更新 Django 中的序列化程序数据

Question

I'm trying to add a dictionary to my serialized data but I'm getting an error dictionary update sequence element #0 has length 6; 2 is required dictionary update sequence element #0 has length 6; 2 is required

This is what I have tried:

def get_data(self, request):

    created_by = User_Detail.objects.get(auth_token__isnull=False)
    newdict = {'created_by': created_by.id}
    details = ExSerializer(Tower.objects.all(), many=True).data
    newdict.update(details)
    return Response({"expenses": newdict})

I tried the above code but it's not working for me.

Answer 1

The root cause of this issue is you are trying to update a dictionary with a list.

The minimal code to simulate this issue:

d = {1: "one", 2: "three"}
d.update([(1,)])

will gives an error of

Traceback (most recent call last):
  File "<stdin>", line 3, in <module>
    d.update([(1,)])
ValueError: dictionary update sequence element #0 has length 1; 2 is required

For your case, you are updating newdict with a list coming from ExSerializer ( Tower.objects.all() with many=True ).

To solve this, you will need to adjust your code to extract only one record from Tower , or make a list of results that combine each user to one Tower record, depends on your exact use case.

-- EDIT --

If you want all records of Tower in one request, you will need to apply multiple serializers.

The code will be similar to this (not tested):

def get_data(self, request):
    created_by = User_Detail.objects.get(auth_token__isnull=False)
    return Response({"expenses": UserDetailSerializer({"created_by": created_by}).data})


class UserDetailSerializer(serializers.ModelSerializer):
    created_by = serializers.IntegerField()
    details = serializers.SerializerMethodField()

    class Meta:
        model = User_Detail
        fields = ('created_by', 'details')

    def get_details(self, obj):
        return ExSerializer(Tower.objects.all(), many=True).data