How to filter Serializers in DjangoRestFramework based on user id? - python-3.x

Question

I'm new to django,
I can't seem to find how to return an api based on the user who requested it and created the Transaction object, can you please guide me through? I have read this, but I can't find a clear guide in the docs to update the Serializer straightaway.
In laravel, I can do:
Transaction::where('user_id', Auth::user()->id)->get();
This is my serializer:
class TransactionSerializer(serializers.HyperlinkedModelSerializer):
user = UserSerializer(read_only=True)
tags = TagShortSerializer(read_only=True, many=True)
def get_fields(self, *args, **kwargs):
# Override this method so that the list of DatabaseUsers presented in the browseable API
# is restricted to the DatabaseUsers owned by the current user.
fields = super(TransactionSerializer, self).get_fields(*args, **kwargs)
view = self.context["view"]
user = view.request.user
return Transaction.objects.filter(user=user)
class Meta:
model = Transaction
fields = ["user", "title", "amount", "category", "tags"]
My viewset:
class TransactionViewSet(viewsets.ModelViewSet):
queryset = Transaction.objects.all()
serializer_class = TransactionSerializer
permission_classes = [permissions.IsAuthenticated, IsOwner]
Currently it returns:
Complete traceback:
Environment:
Request Method: GET
Request URL: http://127.0.0.1:8000/transactions/
Django Version: 3.2.5
Python Version: 3.9.5
Installed Applications:
['djmoney',
'rest_framework',
'finance.apps.FinanceConfig',
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.common.CommonMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware']
Traceback (most recent call last):
File "E:\Development\Python\sharkware-api\.venv\lib\site-packages\django\core\handlers\exception.py", line 47, in inner
response = get_response(request)
File "E:\Development\Python\sharkware-api\.venv\lib\site-packages\django\core\handlers\base.py", line 181, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "E:\Development\Python\sharkware-api\.venv\lib\site-packages\django\views\decorators\csrf.py", line 54, in wrapped_view
return view_func(*args, **kwargs)
File "E:\Development\Python\sharkware-api\.venv\lib\site-packages\rest_framework\viewsets.py", line 125, in view
return self.dispatch(request, *args, **kwargs)
File "E:\Development\Python\sharkware-api\.venv\lib\site-packages\rest_framework\views.py", line 509, in dispatch
response = self.handle_exception(exc)
File "E:\Development\Python\sharkware-api\.venv\lib\site-packages\rest_framework\views.py", line 469, in handle_exception
self.raise_uncaught_exception(exc)
File "E:\Development\Python\sharkware-api\.venv\lib\site-packages\rest_framework\views.py", line 480, in raise_uncaught_exception
raise exc
File "E:\Development\Python\sharkware-api\.venv\lib\site-packages\rest_framework\views.py", line 506, in dispatch
response = handler(request, *args, **kwargs)
File "E:\Development\Python\sharkware-api\.venv\lib\site-packages\rest_framework\mixins.py", line 43, in list
return self.get_paginated_response(serializer.data)
File "E:\Development\Python\sharkware-api\.venv\lib\site-packages\rest_framework\serializers.py", line 745, in data
ret = super().data
File "E:\Development\Python\sharkware-api\.venv\lib\site-packages\rest_framework\serializers.py", line 246, in data
self._data = self.to_representation(self.instance)
File "E:\Development\Python\sharkware-api\.venv\lib\site-packages\rest_framework\serializers.py", line 663, in to_representation
return [
File "E:\Development\Python\sharkware-api\.venv\lib\site-packages\rest_framework\serializers.py", line 664, in <listcomp>
self.child.to_representation(item) for item in iterable
File "E:\Development\Python\sharkware-api\.venv\lib\site-packages\rest_framework\serializers.py", line 500, in to_representation
for field in fields:
File "E:\Development\Python\sharkware-api\.venv\lib\site-packages\rest_framework\serializers.py", line 361, in _readable_fields
for field in self.fields.values():
File "E:\Development\Python\sharkware-api\.venv\lib\site-packages\django\utils\functional.py", line 48, in __get__
res = instance.__dict__[self.name] = self.func(instance)
File "E:\Development\Python\sharkware-api\.venv\lib\site-packages\rest_framework\serializers.py", line 349, in fields
for key, value in self.get_fields().items():
Exception Type: AttributeError at /transactions/
Exception Value: 'QuerySet' object has no attribute 'items'

Answer 1

That is not the correct usage for get_fields. That method returns the list of fields to be used when instantiating the serializer.
What you want is to override get_queryset on your viewset:
class TransactionViewSet(viewsets.ModelViewSet):
queryset = Transaction.objects.all()
serializer_class = TransactionSerializer
permission_classes = [permissions.IsAuthenticated, IsOwner]
def get_queryset(self):
if self.request.user.is_authenticated:
return self.queryset.filter(user=self.request.user)
return Transaction.objects.none()