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import bz2
from autobahn.websocket.compress_base import PerMessageCompressOffer, \
PerMessageCompressOfferAccept, \
PerMessageCompressResponse, \
PerMessageCompressResponseAccept, \
PerMessageCompress
__all__ = (
'PerMessageBzip2Mixin',
'PerMessageBzip2Offer',
'PerMessageBzip2OfferAccept',
'PerMessageBzip2Response',
'PerMessageBzip2ResponseAccept',
'PerMessageBzip2',
)
[docs]class PerMessageBzip2Mixin(object):
"""
Mixin class for this extension.
"""
EXTENSION_NAME = "permessage-bzip2"
"""
Name of this WebSocket extension.
"""
COMPRESS_LEVEL_PERMISSIBLE_VALUES = [1, 2, 3, 4, 5, 6, 7, 8, 9]
"""
Permissible value for compression level parameter.
"""
[docs]class PerMessageBzip2Offer(PerMessageCompressOffer, PerMessageBzip2Mixin):
"""
Set of extension parameters for `permessage-bzip2` WebSocket extension
offered by a client to a server.
"""
[docs] @classmethod
def parse(cls, params):
"""
Parses a WebSocket extension offer for `permessage-bzip2` 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.PerMessageBzip2Offer`.
"""
# extension parameter defaults
accept_max_compress_level = False
request_max_compress_level = 0
# verify/parse client ("client-to-server direction") parameters of permessage-bzip2 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_compress_level':
# 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_max_compress_level = True
elif p == 'server_max_compress_level':
try:
val = int(val)
except:
raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
if val not in PerMessageBzip2Mixin.COMPRESS_LEVEL_PERMISSIBLE_VALUES:
raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
else:
request_max_compress_level = val
else:
raise Exception("illegal extension parameter '%s' for extension '%s'" % (p, cls.EXTENSION_NAME))
offer = cls(accept_max_compress_level,
request_max_compress_level)
return offer
def __init__(self,
accept_max_compress_level=True,
request_max_compress_level=0):
"""
Constructor.
:param accept_max_compress_level: Iff true, client accepts "maximum compression level" parameter.
:type accept_max_compress_level: bool
:param request_max_compress_level: Iff non-zero, client requests given "maximum compression level" - must be 1-9.
:type request_max_compress_level: int
"""
if type(accept_max_compress_level) != bool:
raise Exception("invalid type %s for accept_max_compress_level" % type(accept_max_compress_level))
self.accept_max_compress_level = accept_max_compress_level
if request_max_compress_level != 0 and request_max_compress_level not in self.COMPRESS_LEVEL_PERMISSIBLE_VALUES:
raise Exception("invalid value %s for request_max_compress_level - permissible values %s" % (request_max_compress_level, self.COMPRESS_LEVEL_PERMISSIBLE_VALUES))
self.request_max_compress_level = request_max_compress_level
[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_max_compress_level:
pmce_string += "; client_max_compress_level"
if self.request_max_compress_level != 0:
pmce_string += "; server_max_compress_level=%d" % self.request_max_compress_level
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_max_compress_level': self.accept_max_compress_level,
'request_max_compress_level': self.request_max_compress_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 "PerMessageBzip2Offer(accept_max_compress_level = %s, request_max_compress_level = %s)" % (self.accept_max_compress_level, self.request_max_compress_level)
[docs]class PerMessageBzip2OfferAccept(PerMessageCompressOfferAccept, PerMessageBzip2Mixin):
"""
Set of parameters with which to accept an `permessage-bzip2` offer
from a client by a server.
"""
def __init__(self,
offer,
request_max_compress_level=0,
compress_level=None):
"""
Constructor.
:param offer: The offer being accepted.
:type offer: Instance of :class:`autobahn.compress.PerMessageBzip2Offer`.
:param request_max_compress_level: Iff non-zero, server requests given "maximum compression level" - must be 1-9.
:type request_max_compress_level: int
:param compress_level: Override server ("server-to-client direction") compress level (this must be compatible with offer).
:type compress_level: int
"""
if not isinstance(offer, PerMessageBzip2Offer):
raise Exception("invalid type %s for offer" % type(offer))
self.offer = offer
if request_max_compress_level != 0 and request_max_compress_level not in self.COMPRESS_LEVEL_PERMISSIBLE_VALUES:
raise Exception("invalid value %s for request_max_compress_level - permissible values %s" % (request_max_compress_level, self.COMPRESS_LEVEL_PERMISSIBLE_VALUES))
if request_max_compress_level != 0 and not offer.accept_max_compress_level:
raise Exception("invalid value %s for request_max_compress_level - feature unsupported by client" % request_max_compress_level)
self.request_max_compress_level = request_max_compress_level
if compress_level is not None:
if compress_level not in self.COMPRESS_LEVEL_PERMISSIBLE_VALUES:
raise Exception("invalid value %s for compress_level - permissible values %s" % (compress_level, self.COMPRESS_LEVEL_PERMISSIBLE_VALUES))
if offer.request_max_compress_level != 0 and compress_level > offer.request_max_compress_level:
raise Exception("invalid value %s for compress_level - client requested lower maximum value" % compress_level)
self.compress_level = compress_level
[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_max_compress_level != 0:
pmce_string += "; server_max_compress_level=%d" % self.offer.request_max_compress_level
if self.request_max_compress_level != 0:
pmce_string += "; client_max_compress_level=%d" % self.request_max_compress_level
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_max_compress_level': self.request_max_compress_level,
'compress_level': self.compress_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 "PerMessageBzip2Accept(offer = %s, request_max_compress_level = %s, compress_level = %s)" % (self.offer.__repr__(), self.request_max_compress_level, self.compress_level)
[docs]class PerMessageBzip2Response(PerMessageCompressResponse, PerMessageBzip2Mixin):
"""
Set of parameters for `permessage-bzip2` responded by server.
