django rest framework: SlugRelatedField options- limit by user

Question

Note: I'm new to django rest framework. First project with it. My model has a foreign key which in the serializer I link by a SlugRelatedField. This related model is a small list of options that can be selected however what is available for selection depends on the user (or more specifically the user group).

I have found this question that says how to get the user into a serilaizer. But this doesn't seem to help as the field definition is static right?

Removing the irrelevant parts I have:

class MyModelSerializer(serializers.ModelSerializer):

        sequence =  serializers.SlugRelatedField(
        many=False,
        read_only=False,
        slug_field='prefix',
        queryset=Sequence.objects.filter(active=True,
                sequence_groups__sequence_group_id__in=SequenceGroup.objects.filter(users=serializers.CurrentUserDefault()))
    )

This query works as I also use it in a normal form. When I start the dev. server I get an exception:

TypeError: int() argument must be a string, a bytes-like object or a number, not 'CurrentUserDefault'

So my question is how can I get the current user into the queryset of the SlugRelatedField?

score 1 · Accepted Answer · answered May 27 '20 at 05:25

It's funny how after hours of trying, writing down the question leads one to a working solution.

Add request to sterilizer context in ModelViewSet

Simply add below method to the ModelViewSet:
```
def get_serializer_context(self):
    return {"request": self.request}
```

Adjust the queryset of the SlugRelatedField in the constructor of the Serializer

def __init__(self, *args, **kwargs):
    super(MyModelSerializer, self).__init__(*args, **kwargs)
    # superuser can choose from all sequences, normal users can only choose from
    # active sequences he is assigned to
    request = self.context.get("request")
    if request and hasattr(request, "user"):
        sequence = self.fields['sequence']
        if request.user.is_superuser:
            sequence.queryset = Sequence.objects.all()
        else:
            sequence.queryset = Sequence.objects.filter(active=True,
                    sequence_groups__sequence_group_id__in=SequenceGroup.objects.filter(users=request.user))

In my case the admin should be able to select any of the available options hence the extra condition.

django rest framework: SlugRelatedField options- limit by user

1 Answers1