EMQX Dashboard问题

EMQX
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1

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image1675×379 52.7 KB

EMQX Dashboard的状态只能显示已连接的设备，如何设置才能显示下线的设备？

2

你好，以下线设备无法在 EMQX 中显示。

除非该客户端是以保留会话的模式链接上来的（即 clean_start 或 clean_session 参数设置为 false）。这种模式下，EMQX 会为此类客户端保留一个会话状态在服务器中，这样的话才能在这个页面看到

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可以了，多谢！

4

还有一个问题，不知道有没有超出EMQX主题范围，使用 paho.mqtt.python库，重写的MQTT客户端，如何设置会话过期间隔，代码如下：
mqttc = mqtt.Client(mqtt.CallbackAPIVersion.VERSION2, client_id=hostname, clean_session=False)
mqttc.username_pw_set(mqtt_username, mqtt_password)
mqttc.on_connect = on_connect
mqttc.on_message = on_message
mqttc.on_subscribe = on_subscribe
mqttc.on_publish = on_publish
#用于客户端掉线再次连接客户端
mqttc.on_disconnect = on_disconnect
mqttc.connect(host=mqtt_server, port=mqtt_port, keepalive=60)

5

MQTT V3.1.1 Version:
mqttc = mqtt.Client(mqtt.CallbackAPIVersion.VERSION2,
client_id=hostname, protocol=mqtt.MQTTv311, clean_session=clean_session)
mqttc.connect(host=mqtt_server, port=mqtt_port, keepalive=60)

MQTT V5.0 Version:
mqttc = mqtt.Client(mqtt.CallbackAPIVersion.VERSION2,
client_id=hostname, protocol=mqtt.MQTTv5)
properties = Properties(PacketTypes.CONNECT)
properties.SessionExpiryInterval = session_expiry_interval
mqttc.connect(host=mqtt_server, port=mqtt_port, keepalive=60,
clean_start=clean_start, properties=properties)