"""JSON utility functions.""" import logging from typing import Union, List, Dict, Optional import json import os import tempfile from homeassistant.exceptions import HomeAssistantError _LOGGER = logging.getLogger(__name__) class SerializationError(HomeAssistantError): """Error serializing the data to JSON.""" class WriteError(HomeAssistantError): """Error writing the data.""" def load_json(filename: str, default: Union[List, Dict, None] = None) \ -> Union[List, Dict]: """Load JSON data from a file and return as dict or list. Defaults to returning empty dict if file is not found. """ try: with open(filename, encoding='utf-8') as fdesc: return json.loads(fdesc.read()) # type: ignore except FileNotFoundError: # This is not a fatal error _LOGGER.debug('JSON file not found: %s', filename) except ValueError as error: _LOGGER.exception('Could not parse JSON content: %s', filename) raise HomeAssistantError(error) except OSError as error: _LOGGER.exception('JSON file reading failed: %s', filename) raise HomeAssistantError(error) return {} if default is None else default def save_json(filename: str, data: Union[List, Dict], private: bool = False, *, encoder: Optional[json.JSONEncoder] = None) -> None: """Save JSON data to a file. Returns True on success. """ tmp_filename = "" tmp_path = os.path.split(filename)[0] try: json_data = json.dumps(data, sort_keys=True, indent=4, cls=encoder) # Modern versions of Python tempfile create this file with mode 0o600 with tempfile.NamedTemporaryFile(mode="w", encoding='utf-8', dir=tmp_path, delete=False) as fdesc: fdesc.write(json_data) tmp_filename = fdesc.name if not private: os.chmod(tmp_filename, 0o644) os.replace(tmp_filename, filename) except TypeError as error: _LOGGER.exception('Failed to serialize to JSON: %s', filename) raise SerializationError(error) except OSError as error: _LOGGER.exception('Saving JSON file failed: %s', filename) raise WriteError(error) finally: if os.path.exists(tmp_filename): try: os.remove(tmp_filename) except OSError as err: # If we are cleaning up then something else went wrong, so # we should suppress likely follow-on errors in the cleanup _LOGGER.error("JSON replacement cleanup failed: %s", err)