xterm.js webclient and helper utility
=====================================

This repository contains the client and helper utility to use xterm.js [0] in
the web UI of Proxmox projects like Proxmox VE, Proxmox Mail Gateway or Proxmox
Backup Server.

[0]: https://xtermjs.org

To be able to relay between the frontend and a shell program/console running in
the backend, we provide a tool called termproxy to open a port (where our
websocketproxy connects to) and to open a PTY and execute a program.

For communication originating from the client towards the server, it implements
a simple packet-based protocol where everything is a string. The protocol
consists of the following messages:

* Normal Message
    0:LENGTH:MSG
    where LENGTH is the bytelength of the msg

* Resize Message
    1:COLS:ROWS:
	where COLS is the number of columns the client wants to resize to, and ROWS
	the number of rows, respectively

* Ping Message
    2
    used to keep the connection between client and server alive
    (we have a timeout of 5 minutes)

Every other input from the client will be ignored.

Communication from server to the client uses no protocol, the raw data coming
from the terminal/program will be forwarded 1:1, without any wrapping format.