diff options
Diffstat (limited to 'testing/mochitest/pywebsocket3/mod_pywebsocket/extensions.py')
| -rw-r--r-- | testing/mochitest/pywebsocket3/mod_pywebsocket/extensions.py | 473 |
1 files changed, 473 insertions, 0 deletions
diff --git a/testing/mochitest/pywebsocket3/mod_pywebsocket/extensions.py b/testing/mochitest/pywebsocket3/mod_pywebsocket/extensions.py new file mode 100644 index 0000000000..344539f6fc --- /dev/null +++ b/testing/mochitest/pywebsocket3/mod_pywebsocket/extensions.py @@ -0,0 +1,473 @@ +# Copyright 2012, Google Inc. +# All rights reserved. +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions are +# met: +# +# * Redistributions of source code must retain the above copyright +# notice, this list of conditions and the following disclaimer. +# * Redistributions in binary form must reproduce the above +# copyright notice, this list of conditions and the following disclaimer +# in the documentation and/or other materials provided with the +# distribution. +# * Neither the name of Google Inc. nor the names of its +# contributors may be used to endorse or promote products derived from +# this software without specific prior written permission. +# +# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +from __future__ import absolute_import +from mod_pywebsocket import common +from mod_pywebsocket import util +from mod_pywebsocket.http_header_util import quote_if_necessary + +# The list of available server side extension processor classes. +_available_processors = {} + + +class ExtensionProcessorInterface(object): + def __init__(self, request): + self._logger = util.get_class_logger(self) + + self._request = request + self._active = True + + def request(self): + return self._request + + def name(self): + return None + + def check_consistency_with_other_processors(self, processors): + pass + + def set_active(self, active): + self._active = active + + def is_active(self): + return self._active + + def _get_extension_response_internal(self): + return None + + def get_extension_response(self): + if not self._active: + self._logger.debug('Extension %s is deactivated', self.name()) + return None + + response = self._get_extension_response_internal() + if response is None: + self._active = False + return response + + def _setup_stream_options_internal(self, stream_options): + pass + + def setup_stream_options(self, stream_options): + if self._active: + self._setup_stream_options_internal(stream_options) + + +def _log_outgoing_compression_ratio(logger, original_bytes, filtered_bytes, + average_ratio): + # Print inf when ratio is not available. + ratio = float('inf') + if original_bytes != 0: + ratio = float(filtered_bytes) / original_bytes + + logger.debug('Outgoing compression ratio: %f (average: %f)' % + (ratio, average_ratio)) + + +def _log_incoming_compression_ratio(logger, received_bytes, filtered_bytes, + average_ratio): + # Print inf when ratio is not available. + ratio = float('inf') + if filtered_bytes != 0: + ratio = float(received_bytes) / filtered_bytes + + logger.debug('Incoming compression ratio: %f (average: %f)' % + (ratio, average_ratio)) + + +def _parse_window_bits(bits): + """Return parsed integer value iff the given string conforms to the + grammar of the window bits extension parameters. + """ + + if bits is None: + raise ValueError('Value is required') + + # For non integer values such as "10.0", ValueError will be raised. + int_bits = int(bits) + + # First condition is to drop leading zero case e.g. "08". + if bits != str(int_bits) or int_bits < 8 or int_bits > 15: + raise ValueError('Invalid value: %r' % bits) + + return int_bits + + +class _AverageRatioCalculator(object): + """Stores total bytes of original and result data, and calculates average + result / original ratio. + """ + def __init__(self): + self._total_original_bytes = 0 + self._total_result_bytes = 0 + + def add_original_bytes(self, value): + self._total_original_bytes += value + + def add_result_bytes(self, value): + self._total_result_bytes += value + + def get_average_ratio(self): + if self._total_original_bytes != 0: + return (float(self._total_result_bytes) / + self._total_original_bytes) + else: + return float('inf') + + +class PerMessageDeflateExtensionProcessor(ExtensionProcessorInterface): + """permessage-deflate extension processor. + + Specification: + http://tools.ietf.org/html/draft-ietf-hybi-permessage-compression-08 + """ + + _SERVER_MAX_WINDOW_BITS_PARAM = 'server_max_window_bits' + _SERVER_NO_CONTEXT_TAKEOVER_PARAM = 'server_no_context_takeover' + _CLIENT_MAX_WINDOW_BITS_PARAM = 'client_max_window_bits' + _CLIENT_NO_CONTEXT_TAKEOVER_PARAM = 'client_no_context_takeover' + + def __init__(self, request): + """Construct PerMessageDeflateExtensionProcessor.""" + + ExtensionProcessorInterface.__init__(self, request) + self._logger = util.get_class_logger(self) + + self._preferred_client_max_window_bits = None + self._client_no_context_takeover = False + + def name(self): + # This method returns "deflate" (not "permessage-deflate") for + # compatibility. + return 'deflate' + + def _get_extension_response_internal(self): + for name in self._request.get_parameter_names(): + if name not in [ + self._SERVER_MAX_WINDOW_BITS_PARAM, + self._SERVER_NO_CONTEXT_TAKEOVER_PARAM, + self._CLIENT_MAX_WINDOW_BITS_PARAM + ]: + self._logger.debug('Unknown parameter: %r', name) + return None + + server_max_window_bits = None + if self._request.has_parameter(self._SERVER_MAX_WINDOW_BITS_PARAM): + server_max_window_bits = self._request.get_parameter_value( + self._SERVER_MAX_WINDOW_BITS_PARAM) + try: + server_max_window_bits = _parse_window_bits( + server_max_window_bits) + except ValueError as e: + self._logger.debug('Bad %s parameter: %r', + self._SERVER_MAX_WINDOW_BITS_PARAM, e) + return None + + server_no_context_takeover = self._request.has_parameter( + self._SERVER_NO_CONTEXT_TAKEOVER_PARAM) + if (server_no_context_takeover and self._request.get_parameter_value( + self._SERVER_NO_CONTEXT_TAKEOVER_PARAM) is not None): + self._logger.debug('%s parameter must not have a value: %r', + self._SERVER_NO_CONTEXT_TAKEOVER_PARAM, + server_no_context_takeover) + return None + + # client_max_window_bits from a client indicates whether the client can + # accept client_max_window_bits from a server or not. + client_client_max_window_bits = self._request.has_parameter( + self._CLIENT_MAX_WINDOW_BITS_PARAM) + if (client_client_max_window_bits + and self._request.get_parameter_value( + self._CLIENT_MAX_WINDOW_BITS_PARAM) is not None): + self._logger.debug( + '%s parameter must not have a value in a ' + 'client\'s opening handshake: %r', + self._CLIENT_MAX_WINDOW_BITS_PARAM, + client_client_max_window_bits) + return None + + self._rfc1979_deflater = util._RFC1979Deflater( + server_max_window_bits, server_no_context_takeover) + + # Note that we prepare for incoming messages compressed with window + # bits upto 15 regardless of the client_max_window_bits value to be + # sent to the client. + self._rfc1979_inflater = util._RFC1979Inflater() + + self._framer = _PerMessageDeflateFramer(server_max_window_bits, + server_no_context_takeover) + self._framer.set_bfinal(False) + self._framer.set_compress_outgoing_enabled(True) + + response = common.ExtensionParameter(self._request.name()) + + if server_max_window_bits is not None: + response.add_parameter(self._SERVER_MAX_WINDOW_BITS_PARAM, + str(server_max_window_bits)) + + if server_no_context_takeover: + response.add_parameter(self._SERVER_NO_CONTEXT_TAKEOVER_PARAM, + None) + + if self._preferred_client_max_window_bits is not None: + if not client_client_max_window_bits: + self._logger.debug( + 'Processor is configured to use %s but ' + 'the client cannot accept it', + self._CLIENT_MAX_WINDOW_BITS_PARAM) + return None + response.add_parameter(self._CLIENT_MAX_WINDOW_BITS_PARAM, + str(self._preferred_client_max_window_bits)) + + if self._client_no_context_takeover: + response.add_parameter(self._CLIENT_NO_CONTEXT_TAKEOVER_PARAM, + None) + + self._logger.debug('Enable %s extension (' + 'request: server_max_window_bits=%s; ' + 'server_no_context_takeover=%r, ' + 'response: client_max_window_bits=%s; ' + 'client_no_context_takeover=%r)' % + (self._request.name(), server_max_window_bits, + server_no_context_takeover, + self._preferred_client_max_window_bits, + self._client_no_context_takeover)) + + return response + + def _setup_stream_options_internal(self, stream_options): + self._framer.setup_stream_options(stream_options) + + def set_client_max_window_bits(self, value): + """If this option is specified, this class adds the + client_max_window_bits extension parameter to the handshake response, + but doesn't reduce the LZ77 sliding window size of its inflater. + I.e., you can use this for testing client implementation but cannot + reduce memory usage of this class. + + If this method has been called with True and an offer without the + client_max_window_bits extension parameter is received, + - (When processing the permessage-deflate extension) this processor + declines the request. + - (When processing the permessage-compress extension) this processor + accepts the request. + """ + + self._preferred_client_max_window_bits = value + + def set_client_no_context_takeover(self, value): + """If this option is specified, this class adds the + client_no_context_takeover extension parameter to the handshake + response, but doesn't reset inflater for each message. I.e., you can + use this for testing client implementation but cannot reduce memory + usage of this class. + """ + + self._client_no_context_takeover = value + + def set_bfinal(self, value): + self._framer.set_bfinal(value) + + def enable_outgoing_compression(self): + self._framer.set_compress_outgoing_enabled(True) + + def disable_outgoing_compression(self): + self._framer.set_compress_outgoing_enabled(False) + + +class _PerMessageDeflateFramer(object): + """A framer for extensions with per-message DEFLATE feature.""" + def __init__(self, deflate_max_window_bits, deflate_no_context_takeover): + self._logger = util.get_class_logger(self) + + self._rfc1979_deflater = util._RFC1979Deflater( + deflate_max_window_bits, deflate_no_context_takeover) + + self._rfc1979_inflater = util._RFC1979Inflater() + + self._bfinal = False + + self._compress_outgoing_enabled = False + + # True if a message is fragmented and compression is ongoing. + self._compress_ongoing = False + + # Calculates + # (Total outgoing bytes supplied to this filter) / + # (Total bytes sent to the network after applying this filter) + self._outgoing_average_ratio_calculator = _AverageRatioCalculator() + + # Calculates + # (Total bytes received from the network) / + # (Total incoming bytes obtained after applying this filter) + self._incoming_average_ratio_calculator = _AverageRatioCalculator() + + def set_bfinal(self, value): + self._bfinal = value + + def set_compress_outgoing_enabled(self, value): + self._compress_outgoing_enabled = value + + def _process_incoming_message(self, message, decompress): + if not decompress: + return message + + received_payload_size = len(message) + self._incoming_average_ratio_calculator.add_result_bytes( + received_payload_size) + + message = self._rfc1979_inflater.filter(message) + + filtered_payload_size = len(message) + self._incoming_average_ratio_calculator.add_original_bytes( + filtered_payload_size) + + _log_incoming_compression_ratio( + self._logger, received_payload_size, filtered_payload_size, + self._incoming_average_ratio_calculator.get_average_ratio()) + + return message + + def _process_outgoing_message(self, message, end, binary): + if not binary: + message = message.encode('utf-8') + + if not self._compress_outgoing_enabled: + return message + + original_payload_size = len(message) + self._outgoing_average_ratio_calculator.add_original_bytes( + original_payload_size) + + message = self._rfc1979_deflater.filter(message, + end=end, + bfinal=self._bfinal) + + filtered_payload_size = len(message) + self._outgoing_average_ratio_calculator.add_result_bytes( + filtered_payload_size) + + _log_outgoing_compression_ratio( + self._logger, original_payload_size, filtered_payload_size, + self._outgoing_average_ratio_calculator.get_average_ratio()) + + if not self._compress_ongoing: + self._outgoing_frame_filter.set_compression_bit() + self._compress_ongoing = not end + return message + + def _process_incoming_frame(self, frame): + if frame.rsv1 == 1 and not common.is_control_opcode(frame.opcode): + self._incoming_message_filter.decompress_next_message() + frame.rsv1 = 0 + + def _process_outgoing_frame(self, frame, compression_bit): + if (not compression_bit or common.is_control_opcode(frame.opcode)): + return + + frame.rsv1 = 1 + + def setup_stream_options(self, stream_options): + """Creates filters and sets them to the StreamOptions.""" + class _OutgoingMessageFilter(object): + def __init__(self, parent): + self._parent = parent + + def filter(self, message, end=True, binary=False): + return self._parent._process_outgoing_message( + message, end, binary) + + class _IncomingMessageFilter(object): + def __init__(self, parent): + self._parent = parent + self._decompress_next_message = False + + def decompress_next_message(self): + self._decompress_next_message = True + + def filter(self, message): + message = self._parent._process_incoming_message( + message, self._decompress_next_message) + self._decompress_next_message = False + return message + + self._outgoing_message_filter = _OutgoingMessageFilter(self) + self._incoming_message_filter = _IncomingMessageFilter(self) + stream_options.outgoing_message_filters.append( + self._outgoing_message_filter) + stream_options.incoming_message_filters.append( + self._incoming_message_filter) + + class _OutgoingFrameFilter(object): + def __init__(self, parent): + self._parent = parent + self._set_compression_bit = False + + def set_compression_bit(self): + self._set_compression_bit = True + + def filter(self, frame): + self._parent._process_outgoing_frame(frame, + self._set_compression_bit) + self._set_compression_bit = False + + class _IncomingFrameFilter(object): + def __init__(self, parent): + self._parent = parent + + def filter(self, frame): + self._parent._process_incoming_frame(frame) + + self._outgoing_frame_filter = _OutgoingFrameFilter(self) + self._incoming_frame_filter = _IncomingFrameFilter(self) + stream_options.outgoing_frame_filters.append( + self._outgoing_frame_filter) + stream_options.incoming_frame_filters.append( + self._incoming_frame_filter) + + stream_options.encode_text_message_to_utf8 = False + + +_available_processors[common.PERMESSAGE_DEFLATE_EXTENSION] = ( + PerMessageDeflateExtensionProcessor) + + +def get_extension_processor(extension_request): + """Given an ExtensionParameter representing an extension offer received + from a client, configures and returns an instance of the corresponding + extension processor class. + """ + + processor_class = _available_processors.get(extension_request.name()) + if processor_class is None: + return None + return processor_class(extension_request) + + +# vi:sts=4 sw=4 et |