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Separate method open() and constructor, enhance consistency between connectors. (#584) 

* Add self-open mechanism
* self-open mechanism through the 'device' property
* Separate open() and store connection in 'device'
* Restore device status to False on close()
* Add default value to all params + type annotations
* Add generic DeviceNotFoundError exception
* Update USBNotFoundError return code
* Enhance connectors consistency
* Fix LP printer stall
* Fix LP waste of paper due to auto-flush + flush on close
* Move platform dependent printers' guard to init

---------

Co-authored-by: Patrick Kanzler <4189642+patkan@users.noreply.github.com>
This commit is contained in:
Benito López 2023-10-16 11:36:07 +02:00 committed by GitHub
parent 3a8af8a6f5
commit a00b98937b
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GPG Key ID: 4AEE18F83AFDEB23
10 changed files with 537 additions and 179 deletions
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29
src/escpos/escpos.py
View File

@ -14,7 +14,7 @@ This module contains the abstract base class :py:class:`Escpos`.
import textwrap
from abc import ABCMeta, abstractmethod # abstract base class support
from re import match as re_match
from typing import List, Optional, Union
from typing import List, Literal, Optional, Union
import barcode
import qrcode
@ -114,7 +114,11 @@ class Escpos(object):
class.
"""
device = None
# device status:
# False -> Not initialized
# None -> Initialized but not connected
# object -> The connection object (Usb(), Serial(), Network(), etc.)
_device: Union[Literal[False], Literal[None], object] = False
def __init__(self, profile=None, magic_encode_args=None, **kwargs) -> None:
"""Initialize ESCPOS Printer.
@ -128,6 +132,27 @@ class Escpos(object):
"""Call self.close upon deletion."""
self.close()
@property
def device(self) -> Union[Literal[None], object]:
"""Implements a self-open mechanism.
An attempt to get the property before open the connection
will cause the connection to open.
"""
if self._device is False:
# Open device if not previously opened
self._device = None # None -> Initialized
self.open()
return self._device
@device.setter
def device(self, new_device: Union[Literal[False], Literal[None], object]):
self._device = new_device
def open(self):
"""Open a printer device/connection."""
pass
@abstractmethod
def _raw(self, msg: bytes) -> None:
"""Send raw data to the printer.

37
src/escpos/exceptions.py
View File

@ -13,7 +13,8 @@ Result/Exit codes:
- `60` = Invalid pin to send Cash Drawer pulse :py:exc:`~escpos.exceptions.CashDrawerError`
- `70` = Invalid number of tab positions :py:exc:`~escpos.exceptions.TabPosError`
- `80` = Invalid char code :py:exc:`~escpos.exceptions.CharCodeError`
- `90` = USB device not found :py:exc:`~escpos.exceptions.USBNotFoundError`
- `90` = Device not found :py:exc:`~escpos.exceptions.DeviceNotFoundError`
- `91` = USB device not found :py:exc:`~escpos.exceptions.USBNotFoundError`
- `100` = Set variable out of range :py:exc:`~escpos.exceptions.SetVariableError`
- `200` = Configuration not found :py:exc:`~escpos.exceptions.ConfigNotFoundError`
- `210` = Configuration syntax error :py:exc:`~escpos.exceptions.ConfigSyntaxError`
@ -275,11 +276,35 @@ class CharCodeError(Error):
return "Valid char code must be set ({msg})".format(msg=self.msg)
class USBNotFoundError(Error):
"""Device was not found (probably not plugged in).
class DeviceNotFoundError(Error):
"""Device was not found.
The device seems to be not accessible.
The return code for this exception is `90`.
inheritance:
.. inheritance-diagram:: escpos.exceptions.Error
:parts: 1
"""
def __init__(self, msg=""):
"""Initialize DeviceNotFoundError object."""
Error.__init__(self, msg)
self.msg = msg
self.resultcode = 90
def __str__(self):
"""Return string representation of DeviceNotFoundError."""
return f"Device not found ({self.msg})"
class USBNotFoundError(DeviceNotFoundError):
"""USB device was not found (probably not plugged in).
The USB device seems to be not plugged in.
The return code for this exception is `90`.
The return code for this exception is `91`.
inheritance:
@ -292,11 +317,11 @@ class USBNotFoundError(Error):
"""Initialize USBNotFoundError object."""
Error.__init__(self, msg)
self.msg = msg
self.resultcode = 90
self.resultcode = 91
def __str__(self):
"""Return string representation of USBNotFoundError."""
return "USB device not found ({msg})".format(msg=self.msg)
return f"USB device not found ({self.msg})"
class SetVariableError(Error):

