in ambari-common/src/main/python/ambari_ws4py/streaming.py [0:0]
def receiver(self):
"""
Parser that keeps trying to interpret bytes it is fed with as
incoming frames part of a message.
Control message are single frames only while data messages, like text
and binary, may be fragmented accross frames.
The way it works is by instanciating a :class:`wspy.framing.Frame` object,
then running its parser generator which yields how much bytes
it requires to performs its task. The stream parser yields this value
to its caller and feeds the frame parser.
When the frame parser raises :exc:`StopIteration`, the stream parser
tries to make sense of the parsed frame. It dispatches the frame's bytes
to the most appropriate message type based on the frame's opcode.
Overall this makes the stream parser totally agonstic to
the data provider.
"""
utf8validator = Utf8Validator()
running = True
frame = None
while running:
frame = Frame()
while 1:
try:
some_bytes = yield next(frame.parser)
frame.parser.send(some_bytes)
except GeneratorExit:
running = False
break
except StopIteration:
frame._cleanup()
some_bytes = frame.body
# Let's avoid unmasking when there is no payload
if some_bytes:
if frame.masking_key and self.expect_masking:
some_bytes = frame.unmask(some_bytes)
elif not frame.masking_key and self.expect_masking:
msg = CloseControlMessage(
code=1002, reason="Missing masking when expected"
)
self.errors.append(msg)
break
elif frame.masking_key and not self.expect_masking:
msg = CloseControlMessage(code=1002, reason="Masked when not expected")
self.errors.append(msg)
break
else:
# If we reach this stage, it's because
# the frame wasn't masked and we didn't expect
# it anyway. Therefore, on py2k, the bytes
# are actually a str object and can't be used
# in the utf8 validator as we need integers
# when we get each byte one by one.
# Our only solution here is to convert our
# string to a bytearray.
some_bytes = bytearray(some_bytes)
if frame.opcode == OPCODE_TEXT:
if self.message and not self.message.completed:
# We got a text frame before we completed the previous one
msg = CloseControlMessage(
code=1002, reason="Received a new message before completing previous"
)
self.errors.append(msg)
break
m = TextMessage(some_bytes)
m.completed = frame.fin == 1
self.message = m
if some_bytes:
is_valid, end_on_code_point, _, _ = utf8validator.validate(some_bytes)
if not is_valid or (m.completed and not end_on_code_point):
self.errors.append(
CloseControlMessage(code=1007, reason="Invalid UTF-8 bytes")
)
break
elif frame.opcode == OPCODE_BINARY:
if self.message and not self.message.completed:
# We got a text frame before we completed the previous one
msg = CloseControlMessage(
code=1002, reason="Received a new message before completing previous"
)
self.errors.append(msg)
break
m = BinaryMessage(some_bytes)
m.completed = frame.fin == 1
self.message = m
elif frame.opcode == OPCODE_CONTINUATION:
m = self.message
if m is None:
self.errors.append(
CloseControlMessage(code=1002, reason="Message not started yet")
)
break
m.extend(some_bytes)
m.completed = frame.fin == 1
if m.opcode == OPCODE_TEXT:
if some_bytes:
is_valid, end_on_code_point, _, _ = utf8validator.validate(some_bytes)
if not is_valid or (m.completed and not end_on_code_point):
self.errors.append(
CloseControlMessage(code=1007, reason="Invalid UTF-8 bytes")
)
break
elif frame.opcode == OPCODE_CLOSE:
code = 1005
reason = ""
if frame.payload_length == 0:
self.closing = CloseControlMessage(code=1005)
elif frame.payload_length == 1:
self.closing = CloseControlMessage(
code=1005, reason="Payload has invalid length"
)
else:
try:
# at this stage, some_bytes have been unmasked
# so actually are held in a bytearray
code = int(unpack("!H", bytes(some_bytes[0:2]))[0])
except struct.error:
reason = "Failed at decoding closing code"
else:
# Those codes are reserved or plainly forbidden
if code not in VALID_CLOSING_CODES and not (2999 < code < 5000):
reason = "Invalid Closing Frame Code: %d" % code
code = 1005
elif frame.payload_length > 1:
reason = some_bytes[2:] if frame.masking_key else frame.body[2:]
if not py3k:
reason = bytearray(reason)
is_valid, end_on_code_point, _, _ = utf8validator.validate(reason)
if not is_valid or not end_on_code_point:
self.errors.append(
CloseControlMessage(code=1007, reason="Invalid UTF-8 bytes")
)
break
reason = bytes(reason)
self.closing = CloseControlMessage(code=code, reason=reason)
elif frame.opcode == OPCODE_PING:
self.pings.append(PingControlMessage(some_bytes))
elif frame.opcode == OPCODE_PONG:
self.pongs.append(PongControlMessage(some_bytes))
else:
self.errors.append(CloseControlMessage(code=1003))
break
except ProtocolException:
self.errors.append(CloseControlMessage(code=1002))
break
except FrameTooLargeException:
self.errors.append(
CloseControlMessage(code=1002, reason="Frame was too large")
)
break
frame._cleanup()
frame.body = None
frame = None
if self.message is not None and self.message.completed:
utf8validator.reset()
utf8validator.reset()
utf8validator = None
self._cleanup()