How to only perform action once instance created-CodePudding

my code:

def save(self, *args, **kwargs):
  <My_CODE>
  if <having_register>:
    <send_email_to_admin>

but this function will work when I run an update instance ( The 'force_insert' and 'force_update' parameters can be used to insist that the "save" must be an SQL insert or update ) so if I just want to send an email to admin only once having a new registration? Any way to check the request method or prevent force_insert in this case?

CodePudding user response：

You can check the value of the pk:

def save(self, *args, **kwargs):
  <My_CODE>
  if self.pk is None:
    <send_email_to_admin>

Otherwise you could send the email in the view after having called save.

CodePudding user response：

Another way you can solve this is by using django signals, and use the post_save signal and check the created parameter. A good example for django signals could be this one here, it shows the setup needed for django signals to work.

from django.db.models.signals import post_save
from django.dispatch import receiver

from yourApp.models import yourModel

@receiver(post_save, sender=yourModel)
def new_instance_created(sender, instance, created, **kwargs):
    if created:
       <send_email_to_admin>