minitel
Minitalk
by MaxF (github, mastodon, max@e97.me)
- Code: maxf/minitel
- Instructions
After 3615 GPT, conversations with danbri led me to want to implement some sort of chat system that could let a Minitel user chat with another Minitel. I’ll spare the reader all the considerations and decisions that went into this and will just outline the way I did it.
Hardware
I didn’t use the same serial cable as with 3615 GPT, but went for the Minitel ESP32 dongle (thanks again Dan for pointing me to it), a very nice little device that plugs into the DIN socket at the back and can do lots of very nice things, but in particular connect to a WiFi network and run an SSH client. This is a lot more convenient than the cable.
The SSH clients
We need a server PC, which runs an SSH server. Every Minitel (or indeed any computer connecting via SSH using a terminal) can connect to the sshd server. The server is configures to run client.py, instead of a normal shell. Upon starting, client.py asks for a username and lets the user join the chat.
The talk server
Each client.py programme connects to a server: server.py, which manages the canvas and dispatches each keypress received from each client to every other client. Clients and server communicates via simple Unix sockets.
2D chat
Instead of reusing something like IRC, I remembered the Unix talk command, that let two terminal users chat in full-duplex, split screen mode: every character one of them would type would immediately show on the other’s screen, leading to a very different way of chatting than common other messenging systems.
That way of chatting doesn’t work so well with much more than 2 users, so my idea was to have a single canvas where all connected clients could just write anywhere. A bit like collaborative editors like Google Docs.
client.py implements that: all clients see the same screen, except small labels that show you who is writing where. This is how it looks when both a PC and a Minitel are connected:
Minitel-specific characters
I chose not to use Minitel-specific features like double-size chars and “semi-graphical” characters, because it would be a lot of work to find the best way for the user to use them in chat. And it would make it very difficult to interact with non-Minitel terminals who don’t have those features. So unlike 3615 GPT, this is lacking the signature Minitel screen look-and-feel.
The end
Well that was quite fun to write. And for the first time, I used ChatGPT to write substantial portions of the code and to help me write the rest. I knew nothing about socket programming in python and it just wrote all the code for me.