django-comments-xtd

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Hi there. I'd like some way to delete all comments associated with an object, when the object is deleted. I just did a test and I see that this does not currently happen. Are there any housekeeping functions that do this?

No, there's no special function for this. The way to delete all the comments sent to an instance of a model Story of an app registered as blog, via a receiver function of the post_delete signal would be:

@receiver(post_delete, sender=Story)
def delete_comments(sender, instance, **kwargs):
    ct = ContentType.objects.get(app_label="blog", model="story")
    XtdComment.objects.filter(content_type=ct, object_pk=instance.id).delete()

Thanks @danirus! That's a very helpful pointer and should get me going in the right direction.

One more question -- just a thought?

Is it possible to get the app_label and model names programmatically from the Story class that's passed in, so that this function could be generalized? I'm not a django guru, so thanks for any pointers. Of course, the solution you posted is good enough for my needs, right now.

@danirus I was thinking that this would be a great use case to document: https://github.com/danirus/django-comments-xtd/issues/197

@danirus Update: I was able to generize this a little by getting the model name (in lowercase) programmatically using: sender.__name__.lower()

@receiver(post_delete, sender=Idea)
def delete_comments(sender, instance, **kwargs):
    ct = ContentType.objects.get(app_label="myapp", model=sender.__name__.lower())
    XtdComment.objects.filter(content_type=ct, object_pk=instance.id).delete()

Now, I just need to figure out hot to get the app_label from the sender model instance.

You can use the Meta class from inside the Model class. It's accessible via the _meta attribute of any model class. Using the label attribute of _meta you could get the app_label.

Tell please, is it possible to somehow make it so that when a user is deleted, his comments are also deleted?

The solution is explained along this thread. The code two comments above shows how to delete comments posted to an object. You can write a receiver in the same way called when a user is deleted. Bear in mind that you might break the comments structure by doing so. Deleting a parent comment will leave all nested comments referencing a comment that doesn't exist. You could leave the comment but anonymized, or display a message saying that the user that posted the comment deleted the account. Either way I would recommend not to delete the comment. When the user is deleted the signals pre_delete and post_delete are triggered.