Django RestFramework POST nested request
I'm having a little problem right now with Django Rest Framework. I'm trying to post an object with nested objects in it.
This is my models.py file.
class Supplier(models.Model):
name = models.CharField(max_length=255, blank=True, null=True)
def __str__(self):
return self.name
class Transaction(models.Model):
date = models.CharField(max_length=255, blank=True, null=True)
income = models.IntegerField(blank=True,null=True)
expense = models.IntegerField(blank=True,null=True)
card = models.CharField(max_length=255, blank=True, null=True)
currency = models.CharField(max_length=255, blank=True, null=True)
supplier = models.ForeignKey(Supplier, on_delete=models.CASCADE)
category = models.CharField(max_length=255, blank=True, null=True)
def __str__(self):
return self.date + ' ' + str(self.expense) + ' ' + self.card + ' ' + str(self.supplier)
This is my serializers.py file
class SupplierSerializer(serializers.ModelSerializer):
class Meta:
model = Supplier
fields = ['id', 'name']
class TransactionSerializer(serializers.ModelSerializer):
supplier = SupplierSerializer()
class Meta:
model = Transaction
fields = ['id',
'date',
'income',
'expense',
'card',
'currency',
'supplier',
'category']
read_only_fields = ['id']
def create(self, validated_data):
supplier_data = validated_data.pop('supplier')
supplier = Supplier.objects.create(**supplier_data)
transaction = Transaction.objects.create(supplier=supplier, **validated_data)
return transaction
This is my views.py file
@api_view(['POST', 'GET'])
def transaction(request):
if request.method == 'POST':
transaction_serializer = TransactionSerializer(data=request.data)
if transaction_serializer.is_valid():
transaction_serializer.save()
return Response(transaction_serializer.data, status=status.HTTP_201_CREATED)
if request.method == 'GET':
transactions = Transaction.objects.all()
serializer = TransactionSerializer(transactions, many = True)
return JsonResponse(serializer.data, safe=False)
I'm trying to make this POST Request:
{
"date": "12/10/2022",
"income": 41241,
"expense": null,
"card": "Credit card",
"currency": "CLP",
"supplier": [{
"name": "Cabify"
}],
"category": "Transporte"
}
But in console show me this error:
[28/Nov/2022 19:50:56] "POST /transactions/ HTTP/1.1" 500 73587
Internal Server Error: /transactions/
Traceback (most recent call last):
File "/Users/benjaminandaur/Desktop/projects/drinks-api/venv/lib/python3.9/site-packages/django/core/handlers/exception.py", line 55, in inner
response = get_response(request)
File "/Users/benjaminandaur/Desktop/projects/drinks-api/venv/lib/python3.9/site-packages/django/core/handlers/base.py", line 191, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/Users/benjaminandaur/Desktop/projects/drinks-api/venv/lib/python3.9/site-packages/django/views/decorators/csrf.py", line 54, in wrapped_view
return view_func(*args, **kwargs)
File "/Users/benjaminandaur/Desktop/projects/drinks-api/venv/lib/python3.9/site-packages/django/views/generic/base.py", line 103, in view
return self.dispatch(request, *args, **kwargs)
File "/Users/benjaminandaur/Desktop/projects/drinks-api/venv/lib/python3.9/site-packages/rest_framework/views.py", line 513, in dispatch
self.response = self.finalize_response(request, response, *args, **kwargs)
File "/Users/benjaminandaur/Desktop/projects/drinks-api/venv/lib/python3.9/site-packages/rest_framework/views.py", line 424, in finalize_response
assert isinstance(response, HttpResponseBase), (
AssertionError: Expected a `Response`, `HttpResponse` or `HttpStreamingResponse` to be returned from the view, but received a `<class 'NoneType'>`
[28/Nov/2022 19:54:33] "POST /transactions/ HTTP/1.1" 500 73587
from the DRF api_view decorator documentation, the view would be something like this:
@api_view(['GET', 'POST'])
def transaction(request):
if request.method == 'POST':
transaction_serializer = TransactionSerializer(data=request.data)
if transaction_serializer.is_valid():
transaction_serializer.save()
return Response({"status": status.HTTP_201_CREATED, "data": serializer.data})
transactions = Transaction.objects.all()
serializer = TransactionSerializer(transactions, many = True)
return Response({"data": serializer.data})
I think there’s a serialization problem so you need to treat case your serializer is not valid like that that to get the source of the problem:
@api_view(['POST', 'GET'])
def transaction(request):
if request.method == 'POST':
transaction_serializer = TransactionSerializer(data=request.data)
if transaction_serializer.is_valid():
transaction_serializer.save()
return Response(transaction_serializer.data, status=status.HTTP_201_CREATED)
else:
return Response(transaction_serializer.errors, status=status.HTTP_400_BAD_REQUEST)
if request.method == 'GET':
transactions = Transaction.objects.all()
serializer = TransactionSerializer(transactions, many = True)
return JsonResponse(serializer.data, safe=False)
and i think that the problem with your serializer is that you send a list of suppliers
"supplier": [{
"name": "Cabify"
}]
and in your serializer you are creating just one, and in your model it's a ForeignKey so your serializer is correct referring to your model so i think you need to change your post request:
{
"date": "12/10/2022",
"income": 41241,
"expense": null,
"card": "Credit card",
"currency": "CLP",
"supplier": {
"name": "Cabify"
},
"category": "Transporte"
}
or if you dont have the control of the POST request
you can change your serializer create method and pick juste the first element of suppliers list like that:
class TransactionSerializer(serializers.ModelSerializer):
supplier = SupplierSerializer()
class Meta:
model = Transaction
fields = ['id',
'date',
'income',
'expense',
'card',
'currency',
'supplier',
'category']
read_only_fields = ['id']
def create(self, validated_data):
supplier_data = validated_data.pop('supplier')
if supplier_data:
supplier = Supplier.objects.create(**supplier_data[0])
transaction = Transaction.objects.create(supplier=supplier, **validated_data)
return transaction