def _outgoing_filter(self, frame):
"""Transform outgoing frames. This method is called only by
an _OutgoingFilter instance.
"""
original_payload_size = len(frame.payload)
self._outgoing_average_ratio_calculator.add_original_bytes(
original_payload_size)
if (not self._compress_outgoing
or common.is_control_opcode(frame.opcode)):
self._outgoing_average_ratio_calculator.add_result_bytes(
original_payload_size)
return
frame.payload = self._rfc1979_deflater.filter(frame.payload,
bfinal=self._bfinal)
frame.rsv1 = 1
filtered_payload_size = len(frame.payload)
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())
def _get_message_from_frame(self, frame):
"""Gets a message from frame. If the message is composed of fragmented
frames and the frame is not the last fragmented frame, this method
returns None. The whole message will be returned when the last
fragmented frame is passed to this method.
Raises:
InvalidFrameException: when the frame doesn't match defragmentation
context, or the frame contains invalid data.
"""
if frame.opcode == common.OPCODE_CONTINUATION:
if not self._received_fragments:
if frame.fin:
raise InvalidFrameException(
'Received a termination frame but fragmentation '
'not started')
else:
raise InvalidFrameException(
'Received an intermediate frame but '
'fragmentation not started')
if frame.fin:
# End of fragmentation frame
self._received_fragments.append(frame.payload)
message = ''.join(self._received_fragments)
self._received_fragments = []
return message
else:
# Intermediate frame
self._received_fragments.append(frame.payload)
return None
else:
if self._received_fragments:
if frame.fin:
raise InvalidFrameException(
'Received an unfragmented frame without '
'terminating existing fragmentation')
else:
raise InvalidFrameException(
'New fragmentation started without terminating '
'existing fragmentation')
if frame.fin:
# Unfragmented frame
self._original_opcode = frame.opcode
return frame.payload
else:
# Start of fragmentation frame
if common.is_control_opcode(frame.opcode):
raise InvalidFrameException(
'Control frames must not be fragmented')
self._original_opcode = frame.opcode
self._received_fragments.append(frame.payload)
return None
def _incoming_filter(self, frame):
"""Transform incoming frames. This method is called only by
an _IncomingFilter instance.
"""
received_payload_size = len(frame.payload)
self._incoming_average_ratio_calculator.add_result_bytes(
received_payload_size)
if frame.rsv1 != 1 or common.is_control_opcode(frame.opcode):
self._incoming_average_ratio_calculator.add_original_bytes(
received_payload_size)
return
frame.payload = self._rfc1979_inflater.filter(frame.payload)
frame.rsv1 = 0
filtered_payload_size = len(frame.payload)
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())
def _process_outgoing_frame(self, frame, compression_bit):
if (not compression_bit or common.is_control_opcode(frame.opcode)):
return
frame.rsv1 = 1
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 receive_message(self):
"""Receive a WebSocket frame and return its payload as a text in
unicode or a binary in str.
Returns:
payload data of the frame
- as unicode instance if received text frame
- as str instance if received binary frame
or None iff received closing handshake.
Raises:
BadOperationException: when called on a client-terminated
connection.
ConnectionTerminatedException: when read returns empty
string.
InvalidFrameException: when the frame contains invalid
data.
UnsupportedFrameException: when the received frame has
flags, opcode we cannot handle. You can ignore this
exception and continue receiving the next frame.
"""
if self._request.client_terminated:
raise BadOperationException(
'Requested receive_message after receiving a closing '
'handshake')
while True:
# mp_conn.read will block if no bytes are available.
# Timeout is controlled by TimeOut directive of Apache.
frame = self._receive_frame_as_frame_object()
# Check the constraint on the payload size for control frames
# before extension processes the frame.
# See also http://tools.ietf.org/html/rfc6455#section-5.5
if (common.is_control_opcode(frame.opcode)
and len(frame.payload) > 125):
raise InvalidFrameException(
'Payload data size of control frames must be 125 bytes or '
'less')
for frame_filter in self._options.incoming_frame_filters:
frame_filter.filter(frame)
if frame.rsv1 or frame.rsv2 or frame.rsv3:
raise UnsupportedFrameException(
'Unsupported flag is set (rsv = %d%d%d)' %
(frame.rsv1, frame.rsv2, frame.rsv3))
message = self._get_message_from_frame(frame)
if message is None:
continue
for message_filter in self._options.incoming_message_filters:
message = message_filter.filter(message)
if self._original_opcode == common.OPCODE_TEXT:
# The WebSocket protocol section 4.4 specifies that invalid
# characters must be replaced with U+fffd REPLACEMENT
# CHARACTER.
try:
return message.decode('utf-8')
except UnicodeDecodeError as e:
raise InvalidUTF8Exception(e)
elif self._original_opcode == common.OPCODE_BINARY:
return message
elif self._original_opcode == common.OPCODE_CLOSE:
self._process_close_message(message)
return None
elif self._original_opcode == common.OPCODE_PING:
self._process_ping_message(message)
elif self._original_opcode == common.OPCODE_PONG:
self._process_pong_message(message)
else:
raise UnsupportedFrameException('Opcode %d is not supported' %
self._original_opcode)