Mercurial > public > sg101
comparison downloads/receivers.py @ 922:1a832625c047
Downloads app refactor.
For Django 1.7.7 upgrade.
| author | Brian Neal <bgneal@gmail.com> |
|---|---|
| date | Tue, 07 Apr 2015 20:20:42 -0500 |
| parents | downloads/signals.py@929d0e637a37 |
| children |
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| 921:6d08b1476a52 | 922:1a832625c047 |
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| 1 """Signal handlers for the downloads application. | |
| 2 | |
| 3 We use signals to compute the denormalized category counts whenever a download | |
| 4 is saved. | |
| 5 | |
| 6 """ | |
| 7 from django.db.models.signals import post_save | |
| 8 from django.db.models.signals import post_delete | |
| 9 | |
| 10 from downloads.models import Category, Download, PendingDownload | |
| 11 | |
| 12 | |
| 13 def on_download_save(sender, **kwargs): | |
| 14 """This function updates the count field for all categories. | |
| 15 It is called whenever a download is saved via a signal. | |
| 16 """ | |
| 17 if kwargs['created']: | |
| 18 # we only have to update the parent category | |
| 19 download = kwargs['instance'] | |
| 20 cat = download.category | |
| 21 cat.count = Download.public_objects.filter(category=cat).count() | |
| 22 cat.save() | |
| 23 else: | |
| 24 # update all categories just to be safe (an existing download could | |
| 25 # have been moved from one category to another | |
| 26 cats = Category.objects.all() | |
| 27 for cat in cats: | |
| 28 cat.count = Download.public_objects.filter(category=cat).count() | |
| 29 cat.save() | |
| 30 | |
| 31 | |
| 32 def on_download_delete(sender, **kwargs): | |
| 33 """This function updates the count field for the download's parent | |
| 34 category. It is called when a download is deleted via a signal. | |
| 35 | |
| 36 We now delete the uploaded file when the download is deleted. | |
| 37 """ | |
| 38 # update the parent category | |
| 39 download = kwargs['instance'] | |
| 40 cat = download.category | |
| 41 cat.count = Download.public_objects.filter(category=cat).count() | |
| 42 cat.save() | |
| 43 | |
| 44 # delete the actual file | |
| 45 if download.file: | |
| 46 download.file.delete(save=False) | |
| 47 | |
| 48 | |
| 49 def on_pending_download_delete(sender, **kwargs): | |
| 50 """Delete the uploaded file if it exists.""" | |
| 51 | |
| 52 download = kwargs['instance'] | |
| 53 # delete the actual file | |
| 54 if download.file: | |
| 55 download.file.delete(save=False) | |
| 56 | |
| 57 | |
| 58 post_save.connect(on_download_save, sender=Download, | |
| 59 dispatch_uid='downloads.receivers') | |
| 60 post_delete.connect(on_download_delete, sender=Download, | |
| 61 dispatch_uid='downloads.receivers') | |
| 62 post_delete.connect(on_pending_download_delete, sender=PendingDownload, | |
| 63 dispatch_uid='downloads.receivers') |