The first handler

The MPP side is the same handshake → pull → invocation loop as the Python adapter tutorial; only the handler is new.

Sanitize viewer text

One rule before the code: viewer text is about to be embedded in a console command, and the Zandronum console treats ; as a command separator and " as a string delimiter. Unsanitized, a viewer could redeem hello"; quit and execute arbitrary console commands on the server. Strip both (plus \ and non-printable characters) before quoting:

def sanitize_chat(message):
    cleaned = "".join(
        ch for ch in message
        if 0x20 <= ord(ch) < 0x7F and ch not in ('"', ';', '\\')
    )
    return cleaned.strip()

The handler

def handle_chat_queue(rcon):
    def handler(sock, inv_id, event, params):
        if event != "say":
            failed(sock, inv_id, f"unknown event: {event}")
            return
        message = sanitize_chat(params.get("message", ""))
        if not message:
            failed(sock, inv_id, "message empty after sanitization")
            return
        try:
            rcon.command(f'say "{message}"')
        except RconError as e:
            failed(sock, inv_id, str(e))
            return
        applied_done(sock, inv_id, {"message": message})
    return handler

(failed and applied_done are the small frame helpers from the Python adapter tutorial: failed sends a failed frame with a reason, applied_done sends applied then done.)

The failed path matters as much as the happy path: when the game server is down, the Invocation fails with a reason and the viewer can be refunded — the Pack must never silently swallow a paid redeem.

Run it

Start the bridge with your Pack, set DOOM_RCON_PASSWORD in its environment, redeem a say Cue, and watch the message land in the game’s chat.

One event, end to end. Next: a second event that earns its own queue.