428 lines
16 KiB
Python
428 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) Crossbar.io Technologies 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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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(object):
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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: A new instance of :class:`autobahn.compress.PerMessageSnappyOffer`.
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:rtype: obj
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"""
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# extension parameter defaults
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accept_no_context_takeover = False
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request_no_context_takeover = False
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# verify/parse client ("client-to-server direction") parameters of permessage-snappy offer
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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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accept_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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request_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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offer = cls(accept_no_context_takeover,
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request_no_context_takeover)
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return offer
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def __init__(self,
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accept_no_context_takeover=True,
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request_no_context_takeover=False):
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"""
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:param accept_no_context_takeover: Iff true, client accepts "no context takeover" feature.
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:type accept_no_context_takeover: bool
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:param request_no_context_takeover: Iff true, client request "no context takeover" feature.
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:type request_no_context_takeover: bool
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"""
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if type(accept_no_context_takeover) != bool:
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raise Exception("invalid type %s for accept_no_context_takeover" % type(accept_no_context_takeover))
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self.accept_no_context_takeover = accept_no_context_takeover
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if type(request_no_context_takeover) != bool:
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raise Exception("invalid type %s for request_no_context_takeover" % type(request_no_context_takeover))
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self.request_no_context_takeover = request_no_context_takeover
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def get_extension_string(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: PMCE configuration string.
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:rtype: str
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"""
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pmce_string = self.EXTENSION_NAME
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if self.accept_no_context_takeover:
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pmce_string += "; client_no_context_takeover"
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if self.request_no_context_takeover:
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pmce_string += "; server_no_context_takeover"
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return pmce_string
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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: JSON serializable representation.
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:rtype: dict
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"""
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return {'extension': self.EXTENSION_NAME,
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'accept_no_context_takeover': self.accept_no_context_takeover,
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'request_no_context_takeover': self.request_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: Python string representation.
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:rtype: str
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"""
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return "PerMessageSnappyOffer(accept_no_context_takeover = %s, request_no_context_takeover = %s)" % (self.accept_no_context_takeover, self.request_no_context_takeover)
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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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request_no_context_takeover=False,
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no_context_takeover=None):
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"""
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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 request_no_context_takeover: Iff true, server request "no context takeover" feature.
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:type request_no_context_takeover: bool
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:param no_context_takeover: Override server ("server-to-client direction") context takeover (this must be compatible with offer).
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:type no_context_takeover: 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(request_no_context_takeover) != bool:
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raise Exception("invalid type %s for request_no_context_takeover" % type(request_no_context_takeover))
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if request_no_context_takeover and not offer.accept_no_context_takeover:
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raise Exception("invalid value %s for request_no_context_takeover - feature unsupported by client" % request_no_context_takeover)
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self.request_no_context_takeover = request_no_context_takeover
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if no_context_takeover is not None:
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if type(no_context_takeover) != bool:
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raise Exception("invalid type %s for no_context_takeover" % type(no_context_takeover))
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if offer.request_no_context_takeover and not no_context_takeover:
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raise Exception("invalid value %s for no_context_takeover - client requested feature" % no_context_takeover)
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self.no_context_takeover = no_context_takeover
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def get_extension_string(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: PMCE configuration string.
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:rtype: str
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"""
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pmce_string = self.EXTENSION_NAME
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if self.offer.request_no_context_takeover:
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pmce_string += "; server_no_context_takeover"
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if self.request_no_context_takeover:
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pmce_string += "; client_no_context_takeover"
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return pmce_string
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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: JSON serializable representation.
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:rtype: dict
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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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'request_no_context_takeover': self.request_no_context_takeover,
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'no_context_takeover': self.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: Python string representation.
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:rtype: str
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"""
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return "PerMessageSnappyAccept(offer = %s, request_no_context_takeover = %s, no_context_takeover = %s)" % (self.offer.__repr__(), self.request_no_context_takeover, self.no_context_takeover)
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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: A new instance of :class:`autobahn.compress.PerMessageSnappyResponse`.
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:rtype: obj
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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: JSON serializable representation.
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:rtype: dict
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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: Python string representation.
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:rtype: str
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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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no_context_takeover=None):
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"""
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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 no_context_takeover: Override client ("client-to-server direction") context takeover (this must be compatible with response).
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:type no_context_takeover: 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 no_context_takeover is not None:
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if type(no_context_takeover) != bool:
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raise Exception("invalid type %s for no_context_takeover" % type(no_context_takeover))
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if response.client_no_context_takeover and not no_context_takeover:
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raise Exception("invalid value %s for no_context_takeover - server requested feature" % no_context_takeover)
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self.no_context_takeover = 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: JSON serializable representation.
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:rtype: dict
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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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'no_context_takeover': self.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: Python string representation.
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:rtype: str
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"""
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return "PerMessageSnappyResponseAccept(response = %s, no_context_takeover = %s)" % (self.response.__repr__(), self.no_context_takeover)
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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 create_from_response_accept(cls, is_server, accept):
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pmce = cls(is_server,
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accept.response.server_no_context_takeover,
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accept.no_context_takeover if accept.no_context_takeover 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 create_from_offer_accept(cls, is_server, accept):
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pmce = cls(is_server,
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accept.no_context_takeover if accept.no_context_takeover is not None else accept.offer.request_no_context_takeover,
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accept.request_no_context_takeover)
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return pmce
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def __init__(self,
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is_server,
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server_no_context_takeover,
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client_no_context_takeover):
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self._is_server = is_server
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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(is_server = %s, server_no_context_takeover = %s, client_no_context_takeover = %s)" % (self._is_server, self.server_no_context_takeover, self.client_no_context_takeover)
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def start_compress_message(self):
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if self._is_server:
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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 compress_message_data(self, data):
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return self._compressor.add_chunk(data)
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def end_compress_message(self):
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return b""
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def start_decompress_message(self):
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if self._is_server:
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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 decompress_message_data(self, data):
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return self._decompressor.decompress(data)
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def end_decompress_message(self):
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pass
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