84
src/escpos/printer/cups.py
View File

@ -9,9 +9,12 @@
"""
import functools
import logging
import tempfile
from typing import Literal, Optional, Type, Union
from ..escpos import Escpos
from ..exceptions import DeviceNotFoundError
#: keeps track if the pycups dependency could be loaded (:py:class:`escpos.printer.CupsPrinter`)
_DEP_PYCUPS = False
@ -20,6 +23,9 @@ try:
import cups
_DEP_PYCUPS = True
# Store server defaults before further configuration
DEFAULT_HOST = cups.getServer()
DEFAULT_PORT = cups.getPort()
except ImportError:
pass
@ -78,49 +84,85 @@ class CupsPrinter(Escpos):
return is_usable()
@dependency_pycups
def __init__(self, printer_name=None, *args, **kwargs):
def __init__(self, printer_name: str = "", *args, **kwargs):
"""Class constructor for CupsPrinter.
:param printer_name: CUPS printer name (Optional)
:type printer_name: str
:param host: CUPS server host/ip (Optional)
:type host: str
:param port: CUPS server port (Optional)
:type port: int
"""
Escpos.__init__(self, *args, **kwargs)
host, port = args or (
kwargs.get("host", cups.getServer()),
kwargs.get("port", cups.getPort()),
self.host, self.port = args or (
kwargs.get("host", DEFAULT_HOST),
kwargs.get("port", DEFAULT_PORT),
)
cups.setServer(host)
cups.setPort(port)
self.conn = cups.Connection()
self.tmpfile = None
self.tmpfile = tempfile.NamedTemporaryFile(delete=True)
self.printer_name = printer_name
self.job_name = ""
self.pending_job = False
self.open()
self._device: Union[
Literal[False], Literal[None], Type[cups.Connection]
] = False
@property
def printers(self):
def printers(self) -> dict:
"""Available CUPS printers."""
return self.conn.getPrinters()
if self.device:
return self.device.getPrinters()
return {}
def open(self, job_name="python-escpos"):
def open(
self, job_name: str = "python-escpos", raise_not_found: bool = True
) -> None:
"""Set up a new print job and target the printer.
A call to this method is required to send new jobs to
the same CUPS connection.
the CUPS connection after close.
Defaults to default CUPS printer.
Creates a new temporary file buffer.
By default raise an exception if device is not found.
:param raise_not_found: Default True.
False to log error but do not raise exception.
:raises: :py:exc:`~escpos.exceptions.DeviceNotFoundError`
"""
if self._device:
self.close()
cups.setServer(self.host)
cups.setPort(self.port)
self.job_name = job_name
if self.printer_name not in self.printers:
self.printer_name = self.conn.getDefault()
if self.tmpfile.closed:
self.tmpfile = tempfile.NamedTemporaryFile(delete=True)
try:
# Open device
self.device: Optional[Type[cups.Connection]] = cups.Connection()
if self.device:
# Name validation, set default if no given name
self.printer_name = self.printer_name or self.device.getDefault()
assert self.printer_name in self.printers, "Incorrect printer name"
except (RuntimeError, AssertionError) as e:
# Raise exception or log error and cancel
self.device = None
if raise_not_found:
raise DeviceNotFoundError(
f"Unable to start a print job for the printer {self.printer_name}:"
+ f"\n{e}"
)
else:
logging.error(
"CupsPrinter printing %s not available", self.printer_name
)
return
logging.info("CupsPrinter printer enabled")
def _raw(self, msg):
"""Append any command sent in raw format to temporary file.
@ -134,14 +176,13 @@ class CupsPrinter(Escpos):
self.pending_job = False
raise ValueError("Printer job not opened")
@dependency_pycups
def send(self):
"""Send the print job to the printer."""
if self.pending_job:
# Rewind tempfile
self.tmpfile.seek(0)
# Print temporary file via CUPS printer.
self.conn.printFile(
self.device.printFile(
self.printer_name,
self.tmpfile.name,
self.job_name,
@ -173,8 +214,9 @@ class CupsPrinter(Escpos):
Send pending job to the printer if needed.
"""
if not self._device:
return
if self.pending_job:
self.send()
if self.conn:
print("Closing CUPS connection to printer {}".format(self.printer_name))
self.conn = None
logging.info("Closing CUPS connection to printer %s", self.printer_name)
self._device = False

57
src/escpos/printer/file.py
View File

@ -1,6 +1,6 @@
#!/usr/bin/python
# -*- coding: utf-8 -*-
"""This module contains the implementation of the CupsPrinter printer driver.
"""This module contains the implementation of the File printer driver.
:author: python-escpos developers
:organization: `python-escpos <https://github.com/python-escpos>`_
@ -8,7 +8,11 @@
:license: MIT
"""
import logging
from typing import IO, Literal, Optional, Union
from ..escpos import Escpos
from ..exceptions import DeviceNotFoundError
def is_usable() -> bool:
@ -39,7 +43,7 @@ class File(Escpos):
"""
return is_usable()
def __init__(self, devfile="/dev/usb/lp0", auto_flush=True, *args, **kwargs):
def __init__(self, devfile: str = "", auto_flush: bool = True, *args, **kwargs):
"""Initialize file printer with device file.
:param devfile: Device file under dev filesystem
@ -48,17 +52,40 @@ class File(Escpos):
Escpos.__init__(self, *args, **kwargs)
self.devfile = devfile
self.auto_flush = auto_flush
self.open()
def open(self):
"""Open system file."""
self.device = open(self.devfile, "wb")
self._device: Union[Literal[False], Literal[None], IO[bytes]] = False
if self.device is None:
print("Could not open the specified file {0}".format(self.devfile))
def open(self, raise_not_found: bool = True) -> None:
"""Open system file.
def flush(self):
By default raise an exception if device is not found.
:param raise_not_found: Default True.
False to log error but do not raise exception.
:raises: :py:exc:`~escpos.exceptions.DeviceNotFoundError`
"""
if self._device:
self.close()
try:
# Open device
self.device: Optional[IO[bytes]] = open(self.devfile, "wb")
except OSError as e:
# Raise exception or log error and cancel
self.device = None
if raise_not_found:
raise DeviceNotFoundError(
f"Could not open the specified file {self.devfile}:\n{e}"
)
else:
logging.error("File printer %s not found", self.devfile)
return
logging.info("File printer enabled")
def flush(self) -> None:
"""Flush printing content."""
if self.device:
self.device.flush()
def _raw(self, msg):
@ -71,8 +98,12 @@ class File(Escpos):
if self.auto_flush:
self.flush()
def close(self):
def close(self) -> None:
"""Close system file."""
if self.device is not None:
self.device.flush()
self.device.close()
if not self._device:
return
logging.info("Closing File connection to printer %s", self.devfile)
if not self.auto_flush:
self.flush()
self._device.close()
self._device = False

