205 lines
6.3 KiB
Python
205 lines
6.3 KiB
Python
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import usocket as socket
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import ustruct as struct
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from ubinascii import hexlify
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class MQTTException(Exception):
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pass
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class MQTTClient:
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def __init__(self, client_id, server, port=0, user=None, password=None, keepalive=0,
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ssl=False, ssl_params={}):
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if port == 0:
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port = 8883 if ssl else 1883
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self.client_id = client_id
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self.sock = None
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self.server = server
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self.port = port
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self.ssl = ssl
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self.ssl_params = ssl_params
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self.pid = 0
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self.cb = None
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self.user = user
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self.pswd = password
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self.keepalive = keepalive
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self.lw_topic = None
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self.lw_msg = None
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self.lw_qos = 0
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self.lw_retain = False
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def _send_str(self, s):
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self.sock.write(struct.pack("!H", len(s)))
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self.sock.write(s)
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def _recv_len(self):
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n = 0
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sh = 0
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while 1:
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b = self.sock.read(1)[0]
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n |= (b & 0x7f) << sh
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if not b & 0x80:
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return n
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sh += 7
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def set_callback(self, f):
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self.cb = f
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def set_last_will(self, topic, msg, retain=False, qos=0):
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assert 0 <= qos <= 2
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assert topic
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self.lw_topic = topic
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self.lw_msg = msg
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self.lw_qos = qos
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self.lw_retain = retain
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def connect(self, clean_session=True):
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self.sock = socket.socket()
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addr = socket.getaddrinfo(self.server, self.port)[0][-1]
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self.sock.connect(addr)
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if self.ssl:
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import ussl
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self.sock = ussl.wrap_socket(self.sock, **self.ssl_params)
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premsg = bytearray(b"\x10\0\0\0\0\0")
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msg = bytearray(b"\x04MQTT\x04\x02\0\0")
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sz = 10 + 2 + len(self.client_id)
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msg[6] = clean_session << 1
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if self.user is not None:
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sz += 2 + len(self.user) + 2 + len(self.pswd)
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msg[6] |= 0xC0
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if self.keepalive:
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assert self.keepalive < 65536
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msg[7] |= self.keepalive >> 8
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msg[8] |= self.keepalive & 0x00FF
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if self.lw_topic:
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sz += 2 + len(self.lw_topic) + 2 + len(self.lw_msg)
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msg[6] |= 0x4 | (self.lw_qos & 0x1) << 3 | (self.lw_qos & 0x2) << 3
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msg[6] |= self.lw_retain << 5
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i = 1
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while sz > 0x7f:
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premsg[i] = (sz & 0x7f) | 0x80
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sz >>= 7
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i += 1
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premsg[i] = sz
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self.sock.write(premsg, i + 2)
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self.sock.write(msg)
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#print(hex(len(msg)), hexlify(msg, ":"))
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self._send_str(self.client_id)
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if self.lw_topic:
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self._send_str(self.lw_topic)
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self._send_str(self.lw_msg)
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if self.user is not None:
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self._send_str(self.user)
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self._send_str(self.pswd)
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resp = self.sock.read(4)
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assert resp[0] == 0x20 and resp[1] == 0x02
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if resp[3] != 0:
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raise MQTTException(resp[3])
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return resp[2] & 1
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def disconnect(self):
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self.sock.write(b"\xe0\0")
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self.sock.close()
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def ping(self):
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self.sock.write(b"\xc0\0")
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def publish(self, topic, msg, retain=False, qos=0):
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pkt = bytearray(b"\x30\0\0\0")
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pkt[0] |= qos << 1 | retain
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sz = 2 + len(topic) + len(msg)
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if qos > 0:
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sz += 2
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assert sz < 2097152
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i = 1
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while sz > 0x7f:
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pkt[i] = (sz & 0x7f) | 0x80
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sz >>= 7
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i += 1
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pkt[i] = sz
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#print(hex(len(pkt)), hexlify(pkt, ":"))
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self.sock.write(pkt, i + 1)
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self._send_str(topic)
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if qos > 0:
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self.pid += 1
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pid = self.pid
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struct.pack_into("!H", pkt, 0, pid)
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self.sock.write(pkt, 2)
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self.sock.write(msg)
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if qos == 1:
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while 1:
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op = self.wait_msg()
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if op == 0x40:
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sz = self.sock.read(1)
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assert sz == b"\x02"
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rcv_pid = self.sock.read(2)
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rcv_pid = rcv_pid[0] << 8 | rcv_pid[1]
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if pid == rcv_pid:
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return
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elif qos == 2:
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assert 0
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def subscribe(self, topic, qos=0):
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assert self.cb is not None, "Subscribe callback is not set"
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pkt = bytearray(b"\x82\0\0\0")
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self.pid += 1
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struct.pack_into("!BH", pkt, 1, 2 + 2 + len(topic) + 1, self.pid)
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#print(hex(len(pkt)), hexlify(pkt, ":"))
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self.sock.write(pkt)
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self._send_str(topic)
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self.sock.write(qos.to_bytes(1, "little"))
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while 1:
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op = self.wait_msg()
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if op == 0x90:
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resp = self.sock.read(4)
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#print(resp)
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assert resp[1] == pkt[2] and resp[2] == pkt[3]
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if resp[3] == 0x80:
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raise MQTTException(resp[3])
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return
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# Wait for a single incoming MQTT message and process it.
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# Subscribed messages are delivered to a callback previously
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# set by .set_callback() method. Other (internal) MQTT
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# messages processed internally.
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def wait_msg(self):
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res = self.sock.read(1)
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self.sock.setblocking(True)
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if res is None:
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return None
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if res == b"":
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raise OSError(-1)
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if res == b"\xd0": # PINGRESP
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sz = self.sock.read(1)[0]
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assert sz == 0
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return None
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op = res[0]
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if op & 0xf0 != 0x30:
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return op
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sz = self._recv_len()
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topic_len = self.sock.read(2)
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topic_len = (topic_len[0] << 8) | topic_len[1]
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topic = self.sock.read(topic_len)
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sz -= topic_len + 2
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if op & 6:
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pid = self.sock.read(2)
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pid = pid[0] << 8 | pid[1]
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sz -= 2
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msg = self.sock.read(sz)
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self.cb(topic, msg)
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if op & 6 == 2:
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pkt = bytearray(b"\x40\x02\0\0")
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struct.pack_into("!H", pkt, 2, pid)
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self.sock.write(pkt)
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elif op & 6 == 4:
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assert 0
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# Checks whether a pending message from server is available.
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# If not, returns immediately with None. Otherwise, does
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# the same processing as wait_msg.
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def check_msg(self):
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self.sock.setblocking(False)
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return self.wait_msg()
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