amolenaar / nerves_dnssd

mDNS/DNS-SD implementation for Nerves, based on Apple's Bonjour daemon

Nerves.Dnssd

Nerves_dnssd provides an interface to Apple's Bonjour DNS Service Discovery implementation. Bonjour allows applications to browse, resolve and register network services via link-local multicast DNS on the local network and via unicast DNS over the internet.

This module is based on the Dnssd_erlang project written by Andrew Tunnell-Jones, Radosław Szymczyszyn and others.

Installation

Nerves_dnssd requires Erlang R19 or later and Elixir 1.5.0 or later.

The package can be installed by adding Nerves_dnssd to your list of dependencies in mix.exs:

def deps do
  [{:nerves_dnssd, "~> x.y"}]
end

Further documentation can be found on the (HexDocs page for Nerves_dnssd)[https://hexdocs.pm/nerves_dnssd/].

Example use

In the most basic situation, where one wants to simply register a service on the network, calling

{:ok, pid} = Nerves.Dnssd.register("Fancy service name", "_http._tcp", 8080)

is sufficient to register a HTTP service listening on port 8080. In case there is already a service named "Fancy service name" a new name will be determined by using a follow-up number and that name will be registered, so that after a restart the service will advertise itself with the same name.

License

This project is distributed under the Apache License, version 2.0. The conditions can be found in the LICENSE file.

nerves_dnssd's Issues

Compilation issue with OTP 23

OTP 23 deprecated the header file erl_interface.h so that dnssd.c no longer compiles.

nerves_dnssd/c_src/dnssd.c

Line 26 in 099da5b

#include <erl_interface.h>

The fix is to just #include <ei.h>.

Persist service name once a service is registered

Part of the DNS-SD spec states that a service name should not change. Hence, in the case of a name class on the local network, the service should initially try to register the same name after a reboot.

E.g. if the service tries to register name "Webserver", but that name is already taken, it will register as "Webserver (2)". Next time it boots it should also register itself as "Webserver (2)", not "Webserver" although that name may be available again.

Preferably this should be saved in the SystemRegistry.