context_processors: Cache the realm description in default context.

zerver/context_processors.py

@@ -14,10 +14,10 @@ from zproject.backends import (
     SOCIAL_AUTH_BACKENDS,
 )
 from zerver.decorator import get_client_name
-from zerver.lib.bugdown import convert as bugdown_convert
 from zerver.lib.send_email import FromAddress
 from zerver.lib.subdomains import get_subdomain
 from zerver.lib.realm_icon import get_realm_icon_url
+from zerver.lib.realm_description import get_realm_rendered_description
 
 from version import ZULIP_VERSION, LATEST_RELEASE_VERSION, \
     LATEST_RELEASE_ANNOUNCEMENT, LATEST_MAJOR_VERSION
@@ -69,9 +69,7 @@ def zulip_default_context(request: HttpRequest) -> Dict[str, Any]:
         realm_uri = realm.uri
         realm_name = realm.name
         realm_icon = get_realm_icon_url(realm)
-        realm_description_raw = realm.description or "The coolest place in the universe."
-        realm_description = bugdown_convert(realm_description_raw, message_realm=realm,
-                                            no_previews=True)
+        realm_description = get_realm_rendered_description(realm)
         realm_invite_required = realm.invite_required
         realm_plan_type = realm.plan_type
 

zerver/lib/cache.py

@@ -435,6 +435,7 @@ def flush_realm(sender: Any, **kwargs: Any) -> None:
         cache_delete(realm_alert_words_cache_key(realm))
         cache_delete(realm_alert_words_automaton_cache_key(realm))
         cache_delete(active_non_guest_user_ids_cache_key(realm.id))
+        cache_delete(realm_rendered_description_cache_key(realm))
 
 def realm_alert_words_cache_key(realm: 'Realm') -> str:
     return "realm_alert_words:%s" % (realm.string_id,)
@@ -442,6 +443,9 @@ def realm_alert_words_cache_key(realm: 'Realm') -> str:
 def realm_alert_words_automaton_cache_key(realm: 'Realm') -> str:
     return "realm_alert_words_automaton:%s" % (realm.string_id,)
 
+def realm_rendered_description_cache_key(realm: 'Realm') -> str:
+    return "realm_rendered_description:%s" % (realm.string_id,)
+
 # Called by models.py to flush the stream cache whenever we save a stream
 # object.
 def flush_stream(sender: Any, **kwargs: Any) -> None:

zerver/lib/realm_description.py

@@ -0,0 +1,9 @@
+from zerver.models import Realm
+from zerver.lib.cache import cache_with_key, realm_rendered_description_cache_key
+from zerver.lib.bugdown import convert as bugdown_convert
+
+@cache_with_key(realm_rendered_description_cache_key, timeout=3600*24*7)
+def get_realm_rendered_description(realm: Realm) -> str:
+    realm_description_raw = realm.description or "The coolest place in the universe."
+    return bugdown_convert(realm_description_raw, message_realm=realm,
+                           no_previews=True)

zerver/tests/test_home.py

@@ -228,7 +228,7 @@ class HomeTest(ZulipTestCase):
                 result = self._get_home_page(stream='Denmark')
 
         self.assert_length(queries, 43)
-        self.assert_length(cache_mock.call_args_list, 7)
+        self.assert_length(cache_mock.call_args_list, 8)
 
         html = result.content.decode('utf-8')
 
@@ -292,7 +292,7 @@ class HomeTest(ZulipTestCase):
             with patch('zerver.lib.cache.cache_set') as cache_mock:
                 result = self._get_home_page()
                 self.assertEqual(result.status_code, 200)
-                self.assert_length(cache_mock.call_args_list, 6)
+                self.assert_length(cache_mock.call_args_list, 7)
             self.assert_length(queries, 40)
 
     @slow("Creates and subscribes 10 users in a loop.  Should use bulk queries.")