TermForge Telnet Host

Serve any TermForge app over lightweight telnet/TCP: make telnet-demo (the game), or directly:

node termforge/node/host-telnet.js --app bashcrawl              # telnet clients
node termforge/node/host-telnet.js --app procwatch --raw        # plain nc clients

Flags

Flag	Default	Meaning
--app	bashcrawl	bashcrawl, procwatch, or a path to a module exporting createApp
--port	2323	listen port
--host	127.0.0.1	bind address (see security posture)
--raw	off	dumb line mode: no telnet protocol, no server echo — for nc
--max-sessions	16	concurrent connections; excess get "server full" and are dropped
--idle-timeout	600	seconds of silence before a session is kicked (0 disables)
--width	80	assumed terminal width until NAWS reports one
--data-dir	repo web/data	game data directory for the bashcrawl app

Negotiated mode (default)

On connect the server sends exactly four options and nothing else:

Bytes	Meaning
IAC WILL ECHO	the server echoes — character-at-a-time UX
IAC WILL SGA	suppress go-ahead (server side)
IAC DO SGA	suppress go-ahead (client side)
IAC DO NAWS	please report your window size

Replies: the matching DO ECHO / DO SGA / WILL SGA / WILL NAWS are accepted silently; any other DO x gets WONT x, any other WILL x gets DONT x; incoming DONT/WONT are acknowledged silently and never re-negotiated. IAC SB NAWS w h IAC SE updates the session width; all other subnegotiations are skipped wholesale. IAC IAC is a literal 0xFF; IAC IP acts like ^C (cancels the current line); other two-byte commands are ignored. Both CR LF and CR NUL submit a line.

With echo and SGA in place the framework LineEditor gives telnet clients the full experience: arrow-key history, Tab completion, ^C line-cancel, ^L clear, ^D to disconnect. Output is SGR-colored per the terminal protocol kind table with CRLF line endings.

Raw mode (--raw)

No IAC bytes in either direction, no server echo, no per-character editing: a prompt, a \n-terminated line, the output. Your client's own line editing applies — which is exactly what nc wants:

make telnet-demo ARGS="--raw --port 2324" &
printf 'pwd\nls -F\ncat scroll\n' | nc 127.0.0.1 2324

History arrows and Tab completion don't exist here by design; disconnect with ^C/^D (client side).

Session model

One connection = one fully isolated session: its own runtime, state, view, and editor; nothing is shared between sockets. Limits: session cap (--max-sessions), idle kick (--idle-timeout), 4096-character line cap, 2000-line scrollback cap. A crash inside a command surfaces as an error line; the session survives.

Security posture

Telnet is plaintext — treat it accordingly:

• The bind address defaults to loopback. Binding elsewhere requires an explicit --host and prints a startup warning; for remote access prefer an SSH tunnel: ssh -L 2323:127.0.0.1:2323 host, then telnet 127.0.0.1 2323 locally.
• No real shell and no real filesystem are reachable. Sessions run the TermForge emulator over an in-memory world; VFS providers are read-only; nothing derived from client bytes is ever evaluated, spawned, or written to disk. The host process reads only web/data/*.json.
• Resource bounds: session cap, idle timeout, line-length cap, scrollback cap, per-session isolation.

This is a lab/trusted-network tool in the spirit of classic MUDs and BBSes — not an internet-facing service.