Some reading on IRIs and IDNs

[colecmac at protonmail.com]

Hello,

I didn't see any email mentioning this so I thought I'd share the
link here. Lagrange[1] has gone ahead with IDN support, and the details
are found in this post[2] by skyjake.

The relevant points are as follows.

> * The full URL is NFC normalized before sending it to a server.
> * Domain names with non-ASCII characters are encoded to Punycode before
>   doing a DNS lookup. The Punycode version of the domain name is sent to
>   the server in the request URL, and also used for verifying the server
>   certificate.

This is what I plan on doing in Amfora as well. I will defer to Solderpunk's
judgement, which is coming[3], but until then that's my plan. The only
difference is that I was planning on allowing both punycoded domains and IDNs
in certs, to simplify things for sysadmins. But if Lagrange isn't allowing
it, then maybe I shouldn't... this is quickly approaching "de facto standard"
territory.

For now I will err on the permissive side in that case, allowing both, but this
is something I'd like hear from Solderpunk on.

gemget will do the same, as it uses the go-gemini[4] library as well.


1: https://gmi.skyjake.fi/lagrange/
2: gemini://skyjake.fi/gemlog/2020-12_idns-in-lagrange.gmi
3: gemini://gemini.circumlunar.space/~solderpunk/pikkulog/2020-12.gmi
4: https://github.com/makeworld-the-better-one/go-gemini/issues/10


Cheers,
makeworld