介紹

我在亞馬遜主機(jī)上安裝了mosquitto作為mqtt服務(wù)器，在樹(shù)莓派上找了一個(gè)python客戶(hù)端庫(kù)paho，安裝后找了一個(gè)例程：
https://github.com/eclipse/paho.mqtt.python#constructor-reinitialise
nano test.py:

import paho.mqtt.client as mqtt

# 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("$SYS/#")

# The callback for when a PUBLISH message is received from the server.
def on_message(client, userdata, msg):
    print(msg.topic+" "+str(msg.payload))

client = mqtt.Client()
client.on_connect = on_connect
client.on_message = on_message

client.connect("iot.eclipse.org", 1883, 60)

# 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()

chmod +x test.py
python ./test.py

運(yùn)行正常，但當(dāng)我將服務(wù)器地址改為我在aws上的地址時(shí)，服務(wù)器報(bào)

Invalid protocol "MQTT"...

解決方案

經(jīng)多方查證，問(wèn)題的根源處在mosquitto，我服務(wù)器（ubuntu14.04）上的版本太舊，在mtqq v3.1和v3.11版本兼容性上出了問(wèn)題，那解決之道就是更新mosquitto版本了：

wget http://repo.mosquitto.org/debian/mosquitto-repo.gpg.key
sudo apt-key add mosquitto-repo.gpg.key
cd /etc/apt/sources.list.d/
sudo wget http://repo.mosquitto.org/debian/mosquitto-jessie.list
sudo apt-get update
sudo apt-get install mosquitto

安裝新版本后問(wèn)題解決。