mirror of
https://github.com/PiBrewing/craftbeerpi4.git
synced 2024-11-14 19:18:11 +01:00
410 lines
16 KiB
Python
410 lines
16 KiB
Python
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"""
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*******************************************************************
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Copyright (c) 2017, 2019 IBM Corp.
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All rights reserved. This program and the accompanying materials
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are made available under the terms of the Eclipse Public License v1.0
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and Eclipse Distribution License v1.0 which accompany this distribution.
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The Eclipse Public License is available at
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http://www.eclipse.org/legal/epl-v10.html
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and the Eclipse Distribution License is available at
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http://www.eclipse.org/org/documents/edl-v10.php.
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Contributors:
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Ian Craggs - initial implementation and/or documentation
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*******************************************************************
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"""
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import sys, struct
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from .packettypes import PacketTypes
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class MQTTException(Exception):
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pass
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class MalformedPacket(MQTTException):
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pass
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def writeInt16(length):
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# serialize a 16 bit integer to network format
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return bytearray(struct.pack("!H", length))
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def readInt16(buf):
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# deserialize a 16 bit integer from network format
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return struct.unpack("!H", buf[:2])[0]
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def writeInt32(length):
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# serialize a 32 bit integer to network format
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return bytearray(struct.pack("!L", length))
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def readInt32(buf):
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# deserialize a 32 bit integer from network format
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return struct.unpack("!L", buf[:4])[0]
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def writeUTF(data):
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# data could be a string, or bytes. If string, encode into bytes with utf-8
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if sys.version_info[0] < 3:
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data = bytearray(data, 'utf-8')
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else:
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data = data if type(data) == type(b"") else bytes(data, "utf-8")
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return writeInt16(len(data)) + data
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def readUTF(buffer, maxlen):
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if maxlen >= 2:
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length = readInt16(buffer)
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else:
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raise MalformedPacket("Not enough data to read string length")
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maxlen -= 2
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if length > maxlen:
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raise MalformedPacket("Length delimited string too long")
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buf = buffer[2:2+length].decode("utf-8")
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# look for chars which are invalid for MQTT
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for c in buf: # look for D800-DFFF in the UTF string
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ord_c = ord(c)
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if ord_c >= 0xD800 and ord_c <= 0xDFFF:
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raise MalformedPacket("[MQTT-1.5.4-1] D800-DFFF found in UTF-8 data")
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if ord_c == 0x00: # look for null in the UTF string
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raise MalformedPacket("[MQTT-1.5.4-2] Null found in UTF-8 data")
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if ord_c == 0xFEFF:
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raise MalformedPacket("[MQTT-1.5.4-3] U+FEFF in UTF-8 data")
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return buf, length+2
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def writeBytes(buffer):
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return writeInt16(len(buffer)) + buffer
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def readBytes(buffer):
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length = readInt16(buffer)
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return buffer[2:2+length], length+2
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class VariableByteIntegers: # Variable Byte Integer
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"""
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MQTT variable byte integer helper class. Used
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in several places in MQTT v5.0 properties.
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"""
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@staticmethod
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def encode(x):
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"""
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Convert an integer 0 <= x <= 268435455 into multi-byte format.
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Returns the buffer convered from the integer.
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"""
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assert 0 <= x <= 268435455
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buffer = b''
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while 1:
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digit = x % 128
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x //= 128
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if x > 0:
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digit |= 0x80
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if sys.version_info[0] >= 3:
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buffer += bytes([digit])
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else:
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buffer += bytes(chr(digit))
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if x == 0:
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break
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return buffer
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@staticmethod
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def decode(buffer):
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"""
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Get the value of a multi-byte integer from a buffer
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Return the value, and the number of bytes used.
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[MQTT-1.5.5-1] the encoded value MUST use the minimum number of bytes necessary to represent the value
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"""
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multiplier = 1
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value = 0
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bytes = 0
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while 1:
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bytes += 1
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digit = buffer[0]
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buffer = buffer[1:]
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value += (digit & 127) * multiplier
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if digit & 128 == 0:
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break
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multiplier *= 128
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return (value, bytes)
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class Properties(object):
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"""MQTT v5.0 properties class.
