printer_rbp_py

#!/usr/bin/env python3
from flask import Flask, request, jsonify
from datetime import datetime
import subprocess
from typing import Iterable, List, Union

# The printer must be a CUPS queue configured as RAW,
# otherwise ESC/POS bytes will get mangled into text.
PRINTER_NAME = "TM-T20II"

app = Flask(__name__)

def escpos_bytes(lines: Iterable[Union[str, bytes]], footer_blank: int = 3, cut: bool = True) -> bytes:
    out = bytearray()

    # Reset printer
    out += b"\x1B\x40"

    # Header to visually separate receipts
    out += b"-" * 30 + b"\n"
    out += b"  Task Completed Receipt\n"
    out += b"-" * 30 + b"\n"

    for line in lines:
        if isinstance(line, str):
            out += line.encode("utf-8", errors="replace") + b"\n"
        else:
            out += line + b"\n"

    out += b"\n" * footer_blank
    if cut:
        out += b"\x1D\x56\x00"  # full cut
    return bytes(out)

def print_escpos(data_bytes: bytes) -> None:
    # We rely on the queue being RAW so bytes are passed untouched
    subprocess.run(
        ["lp", "-d", PRINTER_NAME],
        input=data_bytes,
        check=True
    )

@app.post("/print")
def print_receipt():
    j = request.get_json(force=True, silent=False)

    title = j.get("title", "(untitled)")
    listname = j.get("list", "Reminders")
    completed_at = j.get("completed_at") or datetime.now().isoformat(timespec="seconds")
    note = j.get("note", "")

    lines: List[str] = [
        f"Task : {title}",
        f"List : {listname}",
        f"Time : {completed_at}",
    ]
    if note:
        lines += ["", "Note:", note]

    try:
        data = escpos_bytes(lines)
        print_escpos(data)
        return jsonify({"ok": True}), 200
    except subprocess.CalledProcessError as e:
        return jsonify({"ok": False, "error": f"lp failed: {e}"}), 500

@app.get("/health")
def health():
    return jsonify({"ok": True}), 200

if __name__ == "__main__":
    # Bind to all interfaces so you can reach the Pi from other devices on the LAN
    app.run(host="0.0.0.0", port=5000)