Mercurial > public > sg101
annotate weblinks/receivers.py @ 1094:110bbc78a482
GCalendar V3 conversion in progress.
| author | Brian Neal <bgneal@gmail.com> |
|---|---|
| date | Sun, 29 May 2016 23:09:23 -0500 |
| parents | 6d08b1476a52 |
| children |
| rev | line source |
|---|---|
| bgneal@921 | 1 """Signal handlers for the weblinks application. |
| bgneal@921 | 2 |
| bgneal@202 | 3 We use signals to compute the denormalized category counts whenever a weblink |
| bgneal@921 | 4 is saved. |
| bgneal@921 | 5 """ |
| bgneal@202 | 6 from django.db.models.signals import post_save |
| bgneal@202 | 7 from django.db.models.signals import post_delete |
| bgneal@202 | 8 |
| bgneal@202 | 9 from weblinks.models import Category, Link |
| bgneal@202 | 10 |
| bgneal@202 | 11 |
| bgneal@202 | 12 def on_link_save(sender, **kwargs): |
| bgneal@202 | 13 """This function updates the count field for all categories. |
| bgneal@202 | 14 It is called whenever a link is saved via a signal. |
| bgneal@202 | 15 """ |
| bgneal@202 | 16 if kwargs['created']: |
| bgneal@202 | 17 # we only have to update the parent category |
| bgneal@202 | 18 link = kwargs['instance'] |
| bgneal@202 | 19 cat = link.category |
| bgneal@202 | 20 cat.count = Link.public_objects.filter(category=cat).count() |
| bgneal@202 | 21 cat.save() |
| bgneal@202 | 22 else: |
| bgneal@202 | 23 # update all categories just to be safe (an existing link could |
| bgneal@202 | 24 # have been moved from one category to another |
| bgneal@202 | 25 cats = Category.objects.all() |
| bgneal@202 | 26 for cat in cats: |
| bgneal@202 | 27 cat.count = Link.public_objects.filter(category=cat).count() |
| bgneal@202 | 28 cat.save() |
| bgneal@202 | 29 |
| bgneal@202 | 30 |
| bgneal@202 | 31 def on_link_delete(sender, **kwargs): |
| bgneal@202 | 32 """This function updates the count field for the link's parent |
| bgneal@202 | 33 category. It is called when a link is deleted via a signal. |
| bgneal@202 | 34 """ |
| bgneal@202 | 35 # update the parent category |
| bgneal@202 | 36 link = kwargs['instance'] |
| bgneal@202 | 37 cat = link.category |
| bgneal@202 | 38 cat.count = Link.public_objects.filter(category=cat).count() |
| bgneal@202 | 39 cat.save() |
| bgneal@202 | 40 |
| bgneal@202 | 41 |
| bgneal@921 | 42 post_save.connect(on_link_save, sender=Link, dispatch_uid='weblinks.receivers') |
| bgneal@921 | 43 post_delete.connect(on_link_delete, sender=Link, dispatch_uid='weblinks.receivers') |