emq v1.1.3，rel\emqttd\etc\emqttd.config

‘subscription’擴充套件模組支援客戶端上線時，自動訂閱或恢復訂閱某些主題(Topic):

%% Modules
    {modules, [
        %% Client presence management module.
        %% Publish messages when client connected or disconnected
        {presence, [{qos, 0}]},

        %% Subscribe topics automatically when client connected
        {subscription, [

            %% $c will be replaced by clientid
            %% {"$queue/clients/$c", 1},
            {"$c/w", 1}

            %% Static subscriptions from backend
            %%backend
        ]}

        %% Rewrite rules
        %% {rewrite, [{file, "etc/rewrite.config"}]}
    ]},
 

emq v2.3.11，emqx-rel-2.3.11/deps/emq_modules/etc/emq_modules.conf

##--------------------------------------------------------------------
## Subscription Module
##--------------------------------------------------------------------

## Enable Subscription Module.
##
## Value: on | off
module.subscription = on

## Subscribe the Topics automatically when client connected.
module.subscription.1.topic = $client/w
## Qos of the subscription: 0 | 1 | 2
module.subscription.1.qos = 1