mcp_server/cache.py

"""In-memory TTL cache shared by all MCP tools.

Why this exists: IPQS gives 1,000 lookups/month and VirusTotal caps at
4 req/min, 500/day. A single dev/test loop that re-scans the same handful
of domains can burn through either budget in minutes without a cache.
This is intentionally a plain dict, not Redis or anything external —
the process is short-lived (one HF Space container) so in-memory is
enough, and it keeps the MCP server dependency-free.
"""

import time

CACHE_TTL_SECONDS = 3600  # 1 hour, per the design doc

# key -> (stored_at_epoch_seconds, value)
_store: dict[str, tuple[float, dict]] = {}


def cache_get(key: str) -> dict | None:
    """Return the cached value for key if present and not expired, else None."""
    hit = _store.get(key)
    if hit is None:
        return None
    stored_at, value = hit
    if time.time() - stored_at >= CACHE_TTL_SECONDS:
        _store.pop(key, None)
        return None
    return value


def cache_set(key: str, value: dict) -> dict:
    """Store value under key and return it (so callers can `return cache_set(...)`)."""
    _store[key] = (time.time(), value)
    return value


def cache_clear() -> None:
    """Wipe the cache. Used by tests; not called in normal operation."""
    _store.clear()


def cache_size() -> int:
    return len(_store)