feed_plugin: augment cache of aggregated feeds to 1 week

fixes #4838

portail_citoyen2/apps/feed_plugin/models.py

@@ -16,6 +16,8 @@ from . import utils
 
 logger = logging.getLogger(__name__)
 
+FEED_CACHE_TIMEOUT = 86400 # 1 week
+
 class FeedPreference(models.Model):
     user = models.ForeignKey(settings.AUTH_USER_MODEL)
     feed = models.ForeignKey('Feed')
@@ -65,7 +67,7 @@ class Feed(models.Model):
             entries.append((date, title, entry.link))
         entries.sort(reverse=True)
         entries = entries[:limit]
-        cache.set(key, (entries, now))
+        cache.set(key, (entries, now), FEED_CACHE_TIMEOUT)
         duration = datetime.datetime.utcnow()-now
         logger.debug('loaded RSS feed %r in %s seconds', self.url, duration.seconds)
         return entries