/usr/lib/python2.7/dist-packages/autobahn/websocket/compress_deflate.py is in python-autobahn 0.10.3+dfsg1-5.
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#
# The MIT License (MIT)
#
# Copyright (c) Tavendo 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.
#
###############################################################################
from __future__ import absolute_import
import zlib
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 = [8, 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.
"""
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: object -- A new instance of :class:`autobahn.compress.PerMessageDeflateOffer`.
"""
# extension parameter defaults
acceptMaxWindowBits = False
acceptNoContextTakeover = True
# acceptNoContextTakeover = False # FIXME: this may change in draft
requestMaxWindowBits = 0
requestNoContextTakeover = 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 8 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!
# acceptMaxWindowBits = val
acceptMaxWindowBits = True
else:
acceptMaxWindowBits = 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:
acceptNoContextTakeover = 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:
requestMaxWindowBits = 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:
requestNoContextTakeover = True
else:
raise Exception("illegal extension parameter '%s' for extension '%s'" % (p, cls.EXTENSION_NAME))
offer = cls(acceptNoContextTakeover,
acceptMaxWindowBits,
requestNoContextTakeover,
requestMaxWindowBits)
return offer
def __init__(self,
acceptNoContextTakeover=True,
acceptMaxWindowBits=True,
requestNoContextTakeover=False,
requestMaxWindowBits=0):
"""
Constructor.
:param acceptNoContextTakeover: Iff true, client accepts "no context takeover" feature.
:type acceptNoContextTakeover: bool
:param acceptMaxWindowBits: Iff true, client accepts setting "max window size".
:type acceptMaxWindowBits: bool
:param requestNoContextTakeover: Iff true, client request "no context takeover" feature.
:type requestNoContextTakeover: bool
:param requestMaxWindowBits: Iff non-zero, client requests given "max window size" - must be 8-15.
:type requestMaxWindowBits: int
"""
if type(acceptNoContextTakeover) != bool:
raise Exception("invalid type %s for acceptNoContextTakeover" % type(acceptNoContextTakeover))
self.acceptNoContextTakeover = acceptNoContextTakeover
if type(acceptMaxWindowBits) != bool:
raise Exception("invalid type %s for acceptMaxWindowBits" % type(acceptMaxWindowBits))
self.acceptMaxWindowBits = acceptMaxWindowBits
if type(requestNoContextTakeover) != bool:
raise Exception("invalid type %s for requestNoContextTakeover" % type(requestNoContextTakeover))
self.requestNoContextTakeover = requestNoContextTakeover
if requestMaxWindowBits != 0 and requestMaxWindowBits not in self.WINDOW_SIZE_PERMISSIBLE_VALUES:
raise Exception("invalid value %s for requestMaxWindowBits - permissible values %s" % (requestMaxWindowBits, self.WINDOW_SIZE_PERMISSIBLE_VALUES))
self.requestMaxWindowBits = requestMaxWindowBits
def getExtensionString(self):
"""
Returns the WebSocket extension configuration string as sent to the server.
:returns: str -- PMCE configuration string.
"""
pmceString = self.EXTENSION_NAME
if self.acceptNoContextTakeover:
pmceString += "; client_no_context_takeover"
if self.acceptMaxWindowBits:
pmceString += "; client_max_window_bits"
if self.requestNoContextTakeover:
pmceString += "; server_no_context_takeover"
if self.requestMaxWindowBits != 0:
pmceString += "; server_max_window_bits=%d" % self.requestMaxWindowBits
return pmceString
def __json__(self):
"""
Returns a JSON serializable object representation.
:returns: object -- JSON serializable representation.
"""
return {'extension': self.EXTENSION_NAME,
'acceptNoContextTakeover': self.acceptNoContextTakeover,
'acceptMaxWindowBits': self.acceptMaxWindowBits,
'requestNoContextTakeover': self.requestNoContextTakeover,
'requestMaxWindowBits': self.requestMaxWindowBits}
def __repr__(self):
"""
Returns Python object representation that can be eval'ed to reconstruct the object.
:returns: str -- Python string representation.
"""
return "PerMessageDeflateOffer(acceptNoContextTakeover = %s, acceptMaxWindowBits = %s, requestNoContextTakeover = %s, requestMaxWindowBits = %s)" % (self.acceptNoContextTakeover, self.acceptMaxWindowBits, self.requestNoContextTakeover, self.requestMaxWindowBits)
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,
requestNoContextTakeover=False,
requestMaxWindowBits=0,
noContextTakeover=None,
windowBits=None,
memLevel=None):
"""
Constructor.
:param offer: The offer being accepted.
:type offer: Instance of :class:`autobahn.compress.PerMessageDeflateOffer`.
