Add a new field type: AsymmetricRelatedField

rest_framework_extensions/fields.py

@@ -1,4 +1,6 @@
-from rest_framework.relations import HyperlinkedRelatedField
+from rest_framework.relations import HyperlinkedRelatedField, PrimaryKeyRelatedField
+
+from rest_framework import serializers
 
 
 class ResourceUriField(HyperlinkedRelatedField):
@@ -26,3 +28,14 @@ class Meta:
     def __init__(self, *args, **kwargs):
         kwargs.setdefault('source', '*')
         super().__init__(*args, **kwargs)
+
+
+class AsymmetricRelatedField(serializers.PrimaryKeyRelatedField):
+    def __init__(
+        self, serializer_class, *args, **kwargs
+    ) -> None:
+        self.serializer_class = serializer_class
+        super().__init__(*args, **kwargs)
+
+    def to_representation(self, value):
+        return self.serializer_class(value).data

tests_app/tests/unit/fields/models.py

@@ -0,0 +1,10 @@
+from django.db import models
+
+
+class RelatedModel(models.Model):
+    name = models.CharField(max_length=100)
+
+
+class SomeModel(models.Model):
+    name = models.CharField(max_length=100)
+    related_model = models.ForeignKey(RelatedModel, on_delete=models.CASCADE)

tests_app/tests/unit/fields/serializers.py

@@ -0,0 +1,21 @@
+from rest_framework import serializers
+from rest_framework_extensions.fields import AsymmetricRelatedField
+
+from .models import SomeModel, RelatedModel
+
+
+class RelatedModelSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = RelatedModel
+        fields = ('id', 'name')
+
+
+class SomeModelSerializer(serializers.ModelSerializer):
+    related_model = AsymmetricRelatedField(
+        serializer_class=RelatedModelSerializer,
+        queryset=RelatedModel.objects.all()
+    )
+
+    class Meta:
+        model = SomeModel
+        fields = ('id', 'name', 'related_model')

tests_app/tests/unit/fields/tests.py

@@ -0,0 +1,53 @@
+from django.test import TestCase
+from rest_framework import serializers
+from .models import SomeModel, RelatedModel
+from .serializers import SomeModelSerializer, RelatedModelSerializer
+from rest_framework_extensions.fields import AsymmetricRelatedField
+
+
+class TestAsymmetricRelatedField(TestCase):
+    def setUp(self):
+        self.related_model1 = RelatedModel.objects.create(name='related_model1')
+        self.related_model2 = RelatedModel.objects.create(name='related_model2')
+        self.some_model = SomeModel.objects.create(
+            name='some_model', related_model=self.related_model1)
+
+    def test_to_representation(self):
+        field = AsymmetricRelatedField(serializer_class=RelatedModelSerializer)
+        result = field.to_representation(self.related_model1)
+        self.assertEqual(
+            result, {'id': self.related_model1.id, 'name': 'related_model1'})
+
+    def test_create(self):
+        data = {
+            'name': 'new_some_model',
+            'related_model': self.related_model2.id
+        }
+        serializer = SomeModelSerializer(data=data)
+        self.assertTrue(serializer.is_valid())
+        instance = serializer.save()
+        self.assertEqual(instance.name, 'new_some_model')
+        self.assertEqual(instance.related_model, self.related_model2)
+
+    def test_update(self):
+        data = {
+            'name': 'updated_some_model',
+            'related_model': self.related_model2.id
+        }
+        serializer = SomeModelSerializer(
+            instance=self.some_model, data=data, partial=True)
+        self.assertTrue(serializer.is_valid())
+        instance = serializer.save()
+        self.assertEqual(instance.name, 'updated_some_model')
+        self.assertEqual(instance.related_model, self.related_model2)
+
+    def test_read(self):
+        serializer = SomeModelSerializer(instance=self.some_model)
+        self.assertEqual(serializer.data, {
+            'id': self.some_model.id,
+            'name': 'some_model',
+            'related_model': {
+                'id': self.related_model1.id,
+                'name': 'related_model1'
+            }
+        })

tests_app/tests/unit/migrations/0001_initial.py

@@ -65,4 +65,23 @@ class Migration(migrations.Migration):
                 ('users_liked', models.ManyToManyField(blank=True, to='unit.UserModel')),
             ],
         ),
+        migrations.CreateModel(
+            name='RelatedModel',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True,
+                                        serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=100)),
+            ],
+        ),
+        migrations.CreateModel(
+            name='SomeModel',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True,
+                                        serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=100)),
+                ('related_model',
+                 models.ForeignKey(blank=True, to='unit.RelatedModel',
+                                   on_delete=models.CASCADE)),
+            ],
+        ),
     ]