CODEWITHSUNDEEP
djangodjango-rest-framework
shaz
shaz

Reputation: 151

Django Rest Framework - User field may not be null

I am learning Django and Django Rest Framework to create an API and cannot wrap my head around why when i run this command:

http --json POST http://127.0.0.1:8000/api/v1/stocks/ book_code='Abook' 'Authorization: Token 123243434354353'

i get an error which says:

HTTP/1.0 400 Bad Request
Allow: GET, POST, HEAD, OPTIONS
Content-Type: application/json
Date: Thu, 25 May 2017 19:16:37 GMT
Server: WSGIServer/0.2 CPython/3.6.0
Vary: Accept
X-Frame-Options: SAMEORIGIN {
    "user": [
        "This field is required."
    ]}

The 'user' field is required but I am expecting it to populate with the user based on the token I have provided i.e the authenticated user.

This is the bookstock/models.py:

from django.db import models
from django.contrib.auth.models import User

class Stock(models.Model):
'''
Model representing the stock info.
'''
user = models.ForeignKey(User)
book_code = models.CharField(max_length=14, null=True, blank=True)

def __str__(self):
    return self.book_code

This is the api/serializer.py:

from bookstock.models import Stock
from rest_framework import serializers

class StockSerializer(serializers.ModelSerializer):

    class Meta:
        model = Stock
        fields = ('id', 'user', 'book_code')

This is the api/views.py:

from rest_framework import generics
from bookstock.models import Stock
from api.serializers import StockSerializer
from rest_framework.permissions import IsAuthenticated

class StockList(generics.ListCreateAPIView):
    serializer_class = StockSerializer
    permission_classes = (IsAuthenticated,)

    def get_queryset(self):
        user = self.request.user
        return Stock.objects.filter(user=user)

    def perform_create(self, serializer):
        serializer.save(user=self.request.user, )

    def perform_update(self, serializer):
        serializer.save(user=self.request.user)

This is the api/urls.py:

from django.conf.urls import url, include
from api import views
from rest_framework.authtoken.views import obtain_auth_token

urlpatterns = [
    url(r'^v1/stocks/$', views.StockList.as_view()),
    url(r'^v1/api-token-auth/', obtain_auth_token),
    url(r'v1/api-auth/', include('rest_framework.urls', namespace='rest_framework')),

]

What am I missing? Based on answers from SO, the perform_create and perform_update override should be populating the user right?

Upvotes: 2

Views: 1478

Answers (1)

Geotob
Geotob

Reputation: 2945

The perform_create method is called by your View's create method after serializer validation. At this stage, DRF will have found and flagged the missing user field: https://github.com/encode/django-rest-framework/blob/master/rest_framework/mixins.py#L14

There are multiple ways around that, ie setting the serializer field to read_only=True or overriding the validate_user method on the serializer.

The most elegant way I think is to use DRF's currentuserdefault validator: http://www.django-rest-framework.org/api-guide/validators/#currentuserdefault

user = serializers.HiddenField(default=serializers.CurrentUserDefault())

(replace HiddenField with CharField or whatever you prefer)

Upvotes: 2

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