69.1. Superuser username mismatch

The first issue arises when a superuser has a username that is not an email address, preventing them from logging in via the site's login forms, which are designed to accept email inputs only.

To resolve this, we will create a file named signals.py within our store app directory. This file is designed to handle notifications for specific events within the codebase. Inside this file, we will implement the following solution:

signals.py

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

@receiver(post_save, sender=User)
def ensure_client_for_superuser(sender, instance, created, **kwargs):
    if created and instance.is_superuser:  # Check if the user is a superuser
        if not hasattr(instance, 'client'):  # Ensure the superuser has a Client
            Client.objects.create(
                user=instance,
                email=instance.email,  # Use the superuser's email
                name=instance.username  # Use the superuser's username as the name
            )
    if instance.is_superuser and instance.username != instance.email:  # Ensure username matches email
        instance.username = instance.email
        # Prevent recursion by disconnecting the signal temporarily
        post_save.disconnect(ensure_client_for_superuser, sender=User)
        instance.save()
        post_save.connect(ensure_client_for_superuser, sender=User)

• Purpose: Automatically manage Client model instances for superuser accounts in the Django application.

• Signal Trigger:

  • Uses the post_save signal from Django's User model.

  • Triggered after a User instance is saved.

• Signal Handler: ensure_client_for_superuser function.

• Logic Overview:

  • For New Superusers:

    • When a new superuser is created, checks if it has an associated Client.

    • If not, creates a Client with:

      • email from the superuser's email.

      • name from the superuser's username.

  • Username-Email Consistency:

    • Ensures that the superuser's username matches their email.

    • If mismatched, updates the username to the value of email.

• Recursion Prevention:

  • Temporarily disconnects the post_save signal to prevent infinite recursion when instance.save() is called.

  • Reconnects the signal after the save operation.

• Edge Cases Handled:

  • Avoids creating duplicate Client instances for existing superusers.

  • Prevents signal recursion when updating the username.

This ensures a consistent relationship between superuser accounts and Client records while maintaining data integrity.

Next, in the apps.py file, update the StoreConfig class to include a reference to the signals.py file, as shown below:

apps.py

class StoreConfig(AppConfig):
    default_auto_field = 'django.db.models.BigAutoField'
    name = 'store'

    def ready(self):
        import store.signals  

With this change, the superuser's username will automatically be set to their email address, ensuring consistency and preventing any login issues.