feat: initial implementation

[aschmahmann]

WIP, but example Caddyfile:

{
	auto_https off
	servers {
        protocols h1 h2
    }
	libp2p {
		private_key ed25519key.pem
		advertise_amino true
	}
}

http://example.com:4002 {
	# Site-specific options
	bind multiaddr:/ip4/0.0.0.0/udp/4002/quic-v1/webtransport
	# Other site configuration
	respond "I am 4002"
}

Caddy can be built locally with:
xcaddy.exe build --with github.com/aschmahmann/caddy-libp2p-listener=.

[MarcoPolo]

Can we make this a proper multiaddr uri:
bind multiaddr:/ip4/0.0.0.0/udp/4002/quic-v1/webtransport

multiformats/multiaddr#171

[MarcoPolo]

Can we register the well known handler somehow?

[aschmahmann]

Can we make this a proper multiaddr uri:

I don't think so in that I think the bind semantics require namespaces to have // like the unix one here https://caddyserver.com/docs/caddyfile/directives/bind, but I'm not sure.

[aschmahmann]

Can we register the well known handler somehow?

I was thinking about this, but it depends on how we want to use it. Out of the box there's no utility to the well known handler since there are no protocols registered by default. What were you thinking?

[aschmahmann]

I don't think so in that I think the bind semantics require namespaces to have // like the unix one here https://caddyserver.com/docs/caddyfile/directives/bind, but I'm not sure.

Actually might be possible looking at some of the valid example from here: https://caddyserver.com/docs/conventions#network-addresses

Although it's possible we'd have to do some hacks like make the namespace multiaddr: rather than multiaddr and internally add a / to the multiaddr before decoding into bytes.

[aschmahmann]

@MarcoPolo this (along with the hack to add a / to the returned address) seems to allow passing multiaddr URIs. A bit gross, but seems ok