💾 Archived View for rawtext.club › ~sloum › geminilist › 006240.gmi captured on 2024-03-21 at 16:30:18. Gemini links have been rewritten to link to archived content

-=-=-=-=-=-=-

How do you buffer a Gemini connection?

Omar Polo op at omarpolo.com

Mon Mar 29 09:13:07 BST 2021

- - - - - - - - - - - - - - - - - - -

almaember <almaember at disroot.org> writes:

Hello,

I'm planning on creating my own Gemini client (with C99 and OpenSSL, if

you want to know). However, I have a problem with how I should be

implementing the downloading part.

So, how should I be buffering a Gemini connection? Since there is no

size indicator, I can't be sure everything even fits into memory, or

how much time it's going to take to download, or if it's even going to

end at all.

Another problem is long-polling. Through my exploration of Geminispace,

I found a few capsules that used a hack to push live updates to the

client. Specifically, these servers didn't close the connection, but

instead kept it open and just sent new data when something happened.

Since the spec says nothing (or I'm blind) about buffering, so I want

to ask others about what I should be doing, while still being able to

actually parse the output.

My ideas as of right now:

- Have a big buffer and store everything in it until the connection is

closed. The connection would be terminated if:

- the connection closes

- the server didn't send anything for X seconds

- Buffer by line and don't close the connection unless the user

terminates it (by pressing the stop key or by loading another

capsule). Compatible with long polling.

Thanks in advance for any help!

~almaember

I'm working on a client and doing exactly as Ecmel Berk Canlıer outlinedin his mail. I'm fetching the page one chunk at the time (it allows meto use a fixed buffer and plays nice with asynchronous I/O) then getsent to a proper renderer (atm only text/gemini and one generic text/*handler). There it gets parsed and split line by line.

The only part where I have to actually keep a dynamic buffer is whensplitting in lines, because a line can (and often is) splitted acrosschunks, and possibly also bigger than one chunk.

I'm using LibreSSL (plus some other OpenBSD goodies), but if it savesyou some time here is:

the protocol code: https://github.com/omar-polo/telescope/blob/main/gemini.c* generic code shared by the parsers: https://github.com/omar-polo/telescope/blob/main/parser.c* text/plain "parser": https://github.com/omar-polo/telescope/blob/main/textplain.c

Warning: the client is not yet 100% functional, but I'm quite found ofthis design. One additional benefit is that you can also render thepage on the go, and that enables also to stream text/* stuff.

Cheers,

Omar Polo