I'm wondering whether it's possible to selectively suppress a Django signal (such as post_save
or post_init
) on object creation, or, alternatively, send it certain parameters.
What I have is a User
object, which can be created in many different ways and places in my code. So to automatically assign a custom Profile
object to each User
, I use the post_save
signal. However, in one specific case, there is extra information that I want to bind to the created Profile
object. Passing it as arguments to the post_save
signal would be great, but it doesn't look possible.
The other option is to manually create the Profile
object, but then I need to that after the User
is saved, otherwise the Profile
cannot be bound to a User
instance. Saving the User
instance, however, results in another Profile
being created via the function called by the signal.
And I can't just get the just-created Profile
object, since that results in a 'Profile' object is unsubscriptable
error. Any advice?
Update:
Here is an example of a possible situation:
def createUserProfile(sender, instance, created, **kwargs):
if created:
profile, created = Profile.objects.get_or_create(user=instance)
if extra_param:
profile.extra_param = extra_param
profile.save()
post_save.connect(createUserProfile, sender=User)
def signup(request):
...
extra_param = 'param'
user.save()
How do I get the variable extra_param
in the signup
method to the createUserProfile method, where it is to be stored as part of the Profile
object?
There are 3 types of signal. pre_save/post_save: This signal works before/after the method save(). pre_delete/post_delete: This signal works before after delete a model's instance (method delete()) this signal is thrown.
To answer directly: No. It's sync.
Django Signals - post_delete()To notify another part of the application after the delete event of an object happens, you can use the post_delete signal.
Why this doesn't work for you?
user = User(...)
user.save()
# profile has been created transparently by post_save event
profile = user.profile
profile.extra_stuff = '...'
profile.save()
If you are obsessed with parameters passing to event, possible but evil:
user = User()
user._evil_extra_args = { ... }
user.save()
In event:
extra_args = getattr(user, '_evil_extra_args', False)
It is evil because people who will read your code will have no idea what the heck those _evil_extra_args is for and how does it work.
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