Mercurial > public > sg101
annotate gpp/downloads/signals.py @ 218:6dbb8faef085
Implement #86, add a front page expiration date to news stories.
| author | Brian Neal <bgneal@gmail.com> |
|---|---|
| date | Tue, 01 Jun 2010 05:16:40 +0000 |
| parents | 40e5903903e1 |
| children | 3a4bbf9c2cce |
| 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@203 | 40 post_save.connect(on_download_save, sender=Download) |
| bgneal@203 | 41 post_delete.connect(on_download_delete, sender=Download) |