DRF Foreignkey serialization - django

Question

I can't save model with Foreignkey field.
Thanks to "azudo" problem solved. Solution below
For example I have simple models:
class User(AbstractUser):
class Meta:
pass
email_validator = EmailValidator()
username = models.CharField('Name', max_length=150, )
id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
email = models.EmailField('Email', blank=True, unique=True, validators=[email_validator], )
...
class Package(models.Model):
user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='packages')
description = models.CharField('Description', max_length=256, default='description')
weight = models.CharField('weight', max_length=256, default='weight')
...
View (the user is guaranteed to be in the request):
#api_view(["POST"])
def test(request):
data = request.data
data['user'] = User.objects.get(id=request.user.id)
serializer = PackageSerializer(data=data)
if serializer.is_valid():
serializer.save()
return JsonResponse(serializer.data)
else:
return JsonResponse(serializer.errors)
My serializers:
class UserSerializer(ModelSerializer):
class Meta:
model = User
fields = '__all__'
class PackageSerializer(ModelSerializer):
class Meta:
model = Package
fields = (
'user', 'description', 'weight', 'dimensions', 'estimated_shipping_cost', 'deliver_to_date')
def to_representation(self, instance):
self.fields['user'] = UserSerializer(many=False, read_only=True)
self.fields['where_from'] = LocationSerializer(many=False, read_only=True)
self.fields['destination'] = LocationSerializer(many=False, read_only=True)
return super().to_representation(instance)
def create(self, validated_data):
user = User.objects.get(validated_data.pop('user'))
package = Package.objects.create(user=user, **validated_data)
return package
json in request:
{
"description": "Some package",
"weight": "12",
}
So, I'have user in database, and want create package for him. But in overridden create in PackageSerializer, validated_data doesn't have user. Please explain what I'm doing wrong.
Versions of django and drf:
django==2.2.4
djangorestframework==3.10.2
Solution:
Serializer:
class PackageSerializer(ModelSerializer):
user = UserSerializer(many=False, read_only=True)
class Meta:
model = Package
fields = (
'user', 'description', 'weight', 'dimensions', 'estimated_shipping_cost', 'deliver_to_date')
def create(self, validated_data):
user = User.objects.get(validated_data.pop('user'))
package = Package.objects.create(user=user)
return package
View:
#api_view(["POST"])
def create_package(request):
data = request.data
serializer = PackageSerializer(data=data)
if serializer.is_valid():
serializer.save(user=request.user)
return JsonResponse(serializer.data)
else:
return JsonResponse(serializer.errors)

Answer 1

DRF will ignore included fields that are marked as read-only so the caller cannot include read-only data. If you want to include additional attributes simply pass them as keyword args to save:
https://www.django-rest-framework.org/api-guide/serializers/#passing-additional-attributes-to-save
e.g.
#api_view(["POST"])
def test(request):
data = request.data
serializer = PackageSerializer(data=data)
if serializer.is_valid():
serializer.save(user=request.user)
return JsonResponse(serializer.data)
else:
return JsonResponse(serializer.errors)