feat: support rendering XBlocks in the Learning MFE

Rendering blocks directly in the MFE was developed for the Library Authoring
MFE. The solution was then ported to the Learning MFE. This commit includes
backend changes required to retrieve data of non-blockstore XBlocks from LMS.

lms/templates/staff_problem_info.html

@@ -143,7 +143,7 @@ <h2>${_("Submission History Viewer")}</h2>
 <script type="text/javascript">
 // assumes courseware.html's loaded this method.
 $(function () {
-    setup_debug('${element_id | n, js_escaped_string}',
+    (typeof setup_debug !== 'undefined') && setup_debug('${element_id | n, js_escaped_string}',
         %if edit_link:
         '${edit_link | n, js_escaped_string}',
         %else:

openedx/core/djangoapps/xblock/api.py

@@ -15,7 +15,7 @@
 from django.urls import reverse
 from django.utils.translation import gettext as _
 from opaque_keys.edx.keys import UsageKeyV2
-from opaque_keys.edx.locator import BundleDefinitionLocator
+from opaque_keys.edx.locator import BlockUsageLocator, BundleDefinitionLocator
 from rest_framework.exceptions import NotFound
 from xblock.core import XBlock
 from xblock.exceptions import NoSuchViewError
@@ -120,17 +120,27 @@ def get_block_metadata(block, includes=()):
         editable_children: children in the same bundle, as opposed to linked
             children in other bundles.
     """
+    usage_id = block.scope_ids.usage_id
+
+    if isinstance(usage_id, BlockUsageLocator):
+        # The second method is more efficient, but it doesn't work with the DescriptorSystem.
+        display_name = block.display_name
+    else:
+        display_name = get_block_display_name(block)
     data = {
-        "block_id": str(block.scope_ids.usage_id),
+        "block_id": str(usage_id),
         "block_type": block.scope_ids.block_type,
-        "display_name": get_block_display_name(block),
+        "display_name": display_name,
     }
 
     if "index_dictionary" in includes:
         data["index_dictionary"] = block.index_dictionary()
 
     if "student_view_data" in includes:
-        data["student_view_data"] = block.student_view_data() if hasattr(block, 'student_view_data') else None
+        if isinstance(usage_id, BlockUsageLocator):
+            data["student_view_data"] = render_block_view(block, 'student_view', None).content
+        else:
+            data["student_view_data"] = block.student_view_data() if hasattr(block, 'student_view_data') else None
 
     if "children" in includes:
         data["children"] = block.children if hasattr(block, 'children') else []  # List of usage keys of children

openedx/core/djangoapps/xblock/rest_api/views.py

@@ -18,8 +18,10 @@
 from xblock.django.request import DjangoWebobRequest, webob_to_django_response
 from xblock.fields import Scope
 
+from lms.djangoapps.courseware.block_render import get_block_by_usage_id
 from opaque_keys import InvalidKeyError
 from opaque_keys.edx.keys import UsageKey
+from opaque_keys.edx.locator import BlockUsageLocator
 from openedx.core.lib.api.view_utils import view_auth_classes
 from ..api import (
     get_block_display_name,
@@ -52,7 +54,13 @@ def block_metadata(request, usage_key_str):
     except InvalidKeyError as e:
         raise NotFound(invalid_not_found_fmt.format(usage_key=usage_key_str)) from e
 
-    block = load_block(usage_key, request.user)
+    if isinstance(usage_key, BlockUsageLocator):
+        block, __ = get_block_by_usage_id(
+            request, str(usage_key.course_key), str(usage_key), disable_staff_debug_info=True
+        )
+    else:
+        block = load_block(usage_key, request.user)
+
     includes = request.GET.get("include", "").split(",")
     metadata_dict = get_block_metadata(block, includes=includes)
     if 'children' in metadata_dict:
@@ -74,7 +82,13 @@ def render_block_view(request, usage_key_str, view_name):
     except InvalidKeyError as e:
         raise NotFound(invalid_not_found_fmt.format(usage_key=usage_key_str)) from e
 
-    block = load_block(usage_key, request.user)
+    if isinstance(usage_key, BlockUsageLocator):
+        block, __ = get_block_by_usage_id(
+            request, str(usage_key.course_key), str(usage_key), disable_staff_debug_info=True
+        )
+    else:
+        block = load_block(usage_key, request.user)
+
     fragment = _render_block_view(block, view_name, request.user)
     response_data = get_block_metadata(block)
     response_data.update(fragment.to_dict())
@@ -152,7 +166,19 @@ def xblock_handler(request, user_id, secure_token, usage_key_str, handler_name,
         raise AuthenticationFailed("Invalid user ID format.")
 
     request_webob = DjangoWebobRequest(request)  # Convert from django request to the webob format that XBlocks expect
-    block = load_block(usage_key, user)
+
+    if isinstance(usage_key, BlockUsageLocator):
+        # HACK: These requests are coming from ajax calls, so they do not the authenticated HTTP client in in the
+        #  learning MFE. We don't want to modify the signature of the get_block_by_usage_id function, so we just
+        #  manually set the user on the request object. This is safe because the user permissions are checked above and
+        #  the request object is not used for anything else in the function.
+        request.user = user
+        block, __ = get_block_by_usage_id(
+            request, str(usage_key.course_key), str(usage_key), disable_staff_debug_info=True
+        )
+    else:
+        block = load_block(usage_key, user)
+
     # Run the handler, and save any resulting XBlock field value changes:
     response_webob = block.handle(handler_name, request_webob, suffix)
     response = webob_to_django_response(response_webob)