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 from django.utils.translation import ugettext_lazy as _
   9
  10 from catalogue.models import Book, Tag
  11
  12
  13 class Deleted(models.Model):
  14     object_id = models.IntegerField()
  15     slug = models.SlugField(_('slug'), max_length=120, blank=True, db_index=True)
  16     content_type = models.ForeignKey(ContentType)
  17     category = models.CharField(max_length=64, null=True, blank=True, db_index=True)
  18     created_at = models.DateTimeField(editable=False, db_index=True)
  19     deleted_at = models.DateTimeField(auto_now_add=True, db_index=True)
  20
  21     class Meta:
  22         unique_together = (('content_type', 'object_id'),)
  23
  24
  25 def _pre_delete_handler(sender, instance, **kwargs):
  26     """ save deleted objects for change history purposes """
  27
  28     if sender in (Book, Tag):
  29         if sender == Tag:
  30             if instance.category in ('book', 'set'):
  31                 return
  32             else:
  33                 category = instance.category
  34         else:
  35             category = None
  36         content_type = ContentType.objects.get_for_model(sender)
  37         Deleted.objects.create(content_type=content_type, object_id=instance.id,
  38             created_at=instance.created_at, category=category, slug=instance.slug)
  39 pre_delete.connect(_pre_delete_handler)