Cache zoneinfo for smart devices (#1156)

kasa/smart/modules/time.py

@@ -6,8 +6,9 @@ from datetime import datetime, timedelta, timezone, tzinfo
 from time import mktime
 from typing import cast
 
-from zoneinfo import ZoneInfo, ZoneInfoNotFoundError
+from zoneinfo import ZoneInfoNotFoundError
 
+from ...cachedzoneinfo import CachedZoneInfo
 from ...feature import Feature
 from ..smartmodule import SmartModule
 
@@ -18,6 +19,8 @@ class Time(SmartModule):
     REQUIRED_COMPONENT = "time"
     QUERY_GETTER_NAME = "get_device_time"
 
+    _timezone: tzinfo = timezone.utc
+
     def _initialize_features(self):
         """Initialize features after the initial update."""
         self._add_feature(
@@ -32,21 +35,25 @@ class Time(SmartModule):
             )
         )
 
-    @property
-    def timezone(self) -> tzinfo:
-        """Return current timezone."""
+    async def _post_update_hook(self):
+        """Perform actions after a device update."""
         td = timedelta(minutes=cast(float, self.data.get("time_diff")))
         if region := self.data.get("region"):
             try:
                 # Zoneinfo will return a DST aware object
-                tz: tzinfo = ZoneInfo(region)
+                tz: tzinfo = await CachedZoneInfo.get_cached_zone_info(region)
             except ZoneInfoNotFoundError:
                 tz = timezone(td, region)
         else:
             # in case the device returns a blank region this will result in the
             # tzname being a UTC offset
             tz = timezone(td)
-        return tz
+        self._timezone = tz
+
+    @property
+    def timezone(self) -> tzinfo:
+        """Return current timezone."""
+        return self._timezone
 
     @property
     def time(self) -> datetime: