424 lines
16 KiB
Python
424 lines
16 KiB
Python
###############################################################################
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#
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# The MIT License (MIT)
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#
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# Copyright (c) Tavendo GmbH
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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#
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###############################################################################
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from __future__ import absolute_import
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import snappy
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from autobahn.websocket.compress_base import PerMessageCompressOffer, \
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PerMessageCompressOfferAccept, \
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PerMessageCompressResponse, \
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PerMessageCompressResponseAccept, \
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PerMessageCompress
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__all__ = (
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'PerMessageSnappyMixin',
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'PerMessageSnappyOffer',
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'PerMessageSnappyOfferAccept',
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'PerMessageSnappyResponse',
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'PerMessageSnappyResponseAccept',
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'PerMessageSnappy',
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)
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class PerMessageSnappyMixin:
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"""
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Mixin class for this extension.
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"""
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EXTENSION_NAME = "permessage-snappy"
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"""
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Name of this WebSocket extension.
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"""
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class PerMessageSnappyOffer(PerMessageCompressOffer, PerMessageSnappyMixin):
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"""
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Set of extension parameters for `permessage-snappy` WebSocket extension
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offered by a client to a server.
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"""
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@classmethod
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def parse(cls, params):
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"""
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Parses a WebSocket extension offer for `permessage-snappy` provided by a client to a server.
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:param params: Output from :func:`autobahn.websocket.WebSocketProtocol._parseExtensionsHeader`.
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:type params: list
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:returns: object -- A new instance of :class:`autobahn.compress.PerMessageSnappyOffer`.
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"""
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# extension parameter defaults
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##
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acceptNoContextTakeover = False
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requestNoContextTakeover = False
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##
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# verify/parse client ("client-to-server direction") parameters of permessage-snappy offer
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##
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for p in params:
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if len(params[p]) > 1:
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raise Exception("multiple occurrence of extension parameter '%s' for extension '%s'" % (p, cls.EXTENSION_NAME))
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val = params[p][0]
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if p == 'client_no_context_takeover':
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# noinspection PySimplifyBooleanCheck
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if val is not True:
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raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
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else:
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acceptNoContextTakeover = True
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elif p == 'server_no_context_takeover':
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# noinspection PySimplifyBooleanCheck
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if val is not True:
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raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
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else:
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requestNoContextTakeover = True
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else:
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raise Exception("illegal extension parameter '%s' for extension '%s'" % (p, cls.EXTENSION_NAME))
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offer = cls(acceptNoContextTakeover,
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requestNoContextTakeover)
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return offer
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def __init__(self,
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acceptNoContextTakeover=True,
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requestNoContextTakeover=False):
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"""
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Constructor.
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:param acceptNoContextTakeover: Iff true, client accepts "no context takeover" feature.
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:type acceptNoContextTakeover: bool
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:param requestNoContextTakeover: Iff true, client request "no context takeover" feature.
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:type requestNoContextTakeover: bool
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"""
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if type(acceptNoContextTakeover) != bool:
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raise Exception("invalid type %s for acceptNoContextTakeover" % type(acceptNoContextTakeover))
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self.acceptNoContextTakeover = acceptNoContextTakeover
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if type(requestNoContextTakeover) != bool:
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raise Exception("invalid type %s for requestNoContextTakeover" % type(requestNoContextTakeover))
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self.requestNoContextTakeover = requestNoContextTakeover
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def getExtensionString(self):
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"""
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Returns the WebSocket extension configuration string as sent to the server.
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:returns: str -- PMCE configuration string.
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"""
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pmceString = self.EXTENSION_NAME
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if self.acceptNoContextTakeover:
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pmceString += "; client_no_context_takeover"
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if self.requestNoContextTakeover:
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pmceString += "; server_no_context_takeover"
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return pmceString
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def __json__(self):
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"""
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Returns a JSON serializable object representation.
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:returns: object -- JSON serializable representation.
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"""
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return {'extension': self.EXTENSION_NAME,
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'acceptNoContextTakeover': self.acceptNoContextTakeover,
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'requestNoContextTakeover': self.requestNoContextTakeover}
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def __repr__(self):
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"""
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Returns Python object representation that can be eval'ed to reconstruct the object.
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:returns: str -- Python string representation.
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"""
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return "PerMessageSnappyOffer(acceptNoContextTakeover = %s, requestNoContextTakeover = %s)" % (self.acceptNoContextTakeover, self.requestNoContextTakeover)
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class PerMessageSnappyOfferAccept(PerMessageCompressOfferAccept, PerMessageSnappyMixin):
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"""
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Set of parameters with which to accept an `permessage-snappy` offer
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from a client by a server.
