apps/api/models.py

   1 # -*- coding: utf-8 -*-
   2 # This file is part of Wolnelektury, licensed under GNU Affero GPLv3 or later.
   3 # Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information.
   4 #
   5 from django.contrib.contenttypes.models import ContentType
   6 from django.db import models
   7 from django.db.models.signals import pre_delete
   8
   9 from catalogue.models import Book, Tag
  10
  11
  12 class Deleted(models.Model):
  13     object_id = models.IntegerField()
  14     content_type = models.ForeignKey(ContentType)
  15     category = models.CharField(max_length=64, null=True, blank=True, db_index=True)
  16     created_at = models.DateTimeField(editable=False, db_index=True)
  17     deleted_at = models.DateTimeField(auto_now_add=True, db_index=True)
  18
  19     class Meta:
  20         unique_together = (('content_type', 'object_id'),)
  21
  22
  23 def _pre_delete_handler(sender, instance, **kwargs):
  24     """ save deleted objects for change history purposes """
  25
  26     if sender in (Book, Tag):
  27         if sender == Tag:
  28             if instance.category in ('book', 'set'):
  29                 return
  30             else:
  31                 category = instance.category
  32         else:
  33             category = None
  34         content_type = ContentType.objects.get_for_model(sender)
  35         Deleted.objects.create(content_type=content_type, object_id=instance.id,
  36             created_at=instance.created_at, category=category)
  37 pre_delete.connect(_pre_delete_handler)