Properly re-load the fetched cache data

server.py

@@ -1,5 +1,7 @@
 import io
+import json
 import os
+import time
 import uuid
 
 import fastapi
@@ -203,13 +205,13 @@ def preview_url(
                 metadata, _ts = result
                 if ts is None or abs(ts - _ts) < 3600:
                     logging.debug("Optimal cache hit for %r", url)
-                    return metadata
+                    return json.loads(metadata)
             # No close matches, get the latest one
             metadata, _ts = results[-1]
             # If the latest one is more than 3 hours old, re-fetch. Otherwise, return.
             if ts is None or abs(ts - _ts) < 10800:
                 logging.debug("Cache hit for %r", url)
-                return metadata
+                return json.loads(metadata)
 
     domain = os.environ.get("PREVIEW_HOMESERVER", "https://" + req.url.hostname)
 
@@ -308,7 +310,7 @@ def preview_url(
     with sqlite3.connect(CACHE_FILE) as conn:
         conn.execute(
             "INSERT INTO cache (uuid, url, ts, metadata) VALUES (?, ?, ?, ?)",
-            (str(uuid.uuid4()), url, int(response.headers["date"]), str(og_tags))
+            (str(uuid.uuid4()), url, round(time.time()), json.dumps(og_tags))
         )
     return og_tags