CustomContent: Add withinDescendant parameter to API

kolibri/core/content/api.py

@@ -272,6 +272,7 @@ class ContentNodeFilter(IdFilter):
     rght__lt = NumberFilter(field_name="rght", lookup_expr="lt")
     authors = CharFilter(method="filter_by_authors")
     tags = CharFilter(method="filter_by_tags")
+    descendant_of = UUIDFilter(method="filter_descendant_of")
 
     class Meta:
         model = models.ContentNode
@@ -299,6 +300,24 @@ def filter_by_tags(self, queryset, name, value):
         tags = value.split(",")
         return queryset.filter(tags__tag_name__in=tags).order_by("lft")
 
+    def filter_descendant_of(self, queryset, name, value):
+        """
+        Show content that is descendant of the given node
+
+        :param queryset: all content nodes for this channel
+        :param value: the root node to filter descendant of
+        :return: all descendants content
+        """
+        try:
+            node = models.ContentNode.objects.values("lft", "rght", "tree_id").get(
+                pk=value
+            )
+        except (models.ContentNode.DoesNotExist, ValueError):
+            return queryset.none()
+        return queryset.filter(
+            lft__gt=node["lft"], rght__lt=node["rght"], tree_id=node["tree_id"]
+        )
+
     def filter_kind(self, queryset, name, value):
         """
         Show only content of a given kind.

kolibri/plugins/learn/assets/src/views/ChannelRenderer/CustomContentRenderer.vue

@@ -159,6 +159,7 @@
             max_results: options.maxResults ? options.maxResults : 50,
             kind: kind,
             kind_in: kinds,
+            descendant_of: options.descendantOf,
           },
         })
           .then(contentNodes => {

packages/hashi/src/kolibri.js

@@ -114,6 +114,8 @@ export default class Kolibri extends BaseShim {
        * an array of matching metadata
        * @param {Object} options - The different options to filter by
        * @param {string=} options.parent - id of the parent node to filter by, or 'self'
+       * @param {string=} options.descendantOf - id of the root node to filter
+       * by, to show all descendants, not just direct children
        * @param {string[]} options.ids - an array of ids to filter by
        * @param {number} [options.maxResults=50] - the maximum number of nodes per request
        * @param {string[]} options.kinds - an array of kinds to filer by