Django REST Framework (DRF): Set current user id as field value - django

Question

I have model NewsModel and 2 serializers for him:
models.py
class NewsModel(models.Model):
title = models.CharField('Заголовок', max_length=255, help_text='Максимальная длина - 255 символов')
announce = models.TextField('Анонс', help_text='Краткий анонс новости')
author = models.ForeignKey(settings.AUTH_USER_MODEL, help_text='Автор новости', related_name='news')
full_text = models.TextField('Полный текст новости', help_text='Полный текст новости')
pub_date = models.DateTimeField('Дата публикации', auto_now_add=True, default=timezone.now, help_text='Дата публикации')
def comments_count(self):
return NewsComment.objects.filter(news=self.id).count()
def get_author_full_name(self):
return self.author.get_full_name()
class Meta:
db_table = 'news'
ordering = ('-pub_date',)
serilizers.py:
from rest_framework import serializers
from .models import NewsModel
from extuser.serializers import UserMiniSerializer
class NewsReadSerializer(serializers.ModelSerializer):
author = UserMiniSerializer()
class Meta:
model = NewsModel
fields = ('id', 'title', 'announce', 'comments_count', 'reviews', 'author_name')
def get_author_full_name(self, obj):
return obj.get_author_full_name()
class NewsWriteSerializer(serializers.ModelSerializer):
def validate_author(self, value):
value = self.request.user.id
return value
class Meta:
model = NewsModel
I select serializers in the api.py:
class NewsList(ListCreateAPIView):
queryset = NewsModel.objects.order_by('-pub_date')
def get_serializer_class(self, *args, **kwargs):
if self.request.method == 'GET':
return NewsReadSerializer
return NewsWriteSerializer
class Meta:
model = NewsModel
But when I will create NewsModel item, I see Error 400: Bad request [{'author': 'This field is required'}]
How I can set current user id as NewsItem.author value on creating new item?

Answer 1

I don't think you're using the serializer properly. A better practice to set request related data is to override perform_create in your view:
def perform_create(self, serializer):
serializer.save(author=self.request.user)
def perform_update(self, serializer):
serializer.save(author=self.request.user)
and then set your author serializer to read-only:
author = UserMiniSerializer(read_only=True)
this way you can simply use one single NewsSerializer for both read and write actions.

Answer 2

In new DRF you can write
owner = serializers.HiddenField(
default=serializers.CurrentUserDefault()
)
See http://www.django-rest-framework.org/api-guide/validators/#currentuserdefault

Answer 3

In DRF version prior 3 field must be declader with allow_null=True and default=None. DRF don't run checking fields without this params. Result code:
class NewsReadSerializer(serializers.ModelSerializer):
"""
Serializer only for reading.
author field serialized with other custom serializer
"""
author = UserMiniSerializer()
class Meta:
model = NewsModel
fields = ('id', 'title', 'announce', 'comments_count', 'reviews', 'author', 'pub_date',)
class NewsWriteSerializer(serializers.ModelSerializer):
"""
Serializer for creating and updating records.
author here is the instance of PrimaryKeyRelatedField, linked to all users
"""
author = serializers.PrimaryKeyRelatedField(
queryset=User.objects.all(), # Or User.objects.filter(active=True)
required=False,
allow_null=True,
default=None
)
# Get the current user from request context
def validate_author(self, value):
return self.context['request'].user
class Meta:
model = NewsModel
fields = ('title', 'announce', 'full_text', 'author',)

Answer 4

I would try something like this:
your models.py
class NewsModel(models.Model):
title = models.CharField(
'Заголовок', max_length=255,
help_text='Максимальная длина - 255 символов')
announce = models.TextField('Анонс',
help_text='Краткий анонс новости')
author = models.ForeignKey(
settings.AUTH_USER_MODEL,
help_text='Автор новости', related_name='news')
full_text = models.TextField(
'Полный текст новости',
help_text='Полный текст новости')
pub_date = models.DateTimeField(
'Дата публикации', auto_now_add=True,
default=timezone.now, help_text='Дата публикации')
def comments_count(self):
return NewsComment.objects.filter(news=self.id).count()
def get_author_full_name(self):
return self.author.get_full_name()
class Meta:
db_table = 'news'
ordering = ('-pub_date',)
serializers.py
(ref.: http://www.django-rest-framework.org/api-guide/validators/#currentuserdefault)
from <yourapp>.models import NewsModel
from rest_framework import serializers
class NewsModelSerializer(serializers.ModelSerializer):
author = serializers.HiddenField(default=serializers.CurrentUserDefault())
class Meta:
model = NewsModel
Also you should set settings.py to something like this:
REST_FRAMEWORK = {
'DEFAULT_PERMISSION_CLASSES': (
'rest_framework.permissions.IsAuthenticated',)
}