139
src/escpos/printer/lp.py
View File

@ -1,6 +1,6 @@
#!/usr/bin/python
# -*- coding: utf-8 -*-
"""This module contains the implementation of the CupsPrinter printer driver.
"""This module contains the implementation of the LP printer driver.
:author: python-escpos developers
:organization: `python-escpos <https://github.com/python-escpos>`_
@ -9,11 +9,13 @@
"""
import functools
import os
import logging
import subprocess
import sys
from typing import Literal, Optional, Union
from ..escpos import Escpos
from ..exceptions import DeviceNotFoundError
def is_usable() -> bool:
@ -61,40 +63,124 @@ class LP(Escpos):
"""
return is_usable()
def __init__(self, printer_name: str, *args, **kwargs):
@dependency_linux_lp
def __init__(self, printer_name: str = "", *args, **kwargs):
"""LP class constructor.
:param printer_name: CUPS printer name (Optional)
:type printer_name: str
:param auto_flush: Automatic flush after every _raw() (Optional)
:type auto_flush: bool
:type auto_flush: bool (Defaults False)
"""
Escpos.__init__(self, *args, **kwargs)
self.printer_name = printer_name
self.auto_flush = kwargs.get("auto_flush", True)
self.open()
self.auto_flush = kwargs.get("auto_flush", False)
self._flushed = False
@dependency_linux_lp
def open(self):
"""Invoke _lp_ in a new subprocess and wait for commands."""
self.lp = subprocess.Popen(
["lp", "-d", self.printer_name, "-o", "raw"],
stdin=subprocess.PIPE,
stdout=open(os.devnull, "w"),
self._device: Union[Literal[False], Literal[None], subprocess.Popen] = False
@property
def printers(self) -> dict:
"""Available CUPS printers."""
p_names = subprocess.run(
["lpstat", "-e"], # Get printer names
capture_output=True,
text=True,
)
p_devs = subprocess.run(
["lpstat", "-v"], # Get attached devices
capture_output=True,
text=True,
)
# List and trim output lines
names = [name for name in p_names.stdout.split("\n") if name]
devs = [dev for dev in p_devs.stdout.split("\n") if dev]
# return a dict of {printer name: attached device} pairs
return {name: dev.split()[-1] for name in names for dev in devs if name in dev}
def close(self):
def _get_system_default_printer(self) -> str:
"""Return the system's default printer name."""
p_name = subprocess.run(
["lpstat", "-d"],
capture_output=True,
text=True,
)
name = p_name.stdout.split()[-1]
if name not in self.printers:
return ""
return name
def open(
self,
job_name: str = "python-escpos",
raise_not_found: bool = True,
_close_opened: bool = True,
) -> None:
"""Invoke _lp_ in a new subprocess and wait for commands.
By default raise an exception if device is not found.
:param raise_not_found: Default True.
False to log error but do not raise exception.
:raises: :py:exc:`~escpos.exceptions.DeviceNotFoundError`
"""
if self._device and _close_opened:
self.close()
self._is_closing = False
self.job_name = job_name
try:
# Name validation, set default if no given name
self.printer_name = self.printer_name or self._get_system_default_printer()
assert self.printer_name in self.printers, "Incorrect printer name"
# Open device
self.device: Optional[subprocess.Popen] = subprocess.Popen(
["lp", "-d", self.printer_name, "-t", self.job_name, "-o", "raw"],
stdin=subprocess.PIPE,
stdout=subprocess.DEVNULL,
stderr=subprocess.DEVNULL,
)
except (AssertionError, subprocess.SubprocessError) as e:
# Raise exception or log error and cancel
self.device = None
if raise_not_found:
raise DeviceNotFoundError(
f"Unable to start a print job for the printer {self.printer_name}:"
+ f"\n{e}"
)
else:
logging.error("LP printing %s not available", self.printer_name)
return
logging.info("LP printer enabled")
def close(self) -> None:
"""Stop the subprocess."""
self.lp.terminate()
if not self._device:
return
logging.info("Closing LP connection to printer %s", self.printer_name)
self._is_closing = True
if not self.auto_flush:
self.flush()
self._device.terminate()
self._device = False
def flush(self):
def flush(self) -> None:
"""End line and wait for new commands."""
if self.lp.stdin.writable():
self.lp.stdin.write(b"\n")
if self.lp.stdin.closed is False:
self.lp.stdin.close()
self.lp.wait()
self.open()
if not self.device or not self.device.stdin:
return
if self._flushed:
return
if self.device.stdin.writable():
self.device.stdin.write(b"\n")
if self.device.stdin.closed is False:
self.device.stdin.close()
self.device.wait()
self._flushed = True
if not self._is_closing:
self.open(_close_opened=False)
def _raw(self, msg):
"""Write raw command(s) to the printer.
@ -102,9 +188,10 @@ class LP(Escpos):
:param msg: arbitrary code to be printed
:type msg: bytes
"""
if self.lp.stdin.writable():
self.lp.stdin.write(msg)
if self.device.stdin.writable():
self.device.stdin.write(msg)
else:
raise Exception("Not a valid pipe for lp process")
raise subprocess.SubprocessError("Not a valid pipe for lp process")
self._flushed = False
if self.auto_flush:
self.flush()

