############################################################################### # # The MIT License (MIT) # # Copyright (c) typedef int GmbH # # Permission is hereby granted, free of charge, to any person obtaining a copy # of this software and associated documentation files (the "Software"), to deal # in the Software without restriction, including without limitation the rights # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell # copies of the Software, and to permit persons to whom the Software is # furnished to do so, subject to the following conditions: # # The above copyright notice and this permission notice shall be included in # all copies or substantial portions of the Software. # # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN # THE SOFTWARE. # ############################################################################### import zlib from autobahn.util import public from autobahn.websocket.compress_base import PerMessageCompressOffer, \ PerMessageCompressOfferAccept, \ PerMessageCompressResponse, \ PerMessageCompressResponseAccept, \ PerMessageCompress __all__ = ( 'PerMessageDeflateMixin', 'PerMessageDeflateOffer', 'PerMessageDeflateOfferAccept', 'PerMessageDeflateResponse', 'PerMessageDeflateResponseAccept', 'PerMessageDeflate', ) class PerMessageDeflateMixin(object): """ Mixin class for this extension. """ EXTENSION_NAME = "permessage-deflate" """ Name of this WebSocket extension. """ WINDOW_SIZE_PERMISSIBLE_VALUES = [9, 10, 11, 12, 13, 14, 15] """ Permissible value for window size parameter. Higher values use more memory, but produce smaller output. The default is 15. """ MEM_LEVEL_PERMISSIBLE_VALUES = [1, 2, 3, 4, 5, 6, 7, 8, 9] """ Permissible value for memory level parameter. Higher values use more memory, but are faster and produce smaller output. The default is 8. """ @public class PerMessageDeflateOffer(PerMessageCompressOffer, PerMessageDeflateMixin): """ Set of extension parameters for `permessage-deflate` WebSocket extension offered by a client to a server. """ @classmethod def parse(cls, params): """ Parses a WebSocket extension offer for `permessage-deflate` provided by a client to a server. :param params: Output from :func:`autobahn.websocket.WebSocketProtocol._parseExtensionsHeader`. :type params: list :returns: A new instance of :class:`autobahn.compress.PerMessageDeflateOffer`. :rtype: obj """ # extension parameter defaults accept_max_window_bits = False accept_no_context_takeover = True # accept_no_context_takeover = False # FIXME: this may change in draft request_max_window_bits = 0 request_no_context_takeover = False # verify/parse client ("client-to-server direction") parameters of permessage-deflate offer for p in params: if len(params[p]) > 1: raise Exception("multiple occurrence of extension parameter '%s' for extension '%s'" % (p, cls.EXTENSION_NAME)) val = params[p][0] if p == 'client_max_window_bits': # # see: https://tools.ietf.org/html/draft-ietf-hybi-permessage-compression-18 # 8.1.2.2. client_max_window_bits # ".. This parameter has no value or a decimal integer value without # leading zeroes between 9 to 15 inclusive .."" # noinspection PySimplifyBooleanCheck if val is not True: try: val = int(val) except: raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME)) else: if val not in PerMessageDeflateMixin.WINDOW_SIZE_PERMISSIBLE_VALUES: raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME)) else: # FIXME (maybe): possibly forward/process the client hint! # accept_max_window_bits = val accept_max_window_bits = True else: accept_max_window_bits = True elif p == 'client_no_context_takeover': # noinspection PySimplifyBooleanCheck if val is not True: raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME)) else: accept_no_context_takeover = True elif p == 'server_max_window_bits': try: val = int(val) except: raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME)) else: if val not in PerMessageDeflateMixin.WINDOW_SIZE_PERMISSIBLE_VALUES: raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME)) else: request_max_window_bits = val elif p == 'server_no_context_takeover': # noinspection PySimplifyBooleanCheck if val is not True: raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME)) else: request_no_context_takeover = True else: raise Exception("illegal extension parameter '%s' for extension '%s'" % (p, cls.EXTENSION_NAME)) offer = cls(accept_no_context_takeover, accept_max_window_bits, request_no_context_takeover, request_max_window_bits) return offer def __init__(self, accept_no_context_takeover=True, accept_max_window_bits=True, request_no_context_takeover=False, request_max_window_bits=0): """ :param accept_no_context_takeover: When ``True``, the client accepts the "no context takeover" feature. :type accept_no_context_takeover: bool :param accept_max_window_bits: When ``True``, the client accepts setting "max window size". :type accept_max_window_bits: bool :param request_no_context_takeover: When ``True``, the client request the "no context takeover" feature. :type request_no_context_takeover: bool :param request_max_window_bits: When non-zero, the client requests the given "max window size" (must be and integer from the interval ``[9..15]``). :type request_max_window_bits: int """ if type(accept_no_context_takeover) != bool: raise Exception("invalid type %s for accept_no_context_takeover" % type(accept_no_context_takeover)) self.accept_no_context_takeover = accept_no_context_takeover if type(accept_max_window_bits) != bool: raise Exception("invalid type %s for accept_max_window_bits" % type(accept_max_window_bits)) self.accept_max_window_bits = accept_max_window_bits if type(request_no_context_takeover) != bool: raise Exception("invalid type %s for request_no_context_takeover" % type(request_no_context_takeover)) self.request_no_context_takeover = request_no_context_takeover if request_max_window_bits != 0 and request_max_window_bits not in self.WINDOW_SIZE_PERMISSIBLE_VALUES: raise Exception("invalid value %s for request_max_window_bits - permissible values %s" % (request_max_window_bits, self.WINDOW_SIZE_PERMISSIBLE_VALUES)) self.request_max_window_bits = request_max_window_bits def get_extension_string(self): """ Returns the WebSocket extension configuration string as sent to the server. :returns: PMCE configuration string. :rtype: str """ pmce_string = self.EXTENSION_NAME if self.accept_no_context_takeover: pmce_string += "; client_no_context_takeover" if self.accept_max_window_bits: pmce_string += "; client_max_window_bits" if self.request_no_context_takeover: pmce_string += "; server_no_context_takeover" if self.request_max_window_bits != 0: pmce_string += "; server_max_window_bits=%d" % self.request_max_window_bits return pmce_string def __json__(self): """ Returns a JSON serializable object representation. :returns: JSON serializable representation. :rtype: dict """ return {'extension': self.EXTENSION_NAME, 'accept_no_context_takeover': self.accept_no_context_takeover, 'accept_max_window_bits': self.accept_max_window_bits, 'request_no_context_takeover': self.request_no_context_takeover, 'request_max_window_bits': self.request_max_window_bits} def __repr__(self): """ Returns Python object representation that can be eval'ed to reconstruct the object. :returns: Python string representation. :rtype: str """ return "PerMessageDeflateOffer(accept_no_context_takeover = %s, accept_max_window_bits = %s, request_no_context_takeover = %s, request_max_window_bits = %s)" % (self.accept_no_context_takeover, self.accept_max_window_bits, self.request_no_context_takeover, self.request_max_window_bits) @public class PerMessageDeflateOfferAccept(PerMessageCompressOfferAccept, PerMessageDeflateMixin): """ Set of parameters with which to accept an `permessage-deflate` offer from a client by a server. """ def __init__(self, offer, request_no_context_takeover=False, request_max_window_bits=0, no_context_takeover=None, window_bits=None, mem_level=None, max_message_size=None): """ :param offer: The offer being accepted. :type offer: Instance of :class:`autobahn.compress.PerMessageDeflateOffer`. :param request_no_context_takeover: When ``True``, the server requests the "no context takeover" feature. :type request_no_context_takeover: bool :param request_max_window_bits: When non-zero, the server requests the given "max window size" (must be and integer from the interval ``[9..15]``). :param request_max_window_bits: int :param no_context_takeover: Override server ("server-to-client direction") context takeover (this must be compatible with the offer). :type no_context_takeover: bool :param window_bits: Override server ("server-to-client direction") window size (this must be compatible with the offer). :type window_bits: int :param mem_level: Set server ("server-to-client direction") memory level. :type mem_level: int """ if not isinstance(offer, PerMessageDeflateOffer): raise Exception("invalid type %s for offer" % type(offer)) self.offer = offer if type(request_no_context_takeover) != bool: raise Exception("invalid type %s for request_no_context_takeover" % type(request_no_context_takeover)) if request_no_context_takeover and not offer.accept_no_context_takeover: raise Exception("invalid value %s for request_no_context_takeover - feature unsupported