models.py

class OpeningHours(models.Model):
    store = models.ForeignKey('Store', related_name="opening_hour")
    weekday = models.CharField(choices=DAY, max_length=12)
    opening_hour = models.TimeField()
    closing_hour = models.TimeField()

    class Meta:
    	verbose_name = 'Opening Hour'
    	verbose_name_plural = 'Opening Hours'

    def ___str__(self):
        return '{} {} - {}'.format(self.weekday, str(self.opening_hour), str(self.closing_hour))

class Store(models.Model):
    merchant = models.ForeignKey(User, blank=True, null=False)
    token = models.CharField(default=token_generator, max_length=20, unique=True, editable=False)
    name_of_legal_entity = models.CharField(max_length=250, blank=False, null=False)
    pan_number = models.CharField(max_length=20, blank=False, null=False)
    registered_office_address = models.CharField(max_length=200)
    name_of_store = models.CharField(max_length=100)
    email = models.EmailField(blank=False, null=False)
    store_contact_number = models.PositiveIntegerField(blank=False, null=False)
    is_active = models.BooleanField(default=True)

serializers.py

class EagerLoadingMixin:
    @classmethod
    def setup_eager_loading(cls, queryset):
        if hasattr(cls, "_SELECT_RELATED_FIELDS"):
            queryset = queryset.select_related(*cls._SELECT_RELATED_FIELDS)
        if hasattr(cls, "_PREFETCH_RELATED_FIELDS"):
            queryset = queryset.prefetch_related(*cls._PREFETCH_RELATED_FIELDS)
        return queryset

class ProductImageSerializer(serializers.ModelSerializer):
    class Meta:
        model = ProductImage
        fields = "__all__"
        read_only_fields = ('updated', )

class OpeningHoursSerializer(serializers.ModelSerializer):
    class Meta:
        model = OpeningHours
        fields = "__all__"


class ProductSerializer(serializers.ModelSerializer, EagerLoadingMixin):
    # _PREFETCH_RELATED_FIELDS = ['image',]
    class Meta:
        model = Product
        exclude = ('is_active', )

class StoreSerializer(serializers.ModelSerializer, EagerLoadingMixin):
    _SELECT_RELATED_FIELDS = ['merchant', ]
    # product = ProductSerializer(many=True)
    opening_hour = OpeningHoursSerializer(many=True)
    id = serializers.CharField(source='token', read_only=True)
    class Meta:
        model = Store
        exclude = ('is_active', )

views.py

class StoreView(APIView):
    serializer_class = StoreSerializer
    def get(self, request, token=None, format=None):
        """
        Return a list of all stores.
        """
        reply = {}
        try:
            stores = Store.objects.all()
            if token:
                store = stores.get(token=token)
                reply['data'] = self.serializer_class(store).data
            reply['data'] = self.serializer_class(stores, many=True).data
        except:
            reply['data'] = []
        return Response(reply, status.HTTP_200_OK)

    def post(self, request, format=None):
        """
        Post store
        """
        store = None
        reply={}
        if not token is None:
            try:
                store = Store.objects.get(token=token)
            except Store.DoesNotExist:
                return error.RequestedResourceNotFound().as_response()
            except:
                return error.UnknownError().as_response()
        serialized_data = self.serializer_class(instance=store, data=request.data, partial=True)
        if serialized_data.is_valid():
            serialized_data.save(merchant=request.user)
        else:
            return error.ValidationError(serialized_data.errors).as_response()
        return self.get(request)

Hey your StoreView should inherit CreateModelMixin and ListModelMixin along with GenericModelViewSet

Why you are using APIView ?

@vaibhav-jain I am using APIView for custom error response. This is my first time. How would you do the StoreView in best way? Could you please show me an example of better version of api from my code?

Sure just give me few hours. I'm traveling right now.

yeah sure @vaibhav-jain

Hey I don't see any custom response. All of the above can be done using DRF generic View's.

http://www.cdrf.co/3.6/rest_framework.viewsets/ModelViewSet.html

Use the above for reference.