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"""
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def __init__(self,
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offer,
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requestNoContextTakeover=False,
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noContextTakeover=None):
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"""
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Constructor.
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:param offer: The offer being accepted.
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:type offer: Instance of :class:`autobahn.compress.PerMessageSnappyOffer`.
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:param requestNoContextTakeover: Iff true, server request "no context takeover" feature.
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:type requestNoContextTakeover: bool
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:param noContextTakeover: Override server ("server-to-client direction") context takeover (this must be compatible with offer).
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:type noContextTakeover: bool
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"""
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if not isinstance(offer, PerMessageSnappyOffer):
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raise Exception("invalid type %s for offer" % type(offer))
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self.offer = offer
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if type(requestNoContextTakeover) != bool:
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raise Exception("invalid type %s for requestNoContextTakeover" % type(requestNoContextTakeover))
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if requestNoContextTakeover and not offer.acceptNoContextTakeover:
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raise Exception("invalid value %s for requestNoContextTakeover - feature unsupported by client" % requestNoContextTakeover)
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self.requestNoContextTakeover = requestNoContextTakeover
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if noContextTakeover is not None:
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if type(noContextTakeover) != bool:
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raise Exception("invalid type %s for noContextTakeover" % type(noContextTakeover))
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if offer.requestNoContextTakeover and not noContextTakeover:
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raise Exception("invalid value %s for noContextTakeover - client requested feature" % noContextTakeover)
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self.noContextTakeover = noContextTakeover
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def getExtensionString(self):
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"""
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Returns the WebSocket extension configuration string as sent to the server.
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:returns: str -- PMCE configuration string.
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"""
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pmceString = self.EXTENSION_NAME
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if self.offer.requestNoContextTakeover:
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pmceString += "; server_no_context_takeover"
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if self.requestNoContextTakeover:
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pmceString += "; client_no_context_takeover"
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return pmceString
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def __json__(self):
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"""
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Returns a JSON serializable object representation.
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:returns: object -- JSON serializable representation.
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"""
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return {'extension': self.EXTENSION_NAME,
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'offer': self.offer.__json__(),
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'requestNoContextTakeover': self.requestNoContextTakeover,
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'noContextTakeover': self.noContextTakeover}
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def __repr__(self):
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"""
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Returns Python object representation that can be eval'ed to reconstruct the object.
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:returns: str -- Python string representation.
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"""
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return "PerMessageSnappyAccept(offer = %s, requestNoContextTakeover = %s, noContextTakeover = %s)" % (self.offer.__repr__(), self.requestNoContextTakeover, self.noContextTakeover)
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class PerMessageSnappyResponse(PerMessageCompressResponse, PerMessageSnappyMixin):
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"""
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Set of parameters for `permessage-snappy` responded by server.
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"""
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@classmethod
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def parse(cls, params):
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"""
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Parses a WebSocket extension response for `permessage-snappy` provided by a server to a client.
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:param params: Output from :func:`autobahn.websocket.WebSocketProtocol._parseExtensionsHeader`.
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:type params: list
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:returns: object -- A new instance of :class:`autobahn.compress.PerMessageSnappyResponse`.
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"""
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client_no_context_takeover = False
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server_no_context_takeover = False
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for p in params:
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if len(params[p]) > 1:
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raise Exception("multiple occurrence of extension parameter '%s' for extension '%s'" % (p, cls.EXTENSION_NAME))
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val = params[p][0]
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if p == 'client_no_context_takeover':
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# noinspection PySimplifyBooleanCheck
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if val is not True:
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raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
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else:
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client_no_context_takeover = True
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elif p == 'server_no_context_takeover':
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# noinspection PySimplifyBooleanCheck
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if val is not True:
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raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME))
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else:
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server_no_context_takeover = True
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else:
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raise Exception("illegal extension parameter '%s' for extension '%s'" % (p, cls.EXTENSION_NAME))
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response = cls(client_no_context_takeover,
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server_no_context_takeover)
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return response
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def __init__(self,
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client_no_context_takeover,
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server_no_context_takeover):
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self.client_no_context_takeover = client_no_context_takeover
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self.server_no_context_takeover = server_no_context_takeover
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def __json__(self):
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"""
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Returns a JSON serializable object representation.
