I am relatively new to the web development and I am writing backend for webapp for practicing chemical elements and compounds and their formulas in our school. I am using Django and Django Rest Framework. I have encountered a dilemma where I can't decide whether to use GET method or POST method. In frontend it requests compounds and elements from the server with specific criteria. In this view, it recieves request with body (criteria), where are values requested_count, used_ids (to exclude already used compounds/elements), requested_groups, requested_elements (to exclude elements which may students don't know). Each value (except count) could be a list with potentially hundreds of items. Then, it filters the database to return the response. I have tested this many times and it is working correctly. My only question is, which method to use in this view. I know that POST should be used when I want to change something in the database and GET to just get query from the database. According to this I should use GET. But I want to send body with that request and that is something what POST typically does. What do you suggest? Thanks
Here is the view code:
class RequestCompoundsView(views.APIView):serializer_class = RequestCompoundsSerializerdef get(self, request): serializer = self.serializer_class(data=request.data) if serializer.is_valid(): # Get the request data from serializer requested_count = serializer.validated_data.get("count", 10) used_ids = serializer.validated_data.get("used_ids", []) requested_groups = serializer.validated_data.get("groups", []) requested_elements = serializer.validated_data.get("elements", []) # Find the elements and groups objects groups, elements = find_requested_groups_elements( requested_groups, requested_elements ) # Check if the group and element names are correct if groups.count() == 0: context = {"error": "invalid group name"} return Response(context, status=status.HTTP_400_BAD_REQUEST) if elements.count() == 0: context = {"error": "invalid element name"} return Response(context, status=status.HTTP_400_BAD_REQUEST) # Make a query and filter it out the database query = ~Q(id__in=used_ids) & Q(group__in=groups) & Q(elements__in=elements) samples = ( Compound.objects.filter(query) .order_by("?")[:requested_count] .select_related("group") ) count = Compound.objects.filter(query).count() # Check if the wanted conditions are correct if count == 0: context = {"error": "query returned no results"} return Response(context, status=status.HTTP_204_NO_CONTENT) # Return the results serializer = SendCompoundsSerializer(samples, many=True) context = {"data": serializer.data, "count": count} return Response(context, status=status.HTTP_200_OK) # If there is a problem, return bad request else: print(serializer.errors) context = {"error": "invalid request data"} return Response(context, status=status.HTTP_400_BAD_REQUEST)Here are the serializers:
# Serializer for the incomming requestsclass RequestCompoundsSerializer(serializers.Serializer): used_ids = serializers.ListField(child=serializers.IntegerField()) groups = serializers.ListField(child=serializers.CharField()) elements = serializers.ListField(child=serializers.CharField()) count = serializers.IntegerField(max_value=100, min_value=1) class Meta: fields = ("used_ids", "groups", "elements", "count")# Response of the server for the frontendclass SendCompoundsSerializer(serializers.ModelSerializer): class Meta: model = Compound fields = ("id", "formula", "name")