How to discover the nickname of a peer?

[Lebei2046]

Hello, all

To build a chat program in local network, is there way to discover the nickname of a peer?
use mdns/identity or write a custom protocol?

[drHuangMHT]

Using mDNS would be ideal but libp2p doesn't support customizing service name yet, see #5949.
I personally don't think identify is intended for this. Although protocol_version and agent_version are customizable, they don't appear suitable for your case. But protocols are highly composable, those two values should be handled on application level. So I think it's fine(although it looks like a hack, not a real solution) to include additional information in those two values as long as your application handles it correctly. That said, you can also write your own protocol to exchange this information.

[Lebei2046]

It's better for auto discovery of nickname over peer-id, just as network neighborhood on windows. As you said, maybe hack by custom identity protocol.

[drHuangMHT]

It's better for auto discovery of nickname over peer-id, just as network neighborhood on windows. As you said, maybe hack by custom identity protocol.

I should mention that identify is NOT intended for peer discovery. identify on its own won't actively broadcast messages or query for all peers on the network. It only works after a connection is fully established. If you do not have any information of the peer, identify will do nothing. Neighbor-discovery needs broadcast of discovery messages over the network like DHCP, so ideally use mdns first to discover your neighbor's presence and its address, then connect to that address for further exchange of information.

[dariusc93]

In this case, you would need to write your own protocol to track the nickname of a peer. You could also exchange this information through other protocols like request-response, gossipsub, or stream (if you need it to be low-level). You could possibly write a protocol that mimics what identify does when it comes to exchanging information from a peer regarding a nickname and other metadata that would fit your application use-case.