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