Python Paho MQTT回调未触发

我正在使用Paho连接到我的MQTT brooker，但是，回调没有按预期工作。我已经阅读了文档，无法理解为什么这些函数会被忽略

import paho.mqtt.client as mqtt
import mqttUtils as utils

# Subscribe To Topic


def subscribeToTopic(client, topic):
    try:
        result = client.subscribe(topic, 2)
        if result[0] == 0:
            utils.logging.info("Successfuly Subscribed To Topic")
            return 1
    except:
        utils.logging.info("Failed Subscribe Attempt")
        return 0


def on_subscribe(client, userdata, mid, granted_qos):  # subscribe to mqtt broker
    print("Subscribed", userdata)



host = "x"
client = mqtt.Client()
client.connect(host, port=1883, keepalive=60, bind_address="")
# result = utils.connectToMqtt(client,utils.host)
client.on_subscribe = on_subscribe
subscribeResult = subscribeToTopic(client, "test")

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这是我的代码，我在订阅之前声明on_subscribe方法，但是脚本拒绝工作。有人知道为什么没有触发回调吗？

程序必须一直运行并从服务器接收消息，当它从服务器得到确认后，它将在订阅上运行

你可以用ie

client.loop_forever() 

一直运行它

import paho.mqtt.client as mqtt

def on_subscribe(client, userdata, mid, granted_qos):
    print("Subscribed", client, userdata, mid, granted_qos)

def on_message(client, userdata, message):
    #print('on_message:', client, userdata, message)
    #print(dir(message))
    print('on_message:', message.payload.decode())

host = "mqtt.eclipse.org"

client = mqtt.Client()
client.connect(host, port=1883, keepalive=60, bind_address="")
client.on_message = on_message
client.on_subscribe = on_subscribe
client.subscribe('temp', 1)

client.loop_forever()


医生：
您是否收到任何错误消息？始终将完整的错误消息（从单词“Traceback”开始）作为文本（而不是屏幕截图）进行讨论（不是评论）。还有其他有用的信息。没有错误消息，只输出日志。输出为“成功订阅主题”，因此，结果变量的输出为（0,1）