Issue

This Content is from Stack Overflow. Question asked by rediet yosef

I am trying to implement an attendance system as part of a bigger project that handles multiple schools at the same time, I am trying to get some user details from the user that is being marked as present, absent, or on leave

serializer.py

class AttendanceSerializer(serializers.ModelSerializer):

class Meta:
    model = Attendance
    fields = ['user', 'Presence', 'leave_reason', 'Date']
    constraints = [
        UniqueConstraint(
            fields=('user', 'Date'), name='unique_attendance_once_per_date')
    ]

def create(self, validated_data):
    instance = Attendance.objects.create(
        user=validated_data['user'],
        Presence=validated_data['Presence'],
        leave_reason=validated_data['leave_reason'],
        attendance_taker=self.context['request'].user,
        Date=datetime.today
    )
    instance.save()
    return instance

my current implementation of the view:

class AttendanceListCreateAPIView(CreateAPIView):
permission_classes = [IsClassPart]
queryset = Attendance.objects.all()
serializer_class = AttendanceSerializer

def post(self, request, format=None):
    user = request.user
    try:
        perms = Perm.objects.get(user=user)
    except ObjectDoesNotExist:
        perms = None
    serializer = AttendanceSerializer(data=request.data)
    if serializer.is_valid():
        if user.role == "TEACHER":
            if user.homeroom == request.data['user'].room:
                Response({"message": "You don't have permission to perform this action 1"},
                            status=status.HTTP_400_BAD_REQUEST)
            return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
        elif perms is not None:
            if user.role != 'STUDENT' and user.perms.is_monitor:
                if user.room != request.data['user'].room:
                    Response({"message": "You don't have permission to perform this action 2"},
                             status=status.HTTP_400_BAD_REQUEST)
                serializer.save()
                return Response(serializer.data, status=status.HTTP_201_CREATED)
        else:
            return Response({"message": "You don't have permission to perform this action 3"}, status=status.HTTP_400_BAD_REQUEST)
    return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

the error is in request.data['user'].room: as django says 'str' object has no attribute 'room'

Solution

Try to access to serializer.validated_data for getting user instance:

    if serializer.is_valid():
        if user.role == "TEACHER":
            if user.homeroom == serializer.validated_data['user'].room:
                Response({"message": "You don't have permission to perform this action 1"},
                            status=status.HTTP_400_BAD_REQUEST)
            return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
        elif perms is not None:
            if user.role != 'STUDENT' and user.perms.is_monitor:
                if user.room != serializer.validated_data['user'].room:
                    Response({"message": "You don't have permission to perform this action 2"},
                             status=status.HTTP_400_BAD_REQUEST)
                serializer.save()
                return Response(serializer.data, status=status.HTTP_201_CREATED)
        else:
            return Response({"message": "You don't have permission to perform this action 3"}, status=status.HTTP_400_BAD_REQUEST)

Your request.data contains only data sent to the view in str variables. validated_data contains cleaned data from serializer with retrieve instance associated to foreign key if your model is correctly set

This Question was asked in StackOverflow by rediet yosef and Answered by Lucas Grugru It is licensed under the terms of CC BY-SA 2.5. - CC BY-SA 3.0. - CC BY-SA 4.0.