Advertising channel endpoints in a future Pub/Sub conformance class

[ghobona]

During the April 2023 code sprint, a need was identified to be able to advertise MQTT channels on a collection metadata response. An example fragment is shown below.

        {
            "type": "application/json",
            "rel": "items",
            "title": "Subscription information (Pub/Sub)",
            "href": "mqtt://localhost:1883",
            "channel": "collections/weather-observations"
        } 

There is clearly a need to be able to include additional parameters in links. Since RFC 8288 identifies a specific set of link-params that are allowed in links, does that mean that no other link-params are allowed?

If so, how might we address the need to advertise channel endpoints in a future Pub/Sub conformance class of OGC API Standards.

[chris-little]

@ghobona In the draft API-EDR V1.2, we have requirements, courtesy of @tomkralidis :

A. An OGC API endpoint SHALL provide a link reference to a Publish-Subscribe server from an OGC API endpoint when Publish-Subscribe capabilities exist related to the OGC API endpoint.

B: A Publish-Subscribe link reference SHALL provide the channel property to allow for granular subscription.