ha-core/homeassistant/util/json.py

126 lines
3.8 KiB
Python

"""JSON utility functions."""
from __future__ import annotations
from collections import deque
from collections.abc import Callable
import json
import logging
from typing import Any
from homeassistant.core import Event, State
from homeassistant.exceptions import HomeAssistantError
from .file import write_utf8_file, write_utf8_file_atomic
_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: list | dict | None = None) -> 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) from error
except OSError as error:
_LOGGER.exception("JSON file reading failed: %s", filename)
raise HomeAssistantError(error) from error
return {} if default is None else default
def save_json(
filename: str,
data: list | dict,
private: bool = False,
*,
encoder: type[json.JSONEncoder] | None = None,
atomic_writes: bool = False,
) -> None:
"""Save JSON data to a file.
Returns True on success.
"""
try:
json_data = json.dumps(data, indent=4, cls=encoder)
except TypeError as error:
msg = f"Failed to serialize to JSON: {filename}. Bad data at {format_unserializable_data(find_paths_unserializable_data(data))}"
_LOGGER.error(msg)
raise SerializationError(msg) from error
if atomic_writes:
write_utf8_file_atomic(filename, json_data, private)
else:
write_utf8_file(filename, json_data, private)
def format_unserializable_data(data: dict[str, Any]) -> str:
"""Format output of find_paths in a friendly way.
Format is comma separated: <path>=<value>(<type>)
"""
return ", ".join(f"{path}={value}({type(value)}" for path, value in data.items())
def find_paths_unserializable_data(
bad_data: Any, *, dump: Callable[[Any], str] = json.dumps
) -> dict[str, Any]:
"""Find the paths to unserializable data.
This method is slow! Only use for error handling.
"""
to_process = deque([(bad_data, "$")])
invalid = {}
while to_process:
obj, obj_path = to_process.popleft()
try:
dump(obj)
continue
except (ValueError, TypeError):
pass
# We convert objects with as_dict to their dict values so we can find bad data inside it
if hasattr(obj, "as_dict"):
desc = obj.__class__.__name__
if isinstance(obj, State):
desc += f": {obj.entity_id}"
elif isinstance(obj, Event):
desc += f": {obj.event_type}"
obj_path += f"({desc})"
obj = obj.as_dict()
if isinstance(obj, dict):
for key, value in obj.items():
try:
# Is key valid?
dump({key: None})
except TypeError:
invalid[f"{obj_path}<key: {key}>"] = key
else:
# Process value
to_process.append((value, f"{obj_path}.{key}"))
elif isinstance(obj, list):
for idx, value in enumerate(obj):
to_process.append((value, f"{obj_path}[{idx}]"))
else:
invalid[obj_path] = obj
return invalid