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Merge pull request #348 from belono/development 

Add new CUPS printer connector
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Patrick Kanzler 2023-04-19 22:49:05 +02:00 committed by GitHub
parent e4a73ad5c5 98ee06a783
commit d4d3819d55
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5 changed files with 223 additions and 12 deletions
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3
.github/workflows/documentation.yml vendored
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@ -25,7 +25,8 @@ jobs:
- name: Install packages
run:
sudo apt-get update -y &&
sudo apt-get install -y git python3-sphinx graphviz libenchant1c2a &&
sudo apt-get install -y git python3-sphinx graphviz libenchant-2-2 &&
sudo apt-get install -y gcc libcups2-dev python3-dev python3-setuptools &&
sudo pip install tox pycups
- name: Test doc build
run: tox -e docs

4
.gitignore vendored
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@ -6,6 +6,7 @@ $~
.idea/
.directory
.cache/
settings.json
# temporary data
temp
@ -22,6 +23,9 @@ src/escpos/version.py
.hypothesis
.pytest_cache/
# pyenv
.python-version
# testing temporary directories
test/test-cli-output/

2
.mailmap
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@ -14,3 +14,5 @@ Sergio Pulgarin <sergio.pulgarin@gmail.com>
reck31 <rakesh.gunduka@gmail.com>
Alex Debiasio <alex.debiasio@thinkin.io> <alex.debiasio@studenti.unitn.it>
Maximilian Wagenbach <maximilian.wagenbach@native-instruments.de>
<belono@users.noreply.github.com> <tiotil.lindeman@gmail.com>
belono <belono@users.noreply.github.com> Benito López <belono@users.noreply.github.com>

27
doc/user/printers.rst
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@ -1,9 +1,9 @@
********
Printers
********
:Last Reviewed: 2017-01-25
:Last Reviewed: 2022-11-25
As of now there are 5 different type of printer implementations.
As of now there are 7 different type of printer implementations.
USB
---
@ -75,3 +75,26 @@ all of the "output" as raw ESC/POS in a string and returns that.
:member-order: bysource
:noindex:
CUPS
----
This driver uses `pycups` in order to communicate with a CUPS server.
Supports both local and remote CUPS printers and servers.
The printer must be properly configured in CUPS administration.
The connector generates a print job that is added to the CUPS queue.
.. todo:: fix import in documentation
LP
----
This driver uses the UNIX command `lp` in order to communicate with a CUPS server.
Supports local and remote CUPS printers.
The printer must be properly configured in CUPS administration.
The connector spawns a new sub-process where the command lp is executed.
No dependencies required, but somehow the print queue will affect some print job such as barcode.
.. autoclass:: escpos.printer.LP
:members:
:special-members:
:member-order: bysource
:noindex:

199
src/escpos/printer.py
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@ -9,14 +9,35 @@
"""
import serial
import os
import socket
import subprocess
import sys
import serial
import usb.core
import usb.util
from .escpos import Escpos
from .exceptions import USBNotFoundError
_WIN32PRINT = False
try:
import win32print
_WIN32PRINT = True
except ImportError:
pass
_CUPSPRINT = False
try:
import cups
import tempfile
_CUPSPRINT = True
except ImportError:
pass
class Usb(Escpos):
"""USB printer
@ -371,14 +392,6 @@ class Dummy(Escpos):
pass
_WIN32PRINT = False
try:
import win32print
_WIN32PRINT = True
except ImportError:
pass
if _WIN32PRINT:
class Win32Raw(Escpos):
@ -419,3 +432,171 @@ if _WIN32PRINT:
if self.hPrinter is None:
raise Exception("Printer job not opened")
win32print.WritePrinter(self.hPrinter, msg)
if _CUPSPRINT:
class CupsPrinter(Escpos):
"""Simple CUPS printer connector.
.. note::
Requires _pycups_ which in turn needs the cups development library package:
- Ubuntu/Debian: _libcups2-dev_
- OpenSuse/Fedora: _cups-devel_
"""
def __init__(self, printer_name=None, *args, **kwargs):
"""CupsPrinter class constructor.
: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()),
)
cups.setServer(host)
cups.setPort(port)
self.conn = cups.Connection()
self.tmpfile = None
self.printer_name = printer_name
self.job_name = ""
self.pending_job = False
self.open()
@property
def printers(self):
"""Available CUPS printers."""
return self.conn.getPrinters()
def open(self, job_name="python-escpos"):
"""Setup a new print job and target printer.
A call to this method is required to send new jobs to
the same CUPS connection.
Defaults to default CUPS printer.
Creates a new temporary file buffer.
"""
self.job_name = job_name
if self.printer_name not in self.printers:
self.printer_name = self.conn.getDefault()
self.tmpfile = tempfile.NamedTemporaryFile(delete=True)
def _raw(self, msg):
"""Append any command sent in raw format to temporary file
:param msg: arbitrary code to be printed
:type msg: bytes
"""
self.pending_job = True
try:
self.tmpfile.write(msg)
except ValueError:
self.pending_job = False
raise ValueError("Printer job not opened")
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.printer_name,
self.tmpfile.name,
self.job_name,
{"document-format": cups.CUPS_FORMAT_RAW},
)
self._clear()
def _clear(self):
"""Finish the print job.
Remove temporary file.
"""
self.tmpfile.close()
self.pending_job = False
def _read(self):
"""Return a single-item array with the accepting state of the print queue.
states: idle = [3], printing a job = [4], stopped = [5]
"""
printer = self.printers.get(self.printer_name, {})
state = printer.get("printer-state")
if not state:
return []
return [state]
def close(self):
"""Close CUPS connection.
Send pending job to the printer if needed.
"""
if self.pending_job:
self.send()
if self.conn:
print("Closing CUPS connection to printer {}".format(self.printer_name))
self.conn = None
if not sys.platform.startswith("win"):
class LP(Escpos):
"""Simple UNIX lp command raw printing.
Thanks to `Oyami-Srk comment <https://github.com/python-escpos/python-escpos/pull/348#issuecomment-549558316>`_.
"""
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
"""
Escpos.__init__(self, *args, **kwargs)
self.printer_name = printer_name
self.auto_flush = kwargs.get("auto_flush", True)
self.open()
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"),
)
def close(self):
"""Stop the subprocess."""
self.lp.terminate()
def flush(self):
"""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()
def _raw(self, msg):
"""Write raw command(s) to the printer.
:param msg: arbitrary code to be printed
:type msg: bytes
"""
if self.lp.stdin.writable():
self.lp.stdin.write(msg)
else:
raise Exception("Not a valid pipe for lp process")
if self.auto_flush:
self.flush()