CODEWITHSUNDEEP
c#mqtthivemq
tsvedas
tsvedas

Reputation: 1069

HiveMQ shared subscriptions using M2Mqtt

If subscriber has topic as $share/group/my_topic, it doesn't receive any messages, but if I change the topic to /my_topic - everything works just fine.

It seems that M2Mqtt doesn't support shared subscriptions. Is there a workaround for this? I also need persistence to work with shared subscriptions.

If there's no workaround, offers to other libraries are welcome!

Upvotes: 0

Views: 329

Answers (2)

tsvedas
tsvedas

Reputation: 1069

Use MQTTnet library

It can be found at https://github.com/chkr1011/MQTTnet or as NuGET package.
It does the job, as far as I've tested!

Upvotes: 0

hardillb
hardillb

Reputation: 59638

I can't test this but I have a theory.

The problem is that you have a leading / on your base topic /my_topic

If you remove this and publish messages on my_topic then the shared topic should match.

Having a leading / adds a null element to the topic, which you can't include in the $share/group/[null]/my_topic

While leading a / is allowed in the MQTT spec it is considered bad practice (and can lead to issues like this).

Also the client library has no knowledge of shared subscriptions, this is entirely a broker side feature. All clients should "just work"

Upvotes: 1

Related Questions