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Krzysztof kuhy Rudnicki
77c6d9f815
catalog.py was 251 lines. Its five defensive accessors for the loosely-typed /wsg/ JSON -- _get, _as_list, _as_int, _as_md5 and the _MD5_SHAPE / int64 range constants they depend on -- form a cohesive unit distinct from the parsing logic above them, so they move to a sibling _coerce.py and become module-public there. No caller or test referenced the private helpers (downloader.py uses only the six public parse functions), so no re-export shim was needed and the public API is byte-for-byte unchanged. catalog.py 251 -> 175, new _coerce.py 87. Both modules stay at 100% branch coverage; 277 wsg_grabber tests pass. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_011w2Pj4Ek3ZNMQVYcFHgXDY
88 lines
2.7 KiB
Python
88 lines
2.7 KiB
Python
"""Defensive accessors for the loosely-typed /wsg/ JSON payloads.
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The API omits file fields entirely on posts without an attachment and is fed by
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an anonymous imageboard, so nothing here trusts the shape of what it is handed:
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every accessor answers "not usable" rather than raising.
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"""
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from __future__ import annotations
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import re
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from typing import Any
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# base64 of a 16-byte digest is always 22 characters plus "==". Matching the
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# exact shape -- not merely the length -- is what keeps a NUL byte out of a
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# filename: one such value poisons the index permanently, because the crash
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# happens before the row can ever be marked gone.
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_MD5_SHAPE = re.compile(r"[A-Za-z0-9+/]{22}==")
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# sqlite stores signed 64-bit integers; anything wider raises OverflowError deep
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# inside executemany, which used to take the worker thread down with it.
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_INT64_MIN = -(2**63)
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_INT64_MAX = 2**63 - 1
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def get(container: object, key: str) -> object:
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"""Read *key* from *container* when it is a mapping.
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Args:
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container: Anything; only dicts yield a value.
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key: Key to read.
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Returns:
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object: The value, or None.
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"""
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if isinstance(container, dict):
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return container.get(key)
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return None
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def as_list(value: object) -> list[Any]:
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"""Return *value* when it is a list, else an empty list.
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Args:
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value: Candidate.
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Returns:
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list[Any]: Safe list to iterate.
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"""
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return value if isinstance(value, list) else []
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def as_int(value: object) -> int | None:
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"""Coerce *value* to int when it is a real integer.
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Booleans are rejected: ``True`` is an int in Python but never a valid post
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number or timestamp. Values outside sqlite's signed 64-bit range are
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rejected too -- they raise OverflowError on insert, which is not in the
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worker's recoverable set and would kill it silently.
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Args:
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value: Candidate.
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Returns:
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int | None: The integer, or None.
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"""
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if isinstance(value, bool) or not isinstance(value, int):
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return None
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return value if _INT64_MIN <= value <= _INT64_MAX else None
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def as_md5(value: object) -> str | None:
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"""Validate the API's base64 md5 field.
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The charset check is not decoration: the tail of this value ends up in a
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filename via ``store.local_name``, and it arrives from an anonymous
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imageboard. Length alone would let through a NUL byte, which raises deep
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inside the filesystem call instead of being rejected here.
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Args:
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value: Candidate.
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Returns:
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str | None: The 24-character digest, or None when malformed.
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"""
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if not isinstance(value, str):
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return None
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return value if _MD5_SHAPE.fullmatch(value) else None
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