/
MQTTMsgHandler.py
271 lines (224 loc) · 8.67 KB
/
MQTTMsgHandler.py
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import AWSIoTPythonSDK.MQTTConst as mqttConst
import time
import socket
import ssl
import _thread
import select
import struct
class MsgHandler:
def __init__(self, receive_callback):
self._host = ""
self._port = -1
self._cafile = ""
self._key = ""
self._cert = ""
self._sock = None
self._output_queue_size=-1
self._output_queue_dropbehavior=-1
self._mqttOperationTimeout = 5
self._connection_state = mqttConst.STATE_DISCONNECTED
self._conn_state_mutex=_thread.allocate_lock()
self._poll = select.poll()
self._output_queue=[]
self._out_packet_mutex=_thread.allocate_lock()
_thread.stack_size(5120)
_thread.start_new_thread(self._io_thread_func,())
self._recv_callback = receive_callback
self._pingSent=False
self._ping_interval=20
self._waiting_ping_resp=False
self._ping_cutoff=3
self._receive_timeout=3000
self._draining_interval=2
self._draining_cutoff=3
self._shadow_cb_queue=[]
self._shadow_cb_mutex=_thread.allocate_lock()
def setOfflineQueueConfiguration(self, queueSize, dropBehavior):
self._output_queue_size = queueSize
self._output_queue_dropbehavior = dropBehavior
def setCredentials(self, srcCAFile, srcKey, srcCert):
self._cafile = srcCAFile
self._key = srcKey
self._cert = srcCert
def setEndpoint(self, srcHost, srcPort):
self._host = srcHost
self._port = srcPort
def setOperationTimeout(self, timeout):
self._mqttOperationTimeout=timeout
def setDrainingInterval(self, srcDrainingIntervalSecond):
self._draining_interval=srcDrainingIntervalSecond
def insertShadowCallback(self, callback, payload, status, token):
self._shadow_cb_mutex.acquire()
self._shadow_cb_queue.append((callback, payload, status, token))
self._shadow_cb_mutex.release()
def _callShadowCallback(self):
self._shadow_cb_mutex.acquire()
if len(self._shadow_cb_queue) > 0:
cbObj = self._shadow_cb_queue.pop(0)
cbObj[0](cbObj[1],cbObj[2], cbObj[3])
self._shadow_cb_mutex.release()
def createSocketConnection(self):
self._conn_state_mutex.acquire()
self._connection_state = mqttConst.STATE_CONNECTING
self._conn_state_mutex.release()
try:
if self._sock:
self._poll.unregister(self._sock)
self._sock.close()
self._sock = None
self._sock = socket.socket()
if self._cafile:
self._sock = ssl.wrap_socket(
self._sock,
certfile=self._cert,
keyfile=self._key,
ca_certs=self._cafile,
cert_reqs=ssl.CERT_REQUIRED)
self._sock.connect(socket.getaddrinfo(self._host, self._port)[0][-1])
self._poll.register(self._sock, select.POLLIN)
except socket.error as err:
print("Socket create error: {0}".format(err))
self._conn_state_mutex.acquire()
self._connection_state = mqttConst.STATE_DISCONNECTED
self._conn_state_mutex.release()
return False
return True
def disconnect(self):
if self._sock:
self._sock.close()
self._sock = None
def isConnected(self):
connected=False
self._conn_state_mutex.acquire()
if self._connection_state == mqttConst.STATE_CONNECTED:
connected = True
self._conn_state_mutex.release()
return connected
def setConnectionState(self, state):
self._conn_state_mutex.acquire()
self._connection_state = state
self._conn_state_mutex.release()
def _drop_message(self):
if self._output_queue_size == -1:
return False
elif (self._output_queue_size == 0) and (self._connection_state == mqttConst.STATE_CONNECTED):
return False
else:
return True if len(self._output_queue) >= self._output_queue_size else False
def push_on_send_queue(self, packet):
if self._drop_message():
if self._output_queue_dropbehavior == mqttConst.DROP_OLDEST:
self._out_packet_mutex.acquire()
if self._out_packet_mutex.locked():
self._output_queue.pop(0)
self._out_packet_mutex.release()
else:
return False
self._out_packet_mutex.acquire()
if self._out_packet_mutex.locked():
self._output_queue.append(packet)
self._out_packet_mutex.release()
return True
def priority_send(self, packet):
msg_sent = False
self._out_packet_mutex.acquire()
msg_sent = self._send_packet(packet)
self._out_packet_mutex.release()
return msg_sent
def _receive_packet(self):
if not self._poll.poll(self._receive_timeout):
return False
# Read message type
try:
self._sock.setblocking(False)
msg_type = self._sock.recv(1)
except socket.error as err:
print("Socket receive error: {0}".format(err))
return False
else:
if len(msg_type) == 0:
return False
msg_type = struct.unpack("!B", msg_type)[0]
self._sock.setblocking(True)
# Read payload length
multiplier = 1
bytes_read = 0
bytes_remaining = 0
while True:
try:
if self._sock:
byte = self._sock.recv(1)
except socket.error as err:
print("Socket receive error: {0}".format(err))
return False
else:
bytes_read = bytes_read + 1
if bytes_read > 4:
return False
byte = struct.unpack("!B", byte)[0]
bytes_remaining += (byte & 127) * multiplier
multiplier += 128
if (byte & 128) == 0:
break
# Read payload
try:
if self._sock:
if bytes_remaining > 0:
payload = self._sock.recv(bytes_remaining)
else:
payload = b''
except socket.error as err:
print("Socket receive error: {0}".format(err))
return False
return self._recv_callback(msg_type, payload)
def _send_pingreq(self):
pkt = struct.pack('!BB', mqttConst.MSG_PINGREQ, 0)
return self.priority_send(pkt)
def setPingFlag(self, flag):
self._pingSent=flag
def _send_packet(self, packet):
written = -1
try:
if self._sock:
written = self._sock.write(packet)
print('Packet sent. (Length: %d)' % written)
except socket.error as err:
print('Socket send error {0}'.format(err))
return False
return True if len(packet) == written else False
def _verify_connection_state(self):
elapsed = time.time() - self._start_time
if not self._waiting_ping_resp and elapsed > self._ping_interval:
if self._connection_state == mqttConst.STATE_CONNECTED:
self._pingSent=False
self._send_pingreq()
self._waiting_ping_resp=True
elif self._connection_state == mqttConst.STATE_DISCONNECTED:
self.connect()
self._start_time = time.time()
elif self._waiting_ping_resp and (self._connection_state == mqttConst.STATE_CONNECTED or elapsed > self._mqttOperationTimeout):
if not self._pingSent:
if self._ping_failures <= self._ping_cutoff:
self._ping_failures+=1
else:
self.connect()
else:
self._ping_failures=0
self._start_time = time.time()
self._waiting_ping_resp=False
def _io_thread_func(self):
time.sleep(5.0)
self._start_time = time.time()
self._ping_failures=0
while True:
self._verify_connection_state()
self._out_packet_mutex.acquire()
if self._out_packet_mutex.locked() and len(self._output_queue) > 0:
packet=self._output_queue[0]
if self._send_packet(packet):
self._output_queue.pop(0)
self._out_packet_mutex.release()
self._receive_packet()
self._callShadowCallback()
if len(self._output_queue) >= self._draining_cutoff:
time.sleep(self._draining_interval)