# Libreprinter is a software allowing to use the Centronics and serial printing
# functions of vintage computers on modern equipement through a tiny hardware
# interface.
# Copyright (C) 2020-2024 Ysard
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
"""Watchdog for /pcl directory that is able to convert new files into pdfs
The conversion is made thanks to the `pcl_converter_path` setting pointing to
the GhostPCL binary.
"""
# Standard imports
import shlex
from pathlib import Path
import subprocess
from watchdog.observers.inotify import InotifyObserver
from watchdog.events import RegexMatchingEventHandler
# Custom imports
from libreprinter import plugins_handler
from libreprinter.commons import logger
LOGGER = logger()
CONFIG = {
"misc": {
"emulation": "hp",
"endlesstext": "no",
}
}
[docs]
class PclEventHandler(RegexMatchingEventHandler):
"""Watch a directory via a parent Observer and emit events accordingly
This class only reimplement :meth:`on_created` event.
Watched directory:
- `pcl`: `*.pcl`
Attribute:
:param converter_path: Path to GhostPCL binary.
:type converter_path: str
Class attribute:
:param FILES_REGEX: Patterns to detect pcl files.
:type FILES_REGEX: list[str]
"""
FILES_REGEX = [r".*\.pcl$"]
def __init__(self, *args, converter_path=None, **kwargs):
"""Constructor override
Just add pcl_converter_path attr and define watchdog regexes.
"""
super().__init__(*args, regexes=self.FILES_REGEX, **kwargs)
self.converter_path = converter_path
[docs]
def on_closed(self, event):
"""PCL file creation is detected, convert it to PDF"""
LOGGER.info("Event detected: %s", event)
# Directly build arg list; enquote paths to avoid errors
src_path = Path(event.src_path)
pdf_path = src_path.parent / "../pdf" / (src_path.stem + ".pdf")
args = [
self.converter_path,
"-dNOPAUSE",
"-sDEVICE=pdfwrite",
"-sColorConversionStrategy=RGB",
"-dCompatibilityLevel=1.7", # Fix for reproductibility
"-dEmbedAllFonts=true", # Increase the final size
"-dSubsetFonts=true", # Reduce the final size
f"-sOutputFile={shlex.quote(str(pdf_path))}",
shlex.quote(event.src_path)
]
LOGGER.debug("GhostPCL command: %s", args)
try:
# We are in a child thread, we can have blocking calls like run()
# Capture all outputs from the command in case of error with PIPE
subprocess.run(
args, stderr=subprocess.PIPE, stdout=subprocess.PIPE, check=True
)
except subprocess.CalledProcessError as e:
# process exits with a non-zero exit code
LOGGER.error("stdout: %s; stderr: %s", e.stdout, e.stderr)
LOGGER.exception(e)
[docs]
@plugins_handler.register
def setup_pcl_watchdog(config):
"""Initialise a watchdog on `/pcl` directory in configured `output_path`.
Any pcl file created in this directories will be converted in `/pdf` by
the ghostpcl binary whose path is indicated in the variable
`pcl_converter_path`.
:return: Observer that is currently watching directories.
:rtype: watchdog.Observer
"""
LOGGER.info("Launch pcl watchdog...")
# Test existence of pcl converter binary
converter_path = config["misc"]["pcl_converter_path"]
if not Path(converter_path).exists():
LOGGER.error(
"Setting <pcl_converter_path:%s> doesn't exists!", converter_path
)
raise FileNotFoundError("pcl converter not found")
event_handler = PclEventHandler(
converter_path=converter_path, ignore_directories=True
)
# Attach event handler to the configured output_path
observer = InotifyObserver()
observer.schedule(event_handler, config["misc"]["output_path"] + "pcl/", recursive=False)
observer.start()
return observer
if __name__ == "__main__": # pragma: no cover
from libreprinter.commons import PCL_CONVERTER
obs = setup_pcl_watchdog(
{"misc": {"output_path": "./", "pcl_converter_path": PCL_CONVERTER}}
)
obs.join()