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See Properties.names for a list of accepted property names along with their numeric values.
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See Properties.properties for the data type of each property.
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Example of use:
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publish_properties = Properties(PacketTypes.PUBLISH)
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publish_properties.UserProperty = ("a", "2")
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publish_properties.UserProperty = ("c", "3")
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First the object is created with packet type as argument, no properties will be present at
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this point. Then properties are added as attributes, the name of which is the string property
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name without the spaces.
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"""
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def __init__(self, packetType):
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self.packetType = packetType
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self.types = ["Byte", "Two Byte Integer", "Four Byte Integer", "Variable Byte Integer",
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"Binary Data", "UTF-8 Encoded String", "UTF-8 String Pair"]
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self.names = {
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"Payload Format Indicator": 1,
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"Message Expiry Interval": 2,
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"Content Type": 3,
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"Response Topic": 8,
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"Correlation Data": 9,
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"Subscription Identifier": 11,
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"Session Expiry Interval": 17,
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"Assigned Client Identifier": 18,
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"Server Keep Alive": 19,
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"Authentication Method": 21,
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"Authentication Data": 22,
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"Request Problem Information": 23,
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"Will Delay Interval": 24,
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"Request Response Information": 25,
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"Response Information": 26,
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"Server Reference": 28,
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"Reason String": 31,
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"Receive Maximum": 33,
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"Topic Alias Maximum": 34,
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"Topic Alias": 35,
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"Maximum QoS": 36,
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"Retain Available": 37,
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"User Property": 38,
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"Maximum Packet Size": 39,
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"Wildcard Subscription Available": 40,
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"Subscription Identifier Available": 41,
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"Shared Subscription Available": 42
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}
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self.properties = {
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# id: type, packets
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# payload format indicator
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1: (self.types.index("Byte"), [PacketTypes.PUBLISH, PacketTypes.WILLMESSAGE]),
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2: (self.types.index("Four Byte Integer"), [PacketTypes.PUBLISH, PacketTypes.WILLMESSAGE]),
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3: (self.types.index("UTF-8 Encoded String"), [PacketTypes.PUBLISH, PacketTypes.WILLMESSAGE]),
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8: (self.types.index("UTF-8 Encoded String"), [PacketTypes.PUBLISH, PacketTypes.WILLMESSAGE]),
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9: (self.types.index("Binary Data"), [PacketTypes.PUBLISH, PacketTypes.WILLMESSAGE]),
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11: (self.types.index("Variable Byte Integer"),
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[PacketTypes.PUBLISH, PacketTypes.SUBSCRIBE]),
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17: (self.types.index("Four Byte Integer"),
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[PacketTypes.CONNECT, PacketTypes.CONNACK, PacketTypes.DISCONNECT]),
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18: (self.types.index("UTF-8 Encoded String"), [PacketTypes.CONNACK]),
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19: (self.types.index("Two Byte Integer"), [PacketTypes.CONNACK]),
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21: (self.types.index("UTF-8 Encoded String"),
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[PacketTypes.CONNECT, PacketTypes.CONNACK, PacketTypes.AUTH]),
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22: (self.types.index("Binary Data"),
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[PacketTypes.CONNECT, PacketTypes.CONNACK, PacketTypes.AUTH]),
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23: (self.types.index("Byte"),
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[PacketTypes.CONNECT]),
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24: (self.types.index("Four Byte Integer"), [PacketTypes.WILLMESSAGE]),
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25: (self.types.index("Byte"), [PacketTypes.CONNECT]),
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26: (self.types.index("UTF-8 Encoded String"), [PacketTypes.CONNACK]),
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28: (self.types.index("UTF-8 Encoded String"),
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[PacketTypes.CONNACK, PacketTypes.DISCONNECT]),
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31: (self.types.index("UTF-8 Encoded String"),
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[PacketTypes.CONNACK, PacketTypes.PUBACK, PacketTypes.PUBREC,
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PacketTypes.PUBREL, PacketTypes.PUBCOMP, PacketTypes.SUBACK,
