.request_max_window_bits != 0 and window_bits > offer.request_max_window_bits:
- raise Exception("invalid value %s for window_bits - client requested lower maximum value" % window_bits)
-
- self.window_bits = window_bits
-
- if mem_level is not None:
- if mem_level not in self.MEM_LEVEL_PERMISSIBLE_VALUES:
- raise Exception("invalid value %s for mem_level - permissible values %s" % (mem_level, self.MEM_LEVEL_PERMISSIBLE_VALUES))
-
- self.mem_level = mem_level
- self.max_message_size = max_message_size # clamp/check values..?
-
- 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 += "; server_max_window_bits=%d" % 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 += "; client_max_window_bits=%d" % self.request_max_window_bits
- return pmce_string
-
- 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,
- }
-
- def __repr__(self):
- """
- Returns Python object representation that can be eval'ed to reconstruct the object.
-
- :returns: Python string representation.
- :rtype: str
- """
- return "PerMessageDeflateOfferAccept(offer = %s, request_no_context_takeover = %s, request_max_window_bits = %s, no_context_takeover = %s, window_bits = %s, mem_level = %s, max_message_size = %s)" % (self.offer.__repr__(), self.request_no_context_takeover, self.request_max_window_bits, self.no_context_takeover, self.window_bits, self.mem_level, self.max_message_size)
-
-
- @public
- class PerMessageDeflateResponse(PerMessageCompressResponse, PerMessageDeflateMixin):
- """
- Set of parameters for `permessage-deflate` responded by server.
- """
-
- @classmethod
- 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("multiple occurrence of extension parameter '%s' for extension '%s'" % (p, cls.EXTENSION_NAME))
-
- val = params[p][0]
-
- if p == 'client_max_window_bits':
- try:
- val = int(val)
- except:
- raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
- else:
- if val not in PerMessageDeflateMixin.WINDOW_SIZE_PERMISSIBLE_VALUES:
- raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
- else:
- client_max_window_bits = val
-
- elif p == 'client_no_context_takeover':
- # noinspection PySimplifyBooleanCheck
- if val is not True:
- raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
- else:
- client_no_context_takeover = True
-
- elif p == 'server_max_window_bits':
- try:
- val = int(val)
- except:
- raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
- else:
- if val not in PerMessageDeflateMixin.WINDOW_SIZE_PERMISSIBLE_VALUES:
- raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
- else:
- server_max_window_bits = val
-
- elif p == 'server_no_context_takeover':
- # noinspection PySimplifyBooleanCheck
- if val is not True:
- raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
- else:
- server_no_context_takeover = True
-
- else:
- raise Exception("illegal extension parameter '%s' for extension '%s'" % (p, 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
- """
- self.client_max_window_bits = client_max_window_bits
- self.client_no_context_takeover = client_no_context_takeover
- self.server_max_window_bits = server_max_window_bits
- self.server_no_context_takeover = server_no_context_takeover
-
- 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}
-
- def __repr__(self):
- """
- Returns Python object representation that can be eval'ed to reconstruct the object.
-
- :returns: Python string representation.
- :rtype: str
- """
- return "PerMessageDeflateResponse(client_max_window_bits = %s, client_no_context_takeover = %s, server_max_window_bits = %s, server_no_context_takeover = %s)" % (self.client_max_window_bits, self.client_no_context_takeover, self.server_max_window_bits, self.server_no_context_takeover)
-
-
- @public
- 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("invalid type %s for response" % type(response))
-
- self.response = response
-
- if no_context_takeover is not None:
- if type(no_context_takeover) != bool:
- raise Exception("invalid type %s for no_context_takeover" % type(no_context_takeover))
-
- if response.client_no_context_takeover and not no_context_takeover:
- raise Exception("invalid value %s for no_context_takeover - server requested feature" % no_context_takeover)
-
- 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("invalid value %s for window_bits - permissible values %s" % (window_bits, self.WINDOW_SIZE_PERMISSIBLE_VALUES))
-
- if response.client_max_window_bits != 0 and window_bits > response.client_max_window_bits:
- raise Exception("invalid value %s for window_bits - server requested lower maximum value" % window_bits)
-
- self.window_bits = window_bits
-
- if mem_level is not None:
- if mem_level not in self.MEM_LEVEL_PERMISSIBLE_VALUES:
- raise Exception("invalid value %s for mem_level - permissible values %s" % (mem_level, self.MEM_LEVEL_PERMISSIBLE_VALUES))
-
- self.mem_level = mem_level
- self.max_message_size = max_message_size
-
- 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}
-
- def __repr__(self):
- """
- Returns Python object representation that can be eval'ed to reconstruct the object.
-
- :returns: Python string representation.
- :rtype: str
- """
- return "PerMessageDeflateResponseAccept(response = %s, no_context_takeover = %s, window_bits = %s, mem_level = %s)" % (self.response.__repr__(), self.no_context_takeover, self.window_bits, self.mem_level)
-
-
- # noinspection PyArgumentList
- class PerMessageDeflate(PerMessageCompress, PerMessageDeflateMixin):
- """
- `permessage-deflate` WebSocket extension processor.
- """
- DEFAULT_WINDOW_BITS = zlib.MAX_WBITS
- DEFAULT_MEM_LEVEL = 8
-
- @classmethod
- 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
- 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):
- self._is_server = is_server
-
- self.server_no_context_takeover = server_no_context_takeover
- self.client_no_context_takeover = client_no_context_takeover
-
- self.server_max_window_bits = server_max_window_bits if server_max_window_bits != 0 else self.DEFAULT_WINDOW_BITS
- self.client_max_window_bits = client_max_window_bits if client_max_window_bits != 0 else self.DEFAULT_WINDOW_BITS
-
- self.mem_level = mem_level if mem_level else self.DEFAULT_MEM_LEVEL
- self.max_message_size = max_message_size # None means "no limit"
-
- self._compressor = None
- self._decompressor = None
-
- 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}
-
- def __repr__(self):
- return "PerMessageDeflate(is_server = %s, server_no_context_takeover = %s, client_no_context_takeover = %s, server_max_window_bits = %s, client_max_window_bits = %s, mem_level = %s)" % (self._is_server, self.server_no_context_takeover, self.client_no_context_takeover, self.server_max_window_bits, self.client_max_window_bits, self.mem_level)
-
- 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)
-
- def compress_message_data(self, data):
- return self._compressor.compress(data)
-
- def end_compress_message(self):
- data = self._compressor.flush(zlib.Z_SYNC_FLUSH)
- return data[:-4]
-
- 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)
-
- 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)
-
- 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')
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