AttributeError：'NoneType'对象没有属性'订阅'

Question

我试图使用代码来发送帖子给经纪人，并且我遇到了一些问题。代码如下：

import paho.mqtt.client as mqtt 
def on_connect(self, client, userdata, rc): 
    if rc==0: 
    print("successful connection") 
    client.subscribe("HelloWorld") 
else: 
    print("connection fail") #the subscriber will not receive the message 

def on_message (client, userdata, msg): 
print(str(msg.payload.decode('UTF-8'))) #Post Posted 

client= mqtt.Client() 
client.on_connect = on_connect #Create the "client" object 
client.on_message = on_message 
client.username_pw_set("TypeUser",typePassaword) # I omitted username and password 
client.connect('TypeURLBroker',TypePort) #Broker Online. 1º Termo: Url do broker; 2º Termo: Port 
client.loop_start() 

while 0==0: 
mymsg='Hello World' 
client.publish(topic='HelloWorld/', payload=mymsg) 

出现一些错误，我没有任何想法来解决它们。我需要一点帮助。

错误列表：

successful connection 
Exception in thread Thread-6: 
Traceback (most recent call last): 
File "C:\Users\fvs\AppData\Local\Programs\Python\Python35\lib\threading.py", line 914, in _bootstrap_inner 
    self.run() 
    File "C:\Users\fvs\AppData\Local\Programs\Python\Python35\lib\threading.py", line 862, in run 
    self._target(*self._args, **self._kwargs) 
    File "C:\Users\fvs\AppData\Local\Programs\Python\Python35\lib\site-packages\paho\mqtt\client.py", line 2606, in _thread_main 
    self.loop_forever(retry_first_connection=True) 
    File "C:\Users\fvs\AppData\Local\Programs\Python\Python35\lib\site-packages\paho\mqtt\client.py", line 1470, in loop_forever 
    rc = self.loop(timeout, max_packets) 
    File "C:\Users\fvs\AppData\Local\Programs\Python\Python35\lib\site-packages\paho\mqtt\client.py", line 995, in loop 
    rc = self.loop_read(max_packets) 
    File "C:\Users\fvs\AppData\Local\Programs\Python\Python35\lib\site-packages\paho\mqtt\client.py", line 1273, in loop_read 
    rc = self._packet_read() 
    File "C:\Users\fvs\AppData\Local\Programs\Python\Python35\lib\site-packages\paho\mqtt\client.py", line 1838, in _packet_read 
    rc = self._packet_handle() 
    File "C:\Users\fvs\AppData\Local\Programs\Python\Python35\lib\site-packages\paho\mqtt\client.py", line 2291, in _packet_handle 
    return self._handle_connack() 
    File "C:\Users\fvs\AppData\Local\Programs\Python\Python35\lib\site-packages\paho\mqtt\client.py", line 2349, in _handle_connack 
    self.on_connect(self, self._userdata, flags_dict, result) 
    File "C:/Users/fvs/PycharmProjects/HelloWorld.py", line 6, in on_connect 
    client.subscribe("HelloWorld") 
AttributeError: 'NoneType' object has no attribute 'subscribe' 

Answer 1

根据docson_connect应该有下面的签名

on_connect(client, userdata, flags, rc) 

您尝试使用第二个位置参数，这实际上userdata，不client。尝试

def on_connect(client, userdata, flags, rc): 
    if rc==0: 
     print("successful connection") 
     client.subscribe("HelloWorld") 
    else: 
     print("connection fail") #the subscriber will not receive the message