by client" % request_no_context_takeover) self.request_no_context_takeover = request_no_context_takeover if request_max_window_bits != 0 and request_max_window_bits not in self.WINDOW_SIZE_PERMISSIBLE_VALUES: raise Exception("invalid value %s for request_max_window_bits - permissible values %s" % (request_max_window_bits, self.WINDOW_SIZE_PERMISSIBLE_VALUES)) if request_max_window_bits != 0 and not offer.accept_max_window_bits: raise Exception("invalid value %s for request_max_window_bits - feature unsupported by client" % request_max_window_bits) self.request_max_window_bits = request_max_window_bits if no_context_takeover is not None: if type(no_context_takeover) != bool: raise Exception("invalid type %s for no_context_takeover" % type(no_context_takeover)) if offer.request_no_context_takeover and not no_context_takeover: raise Exception("invalid value %s for no_context_takeover - client requested feature" % no_context_takeover) self.no_context_takeover = no_context_takeover if window_bits is not None: if window_bits not in self.WINDOW_SIZE_PERMISSIBLE_VALUES: raise Exception("invalid value %s for window_bits - permissible values %s" % (window_bits, self.WINDOW_SIZE_PERMISSIBLE_VALUES)) if offer.request_max_window_bits != 0 and window_bits > offer.request_max_window_bits: raise Exception("invalid value %s for window_bits - client requested lower maximum value" % window_bits) self.window_bits = window_bits if mem_level is not None: if mem_level not in self.MEM_LEVEL_PERMISSIBLE_VALUES: raise Exception("invalid value %s for mem_level - permissible values %s" % (mem_level, self.MEM_LEVEL_PERMISSIBLE_VALUES)) self.mem_level = mem_level self.max_message_size = max_message_size # clamp/check values..? def get_extension_string(self): """ Returns the WebSocket extension configuration string as sent to the server. :returns: PMCE configuration string. :rtype: str """ pmce_string = self.EXTENSION_NAME if self.offer.request_no_context_takeover: pmce_string += "; server_no_context_takeover" if self.offer.request_max_window_bits != 0: pmce_string += "; server_max_window_bits=%d" % self.offer.request_max_window_bits if self.request_no_context_takeover: pmce_string += "; client_no_context_takeover" if self.request_max_window_bits != 0: pmce_string += "; client_max_window_bits=%d" % self.request_max_window_bits return pmce_string def __json__(self): """ Returns a JSON serializable object representation. :returns: JSON serializable representation. :rtype: dict """ return { 'extension': self.EXTENSION_NAME, 'offer': self.offer.__json__(), 'request_no_context_takeover': self.request_no_context_takeover, 'request_max_window_bits': self.request_max_window_bits, 'no_context_takeover': self.no_context_takeover, 'window_bits': self.window_bits, 'mem_level': self.mem_level, 'max_message_size': self.max_message_size, } def __repr__(self): """ Returns Python object representation that can be eval'ed to reconstruct the object. :returns: Python string representation. :rtype: str """ return "PerMessageDeflateOfferAccept(offer = %s, request_no_context_takeover = %s, request_max_window_bits = %s, no_context_takeover = %s, window_bits = %s, mem_level = %s, max_message_size = %s)" % (self.offer.__repr__(), self.request_no_context_takeover, self.request_max_window_bits, self.no_context_takeover, self.window_bits, self.mem_level, self.max_message_size) @public class PerMessageDeflateResponse(PerMessageCompressResponse, PerMessageDeflateMixin): """ Set of parameters for `permessage-deflate` responded by server. """ @classmethod def parse(cls, params): """ Parses a WebSocket extension response for `permessage-deflate` provided by a server to a client. :param params: Output from :func:`autobahn.websocket.WebSocketProtocol._parseExtensionsHeader`. :type params: list :returns: A new instance of :class:`autobahn.compress.PerMessageDeflateResponse`. :rtype: obj """ client_max_window_bits = 0 client_no_context_takeover = False server_max_window_bits = 0 server_no_context_takeover = False for p in params: if len(params[p]) > 1: raise Exception("multiple occurrence of extension parameter '%s' for extension '%s'" % (p, cls.EXTENSION_NAME)) val = params[p][0] if p == 'client_max_window_bits': try: val = int(val) except: raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME)) else: if val not in PerMessageDeflateMixin.WINDOW_SIZE_PERMISSIBLE_VALUES: raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME)) else: client_max_window_bits = val elif p == 'client_no_context_takeover': # noinspection PySimplifyBooleanCheck if val is not True: raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME)) else: