Optimize asset list endpoint

dandiapi/api/tests/test_asset.py

@@ -1539,4 +1539,5 @@ def test_asset_rest_glob(api_client, asset_factory, version, glob_pattern, expec
         {'glob': glob_pattern},
     )
 
-    assert expected_paths == [asset['path'] for asset in resp.json()['results']]
+    # Sort both lists before comparing since ordering is not considered
+    assert sorted(expected_paths) == sorted([asset['path'] for asset in resp.json()['results']])

dandiapi/api/views/asset.py

@@ -22,7 +22,6 @@
     # This should only be used for type interrogation, never instantiation
     MinioStorage = type('FakeMinioStorage', (), {})
 
-from typing import TYPE_CHECKING
 
 from django.conf import settings
 from django.db import transaction
@@ -57,9 +56,6 @@
     AssetValidationSerializer,
 )
 
-if TYPE_CHECKING:
-    from django.db.models import QuerySet
-
 
 class AssetFilter(filters.FilterSet):
     path = filters.CharFilter(lookup_expr='istartswith')
@@ -232,7 +228,7 @@ class NestedAssetViewSet(NestedViewSetMixin, AssetViewSet, ReadOnlyModelViewSet)
 
     def raise_if_unauthorized(self):
         version = get_object_or_404(
-            Version,
+            Version.objects.select_related('dandiset'),
             dandiset__pk=self.kwargs['versions__dandiset__pk'],
             version=self.kwargs['versions__version'],
         )
@@ -244,6 +240,15 @@ def raise_if_unauthorized(self):
                 # The user does not have ownership permission
                 raise PermissionDenied
 
+    # Override this here to prevent the need for raise_if_unauthorized to exist in get_queryset
+    def get_object(self):
+        self.raise_if_unauthorized()
+        return super().get_object()
+
+    # Override this to skip the call to raise_if_unauthorized in AssetViewSet
+    def get_queryset(self):
+        return super(AssetViewSet, self).get_queryset()
+
     # Redefine info and download actions to update swagger manual_parameters
 
     @swagger_auto_schema(
@@ -389,36 +394,57 @@ def destroy(self, request, versions__dandiset__pk, versions__version, **kwargs):
 
     @swagger_auto_schema(query_serializer=AssetListSerializer, responses={200: AssetSerializer})
     def list(self, request, *args, **kwargs):
+        # Manually call this to ensure user is authorized
+        self.raise_if_unauthorized()
+
         serializer = AssetListSerializer(data=request.query_params)
         serializer.is_valid(raise_exception=True)
 
-        # Fetch initial queryset
-        queryset: QuerySet[Asset] = self.filter_queryset(
-            self.get_queryset().select_related('blob', 'embargoed_blob', 'zarr')
+        # Retrieve version first and then fetch assets, to remove a join
+        version = Version.objects.get(
+            dandiset__pk=self.kwargs['versions__dandiset__pk'],
+            version=self.kwargs['versions__version'],
         )
 
-        # Don't include metadata field if not asked for
-        include_metadata = serializer.validated_data['metadata']
-        if not include_metadata:
-            queryset = queryset.defer('metadata')
+        # Apply filtering from included filter class first
+        asset_queryset = self.filter_queryset(version.assets.all())
 
+        # Must do glob pattern matching before pagination
         glob_pattern: str | None = serializer.validated_data.get('glob')
         if glob_pattern is not None:
             # Escape special characters in the glob pattern. This is a security precaution taken
             # since we are using postgres' regex search. A malicious user who knows this could
             # include a regex as part of the glob expression, which postgres would happily parse
             # and use if it's not escaped.
             glob_pattern = f'^{re.escape(glob_pattern)}$'
-            queryset = queryset.filter(path__iregex=glob_pattern.replace('\\*', '.*'))
+            asset_queryset = asset_queryset.filter(path__iregex=glob_pattern.replace('\\*', '.*'))
+
+        # Retrieve just the first N asset IDs, and use them for pagination
+        page_of_asset_ids = self.paginate_queryset(asset_queryset.values_list('id', flat=True))
+
+        # Not sure when the page is ever None, but this condition is checked for compatibility with
+        # the original implementation: https://github.com/encode/django-rest-framework/blob/f4194c4684420ac86485d9610adf760064db381f/rest_framework/mixins.py#L37-L46
+        # This is checked here since the query can't continue if the page is `None` anyway
+        if page_of_asset_ids is None:
+            serializer = self.get_serializer(Asset.objects.none(), many=True)
+            return Response(serializer.data)
+
+        # Now we can retrieve the actual fully joined rows using the limited number of assets we're
+        # going to return
+        queryset = self.filter_queryset(
+            Asset.objects.filter(id__in=page_of_asset_ids).select_related(
+                'blob', 'embargoed_blob', 'zarr'
+            )
+        )
 
-        # Paginate and return
-        page = self.paginate_queryset(queryset)
-        if page is not None:
-            serializer = self.get_serializer(page, many=True, metadata=include_metadata)
-            return self.get_paginated_response(serializer.data)
+        # Must apply this to the main queryset, since it affects the data returned
+        include_metadata = serializer.validated_data['metadata']
+        if not include_metadata:
+            queryset = queryset.defer('metadata')
 
+        # Paginate and return
         serializer = self.get_serializer(queryset, many=True, metadata=include_metadata)
-        return Response(serializer.data)
+        return self.get_paginated_response(serializer.data)
 
     @swagger_auto_schema(
         query_serializer=AssetPathsQueryParameterSerializer,