feat: rebuild aggregation serializer

requirements-dev.txt

@@ -1,4 +1,5 @@
 -r requirements.txt
 coverage==7.3.2
 psycopg2==2.9.9
+mssql-django==1.5
 ruff==0.3.7

src/django_rest_aggregation/mixins.py

@@ -18,11 +18,15 @@ def aggregation(self, request):
         aggregator = Aggregator(request, queryset, self.get_aggregation_name())
         filtered_queryset = self.filter_aggregated_queryset(aggregator.get_aggregated_queryset())
 
+        context = {
+            "request": request,
+            "name": self.get_aggregation_name()
+        }
         page = self.paginate_queryset(filtered_queryset)
         if page is not None:
-            serializer = self.get_aggregation_serializer_class(page, many=True)
+            serializer = self.get_aggregation_serializer_class(page, many=True, context=context)
             return self.get_paginated_response(serializer.data)
-        serializer = self.get_aggregation_serializer_class(filtered_queryset, many=True)
+        serializer = self.get_aggregation_serializer_class(filtered_queryset, many=True, context=context)
         return Response(serializer.data)
 
     def get_aggregation_serializer_class(self, *args, **kwargs):

src/django_rest_aggregation/serializers.py

@@ -1,17 +1,45 @@
-import decimal
-
 from rest_framework import serializers
-from rest_framework.serializers import BaseSerializer
-
-
-class AggregationSerializer(BaseSerializer):
-    def to_representation(self, instance):
-        ret = {}
-        for field in instance.keys():
-            if isinstance(instance[field], int):
-                ret[field] = serializers.IntegerField(read_only=True).to_representation(instance[field])
-            elif isinstance(instance[field], float) or isinstance(instance[field], decimal.Decimal):
-                ret[field] = serializers.FloatField(read_only=True).to_representation(float(instance[field]))
-            else:
-                ret[field] = serializers.CharField(read_only=True).to_representation(instance[field])
-        return ret
+
+
+class PassTroughField(serializers.Field):
+
+    def to_representation(self, value):
+        return value
+
+    def to_internal_value(self, data):
+        return data
+
+
+class AggregationSerializer(serializers.Serializer):
+    """
+    Serializer for aggregation requests.
+    Authored by Tim Streicher
+    """
+
+    value = serializers.SerializerMethodField(method_name='serialize_value')
+
+    def serialize_value(self, obj):
+        return obj['value']
+
+    def __init__(self, *args, **kwargs):
+        # Instantiate the superclass normally
+        super(AggregationSerializer, self).__init__(*args, **kwargs)
+
+        fields = self.context['request'].query_params.get('group_by')
+        allowed = {self.context['name']}
+        if fields:
+            fields = fields.split(',')
+            allowed.update(fields)
+        else:
+            allowed.add('group')
+
+        # Drop any fields that are not specified in the `fields` argument except value.
+        existing = set(self.fields.keys())
+        for field_name in existing - allowed:
+            self.fields.pop(field_name)
+
+        for field_name in allowed:
+            field = self.fields.get(field_name)
+            # add field for unknown field_names
+            if field is None:
+                self.fields[field_name] = PassTroughField()

tests/test_aggregation.py

@@ -1,3 +1,5 @@
+import datetime
+
 from django.db import connection
 from rest_framework.test import APITestCase
 
@@ -152,7 +154,7 @@ def test_minimum(self):
             format="json",
         )
         self.assertEqual(response.status_code, 200)
-        self.assertEqual(response.data, [{"group": "all", "value": "2020-01-01"}])
+        self.assertEqual(response.data, [{"group": "all", "value": datetime.date(2020, 1, 1)}])
 
     def test_maximum(self):
         # Maximum of IntegerField
@@ -189,7 +191,7 @@ def test_maximum(self):
             format="json",
         )
         self.assertEqual(response.status_code, 200)
-        self.assertEqual(response.data, [{"group": "all", "value": "2020-01-05"}])
+        self.assertEqual(response.data, [{"group": "all", "value": datetime.date(2020, 1, 5)}])
 
 
 class TestGroupingAndAnnotations(APITestCase):
@@ -884,16 +886,16 @@ def test_ordering_all_field(self):
         self.assertEqual(response.status_code, 200)
         self.assertEqual(response.data["results"], [])
 
-    def test_sqlite_exception(self):
-        # throws exception if sqlite version is less than
+    def test_pagiation_count(self):
         response = self.client.get(
-            "/book/aggregation/",
+            "/customized_book/aggregation/",
             {
                 "aggregation": "sum",
                 "aggregation_field": "price",
-                "value__gte": 1,
+                "ordering": "CustomizedValue",
+                "CustomizedValue__lte": 0,
             },
             format="json",
         )
         self.assertEqual(response.status_code, 200)
-        self.assertEqual(response.data, [{"group": "all", "value": 10.55}])
+        self.assertEqual(response.data["count"], 0)