:param requestNoContextTakeover: Iff true, server request "no context takeover" feature.
:type requestNoContextTakeover: bool
:param requestMaxCompressLevel: Iff non-zero, server requests given "maximum compression level" - must be 1-9.
:type requestMaxCompressLevel: int
:param noContextTakeover: Override server ("server-to-client direction") context takeover (this must be compatible with offer).
:type noContextTakeover: bool
:param windowBits: Override server ("server-to-client direction") window size (this must be compatible with offer).
:type windowBits: int
:param memLevel: Set server ("server-to-client direction") memory level.
:type memLevel: int
"""
if not isinstance(offer, PerMessageDeflateOffer):
raise Exception("invalid type %s for offer" % type(offer))
self.offer = offer
if type(requestNoContextTakeover) != bool:
raise Exception("invalid type %s for requestNoContextTakeover" % type(requestNoContextTakeover))
if requestNoContextTakeover and not offer.acceptNoContextTakeover:
raise Exception("invalid value %s for requestNoContextTakeover - feature unsupported by client" % requestNoContextTakeover)
self.requestNoContextTakeover = requestNoContextTakeover
if requestMaxWindowBits != 0 and requestMaxWindowBits not in self.WINDOW_SIZE_PERMISSIBLE_VALUES:
raise Exception("invalid value %s for requestMaxWindowBits - permissible values %s" % (requestMaxWindowBits, self.WINDOW_SIZE_PERMISSIBLE_VALUES))
if requestMaxWindowBits != 0 and not offer.acceptMaxWindowBits:
raise Exception("invalid value %s for requestMaxWindowBits - feature unsupported by client" % requestMaxWindowBits)
self.requestMaxWindowBits = requestMaxWindowBits
if noContextTakeover is not None:
if type(noContextTakeover) != bool:
raise Exception("invalid type %s for noContextTakeover" % type(noContextTakeover))
if offer.requestNoContextTakeover and not noContextTakeover:
raise Exception("invalid value %s for noContextTakeover - client requested feature" % noContextTakeover)
self.noContextTakeover = noContextTakeover
if windowBits is not None:
if windowBits not in self.WINDOW_SIZE_PERMISSIBLE_VALUES:
raise Exception("invalid value %s for windowBits - permissible values %s" % (windowBits, self.WINDOW_SIZE_PERMISSIBLE_VALUES))
if offer.requestMaxWindowBits != 0 and windowBits > offer.requestMaxWindowBits:
raise Exception("invalid value %s for windowBits - client requested lower maximum value" % windowBits)
self.windowBits = windowBits
if memLevel is not None:
if memLevel not in self.MEM_LEVEL_PERMISSIBLE_VALUES:
raise Exception("invalid value %s for memLevel - permissible values %s" % (memLevel, self.MEM_LEVEL_PERMISSIBLE_VALUES))
self.memLevel = memLevel
def getExtensionString(self):
"""
Returns the WebSocket extension configuration string as sent to the server.
:returns: str -- PMCE configuration string.
"""
pmceString = self.EXTENSION_NAME
if self.offer.requestNoContextTakeover:
pmceString += "; server_no_context_takeover"
if self.offer.requestMaxWindowBits != 0:
pmceString += "; server_max_window_bits=%d" % self.offer.requestMaxWindowBits
if self.requestNoContextTakeover:
pmceString += "; client_no_context_takeover"
if self.requestMaxWindowBits != 0:
pmceString += "; client_max_window_bits=%d" % self.requestMaxWindowBits
return pmceString
def __json__(self):
"""
Returns a JSON serializable object representation.
:returns: object -- JSON serializable representation.
"""
return {'extension': self.EXTENSION_NAME,
'offer': self.offer.__json__(),
'requestNoContextTakeover': self.requestNoContextTakeover,
'requestMaxWindowBits': self.requestMaxWindowBits,
'noContextTakeover': self.noContextTakeover,
'windowBits': self.windowBits,
'memLevel': self.memLevel}
def __repr__(self):
"""
Returns Python object representation that can be eval'ed to reconstruct the object.
:returns: str -- Python string representation.
"""
return "PerMessageDeflateOfferAccept(offer = %s, requestNoContextTakeover = %s, requestMaxWindowBits = %s, noContextTakeover = %s, windowBits = %s, memLevel = %s)" % (self.offer.__repr__(), self.requestNoContextTakeover, self.requestMaxWindowBits, self.noContextTakeover, self.windowBits, self.memLevel)
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: object -- A new instance of :class:`autobahn.compress.PerMessageDeflateResponse`.
"""
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):
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: object -- JSON serializable representation.
"""
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: str -- Python string representation.
"""
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)
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,
noContextTakeover=None,
windowBits=None,
memLevel=None):
"""
Constructor.