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PacketTypes.UNSUBACK, PacketTypes.DISCONNECT, PacketTypes.AUTH]),
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33: (self.types.index("Two Byte Integer"),
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[PacketTypes.CONNECT, PacketTypes.CONNACK]),
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34: (self.types.index("Two Byte Integer"),
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[PacketTypes.CONNECT, PacketTypes.CONNACK]),
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35: (self.types.index("Two Byte Integer"), [PacketTypes.PUBLISH]),
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36: (self.types.index("Byte"), [PacketTypes.CONNACK]),
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37: (self.types.index("Byte"), [PacketTypes.CONNACK]),
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38: (self.types.index("UTF-8 String Pair"),
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[PacketTypes.CONNECT, PacketTypes.CONNACK,
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PacketTypes.PUBLISH, PacketTypes.PUBACK,
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PacketTypes.PUBREC, PacketTypes.PUBREL, PacketTypes.PUBCOMP,
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PacketTypes.SUBSCRIBE, PacketTypes.SUBACK,
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PacketTypes.UNSUBSCRIBE, PacketTypes.UNSUBACK,
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PacketTypes.DISCONNECT, PacketTypes.AUTH, PacketTypes.WILLMESSAGE]),
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39: (self.types.index("Four Byte Integer"),
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[PacketTypes.CONNECT, PacketTypes.CONNACK]),
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40: (self.types.index("Byte"), [PacketTypes.CONNACK]),
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41: (self.types.index("Byte"), [PacketTypes.CONNACK]),
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42: (self.types.index("Byte"), [PacketTypes.CONNACK]),
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}
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def allowsMultiple(self, compressedName):
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return self.getIdentFromName(compressedName) in [11, 38]
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def getIdentFromName(self, compressedName):
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# return the identifier corresponding to the property name
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result = -1
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for name in self.names.keys():
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if compressedName == name.replace(' ', ''):
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result = self.names[name]
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break
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return result
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def __setattr__(self, name, value):
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name = name.replace(' ', '')
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privateVars = ["packetType", "types", "names", "properties"]
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if name in privateVars:
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object.__setattr__(self, name, value)
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else:
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# the name could have spaces in, or not. Remove spaces before assignment
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if name not in [aname.replace(' ', '') for aname in self.names.keys()]:
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raise MQTTException(
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"Property name must be one of "+str(self.names.keys()))
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# check that this attribute applies to the packet type
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if self.packetType not in self.properties[self.getIdentFromName(name)][1]:
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raise MQTTException("Property %s does not apply to packet type %s"
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% (name, PacketTypes.Names[self.packetType]))
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if self.allowsMultiple(name):
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if type(value) != type([]):
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value = [value]
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if hasattr(self, name):
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value = object.__getattribute__(self, name) + value
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object.__setattr__(self, name, value)
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def __str__(self):
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buffer = "["
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first = True
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for name in self.names.keys():
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compressedName = name.replace(' ', '')
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if hasattr(self, compressedName):
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if not first:
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buffer += ", "
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buffer += compressedName + " : " + \
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str(getattr(self, compressedName))
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first = False
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buffer += "]"
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return buffer
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def json(self):
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data = {}
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for name in self.names.keys():
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compressedName = name.replace(' ', '')
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if hasattr(self, compressedName):
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data[compressedName] = getattr(self, compressedName)
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return data
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def isEmpty(self):
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rc = True
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for name in self.names.keys():
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compressedName = name.replace(' ', '')
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if hasattr(self, compressedName):
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rc = False
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break
