django rest framework PUT returns 404 instead of creating an object

Question

I want to be able to create or update an object using the same request. The operation should be idempotent.

Sending a PUT request to DRF work as expected if the object exists but if the object doesn't exists I get a 404 instead of creating it.

models.py:

class Btilog(models.Model):
    md5hash = models.CharField(primary_key=True, max_length=32)
    vteip = models.ForeignKey('vte.VTE')
    timestamp = models.DateTimeField(blank=False)
    source = models.TextField()
    code = models.CharField(max_length=10, blank=False)
    msg = models.TextField(blank=False)

api.py:

class BtilogSerializer(serializers.ModelSerializer):
    class Meta:
        model = models.Btilog

class BtilogVSet(viewsets.ModelViewSet):
    queryset = models.Btilog.objects.all()
    serializer_class = BtilogSerializer
    permission_classes = (permissions.AllowAny,)

urls.py:

...
router = routers.DefaultRouter()
router.register(r'btilog', api.BtilogVSet)

urlpatterns = patterns('',
    url(r'^api/', include(router.urls)),
    ...
)

Failing request

http --form PUT http://192.168.10.121:8888/logger/api/btilog/60c6b9e99c43c0bf4d8bc22d671169b1/ vteip='172.25.128.85' 'code'='Test' 'md5hash'='60c6b9e99c43c0bf4d8bc22d671169b1' 'timestamp'='2015-05-31T13:34:01' msg='Test' source='Test'
HTTP/1.0 404 NOT FOUND
Allow: GET, PUT, PATCH, DELETE, HEAD, OPTIONS
Content-Type: application/json
Date: Mon, 09 Feb 2015 15:16:47 GMT
Server: WSGIServer/0.1 Python/2.7.6
Vary: Accept, Cookie

{
    "detail": "Not found"
    }

As described here: http://restcookbook.com/HTTP%20Methods/put-vs-post/ the correct behaviour of put should be to create the object if it doesn't exists.

The same error occurs using The Browsable API Tool from DRF to make the request. Is the behaviour of DRF also alike? What I'm doing wrong?

Answer 1

Well, maybe you should try to overwrite update method inside your modelviewset, which handle the PUT http method:

class BtilogVSet(viewsets.ModelViewSet):
    queryset = models.Btilog.objects.all()
    serializer_class = BtilogSerializer
    permission_classes = (permissions.AllowAny,)

    def update(self, request, *args, **kwargs):
        try:
            instance = Btilog.objects.get(pk=kwargs['pk'])
            serializer = serializers.BtilogSerializer(instance=instance,data=request.data)
            if serializer.is_valid():
                btilog=serializer.save()
                return Response(serializer.data,status=status.HTTP_200_OK)
            return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
        except Btilog.DoesNotExist:
            serializer = serializers.BtilogSerializer(data=request.data)
        if serializer.is_valid():
            btilog=serializer.save()
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)