:param response: The response being accepted.
:type response: Instance of :class:`autobahn.compress.PerMessageDeflateResponse`.
:param noContextTakeover: Override client ("client-to-server direction") context takeover (this must be compatible with response).
:type noContextTakeover: bool
:param windowBits: Override client ("client-to-server direction") window size (this must be compatible with response).
:type windowBits: int
:param memLevel: Set client ("client-to-server direction") memory level.
:type memLevel: int
"""
if not isinstance(response, PerMessageDeflateResponse):
raise Exception("invalid type %s for response" % type(response))
self.response = response
if noContextTakeover is not None:
if type(noContextTakeover) != bool:
raise Exception("invalid type %s for noContextTakeover" % type(noContextTakeover))
if response.client_no_context_takeover and not noContextTakeover:
raise Exception("invalid value %s for noContextTakeover - server requested feature" % noContextTakeover)
self.noContextTakeover = noContextTakeover
if windowBits is not None:
if windowBits not in self.WINDOW_SIZE_PERMISSIBLE_VALUES:
raise Exception("invalid value %s for windowBits - permissible values %s" % (windowBits, self.WINDOW_SIZE_PERMISSIBLE_VALUES))
if response.client_max_window_bits != 0 and windowBits > response.client_max_window_bits:
raise Exception("invalid value %s for windowBits - server requested lower maximum value" % windowBits)
self.windowBits = windowBits
if memLevel is not None:
if memLevel not in self.MEM_LEVEL_PERMISSIBLE_VALUES:
raise Exception("invalid value %s for memLevel - permissible values %s" % (memLevel, self.MEM_LEVEL_PERMISSIBLE_VALUES))
self.memLevel = memLevel
def __json__(self):
"""
Returns a JSON serializable object representation.
:returns: object -- JSON serializable representation.
"""
return {'extension': self.EXTENSION_NAME,
'response': self.response.__json__(),
'noContextTakeover': self.noContextTakeover,
'windowBits': self.windowBits,
'memLevel': self.memLevel}
def __repr__(self):
"""
Returns Python object representation that can be eval'ed to reconstruct the object.
:returns: str -- Python string representation.
"""
return "PerMessageDeflateResponseAccept(response = %s, noContextTakeover = %s, windowBits = %s, memLevel = %s)" % (self.response.__repr__(), self.noContextTakeover, self.windowBits, self.memLevel)
# noinspection PyArgumentList
class PerMessageDeflate(PerMessageCompress, PerMessageDeflateMixin):
"""
`permessage-deflate` WebSocket extension processor.
"""
DEFAULT_WINDOW_BITS = zlib.MAX_WBITS
DEFAULT_MEM_LEVEL = 8
@classmethod
def createFromResponseAccept(cls, isServer, accept):
# accept: instance of PerMessageDeflateResponseAccept
pmce = cls(isServer,
accept.response.server_no_context_takeover,
accept.noContextTakeover if accept.noContextTakeover is not None else accept.response.client_no_context_takeover,
accept.response.server_max_window_bits,
accept.windowBits if accept.windowBits is not None else accept.response.client_max_window_bits,
accept.memLevel)
return pmce
@classmethod
def createFromOfferAccept(cls, isServer, accept):
# accept: instance of PerMessageDeflateOfferAccept
pmce = cls(isServer,
accept.noContextTakeover if accept.noContextTakeover is not None else accept.offer.requestNoContextTakeover,
accept.requestNoContextTakeover,
accept.windowBits if accept.windowBits is not None else accept.offer.requestMaxWindowBits,
accept.requestMaxWindowBits,
accept.memLevel)
return pmce
def __init__(self,
isServer,
server_no_context_takeover,
client_no_context_takeover,
server_max_window_bits,
client_max_window_bits,
mem_level):
self._isServer = isServer
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._compressor = None
self._decompressor = None
def __json__(self):
return {'extension': self.EXTENSION_NAME,
'isServer': self._isServer,
'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(isServer = %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._isServer, self.server_no_context_takeover, self.client_no_context_takeover, self.server_max_window_bits, self.client_max_window_bits, self.mem_level)
def startCompressMessage(self):
# compressobj([level[, method[, wbits[, memlevel[, strategy]]]]])
# http://bugs.python.org/issue19278
# http://hg.python.org/cpython/rev/c54c8e71b79a
if self._isServer:
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 compressMessageData(self, data):
return self._compressor.compress(data)
def endCompressMessage(self):
data = self._compressor.flush(zlib.Z_SYNC_FLUSH)
return data[:-4]
def startDecompressMessage(self):
if self._isServer:
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 decompressMessageData(self, data):
return self._decompressor.decompress(data)
def endDecompressMessage(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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