61
src/escpos/printer/network.py
View File

@ -8,9 +8,12 @@
:license: MIT
"""
import logging
import socket
from typing import Literal, Optional, Union
from ..escpos import Escpos
from ..exceptions import DeviceNotFoundError
def is_usable() -> bool:
@ -54,7 +57,14 @@ class Network(Escpos):
"""
return is_usable()
def __init__(self, host, port=9100, timeout=60, *args, **kwargs):
def __init__(
self,
host: str = "",
port: int = 9100,
timeout: Union[int, float] = 60,
*args,
**kwargs,
):
"""Initialize network printer.
:param host: Printer's host name or IP address
@ -65,16 +75,40 @@ class Network(Escpos):
self.host = host
self.port = port
self.timeout = timeout
self.open()
def open(self):
"""Open TCP socket with ``socket``-library and set it as escpos device."""
self.device = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self._device: Union[Literal[False], Literal[None], socket.socket] = False
def open(self, raise_not_found: bool = True) -> None:
"""Open TCP socket with ``socket``-library and set it as escpos device.
By default raise an exception if device is not found.
:param raise_not_found: Default True.
False to log error but do not raise exception.
:raises: :py:exc:`~escpos.exceptions.DeviceNotFoundError`
"""
if self._device:
self.close()
try:
# Open device
self.device: Optional[socket.socket] = socket.socket(
socket.AF_INET, socket.SOCK_STREAM
)
self.device.settimeout(self.timeout)
self.device.connect((self.host, self.port))
if self.device is None:
print("Could not open socket for {0}".format(self.host))
except OSError as e:
# Raise exception or log error and cancel
self.device = None
if raise_not_found:
raise DeviceNotFoundError(
f"Could not open socket for {self.host}:\n{e}"
)
else:
logging.error("Network device %s not found", self.host)
return
logging.info("Network printer enabled")
def _raw(self, msg):
"""Print any command sent in raw format.
@ -88,11 +122,14 @@ class Network(Escpos):
"""Read data from the TCP socket."""
return self.device.recv(16)
def close(self):
def close(self) -> None:
"""Close TCP connection."""
if self.device is not None:
if not self._device:
return
logging.info("Closing Network connection to printer %s", self.host)
try:
self.device.shutdown(socket.SHUT_RDWR)
self._device.shutdown(socket.SHUT_RDWR)
except socket.error:
pass
self.device.close()
self._device.close()
self._device = False