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return rc
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def clear(self):
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for name in self.names.keys():
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compressedName = name.replace(' ', '')
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if hasattr(self, compressedName):
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delattr(self, compressedName)
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def writeProperty(self, identifier, type, value):
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buffer = b""
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buffer += VariableByteIntegers.encode(identifier) # identifier
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if type == self.types.index("Byte"): # value
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if sys.version_info[0] < 3:
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buffer += chr(value)
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else:
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buffer += bytes([value])
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elif type == self.types.index("Two Byte Integer"):
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buffer += writeInt16(value)
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elif type == self.types.index("Four Byte Integer"):
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buffer += writeInt32(value)
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elif type == self.types.index("Variable Byte Integer"):
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buffer += VariableByteIntegers.encode(value)
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elif type == self.types.index("Binary Data"):
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buffer += writeBytes(value)
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elif type == self.types.index("UTF-8 Encoded String"):
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buffer += writeUTF(value)
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elif type == self.types.index("UTF-8 String Pair"):
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buffer += writeUTF(value[0]) + writeUTF(value[1])
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return buffer
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def pack(self):
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# serialize properties into buffer for sending over network
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buffer = b""
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for name in self.names.keys():
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compressedName = name.replace(' ', '')
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if hasattr(self, compressedName):
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identifier = self.getIdentFromName(compressedName)
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attr_type = self.properties[identifier][0]
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if self.allowsMultiple(compressedName):
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for prop in getattr(self, compressedName):
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buffer += self.writeProperty(identifier,
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attr_type, prop)
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else:
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buffer += self.writeProperty(identifier, attr_type,
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getattr(self, compressedName))
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return VariableByteIntegers.encode(len(buffer)) + buffer
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def readProperty(self, buffer, type, propslen):
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if type == self.types.index("Byte"):
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value = buffer[0]
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valuelen = 1
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elif type == self.types.index("Two Byte Integer"):
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value = readInt16(buffer)
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valuelen = 2
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elif type == self.types.index("Four Byte Integer"):
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value = readInt32(buffer)
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valuelen = 4
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elif type == self.types.index("Variable Byte Integer"):
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|
|
value, valuelen = VariableByteIntegers.decode(buffer)
|
||
|
|
elif type == self.types.index("Binary Data"):
|
||
|
|
value, valuelen = readBytes(buffer)
|
||
|
|
elif type == self.types.index("UTF-8 Encoded String"):
|
||
|
|
value, valuelen = readUTF(buffer, propslen)
|
||
|
|
elif type == self.types.index("UTF-8 String Pair"):
|
||
|
|
value, valuelen = readUTF(buffer, propslen)
|
||
|
|
buffer = buffer[valuelen:] # strip the bytes used by the value
|
||
|
|
value1, valuelen1 = readUTF(buffer, propslen - valuelen)
|
||
|
|
value = (value, value1)
|
||
|
|
valuelen += valuelen1
|
||
|
|
return value, valuelen
|
||
|
|
|
||
|
|
def getNameFromIdent(self, identifier):
|
||
|
|
rc = None
|
||
|
|
for name in self.names:
|
||
|
|
if self.names[name] == identifier:
|
||
|
|
rc = name
|
||
|
|
return rc
|
||
|
|
|
||
|
|
def unpack(self, buffer):
|
||
|
|
if sys.version_info[0] < 3:
|
||
|
|
buffer = bytearray(buffer)
|
||
|
|
self.clear()
|
||
|
|
# deserialize properties into attributes from buffer received from network
|
||
|
|
propslen, VBIlen = VariableByteIntegers.decode(buffer)
|
||
|
|
buffer = buffer[VBIlen:] # strip the bytes used by the VBI
|
||
|
|
propslenleft = propslen
|
||
|
|
while propslenleft > 0: # properties length is 0 if there are none
|
||
|
|
identifier, VBIlen = VariableByteIntegers.decode(
|
||
|
|
buffer) # property identifier
|
||
|
|
buffer = buffer[VBIlen:] # strip the bytes used by the VBI
|
||
|
|
propslenleft -= VBIlen
|
||
|
|
attr_type = self.properties[identifier][0]
|
||
|
|
value, valuelen = self.readProperty(
|
||
|
|
buffer, attr_type, propslenleft)
|
||
|
|
buffer = buffer[valuelen:] # strip the bytes used by the value
|
||
|
|
propslenleft -= valuelen
|
||
|
|
propname = self.getNameFromIdent(identifier)
|
||
|
|
compressedName = propname.replace(' ', '')
|
||
|
|
if not self.allowsMultiple(compressedName) and hasattr(self, compressedName):
|
||
|
|
raise MQTTException(
|
||
|
|
"Property '%s' must not exist more than once" % property)
|
||
|
|
setattr(self, propname, value)
|
||
|
|
return self, propslen + VBIlen
|