def decode_message(cls, protocol_version, user_type_map, stream_id, flags,
opcode, body, decompressor, result_metadata):
"""
Decodes a native protocol message body
:param protocol_version: version to use decoding contents
:param user_type_map: map[keyspace name] = map[type name] = custom type to instantiate when deserializing this type
:param stream_id: native protocol stream id from the frame header
:param flags: native protocol flags bitmap from the header
:param opcode: native protocol opcode from the header
:param body: frame body
:param decompressor: optional decompression function to inflate the body
:return: a message decoded from the body and frame attributes
"""
if (not ProtocolVersion.has_checksumming_support(protocol_version)
and flags & COMPRESSED_FLAG):
if decompressor is None:
raise RuntimeError(
"No de-compressor available for compressed frame!")
body = decompressor(body)
flags ^= COMPRESSED_FLAG
body = io.BytesIO(body)
if flags & TRACING_FLAG:
trace_id = UUID(bytes=body.read(16))
flags ^= TRACING_FLAG
else:
trace_id = None
if flags & WARNING_FLAG:
warnings = read_stringlist(body)
flags ^= WARNING_FLAG
else:
warnings = None
if flags & CUSTOM_PAYLOAD_FLAG:
custom_payload = read_bytesmap(body)
flags ^= CUSTOM_PAYLOAD_FLAG
else:
custom_payload = None
flags &= USE_BETA_MASK # will only be set if we asserted it in connection estabishment
if flags:
log.warning(
"Unknown protocol flags set: %02x. May cause problems.", flags)
msg_class = cls.message_types_by_opcode[opcode]
msg = msg_class.recv_body(body, protocol_version, user_type_map,
result_metadata)
msg.stream_id = stream_id
msg.trace_id = trace_id
msg.custom_payload = custom_payload
msg.warnings = warnings
if msg.warnings:
for w in msg.warnings:
log.warning("Server warning: %s", w)
return msg
def encode_message(cls, msg, stream_id, protocol_version, compressor,
allow_beta_protocol_version):
"""
Encodes a message using the specified frame parameters, and compressor
:param msg: the message, typically of cassandra.protocol._MessageType, generated by the driver
:param stream_id: protocol stream id for the frame header
:param protocol_version: version for the frame header, and used encoding contents
:param compressor: optional compression function to be used on the body
"""
flags = 0
body = io.BytesIO()
if msg.custom_payload:
if protocol_version < 4:
raise UnsupportedOperation(
"Custom key/value payloads can only be used with protocol version 4 or higher"
)
flags |= CUSTOM_PAYLOAD_FLAG
write_bytesmap(body, msg.custom_payload)
msg.send_body(body, protocol_version)
body = body.getvalue()
# With checksumming, the compression is done at the segment frame encoding
if (not ProtocolVersion.has_checksumming_support(protocol_version)
and compressor and len(body) > 0):
body = compressor(body)
flags |= COMPRESSED_FLAG
if msg.tracing:
flags |= TRACING_FLAG
if allow_beta_protocol_version:
flags |= USE_BETA_FLAG
buff = io.BytesIO()
cls._write_header(buff, protocol_version, flags, stream_id, msg.opcode,
len(body))
buff.write(body)
return buff.getvalue()