从MQTT客户端获取连接的客户端ID的列表 [英] Get a list of connected client IDs from MQTT client

问题描述

作为连接到mosquitto的mqtt客户端，是否可以检索也连接到代理的客户端ID列表?

As a mqtt client connected to mosquitto is it possible to retrieve a list of client IDs who are also connected to the broker?

推荐答案

方法I:客户端逻辑中的句柄

如@ user1048839所说，请使用客户端的LWT&在线发布味精， 在自定义主题上维护客户状态. 下标该主题维护客户列表自身.

method I: handle in client logic

as @user1048839 says, use client's LWT & online publish msg, maintain client status on a custom topic. subscript this topic & maintain client list self.

如果发布retain消息，则sub将获得客户端列表.

if pub retain msg, once sub will get the client list.

官方代码不支持在线列表，
所以我修补了mosquitto 1.5.4，添加了2个自定义sys主题:

official code not support online_list,
so I patched mosquitto 1.5.4, add 2 custom sys topic:

mosquitto_sub -i DDD -v -t '$SYS/broker/chen_list'
$SYS/broker/chen_list
0 - CLOUD0_19108
1 - EEE
2 - DDD

2.线上/线下活动

mosquitto_sub -i DDD -v -t '$SYS/broker/chen_state/#'
$SYS/broker/chen_state/DDD 1
$SYS/broker/chen_state/EEE 1
$SYS/broker/chen_state/CLOUD0_19108 1
$SYS/broker/chen_state/EEE 0
$SYS/broker/chen_state/EEE 1

//如果pub retain msg，则本主题下的子主题可以使所有客户端处于联机状态(在有效负载中).

// if pub retain msg, sub this topic can get all clients online state (in payload).

在github上测试源代码:

test source code on github:

4-online-list

5-online-event

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