New DatasetSet model

closes #1712 (closed)

TODO:

• create process dataset issue
• create new API endpoints issue

arkindex/project/serializer_fields.py

@@ -4,7 +4,6 @@ from urllib.parse import quote, unquote
 
 import bleach
 from django.contrib.gis.geos import Point
-from django.db.models import Count
 from drf_spectacular.utils import extend_schema_field
 from rest_framework import serializers
 
@@ -12,6 +11,7 @@ from arkindex.documents.models import MetaType
 from arkindex.ponos.utils import get_process_from_task_auth
 from arkindex.process.models import ProcessMode, WorkerRun
 from arkindex.project.gis import ensure_linear_ring
+from arkindex.project.tools import is_prefetched
 
 
 class EnumField(serializers.ChoiceField):
@@ -269,7 +269,9 @@ class ArchivedField(serializers.BooleanField):
 class DatasetSetsCountField(serializers.DictField):
     """
     Serialize the number of element per set on a dataset.
-    This value can be disabled by setting `sets_count` to False in the context.
+
+    This field is None, unless the sets have been prefetched
+    with a `element_count` annotation holding the number of elements per set.
     """
 
     def __init__(self, **kwargs):
@@ -281,16 +283,17 @@ class DatasetSetsCountField(serializers.DictField):
         )
 
     def get_attribute(self, instance):
-        if not self.context.get("sets_count", True):
+        # Skip this field if sets are not prefetched, or if they are missing a count
+        if (
+            not is_prefetched(instance.sets)
+            or not all(hasattr(set, "element_count") for set in instance.sets.all())
+        ):
             return None
-        elts_count = {k: 0 for k in instance.sets}
-        elts_count.update(
-            instance.dataset_elements
-            .values("set")
-            .annotate(count=Count("id"))
-            .values_list("set", "count")
-        )
-        return elts_count
+
+        return {
+            set.name: set.element_count
+            for set in instance.sets.all()
+        }
 
 
 class NullField(serializers.CharField):