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SoulSync/core/search/cache.py

109 lines
3.3 KiB

"""TTL'd in-memory cache for enhanced-search responses.
The cache key blends the normalized query with the active media server,
configured fallback metadata source, hydrabase-active flag, and the
explicit single-source request (if any). This prevents responses from
colliding when a user changes settings or switches single-source mode.
"""
from __future__ import annotations
import collections
import threading
import time
from typing import Any, Callable, Optional, Tuple
CacheKey = Tuple[str, str, str, bool, str]
CACHE_TTL_SECONDS = 600
CACHE_MAX_ENTRIES = 100
class EnhancedSearchCache:
"""Thread-safe LRU+TTL cache for enhanced-search response payloads.
A single shared instance lives in this module (`_cache`). The module-level
helpers (`get_cache_key`, `get_cached_response`, `set_cached_response`)
operate on it.
"""
def __init__(self, ttl: float = CACHE_TTL_SECONDS, max_entries: int = CACHE_MAX_ENTRIES):
self._ttl = ttl
self._max_entries = max_entries
self._store: "collections.OrderedDict[CacheKey, dict]" = collections.OrderedDict()
self._lock = threading.Lock()
def get(self, key: CacheKey) -> Optional[dict]:
now = time.time()
with self._lock:
entry = self._store.get(key)
if not entry:
return None
if now - entry['timestamp'] < self._ttl:
self._store.move_to_end(key)
return entry['data']
self._store.pop(key, None)
return None
def set(self, key: CacheKey, data: dict) -> None:
with self._lock:
self._store[key] = {'timestamp': time.time(), 'data': data}
self._store.move_to_end(key)
while len(self._store) > self._max_entries:
self._store.popitem(last=False)
def clear(self) -> None:
with self._lock:
self._store.clear()
_cache = EnhancedSearchCache()
def get_cache_key(
query: str,
requested_source: Optional[str],
*,
active_server_provider: Callable[[], str],
fallback_source_provider: Callable[[], str],
hydrabase_active_provider: Callable[[], bool],
) -> CacheKey:
"""Build a cache key for an enhanced-search query.
Each provider arg is a zero-arg callable so the cache key reflects the
LIVE config state at lookup time, not the state at app startup. Each
provider is wrapped in try/except: failures resolve to a sentinel value
so a misconfigured client never breaks search.
"""
normalized_query = (query or '').strip().lower()
try:
active_server = active_server_provider()
except Exception:
active_server = 'unknown'
try:
fallback_source = fallback_source_provider()
except Exception:
fallback_source = 'unknown'
try:
hydrabase_active = hydrabase_active_provider()
except Exception:
hydrabase_active = False
source_tag = (requested_source or '').strip().lower() or 'auto'
return (normalized_query, active_server, fallback_source, hydrabase_active, source_tag)
def get_cached_response(key: CacheKey) -> Optional[dict]:
return _cache.get(key)
def set_cached_response(key: CacheKey, data: Any) -> None:
_cache.set(key, data)
def clear_cache() -> None:
_cache.clear()