Easier and more self documenting patterns for loading/saving Persistent

[python_utils.git] / cached / weather_forecast.py

diff --git a/cached/weather_forecast.py b/cached/weather_forecast.py
index 807f36d2bcd9c5770d6fa5e5bc897dcc791f8ca1..7973bbb4c8b38b185042446efb82cfc2c72e130b 100644 (file)
--- a/cached/weather_forecast.py
+++ b/cached/weather_forecast.py
@@ -1,5 +1,9 @@
 #!/usr/bin/env python3
 
+# © Copyright 2021-2022, Scott Gasch
+
+"""How's the weather going to be tomorrow?"""
+
 import datetime
 import logging
 import os
@@ -52,7 +56,7 @@ class WeatherForecast:
 
 
 @persistent.persistent_autoloaded_singleton()  # type: ignore
-class CachedDetailedWeatherForecast(persistent.Persistent):
+class CachedDetailedWeatherForecast(persistent.PicklingFileBasedPersistent):
     def __init__(self, forecasts=None):
         if forecasts is not None:
             self.forecasts = forecasts
@@ -115,28 +119,24 @@ class CachedDetailedWeatherForecast(persistent.Persistent):
                     description=blurb,
                 )
 
-    @classmethod
+    @staticmethod
     @overrides
-    def load(cls) -> Any:
-        if persistent.was_file_written_within_n_seconds(
-            config.config['weather_forecast_cachefile'],
-            config.config['weather_forecast_stalest_acceptable'].total_seconds(),
-        ):
-            import pickle
-
-            with open(config.config['weather_forecast_cachefile'], 'rb') as rf:
-                weather_data = pickle.load(rf)
-                return cls(weather_data)
-        return None
+    def get_filename() -> str:
+        return config.config['weather_forecast_cachefile']
 
+    @staticmethod
     @overrides
-    def save(self) -> bool:
-        import pickle
-
-        with open(config.config['weather_forecast_cachefile'], 'wb') as wf:
-            pickle.dump(
-                self.forecasts,
-                wf,
-                pickle.HIGHEST_PROTOCOL,
-            )
+    def should_we_save_data(filename: str) -> bool:
         return True
+
+    @staticmethod
+    @overrides
+    def should_we_load_data(filename: str) -> bool:
+        return persistent.was_file_written_within_n_seconds(
+            filename,
+            config.config['weather_forecast_stalest_acceptable'].total_seconds(),
+        )
+
+    @overrides
+    def get_persistent_data(self) -> Any:
+        return self.forecasts