# Copyright 2013, Google Inc. All rights reserved.
#
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# 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 six.moves.urllib import parse
import zlib
from mod_pywebsocket import common
from mod_pywebsocket import util
from mod_pywebsocket.extensions import PerMessageDeflateExtensionProcessor
from mod_pywebsocket.extensions import ExtensionProcessorInterface
from mod_pywebsocket.common import ExtensionParameter
_GOODBYE_MESSAGE = u'Goodbye'
_ENABLE_MESSAGE = u'EnableCompression'
_DISABLE_MESSAGE = u'DisableCompression'
_bfinal = False
_client_max_window_bits = 15
def _get_permessage_deflate_extension_processor(request):
for extension_processor in request.ws_extension_processors:
if isinstance(extension_processor, PerMessageDeflateExtensionProcessor):
return extension_processor
return None
def web_socket_do_extra_handshake(request):
global _bfinal
global _client_max_window_bits
processor = _get_permessage_deflate_extension_processor(request)
# Remove extension processors other than
# PerMessageDeflateExtensionProcessor to avoid conflict.
request.ws_extension_processors = [processor]
if not processor:
return
r = request.ws_resource.split('?', 1)
if len(r) == 1:
return
parameters = parse.parse_qs(r[1], keep_blank_values=True)
if 'client_max_window_bits' in parameters:
window_bits = int(parameters['client_max_window_bits'][0])
processor.set_client_max_window_bits(window_bits)
_client_max_window_bits = window_bits
if 'client_no_context_takeover' in parameters:
processor.set_client_no_context_takeover(True)
if 'set_bfinal' in parameters:
_bfinal = True
def receive(request):
stream = request.ws_stream
possibly_compressed_body = b''
compress = False
while True:
frame = stream._receive_frame_as_frame_object()
if frame.opcode == common.OPCODE_CLOSE:
message = stream._get_message_from_frame(frame)
stream._process_close_message(message)
return (False, None)
compress = compress or frame.rsv1
possibly_compressed_body += frame.payload
if frame.fin:
break
if compress:
return (compress, possibly_compressed_body + b'\x00\x00\xff\xff')
else:
return (compress, possibly_compressed_body)
def web_socket_transfer_data(request):
processor = _get_permessage_deflate_extension_processor(request)
processor.set_bfinal(_bfinal)
inflater = util._Inflater(_client_max_window_bits)
while True:
compress, possibly_compressed_body = receive(request)
body = None
if possibly_compressed_body is None:
return
if compress:
inflater.append(possibly_compressed_body)
body = inflater.decompress(-1)
else:
body = possibly_compressed_body
text = body.decode('utf-8')
if processor:
if text == _ENABLE_MESSAGE:
processor.enable_outgoing_compression()
elif text == _DISABLE_MESSAGE:
processor.disable_outgoing_compression()
request.ws_stream.send_message(text, binary=False)
if text == _GOODBYE_MESSAGE:
return
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