Why does MQTT not connect to the server?-CodePudding

My purpose is to achieve MQTT message publish upon postsave signal sent my DJango models. I have registered on_connect, on disconnect, on_publish callbacks to check when the relevant process is executed. However, none of callbacks I registered works. Here is my post_save signal code. Can someone please give me a hint where I do mistake?

import paho.mqtt.client as mqtt


def on_connect(client, userdata, flags, rc):
    print("connecting")
    print("client:" str(client))
    print("userdata:" str(userdata))
    print("flags:" str(flags))
    print("result:" str(rc))
    global flag_connected
    flag_connected=1


def on_publish(client, userdata, mid):
    print("message published")


def on_connect_fail(client, userdata, flags, rc):
    print("failed to connect")
    print("client:" str(client))
    print("userdata:" str(userdata))
    print("flags:" str(flags))
    print("result:" str(rc))
    global flag_connected
    flag_connected=0


def on_disconnect(client, userdata, rc):
   global flag_connected
   flag_connected = 0



  

def notify_windowsApp(sender,instance, **kwargs):
    

    new_truck_registered={
        "identity":str(instance.truck_identity),
        "doorName":str(instance.registered_door.door_name),
        "doorNumber":str(instance.registered_door.door_number),
        "entryTag":str(instance.entry_tag),
       
        #"depatureTag":str(instance.departure_tag), 
        "entrytime":instance.entry_time.strftime('%Y-%m-%d::%H-%M'),

    }



    



    sendToClient(new_truck_registered)


def sendToClient(payloadTobeSent):
    

    client=mqtt.Client(client_id="django_post_save_signal",
    clean_session=True, )
    mqttBroker="broker.hivemq.com"
    client.on_connect=on_connect
    client.on_publish=on_publish
    client.on_connect_fail=on_connect_fail
    client.on_disconnect=on_disconnect
    client.connect(mqttBroker)
    client.publish('baydoor/truckentrance',payload=str(payloadTobeSent),qos=1, retain=True)

CodePudding user response：

First, there is no on_connect_fail callback in the docs, where did you get that from?

And more importantly, you have not started the client network loop so none of the callbacks will ever get called.