def _h3_event_received(self, event: H3Event) -> None:
if isinstance(event, HeadersReceived):
# Convert from List[Tuple[bytes, bytes]] to Dict[bytes, bytes].
# Only the last header will be kept when there are duplicate
# headers.
headers = {}
for header, value in event.headers:
headers[header] = value
method = headers.get(b":method")
protocol = headers.get(b":protocol")
if method == b"CONNECT" and protocol == b"webtransport":
self._session_stream_id = event.stream_id
self._handshake_webtransport(event, headers)
else:
self._send_error_response(event.stream_id, 400)
if isinstance(event, DataReceived) and\
self._session_stream_id == event.stream_id:
if self._http and not self._http.supports_h3_datagram_04 and\
len(event.data) > 0:
raise ProtocolError('Unexpected data on the session stream')
self._receive_data_on_session_stream(
event.data, event.stream_ended)
elif self._handler is not None:
if isinstance(event, WebTransportStreamDataReceived):
self._handler.stream_data_received(
stream_id=event.stream_id,
data=event.data,
stream_ended=event.stream_ended)
elif isinstance(event, DatagramReceived):
if self._allow_datagrams:
self._handler.datagram_received(data=event.data)
def _receive_data_on_session_stream(self, data: bytes, fin: bool) -> None:
self._capsule_decoder_for_session_stream.append(data)
if fin:
self._capsule_decoder_for_session_stream.final()
for capsule in self._capsule_decoder_for_session_stream:
if capsule.type in {
CapsuleType.DATAGRAM,
CapsuleType.REGISTER_DATAGRAM_CONTEXT,
CapsuleType.CLOSE_DATAGRAM_CONTEXT
}:
raise ProtocolError(
f"Unimplemented capsule type: {capsule.type}")
if capsule.type in {
CapsuleType.REGISTER_DATAGRAM_NO_CONTEXT,
CapsuleType.CLOSE_WEBTRANSPORT_SESSION
}:
# We'll handle this case below.
pass
else:
# We should ignore unknown capsules.
continue
if self._close_info is not None:
raise ProtocolError(
("Receiving a capsule with type = {} after receiving " +
"CLOSE_WEBTRANSPORT_SESSION").format(capsule.type))
if capsule.type == CapsuleType.REGISTER_DATAGRAM_NO_CONTEXT:
buffer = Buffer(data=capsule.data)
format_type = buffer.pull_uint_var()
# https://ietf-wg-webtrans.github.io/draft-ietf-webtrans-http3/draft-ietf-webtrans-http3.html#name-datagram-format-type
WEBTRANPORT_FORMAT_TYPE = 0xff7c00
if format_type != WEBTRANPORT_FORMAT_TYPE:
raise ProtocolError(
"Unexpected datagram format type: {}".format(
format_type))
self._allow_datagrams = True
elif capsule.type == CapsuleType.CLOSE_WEBTRANSPORT_SESSION:
buffer = Buffer(data=capsule.data)
code = buffer.pull_uint32()
# 4 bytes for the uint32.
reason = buffer.pull_bytes(len(capsule.data) - 4)
# TODO(yutakahirano): Make sure `reason` is a UTF-8 text.
self._close_info = (code, reason)
if fin:
self._call_session_closed(self._close_info, abruptly=False)