71
src/escpos/printer/serial.py
View File

@ -1,6 +1,6 @@
#!/usr/bin/python
# -*- coding: utf-8 -*-
"""This module contains the implementation of the CupsPrinter printer driver.
"""This module contains the implementation of the Serial printer driver.
:author: python-escpos developers
:organization: `python-escpos <https://github.com/python-escpos>`_
@ -10,8 +10,11 @@
import functools
import logging
from typing import Literal, Optional, Union
from ..escpos import Escpos
from ..exceptions import DeviceNotFoundError
#: keeps track if the pyserial dependency could be loaded (:py:class:`escpos.printer.Serial`)
_DEP_PYSERIAL = False
@ -73,16 +76,16 @@ class Serial(Escpos):
@dependency_pyserial
def __init__(
self,
devfile="/dev/ttyS0",
baudrate=9600,
bytesize=8,
timeout=1,
parity=None,
stopbits=None,
xonxoff=False,
dsrdtr=True,
devfile: str = "",
baudrate: int = 9600,
bytesize: int = 8,
timeout: Union[int, float] = 1,
parity: Optional[str] = None,
stopbits: Optional[int] = None,
xonxoff: bool = False,
dsrdtr: bool = True,
*args,
**kwargs
**kwargs,
):
"""Initialize serial printer.
@ -111,14 +114,26 @@ class Serial(Escpos):
self.xonxoff = xonxoff
self.dsrdtr = dsrdtr
self.open()
self._device: Union[Literal[False], Literal[None], serial.Serial] = False
@dependency_pyserial
def open(self):
"""Set up serial port and set is as escpos device."""
if self.device is not None and self.device.is_open:
def open(self, raise_not_found: bool = True) -> None:
"""Set up serial port and set is as escpos device.
By default raise an exception if device is not found.
:param raise_not_found: Default True.
False to log error but do not raise exception.
:raises: :py:exc:`~escpos.exceptions.DeviceNotFoundError`
"""
if self._device:
if self.device and self.device.is_open:
self.close()
self.device = serial.Serial(
try:
# Open device
self.device: Optional[serial.Serial] = serial.Serial(
port=self.devfile,
baudrate=self.baudrate,
bytesize=self.bytesize,
@ -128,11 +143,17 @@ class Serial(Escpos):
xonxoff=self.xonxoff,
dsrdtr=self.dsrdtr,
)
if self.device is not None:
print("Serial printer enabled")
except (ValueError, serial.SerialException) as e:
# Raise exception or log error and cancel
self.device = None
if raise_not_found:
raise DeviceNotFoundError(
f"Unable to open serial printer on {self.devfile}:\n{e}"
)
else:
print("Unable to open serial printer on: {0}".format(str(self.devfile)))
logging.error("Serial device %s not found", self.devfile)
return
logging.info("Serial printer enabled")
def _raw(self, msg):
"""Print any command sent in raw format.
@ -146,8 +167,12 @@ class Serial(Escpos):
"""Read the data buffer and return it to the caller."""
return self.device.read(16)
def close(self):
def close(self) -> None:
"""Close Serial interface."""
if self.device is not None and self.device.is_open:
self.device.flush()
self.device.close()
if not self._device:
return
logging.info("Closing Serial connection to printer %s", self.devfile)
if self._device and self._device.is_open:
self._device.flush()
self._device.close()
self._device = False