"""
[docs] @classmethod
def parse(cls, params):
"""
Parses a WebSocket extension response for `permessage-bzip2` 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.PerMessageBzip2Response`.
:rtype: obj
"""
client_max_compress_level = 0
server_max_compress_level = 0
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_compress_level':
try:
val = int(val)
except:
raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
if val not in PerMessageBzip2Mixin.COMPRESS_LEVEL_PERMISSIBLE_VALUES:
raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
else:
client_max_compress_level = val
elif p == 'server_max_compress_level':
try:
val = int(val)
except:
raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
if val not in PerMessageBzip2Mixin.COMPRESS_LEVEL_PERMISSIBLE_VALUES:
raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
else:
server_max_compress_level = val
else:
raise Exception("illegal extension parameter '%s' for extension '%s'" % (p, cls.EXTENSION_NAME))
response = cls(client_max_compress_level,
server_max_compress_level)
return response
def __init__(self,
client_max_compress_level,
server_max_compress_level):
self.client_max_compress_level = client_max_compress_level
self.server_max_compress_level = server_max_compress_level
[docs] def __json__(self):
"""
Returns a JSON serializable object representation.
:returns: JSON serializable representation.
:rtype: dict
"""
return {'extension': self.EXTENSION_NAME,
'client_max_compress_level': self.client_max_compress_level,
'server_max_compress_level': self.server_max_compress_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 "PerMessageBzip2Response(client_max_compress_level = %s, server_max_compress_level = %s)" % (self.client_max_compress_level, self.server_max_compress_level)
[docs]class PerMessageBzip2ResponseAccept(PerMessageCompressResponseAccept, PerMessageBzip2Mixin):
"""
Set of parameters with which to accept an `permessage-bzip2` response
from a server by a client.
"""
def __init__(self,
response,
compress_level=None):
"""
:param response: The response being accepted.
:type response: Instance of :class:`autobahn.compress.PerMessageBzip2Response`.
:param compress_level: Override client ("client-to-server direction") compress level (this must be compatible with response).
:type compress_level: int
"""
if not isinstance(response, PerMessageBzip2Response):
raise Exception("invalid type %s for response" % type(response))
self.response = response
if compress_level is not None:
if compress_level not in self.COMPRESS_LEVEL_PERMISSIBLE_VALUES:
raise Exception("invalid value %s for compress_level - permissible values %s" % (compress_level, self.COMPRESS_LEVEL_PERMISSIBLE_VALUES))
if response.client_max_compress_level != 0 and compress_level > response.client_max_compress_level:
raise Exception("invalid value %s for compress_level - server requested lower maximum value" % compress_level)
self.compress_level = compress_level
[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__(),
'compress_level': self.compress_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 "PerMessageBzip2ResponseAccept(response = %s, compress_level = %s)" % (self.response.__repr__(), self.compress_level)
[docs]class PerMessageBzip2(PerMessageCompress, PerMessageBzip2Mixin):
"""
`permessage-bzip2` WebSocket extension processor.
"""
DEFAULT_COMPRESS_LEVEL = 9
[docs] @classmethod
def create_from_response_accept(cls, is_server, accept):
pmce = cls(is_server,
accept.response.server_max_compress_level,
accept.compress_level if accept.compress_level is not None else accept.response.client_max_compress_level)
return pmce
[docs] @classmethod
def create_from_offer_accept(cls, is_server, accept):
pmce = cls(is_server,
accept.compress_level if accept.compress_level is not None else accept.offer.request_max_compress_level,
accept.request_max_compress_level)
return pmce
def __init__(self,
is_server,
server_max_compress_level,
client_max_compress_level):
self._isServer = is_server
self._compressor = None
self._decompressor = None
self.server_max_compress_level = server_max_compress_level if server_max_compress_level != 0 else self.DEFAULT_COMPRESS_LEVEL
self.client_max_compress_level = client_max_compress_level if client_max_compress_level != 0 else self.DEFAULT_COMPRESS_LEVEL
[docs] def __json__(self):
return {'extension': self.EXTENSION_NAME,
'isServer': self._isServer,
'server_max_compress_level': self.server_max_compress_level,
'client_max_compress_level': self.client_max_compress_level}
[docs] def __repr__(self):
return "PerMessageBzip2(isServer = %s, server_max_compress_level = %s, client_max_compress_level = %s)" % (self._isServer, self.server_max_compress_level, self.client_max_compress_level)
[docs] def start_compress_message(self):
if self._isServer:
if self._compressor is None:
self._compressor = bz2.BZ2Compressor(self.server_max_compress_level)
else:
if self._compressor is None:
self._compressor = bz2.BZ2Compressor(self.client_max_compress_level)
[docs] def compress_message_data(self, data):
return self._compressor.compress(data)
[docs] def end_compress_message(self):
data = self._compressor.flush()
# there seems to be no "flush without close stream", and after
# full flush, compressor must not be reused
self._compressor = None
return data
[docs] def start_decompress_message(self):
if self._decompressor is None:
self._decompressor = bz2.BZ2Decompressor()
[docs] def decompress_message_data(self, data):
return self._decompressor.decompress(data)
[docs] def end_decompress_message(self):
self._decompressor = None