2019-06-19 A Simple Text Client
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OK, this one goes together with the Simple Text Server I wrote about
yesterday. The server is basically a weird Gopher/Finger server that
can only serve text files. It doesn’t know anything about Gopher
menus, of FTP commands, or directory listings. Everything else would
be part of the client.
As @solderpunk said, one vision could be this:
1. All connections are TLS secured
2. Requests are a UTF-8 encoded selector and a CLRF, nothing more
3. Responses are guaranteed UTF-8 encoded text
4. No further structure of response is guaranteed
5. Clients should be able to extract any URLs from anywhere in the
text and construct a menu, with interface of their own choosing.
In my particular case, Nimi Mute (the server I wrote) sadly doesn’t
qualify:
1. TLS is optional. You can run it without encryption.
2. Requests are not decoded. It’s raw bytes. These encode filenames
and since I use UTF-8 encoded filenames, this might work. But it
might also not work: remember that Unicode can be in NFC or in NFD,
both equivalent encodings but using a different sequence of bytes.
See Unicode equivalence for more.
3. Responses are not guaranteed to be UTF-8 encoded. As I prefer using
UTF-8, this usually works. However, yesterday I showed how you can
download binary files from the text server. That alone shows you
that arbitrary bytes are allowed.
4. No further structure of response is guaranteed. This I support,
haha!
5. Clients should be able to extract any URLs from anywhere in the
text and construct a menu, with interface of their own choosing.
And that brings us to the topic of today: I need a proof-of-concept
client.
My main problem is that I want a better Gopher client for my iOS
phone. Since I have no idea how to write a native application, and
since I don’t want to develop on my Mac, that leaves me with a web
app. I can’t write a client-side web app because they all run in the
browser sandbox which doesn’t have access to TCP sockets. All you have
is web sockets. They are not compatible. For a while I tried to use
Fennel, compile it to Lua, and use Fengari to host it. Then I
thought about WebPerl, which is a Perl compiled with Emscripten to
WebAssembly. But it’s all the same: no escaping from the sandbox.
So I decided to write a server-side client: Soweli Lukin. The browser
access the web app I wrote, passes it a Gopher URL, which it fetches
from my Gopher server, and renders as Markdown, with some additional
translation. It works!
You can follow Gopher links to external sources: if they are links to
text files, these URLs are accessed via Soweli Lukin. Everything else
is up to your browser.
Ideally, this would be a native app on my phone, or a command line
program on my laptop. But as it is, this was the simplest proof of
concept I could think of.