105
src/escpos/printer/usb.py
View File

@ -8,9 +8,11 @@
:license: MIT
"""
import functools
import logging
from typing import Dict, Literal, Optional, Type, Union
from ..escpos import Escpos
from ..exceptions import USBNotFoundError
from ..exceptions import DeviceNotFoundError, USBNotFoundError
#: keeps track if the usb dependency could be loaded (:py:class:`escpos.printer.Usb`)
_DEP_USB = False
@ -72,14 +74,14 @@ class Usb(Escpos):
def __init__(
self,
idVendor,
idProduct,
usb_args=None,
timeout=0,
in_ep=0x82,
out_ep=0x01,
idVendor: str = "",
idProduct: str = "",
usb_args: Dict[str, str] = {},
timeout: Union[int, float] = 0,
in_ep: int = 0x82,
out_ep: int = 0x01,
*args,
**kwargs
**kwargs,
):
"""Initialize USB printer.
@ -95,32 +97,65 @@ class Usb(Escpos):
self.in_ep = in_ep
self.out_ep = out_ep
usb_args = usb_args or {}
self.usb_args = usb_args or {}
if idVendor:
usb_args["idVendor"] = idVendor
self.usb_args["idVendor"] = idVendor
if idProduct:
usb_args["idProduct"] = idProduct
self.open(usb_args)
self.usb_args["idProduct"] = idProduct
self._device: Union[
Literal[False], Literal[None], Type[usb.core.Device]
] = False
@dependency_usb
def open(self, usb_args):
def open(self, raise_not_found: bool = True) -> None:
"""Search device on USB tree and set it as escpos device.
:param usb_args: USB arguments
By default raise an exception if device is not found.
:param raise_not_found: Default True.
False to log error but do not raise exception.
:raises: :py:exc:`~escpos.exceptions.DeviceNotFoundError`
:raises: :py:exc:`~escpos.exceptions.USBNotFoundError`
"""
self.device = usb.core.find(**usb_args)
if self.device is None:
raise USBNotFoundError("Device not found or cable not plugged in.")
if self._device:
self.close()
self.idVendor = self.device.idVendor
self.idProduct = self.device.idProduct
# Open device
try:
self.device: Optional[Type[usb.core.Device]] = usb.core.find(
**self.usb_args
)
assert self.device, USBNotFoundError(
f"Device {tuple(self.usb_args.values())} not found"
+ " or cable not plugged in."
)
self._check_driver()
self._configure_usb()
except (AssertionError, usb.core.USBError) as e:
# Raise exception or log error and cancel
self.device = None
if raise_not_found:
raise DeviceNotFoundError(
f"Unable to open USB printer on {tuple(self.usb_args.values())}:"
+ f"\n{e}"
)
else:
logging.error("USB device %s not found", tuple(self.usb_args.values()))
return
logging.info("USB printer enabled")
# pyusb has three backends: libusb0, libusb1 and openusb but
# only libusb1 backend implements the methods is_kernel_driver_active()
# and detach_kernel_driver().
# This helps enable this library to work on Windows.
if self.device.backend.__module__.endswith("libusb1"):
check_driver = None
def _check_driver(self) -> None:
"""Check the driver.
pyusb has three backends: libusb0, libusb1 and openusb but
only libusb1 backend implements the methods is_kernel_driver_active()
and detach_kernel_driver().
This helps enable this library to work on Windows.
"""
if self.device and self.device.backend.__module__.endswith("libusb1"):
check_driver: Optional[bool] = None
try:
check_driver = self.device.is_kernel_driver_active(0)
@ -134,13 +169,17 @@ class Usb(Escpos):
pass
except usb.core.USBError as e:
if check_driver is not None:
print("Could not detatch kernel driver: {0}".format(str(e)))
logging.error("Could not detatch kernel driver: %s", str(e))
def _configure_usb(self) -> None:
"""Configure USB."""
if not self.device:
return
try:
self.device.set_configuration()
self.device.reset()
except usb.core.USBError as e:
print("Could not set configuration: {0}".format(str(e)))
logging.error("Could not set configuration: %s", str(e))
def _raw(self, msg):
"""Print any command sent in raw format.
@ -155,8 +194,12 @@ class Usb(Escpos):
return self.device.read(self.in_ep, 16)
@dependency_usb
def close(self):
def close(self) -> None:
"""Release USB interface."""
if self.device:
usb.util.dispose_resources(self.device)
self.device = None
if not self._device:
return
logging.info(
"Closing Usb connection to printer %s", tuple(self.usb_args.values())
)
usb.util.dispose_resources(self._device)
self._device = False

