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annotate gpp/downloads/signals.py @ 334:6805d15cda13

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Adding a script I had to write on the fly to filter out posts from the posts csv file that had no parent topics. MyISAM let me get away with that, but InnoDB won't.
author Brian Neal <bgneal@gmail.com>
date Sat, 26 Feb 2011 01:28:22 +0000
parents 3a4bbf9c2cce
children
rev   line source
bgneal@203 1 """Signals for the downloads application.
bgneal@203 2 We use signals to compute the denormalized category counts whenever a download
bgneal@203 3 is saved."""
bgneal@203 4 from django.db.models.signals import post_save
bgneal@203 5 from django.db.models.signals import post_delete
bgneal@203 6
bgneal@203 7 from downloads.models import Category, Download
bgneal@203 8
bgneal@203 9
bgneal@203 10 def on_download_save(sender, **kwargs):
bgneal@203 11 """This function updates the count field for all categories.
bgneal@203 12 It is called whenever a download is saved via a signal.
bgneal@203 13 """
bgneal@203 14 if kwargs['created']:
bgneal@203 15 # we only have to update the parent category
bgneal@203 16 download = kwargs['instance']
bgneal@203 17 cat = download.category
bgneal@203 18 cat.count = Download.public_objects.filter(category=cat).count()
bgneal@203 19 cat.save()
bgneal@203 20 else:
bgneal@203 21 # update all categories just to be safe (an existing download could
bgneal@203 22 # have been moved from one category to another
bgneal@203 23 cats = Category.objects.all()
bgneal@203 24 for cat in cats:
bgneal@203 25 cat.count = Download.public_objects.filter(category=cat).count()
bgneal@203 26 cat.save()
bgneal@203 27
bgneal@203 28
bgneal@203 29 def on_download_delete(sender, **kwargs):
bgneal@203 30 """This function updates the count field for the download's parent
bgneal@203 31 category. It is called when a download is deleted via a signal.
bgneal@203 32 """
bgneal@203 33 # update the parent category
bgneal@203 34 download = kwargs['instance']
bgneal@203 35 cat = download.category
bgneal@203 36 cat.count = Download.public_objects.filter(category=cat).count()
bgneal@203 37 cat.save()
bgneal@203 38
bgneal@203 39
bgneal@260 40 post_save.connect(on_download_save, sender=Download,
bgneal@260 41 dispatch_uid='downloads.signals')
bgneal@260 42 post_delete.connect(on_download_delete, sender=Download,
bgneal@260 43 dispatch_uid='downloads.signals')