feat: add new API to retrieve all components in a unit

cms/djangoapps/contentstore/rest_api/v1/serializers/course_waffle_flags.py

@@ -11,6 +11,7 @@ class CourseWaffleFlagsSerializer(serializers.Serializer):
     """
     Serializer for course waffle flags
     """
+
     use_new_home_page = serializers.SerializerMethodField()
     use_new_custom_pages = serializers.SerializerMethodField()
     use_new_schedule_details_page = serializers.SerializerMethodField()
@@ -31,6 +32,7 @@ class CourseWaffleFlagsSerializer(serializers.Serializer):
     use_react_markdown_editor = serializers.SerializerMethodField()
     use_video_gallery_flow = serializers.SerializerMethodField()
     enable_course_optimizer_check_prev_run_links = serializers.SerializerMethodField()
+    enable_unit_expanded_view = serializers.SerializerMethodField()
 
     def get_course_key(self):
         """
@@ -175,3 +177,10 @@ def get_enable_course_optimizer_check_prev_run_links(self, obj):
         """
         course_key = self.get_course_key()
         return toggles.enable_course_optimizer_check_prev_run_links(course_key)
+
+    def get_enable_unit_expanded_view(self, obj):
+        """
+        Method to get the enable_unit_expanded_view waffle flag
+        """
+        course_key = self.get_course_key()
+        return toggles.enable_unit_expanded_view(course_key)

cms/djangoapps/contentstore/rest_api/v1/urls.py

@@ -25,6 +25,7 @@
     HomePageView,
     ProctoredExamSettingsView,
     ProctoringErrorsView,
+    UnitComponentsView,
     VideoDownloadView,
     VideoUsageView,
     vertical_container_children_redirect_view,
@@ -144,6 +145,11 @@
         CourseWaffleFlagsView.as_view(),
         name="course_waffle_flags"
     ),
+    re_path(
+        fr'^unit_handler/{settings.USAGE_KEY_PATTERN}$',
+        UnitComponentsView.as_view(),
+        name="unit_components"
+    ),
 
     # Authoring API
     # Do not use under v1 yet (Nov. 23). The Authoring API is still experimental and the v0 versions should be used

cms/djangoapps/contentstore/rest_api/v1/views/__init__.py

@@ -14,9 +14,6 @@
 from .proctoring import ProctoredExamSettingsView, ProctoringErrorsView
 from .settings import CourseSettingsView
 from .textbooks import CourseTextbooksView
+from .unit_handler import UnitComponentsView
 from .vertical_block import ContainerHandlerView, vertical_container_children_redirect_view
-from .videos import (
-    CourseVideosView,
-    VideoDownloadView,
-    VideoUsageView,
-)
+from .videos import CourseVideosView, VideoDownloadView, VideoUsageView

cms/djangoapps/contentstore/rest_api/v1/views/tests/test_course_waffle_flags.py

@@ -38,6 +38,7 @@ class CourseWaffleFlagsViewTest(CourseTestCase):
         "use_react_markdown_editor": False,
         "use_video_gallery_flow": False,
         "enable_course_optimizer_check_prev_run_links": False,
+        "enable_unit_expanded_view": False,
     }
 
     def setUp(self):

