Client-side MDNS name resolution

[obdevel]

I trying to understand how a Pico W as a client can resolve a local hostname (of another Pico W) to an IP address using multicast DNS. It's simple for a PC or phone as this is built in to the o/s (Bonjour, Avahi, etc); I can just ping straight from the command line. It's also straightforward if there is a DNS server on the local network as we can give the client its IP address with WiFi.setDNS and then call WiFi.getHostname.

I think the only way is to use the MDNS.queryService method and iterate through the results, looking for a match with the target hostname. The gotcha is that this method doesn't appear to be able to resolve just hostnames; it only resolves service names (e.g. "http", "tcp"). This means that the target has to advertise a 'dummy' service (using MDNS.addService), although this could be called anything you like, e.g. "myapp", "tcp". We can then make a call to MDNS.queryService("myapp", "tcp") and iterate through the results.

Have I missed anything ?