Comments on 2020-12-10 International domain names and Phoebe

In Perl, I need to do the following to get the same punycode from a URL provided on the command line:

use Modern::Perl;
my ($url) = @ARGV;
my $iri = IRI->new(value => $url);
say domain_to_ascii(decode_utf8 $iri->host);

But then the client still sends the original IRI to the server which then replies that it won’t proxy, unlike the result of using Firefox.

– 2020-12-10 23:25 UTC

Ah, it’s more complicated, of course. HTTP doesn’t actually send an URI! It sends something like this:

GET /some/path HTTP/1.1
Host: xn--mlanobombus-bbb

Well, I’m working on a branch where my simple command line client and Phoebe work together, at least. I feel like I owe this to my last name. In the previous milenium, I started to write Schroeder instead of Schröder because internationalisation was a big problem. This was before I had ever heard of Unicode and UTF-8.

– 2020-12-11 11:23 UTC

Oh my invisible friend... the changes required aren’t trivial. Still on it!

– 2020-12-11 12:25 UTC

Wow, I’ve been looking at the mailing list. Sooo much discussion! Three threads:

– 2020-12-11 16:22 UTC

Talked about it a bit on the Gemini IRC channel until I got angry. 😒

– 2020-12-11 18:02 UTC

OK, so I abandoned the international domain name (IDN) branch where the client sends gemini://東京.jp/ to the server because I thought it was stupid that the client could send gemini://東京.jp/ but not gemini://東京.jp/日本語. So then I went back to RFC 3987 and read the introduction to section 3, “Relationship between IRIs and URIs”:

IRIs are meant to replace URIs in identifying resources for protocols, formats, and software components that use a UCS-based character repertoire. These protocols and components may never need to use URIs directly, especially when the resource identifier is used simply for identification purposes. However, when the resource identifier is used for resource retrieval, it is in many cases necessary to determine the associated URI, because currently most retrieval mechanisms are only defined for URIs. In this case, IRIs can serve as presentation elements for URI protocol elements. An example would be an address bar in a Web user agent.

This seems ideal. Clients are free to use IRIs to communicate with their users: letting them enter an IRI like gemini://東京.jp/日本語 into the address bar and showing them such URIs. But if these clients communicate with a Gemini server, they need to use URIs. They need to request gemini://

This reduces the problem for Phoebe to a much smaller set of problems.

How does a server administrator start Phoebe such that it serves an international domain name (IDN)? I added code that converts the host name provided from the current locale (which is wha the administrator is using in their shell) to Unicode, and converts that to punycode, and uses that to look up the IP addresses using getaddrinfo(3).

When deciding whether to serve a URL, Phobe checks for the punycode representation of the host names: Anything else is considered to be a proxy request and is most likely denied.

The part handling the percent encoded paths already exists and already works.

What remains is a usability problem, of course. When users write their gemtext, they need to use some sort of tool to do the conversions. It’s basically delegated to Editor support. I guess I’m fine with that, for the moment. Allowing users to link to IRIs and transparently translating them to URIs as they get sent to the client would be an easy change to make. I’d still have to solve such problems as how to handle a space character. If the server sees “⇒ One Two Three” this is a relative link to “One”. Otherwise the user would have had to write “⇒ One%20Two Three” or “⇒ One%20Two%20Three”. Then again, perhaps I can just leave it as-is because I often copy and paste weird URIs from elsewhere.

In either case, I can definitely delay this. 😁

So now all I need to do to get some closure is to add some sort of IRI handling to my simple command-line client.

My “/etc/hosts” has the punycode encoding of the new hostname:	localhost	melanobombus	xn--mlanobombus-bbb

I start Phoebe using a non-ASCII hostname and a non-ASCII pagename:

script/phoebe --host=mélanobombus --wiki_page=Schröder

Then I use the “gemini” client:

$ script/gemini --verbose gemini://mélanobombus/page/Schröder
Contacting xn--mlanobombus-bbb:1965
Requesting gemini://xn--mlanobombus-bbb:1965/page/Schr%C3%83%C2%B6der
20 text/gemini; charset=UTF-8
# Schröder
This page does not yet exist.

=> gemini://xn--mlanobombus-bbb:1965/history/Schr%C3%83%C2%B6der History
=> gemini://xn--mlanobombus-bbb:1965/raw/Schr%C3%83%C2%B6der Raw text
=> gemini://xn--mlanobombus-bbb:1965/html/Schr%C3%83%C2%B6der HTML

Happy! 🥳🚀🚀🎉

And when I use Firefox, it works as well. 🙂

The log. Notice the host header.

[debug] HTTP headers: referer => 'https://xn--mlanobombus-bbb:1965/', dnt => '1', accept-encoding => 'gzip, deflate, br', upgrade-insecure-requests => '1', user-agent => 'Mozilla/5.0 (Windows NT 10.0; rv:78.0) Gecko/20100101 Firefox/78.0', accept-language => 'de-CH,de;q=0.8,en-US;q=0.5,en;q=0.3', accept => 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8', host => 'xn--mlanobombus-bbb:1965', connection => 'keep-alive'
[info] Looking at GET /page/Schr%C3%B6der HTTP/1.1
[info] Serving Schröder as HTML via HTTP

– Alex

OK, I got something!

– 2020-12-14 18:49 UTC

URL Interop, by @bagder. “This document is an attempt to describe where and how RFC 3986 (86), RFC 3987 (87) and the WHATWG URL Specification (TWUS) differ. This might be useful input when trying to interop with URLs on the modern Internet.”

– Alex 2021-01-18 10:25 UTC

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