main.py

#!/usr/bin/env python3

import os
import sys
import json
import re
import io
import base64
import logging
from PIL import Image
from urllib.parse import parse_qs
import escpos.config

logging.basicConfig(
    level=logging.DEBUG,
    force=True
)
logextras = [
    os.environ.get('REMOTE_ADDR', '-'),
    os.environ.get('REQUEST_METHOD', '-'),
    os.environ.get('REQUEST_URI', '-')
]

logger = logging.getLogger(__name__)

config = escpos.config.Config()
config.load('config.yaml')

printer = config.printer()

METHOD = os.environ.get('REQUEST_METHOD')

if METHOD == 'GET':
    logger.info('%s %s %s: printer status', logextras[0], logextras[1], logextras[2])
    try:
        is_online = printer.is_online()
        paper_status = printer.paper_status()
        print(json.dumps({
            "online": is_online,
            "paper_empty": True if paper_status == 0 else False,
            "paper_low": True if paper_status == 1 else False,
        }))
    except Exception as e:
        print("Could not connect to printer.")
        logger.error(e)
        logger.warning("Could not connect to printer.")
    sys.exit(0)

if METHOD != 'POST':
    print('Bad Request')
    logger.warning("Invalid Method %s", METHOD)
    sys.exit(0)

logger.info('%s %s %s: print job', logextras[0], logextras[1], logextras[2])

QS = parse_qs(os.environ.get('QUERY_STRING'))
POST_DATA = sys.stdin.read().strip()

def parse(text):
    pattern = re.compile(r'(?<!\\)\{([^}]*)\}')
    result = []
    current_tag = []
    pos = 0

    for match in pattern.finditer(text):
        # Text before this tag belongs to the current tag
        if match.start() > pos:
            value = text[pos:match.start()]
            value = value.replace(r'\{', '{').replace(r'\}', '}')
            result.append((current_tag, value))

        tag = match.group(1)
        current_tag = tag.lower().split(',') if tag else []
        pos = match.end()

    # Remaining text
    if pos < len(text):
        value = text[pos:]
        value = value.replace(r'\{', '{').replace(r'\}', '}')
        result.append((current_tag, value))

    return result

def to_bool(input):
    return str(input).lower() in ('1', 'true', 'yes', 'on', 'y', 't')

def qs_get(index, default = None):
    return QS.get(index, [default])[0]

def tag_arg(tags, key):
    value = next(
        (m.group(1) for x in tags if (m := re.search(f"^{re.escape(key)}=(.+)$", x))),
        None,
    )

    return value

def _print_image(tags, payload):
    if payload.startswith("http://") or payload.startswith("https://"):
        logger.debug("printing image from URL (%s): %s", tags, payload)
        fd = urllib.urlopen(payload)
        image_data = fd.read()
    else:
        logger.debug("printing image from raw data (%s)", tags)
        image_data = base64.b64decode(payload)

    image = Image.open(io.BytesIO(image_data))
    center = True if 'c' in tags else False

    printer.image(image, center = center)

def _print_qr(tags, payload):
    logger.debug("printing QR code (%s): %s", tags, payload)
    kwargs = {
        "native": True
    }
    if 'c' in tags:
        kwargs['native'] = False
        kwargs['center'] = True

    if size := tag_arg(tags, 's'):
        kwargs['size'] = int(size)

    if ec := tag_arg(tags, 'ec'):
        if ec_const := getattr(escpos.constants, f"QR_ECLEVEL_{ec.upper()}", None):
            kwargs['ec'] = ec_const

    printer.qr(payload, **kwargs)

def _print_barcode(tags, payload):
    logger.debug("printing barcode (%s): %s", tags, payload)
    kwargs = {
        "bc": "EAN13"
    }
    if bctype := tag_arg(tags, 't'):
        kwargs['bc'] = bctype

    if width := tag_arg(tags, 'w'):
        kwargs['width'] = int(width)
    if height := tag_arg(tags, 'height'):
        kwargs['height'] = int(h)

    if font := tag_arg(tags, 'ft'):
        kwargs['font'] = font

    if pos := tag_arg(tags, 'p'):
        pos_const_map = {
            'a': 'ABOVE',
            'b': 'BELOW',
            'ab': 'BOTH',
            '0': 'OFF',
            'o': 'OFF',
        }

        if pos_const := pos_const_map.get(pos.lower()):
            kwargs['pos'] = pos_const

    if "l" in tags:
        kwargs['align_ct'] = False
    if "c" in tags:
        kwargs['align_ct'] = True

    printer.barcode(payload, **kwargs)

def _print_text(tags, payload):
    logger.debug("printing text (%s): %s", tags, payload)

    kwargs = {}

    if "c" in tags:
        kwargs['align'] = "center"
    elif "r" in tags:
        kwargs['align'] = "right"
    elif "l" in tags:
        kwargs['align'] = "left"

    if "b" in tags:
        kwargs['bold'] = True
    if "u" in tags:
        kwargs['underline'] = True

    if width := tag_arg(tags, 'w'):
        kwargs['width'] = int(width)
        kwargs['custom_size'] = True
    if height := tag_arg(tags, 'h'):
        kwargs['height'] = int(height)
        kwargs['custom_size'] = True

    if font := tag_arg(tags, 'ft'):
        kwargs['font'] = font

    printer.set(**kwargs)
    printer.text(payload)

    if "ln" in tags:
        printer.ln()

def _cashdraw(tags, payload):
    logger.debug("triggering cash drawer (%s)", tags)
    if pin := tag_arg(tags, 'd'):
        printer.cashdraw(pin)

for segment in parse(POST_DATA):
    tags = segment[0]
    payload = segment[1]

    if len(tags) < 1:
        tags = ["tx"]

    printer.set_with_default()

    if "f" in tags:
        printer.set(flip=True)
    if "i" in tags:
        printer.set(invert=True)

    if tags[0] == "im":
        _print_image(tags, payload)
    elif tags[0] == "qr":
        _print_qr(tags, payload)
    elif tags[0] == "bc":
        _print_barcode(tags, payload)
    elif tags[0] == "cd":
        _cashdraw(tags, payload)
        _print_text(tags, payload)
    elif tags[0] == "cut":
        logger.debug("cutting")
        printer.cut()
    else:
        _print_text(tags, payload)

if to_bool(qs_get('cut', True)):
    logger.debug("cutting at the end")
    printer.cut()
elif to_bool(qs_get('feed', True)):
    logger.debug("feeding at the end")
    printer.print_and_feed()

print("OK")