"""ESC/POS configuration manager.
This module contains the implementations of abstract base class :py:class:`Config`.
"""
import os
import pathlib
import appdirs
import yaml
from . import exceptions, printer
[docs]
class Config:
"""Configuration handler class.
This class loads configuration from a default or specified directory. It
can create your defined printer and return it to you.
"""
_app_name = "python-escpos"
_config_file = "config.yaml"
def __init__(self) -> None:
"""Initialize configuration.
Remember to add anything that needs to be reset between configurations
to self._reset_config
"""
self._has_loaded = False
self._printer = None
self._printer_name = None
self._printer_config = None
def _reset_config(self) -> None:
"""Clear the loaded configuration.
If we are loading a changed config, we don't want to have leftover
data.
"""
self._has_loaded = False
self._printer = None
self._printer_name = None
self._printer_config = None
[docs]
def load(self, config_path=None):
"""Load and parse the configuration file using pyyaml.
:param config_path: An optional file path, file handle, or byte string
for the configuration file.
"""
self._reset_config()
if not config_path:
config_path = os.path.join(
appdirs.user_config_dir(self._app_name), self._config_file
)
if isinstance(config_path, pathlib.Path):
# store string if posixpath
config_path = config_path.as_posix()
if not os.path.isfile(config_path):
# supplied path is not a file --> assume default file
config_path = os.path.join(config_path, self._config_file)
try:
with open(config_path, "rb") as config_file:
config = yaml.safe_load(config_file)
except EnvironmentError:
raise exceptions.ConfigNotFoundError(
f"Couldn't read config at {config_path}"
)
except yaml.YAMLError:
raise exceptions.ConfigSyntaxError("Error parsing YAML")
if "printer" in config:
self._printer_config = config["printer"]
self._printer_name = self._printer_config.pop("type").title()
if not self._printer_name or not hasattr(printer, self._printer_name):
raise exceptions.ConfigSyntaxError(
f'Printer type "{self._printer_name}" is invalid'
)
self._has_loaded = True
[docs]
def printer(self):
"""Return a printer that was defined in the config.
Throw an exception on error.
This method loads the default config if one has not been already loaded.
"""
if not self._has_loaded:
self.load()
if not self._printer_name:
raise exceptions.ConfigSectionMissingError("printer")
if not self._printer:
# We could catch init errors and make them a ConfigSyntaxError,
# but I'll just let them pass
self._printer = getattr(printer, self._printer_name)(**self._printer_config)
return self._printer