DJANGO - Save data with genericforeignkey on POST method using rest framework

Question

I would like to save an instance of 'Feedback' object on my database, the feedback object have a foreignkey to 'Client', and a genericforeignkey because it can be related to 'Vendor' or 'Store', i made 2 url's that allows POST, one to create feedback for vendor and another to create feedback for store, both receive the primarykey.

Class diagram example:

This is my approach:

@api_view(['POST'])
def store_feedback_view(request, store_id):
    serializer = FeedbackSerializer(data=request.DATA)
    if serializer.is_valid():
        serializer.save()
        return Response(serializer.data, status=status.HTTP_201_CREATED)
    return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

The serializer is valid, but while trying to save give me the following error:

NOT NULL constraint failed: feedback_feedback.object_id
NOT NULL constraint failed: feedback_feedback.content_type_id

This happens because the feedback object have the genericforeignkey not NULL:

class Feedback(models.Model):
    comment = models.TextField(verbose_name='Comment', max_length=300, blank=True, null=True)
    client = models.ForeignKey(Client, verbose_name="Client feedback", related_name="feedbacks")

    limit = models.Q(app_label='core', model='store') | models.Q(app_label='core', model='vendor')
    content_type = models.ForeignKey(ContentType,
                                     limit_choices_to=limit)
    object_id = models.PositiveIntegerField(verbose_name="Related object ID")
    content_object = GenericForeignKey('content_type', 'object_id')

    class Meta:
        app_label = 'feedback'

How i can create an object of feedback on POST method?

This is a example of request on feedback/store/(?P<store_id>\d+)/

{
  "comment": "Nice store",
  "client": 1
}

score 3 · Accepted Answer · answered Oct 21 '14 at 13:30

3

Set store to serializer.object:

@api_view(['POST'])
def store_feedback_view(request, store_id):
    serializer = FeedbackSerializer(data=request.DATA)
    if serializer.is_valid():
        # this line added:
        serializer.object.content_object = get_object_or_404(Store, id=store_id)
        serializer.save()
        return Response(serializer.data, status=status.HTTP_201_CREATED)
    return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

answered Oct 21 '14 at 13:30

zymud

2,221
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1

This is for versions of DRF older than DRF 3.0. See here for how this should be handled in 3.0+: http://stackoverflow.com/a/13564519/2133271 – IAmKale Apr 06 '15 at 22:52

DJANGO - Save data with genericforeignkey on POST method using rest framework

1 Answers1