CODEWITHSUNDEEP
djangodjango-rest-frameworkdjango-serializer
skassi
skassi

Reputation: 138

How to update an existing record in Django?

I am trying to update an existing record in Django but whenever I PUT request with postman I get the following.

Postman Request

It says that it already exists. So i tried to assign

task_1 = Task.objects.get(pk=task_id)
task_1 = ser

But I get an error that i can't assign it

===============================

My current code:

models.py and urls.py

class TaskView(APIView):

    permission_classes = (IsAuthenticated,)

        def put(self, request, task_id):
        task_obj = find_task(request.auth, task_id)
        if task_obj:
            task = task_obj.data
            my_data = json.loads(request.body)
            keys = list(my_data.keys())

            for key in keys:
                task[key] = my_data[key]

            ser = TaskSerializer(data=task)
            ser.is_valid(raise_exception=True)
            ser.save()

            return Response(ser.data)
        else:
            return Response(status=status.HTTP_404_NOT_FOUND)

# Returns the task only if its assigned to current user
def find_task(token, task_id):
    u_id = Token.objects.get(key=token).user_id
    assign_to = AssignTo.objects.filter(task_id=task_id, user_id=u_id)
    if len(assign_to) > 0:
        task = Task.objects.get(pk=task_id)
        serializer = TaskSerializer(task)
        return serializer
    else:
        return False

I believe it has nothing to do with the method i use ( POST, PUT, PATCH) because it works perfect when I comment out this part of code:

            # ser = TaskSerializer(data=task)
            # print(ser)
            # ser.is_valid(raise_exception=True)
            # ser.save()

            return Response(task)

So it's something with serialization and task Instances

===============================

SECOND VERSION OF MY CODE:

    def put(self, request, task_id):
        u_id = Token.objects.get(key=request.auth).user_id
        assign_to = AssignTo.objects.filter(task_id=task_id, user_id=u_id)

        if len(assign_to) > 0:
            task = Task.objects.get(pk=task_id)
            my_data = json.loads(request.body)
            keys = list(my_data.keys())

            for key in keys:
                task[key] = my_data[key]

            print(task)
            return Response(task)
        else:
            return Response(status=status.HTTP_404_NOT_FOUND)

The error I get from my SECOND VERSION of code is : TypeError: 'Task' object does not support item assignment

So how do I update JUST the given keys from the request body.

Upvotes: 0

Views: 1628

Answers (1)

skassi
skassi

Reputation: 138

So the solution was pretty simple.

I just had to add some args inside the save function => task.save(update_fields=keys)

This is my working code:

    def put(self, request, task_id):
        # task = Task.objects.get(pk=task_id)
        # Task is the returned Model value
        task = find_task(request.auth, task_id)
        if task:
            my_data = json.loads(request.body)
            keys = list(my_data.keys())

            for key in keys:
                setattr(task, key, my_data[key])

            task.save(update_fields=keys)
            ser = TaskSerializer(task)
            return Response(ser.data)
        else:
            return Response(status=status.HTTP_404_NOT_FOUND)

Upvotes: 1

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