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