136 lines
4.3 KiB
Python
136 lines
4.3 KiB
Python
import gzip
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import json
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PROTOCOL_VERSION = 0b0001
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DEFAULT_HEADER_SIZE = 0b0001
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PROTOCOL_VERSION_BITS = 4
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HEADER_BITS = 4
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MESSAGE_TYPE_BITS = 4
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MESSAGE_TYPE_SPECIFIC_FLAGS_BITS = 4
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MESSAGE_SERIALIZATION_BITS = 4
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MESSAGE_COMPRESSION_BITS = 4
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RESERVED_BITS = 8
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# Message Type:
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CLIENT_FULL_REQUEST = 0b0001
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CLIENT_AUDIO_ONLY_REQUEST = 0b0010
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SERVER_FULL_RESPONSE = 0b1001
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SERVER_ACK = 0b1011
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SERVER_ERROR_RESPONSE = 0b1111
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# Message Type Specific Flags
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NO_SEQUENCE = 0b0000 # no check sequence
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POS_SEQUENCE = 0b0001
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NEG_SEQUENCE = 0b0010
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NEG_SEQUENCE_1 = 0b0011
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MSG_WITH_EVENT = 0b0100
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# Message Serialization
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NO_SERIALIZATION = 0b0000
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JSON = 0b0001
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THRIFT = 0b0011
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CUSTOM_TYPE = 0b1111
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# Message Compression
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NO_COMPRESSION = 0b0000
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GZIP = 0b0001
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CUSTOM_COMPRESSION = 0b1111
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def generate_header(
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version=PROTOCOL_VERSION,
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message_type=CLIENT_FULL_REQUEST,
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message_type_specific_flags=MSG_WITH_EVENT,
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serial_method=JSON,
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compression_type=GZIP,
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reserved_data=0x00,
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extension_header=bytes()
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):
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"""
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protocol_version(4 bits), header_size(4 bits),
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message_type(4 bits), message_type_specific_flags(4 bits)
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serialization_method(4 bits) message_compression(4 bits)
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reserved （8bits) 保留字段
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header_extensions 扩展头(大小等于 8 * 4 * (header_size - 1) )
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"""
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header = bytearray()
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header_size = int(len(extension_header) / 4) + 1
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header.append((version << 4) | header_size)
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header.append((message_type << 4) | message_type_specific_flags)
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header.append((serial_method << 4) | compression_type)
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header.append(reserved_data)
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header.extend(extension_header)
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return header
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def parse_response(res):
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"""
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- header
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- (4bytes)header
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- (4bits)version(v1) + (4bits)header_size
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- (4bits)messageType + (4bits)messageTypeFlags
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-- 0001 CompleteClient | -- 0001 hasSequence
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-- 0010 audioonly | -- 0010 isTailPacket
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| -- 0100 hasEvent
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- (4bits)payloadFormat + (4bits)compression
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- (8bits) reserve
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- payload
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- [optional 4 bytes] event
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- [optional] session ID
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-- (4 bytes)session ID len
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-- session ID data
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- (4 bytes)data len
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- data
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"""
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if isinstance(res, str):
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return {}
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protocol_version = res[0] >> 4
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header_size = res[0] & 0x0f
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message_type = res[1] >> 4
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message_type_specific_flags = res[1] & 0x0f
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serialization_method = res[2] >> 4
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message_compression = res[2] & 0x0f
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reserved = res[3]
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header_extensions = res[4:header_size * 4]
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payload = res[header_size * 4:]
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result = {}
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payload_msg = None
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payload_size = 0
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start = 0
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if message_type == SERVER_FULL_RESPONSE or message_type == SERVER_ACK:
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result['message_type'] = 'SERVER_FULL_RESPONSE'
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if message_type == SERVER_ACK:
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result['message_type'] = 'SERVER_ACK'
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if message_type_specific_flags & NEG_SEQUENCE > 0:
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result['seq'] = int.from_bytes(payload[:4], "big", signed=False)
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start += 4
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if message_type_specific_flags & MSG_WITH_EVENT > 0:
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result['event'] = int.from_bytes(payload[:4], "big", signed=False)
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start += 4
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payload = payload[start:]
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session_id_size = int.from_bytes(payload[:4], "big", signed=True)
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session_id = payload[4:session_id_size+4]
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result['session_id'] = str(session_id)
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payload = payload[4 + session_id_size:]
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payload_size = int.from_bytes(payload[:4], "big", signed=False)
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payload_msg = payload[4:]
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elif message_type == SERVER_ERROR_RESPONSE:
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code = int.from_bytes(payload[:4], "big", signed=False)
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result['code'] = code
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payload_size = int.from_bytes(payload[4:8], "big", signed=False)
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payload_msg = payload[8:]
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if payload_msg is None:
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return result
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if message_compression == GZIP:
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payload_msg = gzip.decompress(payload_msg)
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if serialization_method == JSON:
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payload_msg = json.loads(str(payload_msg, "utf-8"))
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elif serialization_method != NO_SERIALIZATION:
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payload_msg = str(payload_msg, "utf-8")
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result['payload_msg'] = payload_msg
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result['payload_size'] = payload_size
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return result
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