add wrapper that thros RuntimeError if not importable for pycups
This commit is contained in:
Patrick Kanzler
parent
1a2273a5b3
commit
33329867d2
@ -2,7 +2,7 @@
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"""printer implementations."""
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# from .win32raw import Win32Raw
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# from .cups import CupsPrinter
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from .cups import CupsPrinter
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from .dummy import Dummy
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from .file import File
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from .lp import LP
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@ -17,7 +17,7 @@ __all__ = [
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"Serial",
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"LP",
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"Dummy",
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# "CupsPrinter",
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"CupsPrinter",
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# "Win32Raw",
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]
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@ -8,132 +8,156 @@
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:license: MIT
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"""
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import functools
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import tempfile
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from ..escpos import Escpos
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_CUPSPRINT = False
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try:
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import tempfile
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#: keeps track if the pycups dependency could be loaded (:py:class:`escpos.printer.CupsPrinter`)
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_DEP_PYCUPS = False
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try:
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import cups
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_CUPSPRINT = True
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_DEP_PYCUPS = True
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except ImportError:
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pass
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if _CUPSPRINT:
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class CupsPrinter(Escpos):
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"""Simple CUPS printer connector.
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# TODO: dev build mode that let's the wrapper bypass?
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.. note::
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Requires ``pycups`` which in turn needs the cups development library package:
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- Ubuntu/Debian: ``libcups2-dev``
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- OpenSuse/Fedora: ``cups-devel``
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def dependency_pycups(func):
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"""Indicate dependency on pycups."""
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inheritance:
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.. inheritance-diagram:: escpos.printer.CupsPrinter
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:parts: 1
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"""
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def __init__(self, printer_name=None, *args, **kwargs):
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"""Class constructor for CupsPrinter.
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:param printer_name: CUPS printer name (Optional)
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:type printer_name: str
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:param host: CUPS server host/ip (Optional)
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:type host: str
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:param port: CUPS server port (Optional)
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:type port: int
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"""
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Escpos.__init__(self, *args, **kwargs)
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host, port = args or (
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kwargs.get("host", cups.getServer()),
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kwargs.get("port", cups.getPort()),
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@functools.wraps(func)
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def wrapper(*args, **kwargs):
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"""Throw a RuntimeError if pycups is not imported."""
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if not _DEP_PYCUPS:
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raise RuntimeError(
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"Printing with PyCups requires the pycups library to"
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"be installed. Please refer to the documentation on"
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"what to install and install the dependencies for pycups."
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)
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cups.setServer(host)
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cups.setPort(port)
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self.conn = cups.Connection()
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self.tmpfile = None
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self.printer_name = printer_name
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self.job_name = ""
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return func(*args, **kwargs)
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return wrapper
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class CupsPrinter(Escpos):
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"""Simple CUPS printer connector.
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.. note::
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Requires ``pycups`` which in turn needs the cups development library package:
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- Ubuntu/Debian: ``libcups2-dev``
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- OpenSuse/Fedora: ``cups-devel``
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inheritance:
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.. inheritance-diagram:: escpos.printer.CupsPrinter
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:parts: 1
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"""
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@dependency_pycups
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def __init__(self, printer_name=None, *args, **kwargs):
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"""Class constructor for CupsPrinter.
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:param printer_name: CUPS printer name (Optional)
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:type printer_name: str
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:param host: CUPS server host/ip (Optional)
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:type host: str
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:param port: CUPS server port (Optional)
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:type port: int
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"""
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Escpos.__init__(self, *args, **kwargs)
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host, port = args or (
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kwargs.get("host", cups.getServer()),
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kwargs.get("port", cups.getPort()),
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)
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cups.setServer(host)
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cups.setPort(port)
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self.conn = cups.Connection()
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self.tmpfile = None
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self.printer_name = printer_name
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self.job_name = ""
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self.pending_job = False
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self.open()
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@property
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def printers(self):
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"""Available CUPS printers."""
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return self.conn.getPrinters()
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def open(self, job_name="python-escpos"):
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"""Set up a new print job and target the printer.
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A call to this method is required to send new jobs to
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the same CUPS connection.
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Defaults to default CUPS printer.
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Creates a new temporary file buffer.
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"""
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self.job_name = job_name
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if self.printer_name not in self.printers:
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self.printer_name = self.conn.getDefault()
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self.tmpfile = tempfile.NamedTemporaryFile(delete=True)
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def _raw(self, msg):
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"""Append any command sent in raw format to temporary file.
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:param msg: arbitrary code to be printed
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:type msg: bytes
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"""
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self.pending_job = True
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try:
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self.tmpfile.write(msg)
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except ValueError:
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self.pending_job = False
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self.open()
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raise ValueError("Printer job not opened")
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@property
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def printers(self):
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"""Available CUPS printers."""
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return self.conn.getPrinters()
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@dependency_pycups
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def send(self):
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"""Send the print job to the printer."""
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if self.pending_job:
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# Rewind tempfile
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self.tmpfile.seek(0)
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# Print temporary file via CUPS printer.
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self.conn.printFile(
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self.printer_name,
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self.tmpfile.name,
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self.job_name,
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{"document-format": cups.CUPS_FORMAT_RAW},
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)
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self._clear()
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def open(self, job_name="python-escpos"):
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"""Set up a new print job and target the printer.
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def _clear(self):
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"""Finish the print job.
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A call to this method is required to send new jobs to
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the same CUPS connection.
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Remove temporary file.
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"""
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self.tmpfile.close()
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self.pending_job = False
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Defaults to default CUPS printer.
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Creates a new temporary file buffer.
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"""
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self.job_name = job_name
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if self.printer_name not in self.printers:
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self.printer_name = self.conn.getDefault()
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self.tmpfile = tempfile.NamedTemporaryFile(delete=True)
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def _read(self):
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"""Return a single-item array with the accepting state of the print queue.
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def _raw(self, msg):
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"""Append any command sent in raw format to temporary file.
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states: idle = [3], printing a job = [4], stopped = [5]
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"""
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printer = self.printers.get(self.printer_name, {})
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state = printer.get("printer-state")
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if not state:
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return []
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return [state]
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:param msg: arbitrary code to be printed
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:type msg: bytes
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"""
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self.pending_job = True
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try:
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self.tmpfile.write(msg)
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except ValueError:
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self.pending_job = False
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raise ValueError("Printer job not opened")
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def close(self):
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"""Close CUPS connection.
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def send(self):
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"""Send the print job to the printer."""
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if self.pending_job:
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# Rewind tempfile
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self.tmpfile.seek(0)
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# Print temporary file via CUPS printer.
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self.conn.printFile(
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self.printer_name,
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self.tmpfile.name,
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self.job_name,
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{"document-format": cups.CUPS_FORMAT_RAW},
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)
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self._clear()
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def _clear(self):
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"""Finish the print job.
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Remove temporary file.
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"""
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self.tmpfile.close()
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self.pending_job = False
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def _read(self):
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"""Return a single-item array with the accepting state of the print queue.
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states: idle = [3], printing a job = [4], stopped = [5]
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"""
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printer = self.printers.get(self.printer_name, {})
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state = printer.get("printer-state")
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if not state:
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return []
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return [state]
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def close(self):
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"""Close CUPS connection.
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Send pending job to the printer if needed.
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"""
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if self.pending_job:
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self.send()
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if self.conn:
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print("Closing CUPS connection to printer {}".format(self.printer_name))
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self.conn = None
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Send pending job to the printer if needed.
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"""
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if self.pending_job:
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self.send()
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if self.conn:
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print("Closing CUPS connection to printer {}".format(self.printer_name))
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self.conn = None
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