doc change and small optimization of register_frontend_media()

Author: vdboor

fluent_contents/rendering/media.py

@@ -10,6 +10,9 @@ def register_frontend_media(request, media):
     Add a :class:`~django.forms.Media` class to the current request.
     This will be rendered by the ``render_plugin_media`` template tag.
     """
+    if media is ImmutableMedia.empty_instance:
+        return
+
     if not hasattr(request, "_fluent_contents_frontend_media"):
         request._fluent_contents_frontend_media = Media()
 
@@ -19,6 +22,11 @@ def register_frontend_media(request, media):
 def get_frontend_media(request):
     """
     Return the media that was registered in the request object.
+
+    .. note::
+        The output of plugins is typically cached. Changes the the
+        registered media only show up after flushing the cache,
+        or re-saving the items (which flushes the cache).
     """
     return (
         getattr(request, "_fluent_contents_frontend_media", None)

fluent_contents/templatetags/fluent_contents_tags.py

@@ -368,6 +368,11 @@ def render_content_items_media(parser, token):
         {% render_content_items_media js %}
         {% render_content_items_media js local %}
         {% render_content_items_media js external %}
+
+    .. note::
+        The output of plugins is typically cached. Changes the the
+        registered media only show up after flushing the cache,
+        or re-saving the items (which flushes the cache).
     """
     return RenderContentItemsMedia.parse(parser, token)