cms/djangoapps/contentstore/rest_api/v1/views/unit_handler.py

@@ -0,0 +1,135 @@
+"""API Views for unit components handler"""
+
+import logging
+
+import edx_api_doc_tools as apidocs
+from django.http import HttpResponseBadRequest, HttpResponseForbidden
+from opaque_keys.edx.keys import UsageKey
+from rest_framework.request import Request
+from rest_framework.response import Response
+from rest_framework.views import APIView
+
+from cms.djangoapps.contentstore.rest_api.v1.mixins import ContainerHandlerMixin
+from cms.djangoapps.contentstore.toggles import enable_unit_expanded_view
+from openedx.core.lib.api.view_utils import view_auth_classes
+from xmodule.modulestore.django import modulestore
+from xmodule.modulestore.exceptions import ItemNotFoundError
+
+log = logging.getLogger(__name__)
+
+
+@view_auth_classes(is_authenticated=True)
+class UnitComponentsView(APIView, ContainerHandlerMixin):
+    """
+    View to get all components in a unit by usage key.
+    """
+
+    @apidocs.schema(
+        parameters=[
+            apidocs.string_parameter(
+                "usage_key_string",
+                apidocs.ParameterLocation.PATH,
+                description="Unit usage key",
+            ),
+        ],
+        responses={
+            200: "List of components in the unit",
+            400: "Invalid usage key or unit not found.",
+            401: "The requester is not authenticated.",
+            404: "The requested unit does not exist.",
+        },
+    )
+    def get(self, request: Request, usage_key_string: str):
+        """
+        Get all components in a unit.
+
+        **Example Request**
+
+            GET /api/contentstore/v1/unit_handler/{usage_key_string}
+
+        **Response Values**
+
+        If the request is successful, an HTTP 200 "OK" response is returned.
+
+        The HTTP 200 response contains a dict with a list of all components
+        in the unit, including their display names, block types, and block IDs.
+
+        **Example Response**
+
+        ```json
+        {
+            "unit_id": "block-v1:edX+DemoX+Demo_Course+type@vertical+block@vertical_id",
+            "display_name": "My Unit",
+            "components": [
+                {
+                    "block_id": "block-v1:edX+DemoX+Demo_Course+type@video+block@video_id",
+                    "block_type": "video",
+                    "display_name": "Introduction Video"
+                },
+                {
+                    "block_id": "block-v1:edX+DemoX+Demo_Course+type@html+block@html_id",
+                    "block_type": "html",
+                    "display_name": "Text Content"
+                },
+                {
+                    "block_id": "block-v1:edX+DemoX+Demo_Course+type@problem+block@problem_id",
+                    "block_type": "problem",
+                    "display_name": "Practice Problem"
+                }
+            ]
+        }
+        ```
+        """
+        try:
+            usage_key = UsageKey.from_string(usage_key_string)
+        except Exception as e:  # pylint: disable=broad-exception-caught
+            log.error(f"Invalid usage key: {usage_key_string}, error: {str(e)}")
+            return HttpResponseBadRequest("Invalid usage key format")
+
+        try:
+            # Get the unit xblock
+            unit_xblock = modulestore().get_item(usage_key)
+
+            # Verify it's a vertical (unit)
+            if unit_xblock.category != "vertical":
+                return HttpResponseBadRequest(
+                    "The provided usage key is not a unit (vertical)"
+                )
+
+            if not enable_unit_expanded_view(unit_xblock.location.course_key):
+                return HttpResponseForbidden(
+                    "Unit expanded view is disabled for this course"
+                )
+
+            components = []
+
+            # Get all children (components) of the unit
+            if unit_xblock.has_children:
+                for child_usage_key in unit_xblock.children:
+                    try:
+                        child_xblock = modulestore().get_item(child_usage_key)
+                        components.append(
+                            {
+                                "block_id": str(child_xblock.location),
+                                "block_type": child_xblock.category,
+                                "display_name": child_xblock.display_name_with_default,
+                            }
+                        )
+                    except ItemNotFoundError:
+                        log.warning(f"Child block not found: {child_usage_key}")
+                        continue
+
+            response_data = {
+                "unit_id": str(usage_key),
+                "display_name": unit_xblock.display_name_with_default,
+                "components": components,
+            }
+
+            return Response(response_data)
+
+        except ItemNotFoundError:
+            log.error(f"Unit not found: {usage_key_string}")
+            return HttpResponseBadRequest("Unit not found")
+        except Exception as e:  # pylint: disable=broad-exception-caught
+            log.error(f"Error retrieving unit components: {str(e)}")
+            return HttpResponseBadRequest(f"Error retrieving unit components: {str(e)}")

cms/djangoapps/contentstore/toggles.py

@@ -682,3 +682,23 @@ def enable_course_optimizer_check_prev_run_links(course_key):
     Returns a boolean if previous run course optimizer feature is enabled for the given course.
     """
     return ENABLE_COURSE_OPTIMIZER_CHECK_PREV_RUN_LINKS.is_enabled(course_key)
+
+
+# .. toggle_name: contentstore.enable_unit_expanded_view
+# .. toggle_implementation: CourseWaffleFlag
+# .. toggle_default: False
+# .. toggle_description: When enabled, the Unit Expanded View feature in the Course Outline is activated.
+# .. toggle_use_cases: temporary
+# .. toggle_creation_date: 2026-01-01
+# .. toggle_target_removal_date: 2026-06-01
+# .. toggle_tickets: TNL2-473
+ENABLE_UNIT_EXPANDED_VIEW = CourseWaffleFlag(
+    f"{CONTENTSTORE_NAMESPACE}.enable_unit_expanded_view", __name__
+)
+
+
+def enable_unit_expanded_view(course_key):
+    """
+    Returns a boolean if the Unit Expanded View feature is enabled for the given course.
+    """
+    return ENABLE_UNIT_EXPANDED_VIEW.is_enabled(course_key)