如何使用PAHO MQTT客户端连接到Digitransit经纪人

Question

我是MQTT的新手，我想建立与Digitransit MQTT经纪人的连接，以使用Python Paho MQTT客户端接收公共交通数据。要连接到经纪人端口，需要主题。

关于经纪人来源中提供的信息，我想我至少需要两个信息，但我不确定是否缺少某些信息。请不要说脚本是通过基于浏览器的jupyter笔记本执行的。

经纪人来源： https://digitransit.fi/en/开发人员/API/4-REALTIME-API/车辆位置/ paho文档： https://www.eclipse.org /paho/index.php?page=clients/python/index.php

• 端口：8883
• 主题：/hfp/v2/journey/＃
• broker：mqtt.hsl.fi

通过命令行运行时可以接收数据，例如，

/hfp/v2/journey/ongoing/vp/bus/0022/01281/1040/2/Elielinaukio/14:29/1140118/0//// {"VP":{"desi":"40","dir":"2","oper":22,"veh":1281,"tst":"2022-07-06T11:56:53.417Z","tsi":1657108613,"spd":null,"hdg":null,"lat":null,"long":null,"acc":null,"dl":-101,"odo":8530,"drst":0,"oday":"2022-07-06","jrn":2646,"line":62,"start":"14:29","loc":"ODO","stop":null,"route":"1040","occu":0}}

您可以使用两个命令尝试一下：

npm install -g mqtt

mqtt subscribe -h mqtt.hsl.fi -p 8883 -l mqtts -v -t "/hfp/v2/journey/#"

在jupyter Notebook或Python上运行时脚本我只看到定义的输出on_connect方法，但没有显示数据。

我的代码片段是：

# pip install paho-mqtt

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("/hfp/v2/journey/#")

# 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.tls_set()
client.connect("mqtt.hsl.fi", 8883, 60)

client.loop_forever()

有人知道哪种细节是错误的还是缺少的？

更新：接受的解决方案适用于通过Pycharm或Visual Studio Code执行的Python脚本，但不使用基于浏览器的IDE（例如Jupyter Notebook）。

Answer 1

问题是您尚未告诉使用TLS连接的Python Paho客户端。

在调用contry> connect（）之前，添加client.tls_set（）

client = mqtt.Client()
client.on_connect = on_connect
client.on_message = on_message
client.tls_set()
client.connect("mqtt.hsl.fi", 8883, 60)

client.loop_forever()