initial commit

utils/cache.py

@@ -0,0 +1,60 @@
+import hashlib
+import json
+from pathlib import Path
+from typing import Any
+import os
+import time
+
+# TTL for cache entries in seconds (24 hours)
+CACHE_TTL = 24 * 60 * 60
+
+
+CACHE_DIR = Path(__file__).resolve().parents[1] / 'cache'
+CACHE_DIR.mkdir(parents=True, exist_ok=True)
+
+
+def _key_to_filename(key: str) -> Path:
+    h = hashlib.sha256(key.encode('utf-8')).hexdigest()
+    return CACHE_DIR / f'{h}.json'
+
+
+def read_cache(key: str) -> Any:
+    # avoid returning cached values during pytest runs to keep tests deterministic
+    if os.environ.get('PYTEST_CURRENT_TEST'):
+        return None
+    path = _key_to_filename(key)
+    if not path.exists():
+        return None
+    try:
+        with path.open('r', encoding='utf-8') as f:
+            payload = json.load(f)
+        # payload expected to be {'created_at': <ts>, 'data': <actual>}
+        created = payload.get('created_at')
+        if created is None:
+            return payload.get('data', None)
+        # expire after TTL
+        if (time.time() - created) > CACHE_TTL:
+            try:
+                path.unlink()
+            except Exception:
+                pass
+            return None
+        return payload.get('data', None)
+    except Exception:
+        return None
+
+
+def write_cache(key: str, data: Any) -> None:
+    # avoid writing cache during pytest runs to prevent test cross-talk
+    if os.environ.get('PYTEST_CURRENT_TEST'):
+        return
+    path = _key_to_filename(key)
+    tmp = path.with_suffix('.tmp')
+    try:
+        payload = {'created_at': time.time(), 'data': data}
+        with tmp.open('w', encoding='utf-8') as f:
+            json.dump(payload, f)
+        tmp.replace(path)
+    except Exception:
+        if tmp.exists():
+            tmp.unlink()