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Maybe it's just late, but I cannot figure out why this isn't working. When I have a post_save signal call a generic function, it works, but when I have a post_save signal call a method from a model, nothing happens. Here is code that works:
class Revision(models.Model): # Model junk... def send_email(sender, instance, created, **kwargs): if created: print "DO STUFF" signals.post_save.connect(send_email, sender=Revision) But this does not work:
class Revision(models.Model): # Model junk... def send_email(sender, instance, created, **kwargs): if created: print "DO STUFF" signals.post_save.connect(Revision.send_email, sender=Revision) Is there a kind soul out there who will keep me from smashing my head into the wall? Thanks.
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There are two ways to send signals in Django. To send a signal, call either Signal. send() (all built-in signals use this) or Signal. send_robust() .
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.
pre_save. This is sent at the beginning of a model's save() method. Arguments sent with this signal: sender.
The post_save logic is just a normal function, the receiver function, but it's connected to a sender, which is the Order model. The code block below demonstrates the sample receiver function as a post-save. 1from django. db. models.
It seems to me that the problem in the second one is you are using an unbounded method send_mail. If you really want to call send_mail from within a class, maybe @classmethod or @staticmethod will help you out:
class Revision(models.Model): # Model junk... @classmethod def send_email(cls, sender, instance, created, **kwargs): if created: print "DO STUFF" signals.post_save.connect(Revision.send_email, sender=Revision) or
class Revision(models.Model): # Model junk... @staticmethod def send_email(sender, instance, created, **kwargs): if created: print "DO STUFF" signals.post_save.connect(Revision.send_email, sender=Revision) Alternatively without using these decorators, you can pass the bounded instance method:
class Revision(models.Model): # Model junk... def send_email(self, sender, instance, created, **kwargs): if created: print "DO STUFF" signals.post_save.connect(Revision().send_email, sender=Revision) References:
From the Django source code:
def connect(self, receiver, sender=None, weak=True, dispatch_uid=None): """ Connect receiver to sender for signal. Arguments: receiver A function or an instance method which is to receive signals. Receivers must be hashable objects. If weak is True, then receiver must be weak-referencable (more precisely saferef.safeRef() must be able to create a reference to the receiver). Receivers must be able to accept keyword arguments. If receivers have a dispatch_uid attribute, the receiver will not be added if another receiver already exists with that dispatch_uid. Difference between @classmethod and @staticmethod: What is the difference between @staticmethod and @classmethod in Python?
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