client_no_context_takeover = True elif p == 'server_max_window_bits': try: val = int(val) except: raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME)) else: if val not in PerMessageDeflateMixin.WINDOW_SIZE_PERMISSIBLE_VALUES: raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME)) else: server_max_window_bits = val elif p == 'server_no_context_takeover': # noinspection PySimplifyBooleanCheck if val is not True: raise Exception("illegal extension parameter value '%s' for parameter '%s' of extension '%s'" % (val, p, cls.EXTENSION_NAME)) else: server_no_context_takeover = True else: raise Exception("illegal extension parameter '%s' for extension '%s'" % (p, cls.EXTENSION_NAME)) response = cls(client_max_window_bits, client_no_context_takeover, server_max_window_bits, server_no_context_takeover) return response def __init__(self, client_max_window_bits, client_no_context_takeover, server_max_window_bits, server_no_context_takeover): """ :param client_max_window_bits: FIXME :type client_max_window_bits: int :param client_no_context_takeover: FIXME :type client_no_context_takeover: bool :param server_max_window_bits: FIXME :type server_max_window_bits: int :param server_no_context_takeover: FIXME :type server_no_context_takeover: bool """ self.client_max_window_bits = client_max_window_bits self.client_no_context_takeover = client_no_context_takeover self.server_max_window_bits = server_max_window_bits self.server_no_context_takeover = server_no_context_takeover def __json__(self): """ Returns a JSON serializable object representation. :returns: JSON serializable representation. :rtype: dict """ return {'extension': self.EXTENSION_NAME, 'client_max_window_bits': self.client_max_window_bits, 'client_no_context_takeover': self.client_no_context_takeover, 'server_max_window_bits': self.server_max_window_bits, 'server_no_context_takeover': self.server_no_context_takeover} def __repr__(self): """ Returns Python object representation that can be eval'ed to reconstruct the object. :returns: Python string representation. :rtype: str """ return "PerMessageDeflateResponse(client_max_window_bits = %s, client_no_context_takeover = %s, server_max_window_bits = %s, server_no_context_takeover = %s)" % (self.client_max_window_bits, self.client_no_context_takeover, self.server_max_window_bits, self.server_no_context_takeover) @public class PerMessageDeflateResponseAccept(PerMessageCompressResponseAccept, PerMessageDeflateMixin): """ Set of parameters with which to accept an `permessage-deflate` response from a server by a client. """ def __init__(self, response, no_context_takeover=None, window_bits=None, mem_level=None, max_message_size=None): """ :param response: The response being accepted. :type response: Instance of :class:`autobahn.compress.PerMessageDeflateResponse`. :param no_context_takeover: Override client ("client-to-server direction") context takeover (this must be compatible with response). :type no_context_takeover: bool :param window_bits: Override client ("client-to-server direction") window size (this must be compatible with response). :type window_bits: int :param mem_level: Set client ("client-to-server direction") memory level. :type mem_level: int """ if not isinstance(response, PerMessageDeflateResponse): raise Exception("invalid type %s for response" % type(response)) self.response = response if no_context_takeover is not None: if type(no_context_takeover) != bool: raise Exception("invalid type %s for no_context_takeover" % type(no_context_takeover)) if response.client_no_context_takeover and not no_context_takeover: raise Exception("invalid value %s for no_context_takeover - server requested feature" % no_context_takeover) self.no_context_takeover = no_context_takeover if window_bits is not None: if window_bits not in self.WINDOW_SIZE_PERMISSIBLE_VALUES: raise Exception("invalid value %s for window_bits - permissible values %s" % (window_bits, self.WINDOW_SIZE_PERMISSIBLE_VALUES)) if response.client_max_window_bits != 0 and window_bits > response.client_max_window_bits: raise Exception("invalid value %s for window_bits - server requested lower maximum value" % window_bits) self.window_bits = window_bits if mem_level is not None: if mem_level not in self.MEM_LEVEL_PERMISSIBLE_VALUES: raise Exception("invalid value %s for mem_level - permissible values %s" % (mem_level, self.MEM_LEVEL_PERMISSIBLE_VALUES)) self.mem_level = mem_level self.max_message_size = max_message_size def __json__(self): """ Returns a JSON serializable object representation. :returns: JSON serializable representation. :rtype: dict """ return {'extension': self.EXTENSION_NAME, 'response': self.response.