python - Pass extra arguments to Serializer Class in Django Rest Framework

Question

I want to pass some arguments to DRF Serializer class from Viewset, so for I have tried this:

class OneZeroSerializer(rest_serializer.ModelSerializer):

    def __init__(self, *args, **kwargs):
        print args # show values that passed

    location = rest_serializer.SerializerMethodField('get_alternate_name')

    def get_alternate_name(self, obj):
        return ''


    class Meta:
        model = OneZero

        fields = ('id', 'location')

Views

class OneZeroViewSet(viewsets.ModelViewSet):

   serializer_class = OneZeroSerializer(realpart=1)
   #serializer_class = OneZeroSerializer

   queryset = OneZero.objects.all()

Basically I want to pass some value based on querystring from views to Serializer class and then these will be allocate to fields.

These fields are not include in Model in fact dynamically created fields.

Same case in this question stackoverflow, but I cannot understand the answer.

Can anyone help me in this case or suggest me better options.

Answer 1

It's very easy with "context" arg for "ModelSerializer" constructor.

For example:

in view:

my_objects = MyModelSerializer(
    input_collection, 
    many=True, 
    context={'user_id': request.user.id}
).data

in serializers:

class MyModelSerializer(serializers.ModelSerializer):
...

    is_my_object = serializers.SerializerMethodField('_is_my_find')
...

    def _is_my_find(self, obj):
        user_id = self.context.get("user_id")
        if user_id:
            return user_id in obj.my_objects.values_list("user_id", flat=True)
        return False
...

so you can use "self.context" for getting extra params.

Reference