spradio-server-django/savepointradio/profiles/signals.py

from django.conf import settings
from django.db.models import F
from django.db.models.signals import post_save
from django.dispatch import receiver

from .models import RadioProfile, SongRequest


@receiver(post_save, sender=settings.AUTH_USER_MODEL)
def create_profile(sender, instance, created, **kwargs):
    """
    Create a profile object after a new user is created and link them.
    """
    if created:
        profile, new = RadioProfile.objects.get_or_create(user=instance)


@receiver(post_save, sender=SongRequest)
def update_song_plays(sender, instance, created, update_fields, **kwargs):
    """
    Update the song data with the latest play time and the number of times
    played.
    """
    if not created and update_fields:
        if 'played_at' in update_fields:
            song = instance.song
            song.last_played = instance.played_at
            song.num_played = F('num_played') + 1
            song.save()