Django update modelform with field constraints - django

Question

Having the following Model:
class Book(models.Model):
name = models.CharField()
author = models.CharField()
date = models.DateField()
class Meta:
unique_together = ('name', 'author')
class BookSerializerWrite(serializers.ModelSerializer):
class Meta:
model = Book
class BookView(ApiView):
def put(self, request, *args, **kwargs):
serializer = BookSerializerWrite(data=request.data)
if serializer.is_valid():
serializer.save()
The view above does not work as the serializer.is_valid() is False.
The message is:
'The fields name, author must make a unique set'
Which is the constraint of the model.
How do I update the model?
I would rather not override the serializer's validation method.
I also cannot access the validated_data for an update as in
https://www.django-rest-framework.org/api-guide/serializers/#saving-instances
as this is empty due to the fact that the form does not validate.
Is there a builtin solution?

Answer 1

You can achieve it using UpdateAPIview
serializers.py
class BookSerializer(serializers.ModelSerializer):
class Meta:
model = Book
fields = ('name', 'author', 'date')
views.py
from rest_framework.generics import UpdateAPIview
from .serializers import BookSerializer
class BookUpdateView(UpdateAPIView):
serializer_class = BookSerializer
urls.py
from django.urls import path
from . import views
url_patterns = [
path('api/book/<int:pk>/update/', views.BookUpdateView.as_view(), name="book_update"),
]
Now, post your data to above url. It should work.
Reference: https://github.com/encode/django-rest-framework/blob/master/rest_framework/generics.py