mqtt客户端问题

Question

我有以下代码用于mqtt客户端从代理接收消息。如果客户端与broker断开连接，则客户端再次尝试使用connect()调用与broker连接。我读过paho文档，说loop_start()将处理与broker的重新连接。请让我知道使用connect() call与broker重新连接或让它自己处理是否正确。

import paho.mqtt.client as mqtt
import json
import time

is_connect = False

# The callback for when the client receives a CONNACK response from the server.
def on_connect(client, userdata, flags, rc):
    print("Connected with result code "+str(rc))
    # Subscribing in on_connect() means that if we lose the connection and
    # reconnect then subscriptions will be renewed.
    client.subscribe("#")

# The callback for when a PUBLISH message is received from the server.
def on_message(client, userdata, msg):
    print("Message received on "+msg.topic)
    parsed_message = json.loads(msg.payload)
    print(json.dumps(parsed_message, indent=4, sort_keys=True))

def on_disconnect(client, userdata, rc):

    if rc != 0:

        print "Unexpected disconnection." , (rc)
        global is_connect
        is_connect = False
while True:
    global is_connect
    #If client is not connected, initiate connection again 
    if not is_connect:
        try:
            client = mqtt.Client(client_id='testing_purpose', clean_session=False)
            client.loop_stop()
            client.on_connect = on_connect
            client.on_message = on_message
            client.on_disconnect = on_disconnect
            client.connect("localhost", 1883, 5)
            is_connect = True
            client.loop_start()
            time.sleep(15)
        except Exception as err:
            is_connect = False


# Blocking call that processes network traffic, dispatches callbacks and
# handles reconnecting.
# Other loop*() functions are available that give a threaded interface and a
# manual interface.
#client.loop_forever()

Answer 1

好的，所以只有在您使用loop_forever函数时，Paho客户端才会重新连接。

因此，如果您想控制网络循环，您可以随时使用reconnect函数重新连接，而不是断开整个连接。但最简单的方法是只使用loop_forever函数，如下所示：

import paho.mqtt.client as mqtt
import json

# The callback for when the client receives a CONNACK response from the server.
def on_connect(client, userdata, flags, rc):
    print("Connected with result code "+str(rc))
    # Subscribing in on_connect() means that if we lose the connection and
    # reconnect then subscriptions will be renewed.
    client.subscribe("#")

# The callback for when a PUBLISH message is received from the server.
def on_message(client, userdata, msg):
    print("Message received on "+msg.topic)
    parsed_message = json.loads(msg.payload)
    print(json.dumps(parsed_message, indent=4, sort_keys=True))

def on_disconnect(client, userdata, rc):
    if rc != 0:
        print "Unexpected disconnection." , (rc)

# Blocking call that processes network traffic, dispatches callbacks and
# handles reconnecting.
# Other loop*() functions are available that give a threaded interface and a
# manual interface.
client = mqtt.Client(client_id='testing_purpose', clean_session=False)
client.on_connect = on_connect
client.on_message = on_message
client.on_disconnect = on_disconnect
client.loop_forever()