amqtt/hbmqtt/mqtt/subscribe.py

63 wiersze
2.3 KiB
Python

# Copyright (c) 2015 Nicolas JOUANIN
#
# See the file license.txt for copying permission.
from hbmqtt.mqtt.packet import MQTTPacket, MQTTFixedHeader, SUBSCRIBE, PacketIdVariableHeader, MQTTPayload, MQTTVariableHeader
from hbmqtt.errors import HBMQTTException, MQTTException
from hbmqtt.codecs import *
class SubscribePayload(MQTTPayload):
def __init__(self, topics=[]):
super().__init__()
self.topics = topics
def to_bytes(self, fixed_header: MQTTFixedHeader, variable_header: MQTTVariableHeader):
out = b''
for topic in self.topics:
out += encode_string(topic[0])
out += int_to_bytes(topic[1], 1)
return out
@classmethod
@asyncio.coroutine
def from_stream(cls, reader: asyncio.StreamReader, fixed_header: MQTTFixedHeader,
variable_header: MQTTVariableHeader):
topics = []
payload_length = fixed_header.remaining_length - variable_header.bytes_length
read_bytes = 0
while read_bytes < payload_length:
try:
topic = yield from decode_string(reader)
qos_byte = yield from read_or_raise(reader, 1)
qos = bytes_to_int(qos_byte)
topics.append((topic, qos))
read_bytes += 2 + len(topic.encode('utf-8')) + 1
except NoDataException as exc:
break
return cls(topics)
def __repr__(self):
return type(self).__name__ + '(topics={0!r})'.format(self.topics)
class SubscribePacket(MQTTPacket):
VARIABLE_HEADER = PacketIdVariableHeader
PAYLOAD = SubscribePayload
def __init__(self, fixed: MQTTFixedHeader=None, variable_header: PacketIdVariableHeader=None, payload=None):
if fixed is None:
header = MQTTFixedHeader(SUBSCRIBE, 0x02) # [MQTT-3.8.1-1]
else:
if fixed.packet_type is not SUBSCRIBE:
raise HBMQTTException("Invalid fixed packet type %s for SubscribePacket init" % fixed.packet_type)
header = fixed
super().__init__(header)
self.variable_header = variable_header
self.payload = payload
@classmethod
def build(cls, topics, packet_id):
v_header = PacketIdVariableHeader(packet_id)
payload = SubscribePayload(topics)
return SubscribePacket(variable_header=v_header, payload=payload)