CODEWITHSUNDEEP
djangodjango-admindjango-users
rptfrg
rptfrg

Reputation: 113

Erroneous custom field of the one-to-one User model in the Admin Panel

I created the custom Subscriber one-to-one model to extend the existing Django's User model. (I know that it's better to use an AbstractUser, but I just wanted to try this out for the sake of learning)

I can create a new User successfully through the shell, and I can edit (in the admin panel) the custom fields that User has after the creation. However, I can't create new users in the admin panel without the usage of shell, because of an error.

I suppose there is something wrong with admin.py?

Error:

IntegrityError at /admin/auth/user/add/

UNIQUE constraint failed: app_subscriber.user_id

models.py

from django.db import models
from django.contrib.auth.models import User
from django.db.models.signals import post_save
from django.dispatch import receiver


class Subscriber(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE)
    location = models.CharField(max_length=30, blank=True)


@receiver(post_save, sender=User)
def create_user_subscriber(sender, instance, created, **kwargs):
    if created:
        Subscriber.objects.create(user=instance)


@receiver(post_save, sender=User)
def save_user_subscriber(sender, instance, **kwargs):
    instance.subscriber.save()

admin.py

from django.contrib import admin
from django.contrib.auth.admin import UserAdmin as BaseUserAdmin
from django.contrib.auth.models import User

from . import models


# Define an inline admin descriptor for Subscriber model
# which acts a bit like a singleton
class SubscriberInline(admin.StackedInline):
    model = models.Subscriber
    can_delete = False
    verbose_name_plural = 'subscribers'

# Define a new User admin
class UserAdmin(BaseUserAdmin):
    inlines = (SubscriberInline,)

# Re-register UserAdmin
admin.site.unregister(User)
admin.site.register(User, UserAdmin)

Upvotes: 0

Views: 84

Answers (1)

rgermain
rgermain

Reputation: 708

is not good to create tow same signal ( post_save for User), create only one and do all things on it

@receiver(post_save, sender=User)
def create_user_subscriber(sender, instance, created, **kwargs):
    if created:
        Subscriber.objects.create(user=instance)


@receiver(post_save, sender=User)
def save_user_subscriber(sender, instance, **kwargs):
    instance.subscriber.save()

Your error tell you can't create 2 subriber with same user ( UNIQUE constraint )

this slove your probleme

@receiver(post_save, sender=User)
def create_user_subscriber(sender, instance, created, **kwargs):
    # you check if instance are 'subscriber' related name create by OneToOneField , if not create Subcriber model
    if created and not hasattr(instance, 'subscriber'):
        Subscriber.objects.create(user=instance)

Upvotes: 1

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