98
src/escpos/printer/win32raw.py
View File

@ -1,6 +1,6 @@
#!/usr/bin/python
# -*- coding: utf-8 -*-
"""This module contains the implementation of the CupsPrinter printer driver.
"""This module contains the implementation of the Win32Raw printer driver.
:author: python-escpos developers
:organization: `python-escpos <https://github.com/python-escpos>`_
@ -9,12 +9,16 @@
"""
import functools
import logging
from typing import Literal, Optional, Type, Union
from ..escpos import Escpos
from ..exceptions import DeviceNotFoundError
#: keeps track if the win32print dependency could be loaded (:py:class:`escpos.printer.Win32Raw`)
_DEP_WIN32PRINT = False
try:
import win32print
@ -70,38 +74,78 @@ class Win32Raw(Escpos):
return is_usable()
@dependency_win32print
def __init__(self, printer_name=None, *args, **kwargs):
def __init__(self, printer_name: str = "", *args, **kwargs):
"""Initialize default printer."""
Escpos.__init__(self, *args, **kwargs)
if printer_name is not None:
self.printer_name = printer_name
else:
self.printer_name = win32print.GetDefaultPrinter()
self.hPrinter = None
self.open()
self.job_name = ""
@dependency_win32print
def open(self, job_name="python-escpos"):
"""Open connection to default printer."""
if self.printer_name is None:
raise Exception("Printer not found")
self.hPrinter = win32print.OpenPrinter(self.printer_name)
self._device: Union[
Literal[False],
Literal[None],
Type[win32print.OpenPrinter],
] = False
@property
def printers(self) -> dict:
"""Available Windows printers."""
return {
printer["pPrinterName"]: printer
for printer in win32print.EnumPrinters(win32print.PRINTER_ENUM_NAME, "", 4)
}
def open(
self, job_name: str = "python-escpos", raise_not_found: bool = True
) -> None:
"""Open connection to default printer.
By default raise an exception if device is not found.
:param raise_not_found: Default True.
False to log error but do not raise exception.
:raises: :py:exc:`~escpos.exceptions.DeviceNotFoundError`
"""
if self._device:
self.close()
self.job_name = job_name
try:
# Name validation, set default if no given name
self.printer_name = self.printer_name or win32print.GetDefaultPrinter()
assert self.printer_name in self.printers, "Incorrect printer name"
# Open device
self.device: Optional[
Type[win32print.OpenPrinter]
] = win32print.OpenPrinter(self.printer_name)
if self.device:
self.current_job = win32print.StartDocPrinter(
self.hPrinter, 1, (job_name, None, "RAW")
self.device, 1, (job_name, None, "RAW")
)
win32print.StartPagePrinter(self.hPrinter)
@dependency_win32print
def close(self):
"""Close connection to default printer."""
if not self.hPrinter:
win32print.StartPagePrinter(self.device)
except AssertionError as e:
# Raise exception or log error and cancel
self.device = None
if raise_not_found:
raise DeviceNotFoundError(
f"Unable to start a print job for the printer {self.printer_name}:"
+ f"\n{e}"
)
else:
logging.error("Win32Raw printing %s not available", self.printer_name)
return
win32print.EndPagePrinter(self.hPrinter)
win32print.EndDocPrinter(self.hPrinter)
win32print.ClosePrinter(self.hPrinter)
self.hPrinter = None
logging.info("Win32Raw printer enabled")
def close(self) -> None:
"""Close connection to default printer."""
if not self._device:
return
logging.info("Closing Win32Raw connection to printer %s", self.printer_name)
win32print.EndPagePrinter(self._device)
win32print.EndDocPrinter(self._device)
win32print.ClosePrinter(self._device)
self._device = False
@dependency_win32print
def _raw(self, msg):
"""Print any command sent in raw format.
@ -110,6 +154,6 @@ class Win32Raw(Escpos):
"""
if self.printer_name is None:
raise Exception("Printer not found")
if self.hPrinter is None:
if not self.device:
raise Exception("Printer job not opened")
win32print.WritePrinter(self.hPrinter, msg)
win32print.WritePrinter(self.device, msg)

1
tox.ini
View File

@ -57,7 +57,6 @@ deps = mypy
types-appdirs
types-Pillow
types-pyserial
types-pywin32
hypothesis>=6.83
jaconv
commands = mypy src test