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:returns: object -- JSON serializable representation.
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"""
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return {'extension': self.EXTENSION_NAME,
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'client_no_context_takeover': self.client_no_context_takeover,
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'server_no_context_takeover': self.server_no_context_takeover}
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def __repr__(self):
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"""
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Returns Python object representation that can be eval'ed to reconstruct the object.
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:returns: str -- Python string representation.
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"""
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return "PerMessageSnappyResponse(client_no_context_takeover = %s, server_no_context_takeover = %s)" % (self.client_no_context_takeover, self.server_no_context_takeover)
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class PerMessageSnappyResponseAccept(PerMessageCompressResponseAccept, PerMessageSnappyMixin):
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"""
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Set of parameters with which to accept an `permessage-snappy` response
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from a server by a client.
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"""
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def __init__(self,
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response,
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noContextTakeover=None):
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"""
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Constructor.
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:param response: The response being accepted.
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:type response: Instance of :class:`autobahn.compress.PerMessageSnappyResponse`.
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:param noContextTakeover: Override client ("client-to-server direction") context takeover (this must be compatible with response).
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:type noContextTakeover: bool
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"""
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if not isinstance(response, PerMessageSnappyResponse):
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raise Exception("invalid type %s for response" % type(response))
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self.response = response
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if noContextTakeover is not None:
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if type(noContextTakeover) != bool:
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raise Exception("invalid type %s for noContextTakeover" % type(noContextTakeover))
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if response.client_no_context_takeover and not noContextTakeover:
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raise Exception("invalid value %s for noContextTakeover - server requested feature" % noContextTakeover)
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self.noContextTakeover = noContextTakeover
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def __json__(self):
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"""
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Returns a JSON serializable object representation.
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:returns: object -- JSON serializable representation.
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"""
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return {'extension': self.EXTENSION_NAME,
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'response': self.response.__json__(),
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'noContextTakeover': self.noContextTakeover}
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def __repr__(self):
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"""
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Returns Python object representation that can be eval'ed to reconstruct the object.
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:returns: str -- Python string representation.
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"""
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return "PerMessageSnappyResponseAccept(response = %s, noContextTakeover = %s)" % (self.response.__repr__(), self.noContextTakeover)
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class PerMessageSnappy(PerMessageCompress, PerMessageSnappyMixin):
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"""
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`permessage-snappy` WebSocket extension processor.
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"""
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@classmethod
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def createFromResponseAccept(cls, isServer, accept):
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pmce = cls(isServer,
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accept.response.server_no_context_takeover,
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accept.noContextTakeover if accept.noContextTakeover is not None else accept.response.client_no_context_takeover)
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return pmce
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@classmethod
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def createFromOfferAccept(cls, isServer, accept):
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pmce = cls(isServer,
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accept.noContextTakeover if accept.noContextTakeover is not None else accept.offer.requestNoContextTakeover,
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accept.requestNoContextTakeover)
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return pmce
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def __init__(self,
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isServer,
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server_no_context_takeover,
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client_no_context_takeover):
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self._isServer = isServer
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self.server_no_context_takeover = server_no_context_takeover
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self.client_no_context_takeover = client_no_context_takeover
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self._compressor = None
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self._decompressor = None
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def __json__(self):
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return {'extension': self.EXTENSION_NAME,
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'server_no_context_takeover': self.server_no_context_takeover,
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'client_no_context_takeover': self.client_no_context_takeover}
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def __repr__(self):
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return "PerMessageSnappy(isServer = %s, server_no_context_takeover = %s, client_no_context_takeover = %s)" % (self._isServer, self.server_no_context_takeover, self.client_no_context_takeover)
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def startCompressMessage(self):
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if self._isServer:
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if self._compressor is None or self.server_no_context_takeover:
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self._compressor = snappy.StreamCompressor()
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else:
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if self._compressor is None or self.client_no_context_takeover:
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self._compressor = snappy.StreamCompressor()
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def compressMessageData(self, data):
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return self._compressor.add_chunk(data)
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def endCompressMessage(self):
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return ""
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def startDecompressMessage(self):
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if self._isServer:
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if self._decompressor is None or self.client_no_context_takeover:
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self._decompressor = snappy.StreamDecompressor()
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else:
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if self._decompressor is None or self.server_no_context_takeover:
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self._decompressor = snappy.StreamDecompressor()
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def decompressMessageData(self, data):
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return self._decompressor.decompress(data)
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def endDecompressMessage(self):
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pass
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