fix: Only clear the cache when the feed url or filters have changed

Right now it clears the cache when storing the cache, oops

Author: kevinrenskers

example/uv.lock

@@ -1,6 +1,6 @@
 [project]
 name = "django-rss-filter"
-version = "0.10.0"
+version = "0.10.1"
 description = "Filter public RSS feeds, remove articles that contain certain keywords or categories."
 authors = [
     {name = "Kevin Renskers", email = "kevin@loopwerk.io"},

pyproject.toml

@@ -36,8 +36,16 @@ def clean(self):
                 raise ValidationError({"feed_url": result.error})
 
     def save(self, *args, **kwargs):
-        self.cache_date = None
-        self.filtered_feed_body = ""
+        if self.pk:
+            old = FilteredFeed.objects.get(pk=self.pk)
+            if (
+                old.feed_url != self.feed_url
+                or old.filtered_words != self.filtered_words
+                or old.filtered_categories != self.filtered_categories
+            ):
+                self.cache_date = None
+                self.filtered_feed_body = ""
+
         super().save(*args, **kwargs)
 
     def get_filtered_feed_body(self) -> str: