'str' object is not callable Django Rest Framework

Question

I'm trying to create an API view but I'm getting an error. Can anyone help?

urls.py:

app_name = 'ads'
urlpatterns = [
    # ex: /ads/
    url(r'^$', views.ListBrand.as_view(), name='brand_list'),
]

views.py:

from rest_framework.views import APIView
from rest_framework.response import Response
from . import models
from . import serializers


class ListBrand(APIView):
    def get(self, request, format=None):
        brands = models.Brand.objects.all()
        serializer = serializers.BrandSerializer(brands, many=True)
        data = serializer.data
        return Response(data)

UPDATE: HERE IS THE ERROR, it is a string error. And I can't seem to find where its coming from.

TypeError at /api/v1/ads/
'str' object is not callable
Request Method: GET
Request URL:    http://localhost/api/v1/ads/
Django Version: 1.10.2
Exception Type: TypeError
Exception Value:    
'str' object is not callable
Exception Location: C:\Users\Leon\Desktop\esriom\lib\site-packages\rest_framework\views.py in <listcomp>, line 264
Python Executable:  C:\Users\Leon\Desktop\esriom\Scripts\python.exe
Python Version: 3.5.2
Python Path:    
['C:\\Users\\Leon\\Desktop\\esirom',
 'C:\\Users\\Leon\\Desktop\\esriom\\lib\\site-packages\\setuptools-18.1-py3.5.egg',
 'C:\\Users\\Leon\\Desktop\\esriom\\lib\\site-packages\\pip-7.1.0-py3.5.egg',
 'C:\\Users\\Leon\\Desktop\\esriom\\Scripts\\python35.zip',
 'C:\\Users\\Leon\\AppData\\Local\\Programs\\Python\\Python35-32\\DLLs',
 'C:\\Users\\Leon\\AppData\\Local\\Programs\\Python\\Python35-32\\lib',
 'C:\\Users\\Leon\\AppData\\Local\\Programs\\Python\\Python35-32',
 'C:\\Users\\Leon\\Desktop\\esriom',
 'C:\\Users\\Leon\\Desktop\\esriom\\lib\\site-packages']
Server time:    Fri, 7 Oct 2016 12:44:04 -0500

HERE IS THERE TRACEBACK TOO

Environment:


Request Method: GET
Request URL: http://localhost/api/v1/ads/

Django Version: 1.10.2
Python Version: 3.5.2
Installed Applications:
['rest_framework',
 'ads.apps.AdsConfig',
 '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:

File "C:\Users\Leon\Desktop\esriom\lib\site-packages\django\core\handlers\exception.py" in inner
  39.             response = get_response(request)

File "C:\Users\Leon\Desktop\esriom\lib\site-packages\django\core\handlers\base.py" in _get_response
  187.                 response = self.process_exception_by_middleware(e, request)

File "C:\Users\Leon\Desktop\esriom\lib\site-packages\django\core\handlers\base.py" in _get_response
  185.                 response = wrapped_callback(request, *callback_args, **callback_kwargs)

File "C:\Users\Leon\Desktop\esriom\lib\site-packages\django\views\decorators\csrf.py" in wrapped_view
  58.         return view_func(*args, **kwargs)

File "C:\Users\Leon\Desktop\esriom\lib\site-packages\django\views\generic\base.py" in view
  68.             return self.dispatch(request, *args, **kwargs)

File "C:\Users\Leon\Desktop\esriom\lib\site-packages\rest_framework\views.py" in dispatch
  457.         request = self.initialize_request(request, *args, **kwargs)

File "C:\Users\Leon\Desktop\esriom\lib\site-packages\rest_framework\views.py" in initialize_request
  364.             authenticators=self.get_authenticators(),

File "C:\Users\Leon\Desktop\esriom\lib\site-packages\rest_framework\views.py" in get_authenticators
  264.         return [auth() for auth in self.authentication_classes]

File "C:\Users\Leon\Desktop\esriom\lib\site-packages\rest_framework\views.py" in <listcomp>
  264.         return [auth() for auth in self.authentication_classes]

