implement caching for TeslaCam directory scan and add refresh endpoint

videoplayer.py

@@ -11,6 +11,7 @@ play videos from different camera views.
 
 import os
 import re
+import time
 
 from dotenv import load_dotenv
 from flask import Flask, render_template, send_from_directory, abort
@@ -39,8 +40,15 @@ CAMERA_VIEW_MAPPING = {
     'right_pillar': 'Right Pillar'
 }
 
+# In-memory scan cache. Scanning a large TeslaCam tree on every request is
+# expensive, so the result is cached and only refreshed after this many seconds
+# (or when /refresh is hit). Override via the SCAN_CACHE_TTL env var.
+SCAN_CACHE_TTL = int(os.environ.get('SCAN_CACHE_TTL', '3600'))
 
-def scan_teslacam_videos():
+_scan_cache = {'data': None, 'expires_at': 0.0}
+
+
+def _scan_teslacam_videos_uncached():
     """
     Recursively scans the TeslaCam directory tree for video files and categorizes
     them by camera view.
@@ -84,6 +92,22 @@ def scan_teslacam_videos():
     return videos_by_camera
 
 
+def scan_teslacam_videos(force_refresh=False):
+    """
+    Returns the cached TeslaCam video scan, refreshing it when the TTL expires
+    or when `force_refresh` is True. Safe to call on every request.
+    """
+    now = time.time()
+    if (
+        _scan_cache['data'] is None
+        or now >= _scan_cache['expires_at']
+        or force_refresh
+    ):
+        _scan_cache['data'] = _scan_teslacam_videos_uncached()
+        _scan_cache['expires_at'] = now + SCAN_CACHE_TTL
+    return _scan_cache['data']
+
+
 def get_camera_display_name(camera_view):
     """Returns human-readable title for a camera view key."""
     return CAMERA_VIEW_MAPPING.get(camera_view, camera_view.replace('_', ' ').title())
@@ -137,6 +161,16 @@ def serve_video(filepath):
     return send_from_directory(TESLACAM_DIRECTORY, filepath)
 
 
+@app.route('/refresh')
+def refresh():
+    """
+    Forces a re-scan of the TeslaCam directory, bypassing the cache TTL.
+    Useful after copying new clips onto the drive.
+    """
+    scan_teslacam_videos(force_refresh=True)
+    return 'Cache refreshed', 200
+
+
 if __name__ == '__main__':
     # Local dev server. For production, run behind a WSGI server instead, e.g.:
     #   gunicorn -w 4 -b 0.0.0.0:5000 'videoplayer:app'