Fix geocoding: validate API responses, clean poisoned cache, improve logging

- Cache lookup now requires non-NULL lat/lon — previously a row with
  NULL coordinates counted as a cache hit, returning {lat: None, lon: None}
  which the frontend silently ignored (tower in list but no map pin)
- API response handler validates lat/lon exist before caching, preventing
  error responses (status 200 with error body) from poisoning the cache
- On geocoding worker start, delete any existing poisoned cache rows
- Geocoding worker now logs "API key not configured" vs "rate limit
  reached" so the actual problem is visible in logs
- API error responses now log the response body for easier debugging

routes/gsm_spy.py

@@ -104,6 +104,19 @@ def can_use_api():
 def start_geocoding_worker():
     """Start background thread for async geocoding."""
     global _geocoding_worker_thread
+
+    # Clean poisoned cache entries (rows with NULL lat/lon from failed API responses)
+    try:
+        with get_db() as conn:
+            deleted = conn.execute(
+                'DELETE FROM gsm_cells WHERE lat IS NULL OR lon IS NULL'
+            ).rowcount
+            conn.commit()
+            if deleted:
+                logger.info(f"Cleaned {deleted} poisoned cache entries (NULL coordinates)")
+    except Exception as e:
+        logger.warning(f"Could not clean cache: {e}")
+
     if _geocoding_worker_thread is None or not _geocoding_worker_thread.is_alive():
         _geocoding_worker_thread = threading.Thread(
             target=geocoding_worker,
@@ -125,10 +138,13 @@ def geocoding_worker():
             # Wait for pending tower with timeout
             tower_data = geocoding_queue.get(timeout=5)
 
-            # Check rate limit
+            # Check API key and rate limit
             if not can_use_api():
-                current_usage = get_api_usage_today()
-                logger.warning(f"OpenCellID API rate limit reached ({current_usage}/{config.GSM_API_DAILY_LIMIT})")
+                if not config.GSM_OPENCELLID_API_KEY:
+                    logger.warning("OpenCellID API key not configured (set INTERCEPT_GSM_OPENCELLID_API_KEY)")
+                else:
+                    current_usage = get_api_usage_today()
+                    logger.warning(f"OpenCellID API daily limit reached ({current_usage}/{config.GSM_API_DAILY_LIMIT})")
                 geocoding_queue.task_done()
                 continue
 

utils/gsm_geocoding.py

@@ -47,7 +47,7 @@ def lookup_cell_coordinates(mcc: int, mnc: int, lac: int, cid: int) -> dict[str,
                 WHERE mcc = ? AND mnc = ? AND lac = ? AND cid = ?
             ''', (mcc, mnc, lac, cid)).fetchone()
 
-            if result:
+            if result and result['lat'] is not None and result['lon'] is not None:
                 return {
                     'lat': result['lat'],
                     'lon': result['lon'],
@@ -95,6 +95,16 @@ def lookup_cell_from_api(mcc: int, mnc: int, lac: int, cid: int) -> dict[str, An
 
         if response.status_code == 200:
             cell_data = response.json()
+            lat = cell_data.get('lat')
+            lon = cell_data.get('lon')
+
+            # Validate response has actual coordinates
+            if lat is None or lon is None:
+                logger.warning(
+                    f"OpenCellID API returned 200 but no coordinates for "
+                    f"MCC={mcc} MNC={mnc} LAC={lac} CID={cid}: {cell_data}"
+                )
+                return None
 
             # Cache the result
             with get_db() as conn:
@@ -104,8 +114,7 @@ def lookup_cell_from_api(mcc: int, mnc: int, lac: int, cid: int) -> dict[str, An
                     VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, CURRENT_TIMESTAMP)
                 ''', (
                     mcc, mnc, lac, cid,
-                    cell_data.get('lat'),
-                    cell_data.get('lon'),
+                    lat, lon,
                     cell_data.get('azimuth'),
                     cell_data.get('range'),
                     cell_data.get('samples'),
@@ -114,11 +123,11 @@ def lookup_cell_from_api(mcc: int, mnc: int, lac: int, cid: int) -> dict[str, An
                 ))
                 conn.commit()
 
-            logger.info(f"Cached cell tower from API: MCC={mcc} MNC={mnc} LAC={lac} CID={cid}")
+            logger.info(f"Cached cell tower from API: MCC={mcc} MNC={mnc} LAC={lac} CID={cid} -> ({lat}, {lon})")
 
             return {
-                'lat': cell_data.get('lat'),
-                'lon': cell_data.get('lon'),
+                'lat': lat,
+                'lon': lon,
                 'source': 'api',
                 'azimuth': cell_data.get('azimuth'),
                 'range_meters': cell_data.get('range'),
@@ -126,7 +135,10 @@ def lookup_cell_from_api(mcc: int, mnc: int, lac: int, cid: int) -> dict[str, An
                 'radio': cell_data.get('radio')
             }
         else:
-            logger.warning(f"OpenCellID API returned {response.status_code} for MCC={mcc} MNC={mnc} LAC={lac} CID={cid}")
+            logger.warning(
+                f"OpenCellID API returned {response.status_code} for "
+                f"MCC={mcc} MNC={mnc} LAC={lac} CID={cid}: {response.text[:200]}"
+            )
             return None
 
     except Exception as e: