def receive_filtered_frame(self):
"""Receives a frame and applies frame filters and message filters.
The frame to be received must satisfy following conditions:
- The frame is not fragmented.
- The opcode of the frame is TEXT or BINARY.
DO NOT USE this method except for testing purpose.
"""
frame = self._receive_frame_as_frame_object()
if not frame.fin:
raise InvalidFrameException(
'Segmented frames must not be received via '
'receive_filtered_frame()')
if (frame.opcode != common.OPCODE_TEXT
and frame.opcode != common.OPCODE_BINARY):
raise InvalidFrameException(
'Control frames must not be received via '
'receive_filtered_frame()')
for frame_filter in self._options.incoming_frame_filters:
frame_filter.filter(frame)
for message_filter in self._options.incoming_message_filters:
frame.payload = message_filter.filter(frame.payload)
return frame
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 = b''.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 _process_close_message(self, message):
"""Processes close message.
Args:
message: close message.
Raises:
InvalidFrameException: when the message is invalid.
"""
self._request.client_terminated = True
# Status code is optional. We can have status reason only if we
# have status code. Status reason can be empty string. So,
# allowed cases are
# - no application data: no code no reason
# - 2 octet of application data: has code but no reason
# - 3 or more octet of application data: both code and reason
if len(message) == 0:
self._logger.debug('Received close frame (empty body)')
self._request.ws_close_code = common.STATUS_NO_STATUS_RECEIVED
elif len(message) == 1:
raise InvalidFrameException(
'If a close frame has status code, the length of '
'status code must be 2 octet')
elif len(message) >= 2:
self._request.ws_close_code = struct.unpack('!H', message[0:2])[0]
self._request.ws_close_reason = message[2:].decode(
'utf-8', 'replace')
self._logger.debug('Received close frame (code=%d, reason=%r)',
self._request.ws_close_code,
self._request.ws_close_reason)
# As we've received a close frame, no more data is coming over the
# socket. We can now safely close the socket without worrying about
# RST sending.
if self._request.server_terminated:
self._logger.debug(
'Received ack for server-initiated closing handshake')
return
self._logger.debug('Received client-initiated closing handshake')
code = common.STATUS_NORMAL_CLOSURE
reason = ''
if hasattr(self._request, '_dispatcher'):
dispatcher = self._request._dispatcher
code, reason = dispatcher.passive_closing_handshake(self._request)
if code is None and reason is not None and len(reason) > 0:
self._logger.warning(
'Handler specified reason despite code being None')
reason = ''
if reason is None:
reason = ''
self._send_closing_handshake(code, reason)
self._logger.debug(
'Acknowledged closing handshake initiated by the peer '
'(code=%r, reason=%r)', code, reason)
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.
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)
def parse_frame(receive_bytes,
logger=None,
ws_version=common.VERSION_HYBI_LATEST,
unmask_receive=True):
"""Parses a frame. Returns a tuple containing each header field and
payload.
Args:
receive_bytes: a function that reads frame data from a stream or
something similar. The function takes length of the bytes to be
read. The function must raise ConnectionTerminatedException if
there is not enough data to be read.
logger: a logging object.
ws_version: the version of WebSocket protocol.
unmask_receive: unmask received frames. When received unmasked
frame, raises InvalidFrameException.
Raises:
ConnectionTerminatedException: when receive_bytes raises it.
InvalidFrameException: when the frame contains invalid data.
"""
if not logger:
logger = logging.getLogger()
logger.log(common.LOGLEVEL_FINE, 'Receive the first 2 octets of a frame')
first_byte = ord(receive_bytes(1))
fin = (first_byte >> 7) & 1
rsv1 = (first_byte >> 6) & 1
rsv2 = (first_byte >> 5) & 1
rsv3 = (first_byte >> 4) & 1
opcode = first_byte & 0xf
second_byte = ord(receive_bytes(1))
mask = (second_byte >> 7) & 1
payload_length = second_byte & 0x7f
logger.log(
common.LOGLEVEL_FINE, 'FIN=%s, RSV1=%s, RSV2=%s, RSV3=%s, opcode=%s, '
'Mask=%s, Payload_length=%s', fin, rsv1, rsv2, rsv3, opcode, mask,
payload_length)
if (mask == 1) != unmask_receive:
raise InvalidFrameException(
'Mask bit on the received frame did\'nt match masking '
'configuration for received frames')
# The HyBi and later specs disallow putting a value in 0x0-0xFFFF
# into the 8-octet extended payload length field (or 0x0-0xFD in
# 2-octet field).
valid_length_encoding = True
length_encoding_bytes = 1
if payload_length == 127:
logger.log(common.LOGLEVEL_FINE,
'Receive 8-octet extended payload length')
extended_payload_length = receive_bytes(8)
payload_length = struct.unpack('!Q', extended_payload_length)[0]
if payload_length > 0x7FFFFFFFFFFFFFFF:
raise InvalidFrameException('Extended payload length >= 2^63')
if ws_version >= 13 and payload_length < 0x10000:
valid_length_encoding = False
length_encoding_bytes = 8
logger.log(common.LOGLEVEL_FINE, 'Decoded_payload_length=%s',
payload_length)
elif payload_length == 126:
logger.log(common.LOGLEVEL_FINE,
'Receive 2-octet extended payload length')
extended_payload_length = receive_bytes(2)
payload_length = struct.unpack('!H', extended_payload_length)[0]
if ws_version >= 13 and payload_length < 126:
valid_length_encoding = False
length_encoding_bytes = 2
logger.log(common.LOGLEVEL_FINE, 'Decoded_payload_length=%s',
payload_length)
if not valid_length_encoding:
logger.warning(
'Payload length is not encoded using the minimal number of '
'bytes (%d is encoded using %d bytes)', payload_length,
length_encoding_bytes)
if mask == 1:
logger.log(common.LOGLEVEL_FINE, 'Receive mask')
masking_nonce = receive_bytes(4)
masker = util.RepeatedXorMasker(masking_nonce)
logger.log(common.LOGLEVEL_FINE, 'Mask=%r', masking_nonce)
else:
masker = _NOOP_MASKER
logger.log(common.LOGLEVEL_FINE, 'Receive payload data')
if logger.isEnabledFor(common.LOGLEVEL_FINE):
receive_start = time.time()
raw_payload_bytes = receive_bytes(payload_length)
if logger.isEnabledFor(common.LOGLEVEL_FINE):
logger.log(
common.LOGLEVEL_FINE, 'Done receiving payload data at %s MB/s',
payload_length / (time.time() - receive_start) / 1000 / 1000)
logger.log(common.LOGLEVEL_FINE, 'Unmask payload data')
if logger.isEnabledFor(common.LOGLEVEL_FINE):
unmask_start = time.time()
unmasked_bytes = masker.mask(raw_payload_bytes)
if logger.isEnabledFor(common.LOGLEVEL_FINE):
logger.log(common.LOGLEVEL_FINE,
'Done unmasking payload data at %s MB/s',
payload_length / (time.time() - unmask_start) / 1000 / 1000)
return opcode, unmasked_bytes, fin, rsv1, rsv2, rsv3