Exception Type: TypeError at /api/v1/ads/
Exception Value: 'str' object is not callable

You're making us guess where the error is happening. Please post the entire error traceback, including the line of code where the error actually occurs. — John Gordon
– John Gordon, Commented Oct 7, 2016 at 18:16
Do you have a __str__(self) function in your model? Like this: docs.djangoproject.com/en/1.10/ref/models/instances/#str — 1GDST
– 1GDST, Commented Oct 7, 2016 at 18:26
What's the value of REST_FRAMEWORK['DEFAULT_AUTHENTICATION_CLASSES'] in your settings.py? — Philip Tzou
– Philip Tzou, Commented Oct 7, 2016 at 18:40

Matt Seymour · Accepted Answer · 2017-06-11 10:48:06Z

22

My problem was in my settings.py file:

Diff:

    REST_FRAMEWORK = {
-       'DEFAULT_AUTHENTICATION_CLASSES': {
+       'DEFAULT_AUTHENTICATION_CLASSES': (
            'rest_framework.authentication.SessionAuthentication',
-        }
+        ),
-        'DEFAULT_PERMISSION_CLASSES': {
+        'DEFAULT_PERMISSION_CLASSES': (
            'rest_framework.permissions.IsAuthenticatedOrReadOnly',
-        },
+        ),
    }

edited Jun 11, 2017 at 10:48

Matt Seymour

9,4437 gold badges64 silver badges106 bronze badges

answered Oct 7, 2016 at 19:00

Leon Wright

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4 Comments

Philip Tzou Over a year ago

Good to know you located the problem. The problem is because of this if condition: github.com/tomchristie/django-rest-framework/blob/3.4.7/…, which only considers list and tuple but not set.

Matthew Hegarty Over a year ago

the difference is the curly braces in case anyone spends a few minutes scrutinising the differences!

Nick T Over a year ago

Ugh, derp. I wonder why tuples are preferred in Django settings; some tiny constant time/space savings over a list?

Nick T Over a year ago

Oh, not since Dj 1.9 but it seems DRF didn't get the memo in its docs :P

Steven · Accepted Answer · 2018-07-13 11:41:23Z

Just want to give an example from the previous correct answers with Django v2.0.6 and Django REST framework v3.8.2.

For example in settings.py:

REST_FRAMEWORK = {
        'DEFAULT_AUTHENTICATION_CLASSES': {
            'rest_framework.authentication.BasicAuthentication',
            'rest_framework.authentication.SessionAuthentication',
            }
    }

Change:

'DEFAULT_AUTHENTICATION_CLASSES': {
                'rest_framework.authentication.BasicAuthentication',
                'rest_framework.authentication.SessionAuthentication',
                }

Into:

'DEFAULT_AUTHENTICATION_CLASSES': (
                'rest_framework.authentication.BasicAuthentication',
                'rest_framework.authentication.SessionAuthentication',
                )

By just replacing the "{ }" with "( )".

abdelrahman aboneda · Accepted Answer · 2022-10-23 21:21:19Z

2

if you are using simple_jwt also check this , don't use these brackets {} but () and add comma at the end

    SIMPLE_JWT = {
   'AUTH_HEADER_TYPES': ('JWT',),
   'ACCESS_TOKEN_LIFETIME': timedelta(minutes=100),
#    'ROTATE_REFRESH_TOKENS': False,
#    'BLACKLIST_AFTER_ROTATION': False,
#    'UPDATE_LAST_LOGIN': False,
     'AUTH_TOKEN_CLASSES': ('rest_framework_simplejwt.tokens.AccessToken',),
}

edited Oct 23, 2022 at 21:21

answered Oct 23, 2022 at 21:20

abdelrahman aboneda

99010 silver badges10 bronze badges

Comments

Fadex022 · Accepted Answer · 2021-07-11 20:24:19Z

0

just replace {} by () in settings.py REST_FRAMEWORK

answered Jul 11, 2021 at 20:24

Fadex022

112 bronze badges

1 Comment

Simas Joneliunas Over a year ago

Could you clarify on why this would fix the issue?

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