__json__(), 'no_context_takeover': self.no_context_takeover, 'window_bits': self.window_bits, 'mem_level': self.mem_level} def __repr__(self): """ Returns Python object representation that can be eval'ed to reconstruct the object. :returns: Python string representation. :rtype: str """ return "PerMessageDeflateResponseAccept(response = %s, no_context_takeover = %s, window_bits = %s, mem_level = %s)" % (self.response.__repr__(), self.no_context_takeover, self.window_bits, self.mem_level) # noinspection PyArgumentList class PerMessageDeflate(PerMessageCompress, PerMessageDeflateMixin): """ `permessage-deflate` WebSocket extension processor. """ DEFAULT_WINDOW_BITS = zlib.MAX_WBITS DEFAULT_MEM_LEVEL = 8 @classmethod def create_from_response_accept(cls, is_server, accept): # accept: instance of PerMessageDeflateResponseAccept pmce = cls( is_server, accept.response.server_no_context_takeover, accept.no_context_takeover if accept.no_context_takeover is not None else accept.response.client_no_context_takeover, accept.response.server_max_window_bits, accept.window_bits if accept.window_bits is not None else accept.response.client_max_window_bits, accept.mem_level, accept.max_message_size, ) return pmce @classmethod def create_from_offer_accept(cls, is_server, accept): # accept: instance of PerMessageDeflateOfferAccept pmce = cls(is_server, accept.no_context_takeover if accept.no_context_takeover is not None else accept.offer.request_no_context_takeover, accept.request_no_context_takeover, accept.window_bits if accept.window_bits is not None else accept.offer.request_max_window_bits, accept.request_max_window_bits, accept.mem_level, accept.max_message_size,) return pmce def __init__(self, is_server, server_no_context_takeover, client_no_context_takeover, server_max_window_bits, client_max_window_bits, mem_level, max_message_size=None): self._is_server = is_server self.server_no_context_takeover = server_no_context_takeover self.client_no_context_takeover = client_no_context_takeover self.server_max_window_bits = server_max_window_bits if server_max_window_bits != 0 else self.DEFAULT_WINDOW_BITS self.client_max_window_bits = client_max_window_bits if client_max_window_bits != 0 else self.DEFAULT_WINDOW_BITS self.mem_level = mem_level if mem_level else self.DEFAULT_MEM_LEVEL self.max_message_size = max_message_size # None means "no limit" self._compressor = None self._decompressor = None def __json__(self): return {'extension': self.EXTENSION_NAME, 'is_server': self._is_server, 'server_no_context_takeover': self.server_no_context_takeover, 'client_no_context_takeover': self.client_no_context_takeover, 'server_max_window_bits': self.server_max_window_bits, 'client_max_window_bits': self.client_max_window_bits, 'mem_level': self.mem_level} def __repr__(self): return "PerMessageDeflate(is_server = %s, server_no_context_takeover = %s, client_no_context_takeover = %s, server_max_window_bits = %s, client_max_window_bits = %s, mem_level = %s)" % (self._is_server, self.server_no_context_takeover, self.client_no_context_takeover, self.server_max_window_bits, self.client_max_window_bits, self.mem_level) def start_compress_message(self): # compressobj([level[, method[, wbits[, mem_level[, strategy]]]]]) # http://bugs.python.org/issue19278 # http://hg.python.org/cpython/rev/c54c8e71b79a if self._is_server: if self._compressor is None or self.server_no_context_takeover: self._compressor = zlib.compressobj(zlib.Z_DEFAULT_COMPRESSION, zlib.DEFLATED, -self.server_max_window_bits, self.mem_level) else: if self._compressor is None or self.client_no_context_takeover: self._compressor = zlib.compressobj(zlib.Z_DEFAULT_COMPRESSION, zlib.DEFLATED, -self.client_max_window_bits, self.mem_level) def compress_message_data(self, data): return self._compressor.compress(data) def end_compress_message(self): data = self._compressor.flush(zlib.Z_SYNC_FLUSH) return data[:-4] def start_decompress_message(self): if self._is_server: if self._decompressor is None or self.client_no_context_takeover: self._decompressor = zlib.decompressobj(-self.client_max_window_bits) else: if self._decompressor is None or self.server_no_context_takeover: self._decompressor = zlib.decompressobj(-self.server_max_window_bits) def decompress_message_data(self, data): if self.max_message_size is not None: return self._decompressor.decompress(data, self.max_message_size) return self._decompressor.decompress(data) def end_decompress_message(self): # Eat stripped LEN and NLEN field of a non-compressed block added # for Z_SYNC_FLUSH. self._decompressor.decompress(b'\x00\x00\xff\xff')