Django REST - AssertionError: `fields` must be a list or tuple
django-rest-framework, python
Solution
You need to use a tuple or list for `fields`, to represent a tuple with single item you need to use a trailing comma:
fields = ('test', )
Without a comma `fields = ('test')` is actually equivalent to `fields = 'test'`.
From docs:
A special problem is the construction of tuples containing 0 or 1 items: the syntax has some extra quirks to accommodate these. Empty tuples are constructed by an empty pair of parentheses; a tuple with one item is constructed by following a value with a comma (it is not sufficient to enclose a single value in parentheses). Ugly, but effective.
Problem
When querying Django via REST using the Django REST framework I get the error, ``` File "/folder/pythonenv/project/lib/python2.7/site-packages/rest_framework/serializers.py", line 241, in get_fields assert isinstance(self.opts.fields, (list, tuple)), '`fields` must be a list or tuple' AssertionError: `fields` must be a list or tuple ``` My settings are.... settings.py ``` THIRD_PARTY_APPS = ( 'south', # Database migration helpers: 'crispy_forms', # Form layouts 'rest_framework', ) REST_FRAMEWORK = { 'DEFAULT_PERMISSION_CLASSES': ( 'rest_framework.permissions.AllowAny', ) } ``` views ``` from django.shortcuts import render from rest_framework import viewsets from quickstart.serializers import from quickstart.serializers import TicketInputSerializer from models import Abc class TicketInputViewSet(viewsets.ModelViewSet): queryset = Abc.objects.all() serializer_class = TicketInputSerializer ``` urls.py ``` router = routers.DefaultRouter() router.register(r'ticket', views.TicketViewSet) urlpatterns = patterns('', url(r'^', include(router.urls)), url(r'^test', include('rest_framework.urls', namespace='rest_framework')), ) ``` Serializers ``` from models import Abc from django.contrib.auth.models import User, Group from rest_framework import serializers class TicketInputSerializer(serializers.HyperlinkedModelSerializer): class Meta: model = Abc fields = ('test',) ``` Models ``` from django.db import models class Abc(models.Model): test = models.CharField(max_length=12) ``` Any ideas ?