Why is this MQTT client example failing?

问题

I am trying out MQTT for the first time using Python and the mosquitto library. My client program is below. I'm trying to use the public demo MQTT server at http://www.mqtt-dashboard.com/subscribe. However the client code is failing, see error below. Any ideas on what's going on?

#!/usr/bin/env python

import mosquitto

client = mosquitto.Mosquitto("fredtest", clean_session=True)
client.connect("broker.mqttdashboard.com", 1883)

client.publish("fred.test", "hello world", 1)

client.loop_forever()

Error message:

C:\tmp>python mqttclient.py
Traceback (most recent call last):
  File "mqttclient.py", line 6, in 
    client.connect("broker.mqttdashboard.com", 1883)
  File "build\bdist.win-amd64\egg\mosquitto.py", line 582, in connect
  File "build\bdist.win-amd64\egg\mosquitto.py", line 657, in reconnect
  File "c:\python27\lib\socket.py", line 571, in create_connection
    raise err
socket.error: [Errno 10060] A connection attempt failed because the connected pa
rty did not properly respond after a period of time, or established connection f
ailed because connected host has failed to respond

回答1:

I'm not currently able to connect any client to broker.mqttdashboard.com:1883 - so this probably isn't an issue with your code.

To sanity check, have you tried connected to another broker, such as iot.eclipse.org:1883 ?

来源：https://stackoverflow.com/questions/23436185/why-is-this-mqtt-client-example-failing