API for Topics management

[hopeyen]

It would be really nice to have a function returning topics related to the running node, such as

• subscribed/unsubscribed pubsub/content topics
• peer ids (as filter protocol is specific to peers)

This makes it easier to track and manage the topics

[danielSanchezQ]

@richard-ramos do we have something like that in the underlaying lib?

[richard-ramos]

Hm. In go-waku we could access the list of topics via wakuNode.Relay().Topics() so we could expose that easily.
For the list of peers, in the current version of go-waku filter, there's no subscription management at client side, so there's no easy way to obtain the list of peers. One solution i could provide could be to instead of returning true when waku_filter_subscribe is executed, to instead return an object with the info for the subscription:

{
  peerId: ....,
  topic: ....,
  contentTopics: [ ... ]
}

and then subscription management could be done by the application using go-waku library.

...

In vacp2p/rfc#562 a lot of improvements over filter protocol are being done, and once they land in go-waku and nwaku i believe it will be easier to provide a list of active filter subscriptions.

[chair28980]

This will need to be added to nwaku when we switch from go-waku to nwaku for Rust bindings.