Why Django model signals are not working?

Question

I am trying to create activity streams of users from their status.

models:

class Status(models.Model):     body = models.TextField(max_length=200)     image = models.ImageField(blank=True, null=True, upload_to=get_upload_file_name)     privacy = models.CharField(max_length=1,choices=PRIVACY, default='F')     pub_date = models.DateTimeField(auto_now_add=True, auto_now=False)     user = models.ForeignKey(User)  class Activity(models.Model):     actor = models.ForeignKey(User)     action = models.CharField(max_length=100)     content_type = models.ForeignKey(ContentType)     object_id = models.PositiveIntegerField()     content_object = generic.GenericForeignKey('content_type', 'object_id')     pub_date = models.DateTimeField(auto_now_add=True, auto_now=False) 

However, although I create a new status, it does not create a new activity from the post_save signal.

signals:

from django.contrib.contenttypes.models import ContentType from django.db.models.signals import post_save from status.models import Status from models import Activity  def create_activity_item(sender, instance, signal, *args, **kwargs):     if kwargs.get('created', True):         ctype = ContentType.objects.get_for_model(instance)          if ctype.name == 'Status':             action = ' shared '              activity = Activity.objects.get_or_create(                 actor = instance.user,                 action = action,                 content_type = ctype,                 object_id = instance.id,                 pub_date = instance.pubdate             )  post_save.connect(create_activity_item, sender=Status) 

What am I doing wrong? Please help me solve this problem. I will be very much grateful. Thank you.

Update:

However doing like this creates the activity:

@receiver(post_save, sender=Status) def create(sender, instance, **kwargs):     if kwargs.get('created',True):         ctype = ContentType.objects.get_for_model(instance)         activity = Activity.objects.get_or_create(             actor = instance.user,             action = ' shared ',             content_type = ctype,             object_id = instance.id,             pub_date = instance.pub_date         ) 

Why doesn't the above works then?

Answer 1

Seems like your post_save.connect is not executed. You should import signals somewhere. For django 1.7 it is recommended to do this in the app's config ready() function. Read the "Where should this code live?" side note in the docs.

For example if your app is called activity:

activity/__init__.py

default_app_config = 'activity.apps.ActivityAppConfig' 

activity/apps.py

from django.apps import AppConfig  class ActivityAppConfig(AppConfig):     name = 'activity'      def ready(self):         import activity.signals 

And don't forget to add dispatch_uid to your connect() call:

post_save.connect(create_activity_item, sender=Status,                   dispatch_uid="create_activity_item") 

UPDATE: name attribute of ContentType is always in lower case. So you should change the if statement to:

if ctype.name == 'status':