Ports the intelligent-caching branch concept to a plain Python in-memory
implementation — no SQLAlchemy, no extra DB table, no new dependencies.
_LiveCache (threading.Lock + dicts) caches:
- device info: indefinite, invalidated by POST /device/config
- events: keyed by (conn_key, device_event_count); count-probe fast path
(~2s poll+count_events) avoids full downloads when nothing is new
- monitor status: 30-second TTL, invalidated by monitor start/stop
- waveforms: permanent per (conn_key, event_index)
All four cached endpoints accept ?force=true to bypass the cache.
Removes sfm/cache.py (SQLAlchemy experiment, now superseded).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
claude
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