X-Git-Url: https://git.mdrn.pl/wolnelektury.git/blobdiff_plain/f8e66ed30238e40a08b6758dbed68cb2e5cf2db9..1d85ebc2439c19626574166d4f37ae4990fdbf27:/apps/catalogue/models.py
diff --git a/apps/catalogue/models.py b/apps/catalogue/models.py
index dd251c16a..129bb8abe 100644
--- a/apps/catalogue/models.py
+++ b/apps/catalogue/models.py
@@ -8,10 +8,13 @@ from django.utils.translation import ugettext_lazy as _
from django.contrib.auth.models import User
from django.core.files import File
from django.template.loader import render_to_string
+from django.template.defaultfilters import slugify
from django.utils.safestring import mark_safe
from django.utils.translation import get_language
from django.core.urlresolvers import reverse
-from datetime import datetime
+from django.db.models.signals import post_save, m2m_changed, pre_delete
+
+from django.conf import settings
from newtagging.models import TagBase, tags_updated
from newtagging import managers
@@ -31,6 +34,12 @@ TAG_CATEGORIES = (
('book', _('book')),
)
+MEDIA_FORMATS = (
+ ('odt', _('ODT file')),
+ ('mp3', _('MP3 file')),
+ ('ogg', _('OGG file')),
+ ('daisy', _('DAISY file')),
+)
class TagSubcategoryManager(models.Manager):
def __init__(self, subcategory):
@@ -44,15 +53,14 @@ class TagSubcategoryManager(models.Manager):
class Tag(TagBase):
name = models.CharField(_('name'), max_length=50, db_index=True)
slug = models.SlugField(_('slug'), max_length=120, db_index=True)
- sort_key = models.SlugField(_('sort key'), max_length=120, db_index=True)
+ sort_key = models.CharField(_('sort key'), max_length=120, db_index=True)
category = models.CharField(_('category'), max_length=50, blank=False, null=False,
db_index=True, choices=TAG_CATEGORIES)
description = models.TextField(_('description'), blank=True)
main_page = models.BooleanField(_('main page'), default=False, db_index=True, help_text=_('Show tag on main page'))
user = models.ForeignKey(User, blank=True, null=True)
- book_count = models.IntegerField(_('book count'), blank=False, null=True)
- death = models.IntegerField(_(u'year of death'), blank=True, null=True)
+ book_count = models.IntegerField(_('book count'), blank=True, null=True)
gazeta_link = models.CharField(blank=True, max_length=240)
wiki_link = models.CharField(blank=True, max_length=240)
@@ -87,17 +95,6 @@ class Tag(TagBase):
has_description.short_description = _('description')
has_description.boolean = True
- def alive(self):
- return self.death is None
-
- def in_pd(self):
- """ tests whether an author is in public domain """
- return self.death is not None and self.goes_to_pd() <= datetime.now().year
-
- def goes_to_pd(self):
- """ calculates the year of public domain entry for an author """
- return self.death + 71 if self.death is not None else None
-
def get_count(self):
""" returns global book count for book tags, fragment count for themes """
@@ -159,39 +156,78 @@ class Tag(TagBase):
# TODO: why is this hard-coded ?
-def book_upload_path(ext):
- def get_dynamic_path(book, filename):
- return 'lektura/%s.%s' % (book.slug, ext)
+def book_upload_path(ext=None):
+ def get_dynamic_path(media, filename, ext=ext):
+ # how to put related book's slug here?
+ if not ext:
+ ext = media.type
+ if not media.name:
+ name = slugify(filename.split(".")[0])
+ else:
+ name = slugify(media.name)
+ return 'lektura/%s.%s' % (name, ext)
return get_dynamic_path
-class Book(models.Model):
- title = models.CharField(_('title'), max_length=120)
- slug = models.SlugField(_('slug'), max_length=120, unique=True, db_index=True)
- description = models.TextField(_('description'), blank=True)
- created_at = models.DateTimeField(_('creation date'), auto_now=True)
- _short_html = models.TextField(_('short HTML'), editable=False)
- parent_number = models.IntegerField(_('parent number'), default=0)
- extra_info = JSONField(_('extra information'))
- gazeta_link = models.CharField(blank=True, max_length=240)
- wiki_link = models.CharField(blank=True, max_length=240)
+class BookMedia(models.Model):
+ type = models.CharField(_('type'), choices=MEDIA_FORMATS, max_length="100")
+ name = models.CharField(_('name'), max_length="100", blank=True)
+ file = models.FileField(_('file'), upload_to=book_upload_path(), blank=True)
+ uploaded_at = models.DateTimeField(_('creation date'), auto_now_add=True, editable=False)
+ extra_info = JSONField(_('extra information'), default='{}')
+ def __unicode__(self):
+ return "%s (%s)" % (self.name, self.file.name.split("/")[-1])
- # Formats
- xml_file = models.FileField(_('XML file'), upload_to=book_upload_path('xml'), blank=True)
- html_file = models.FileField(_('HTML file'), upload_to=book_upload_path('html'), blank=True)
- pdf_file = models.FileField(_('PDF file'), upload_to=book_upload_path('pdf'), blank=True)
- epub_file = models.FileField(_('EPUB file'), upload_to=book_upload_path('epub'), blank=True)
- odt_file = models.FileField(_('ODT file'), upload_to=book_upload_path('odt'), blank=True)
- txt_file = models.FileField(_('TXT file'), upload_to=book_upload_path('txt'), blank=True)
- mp3_file = models.FileField(_('MP3 file'), upload_to=book_upload_path('mp3'), blank=True)
- ogg_file = models.FileField(_('OGG file'), upload_to=book_upload_path('ogg'), blank=True)
+ class Meta:
+ ordering = ('type', 'name')
+ verbose_name = _('book media')
+ verbose_name_plural = _('book media')
+
+ def save(self, force_insert=False, force_update=False):
+ media = super(BookMedia, self).save(force_insert, force_update)
+ if self.type == 'mp3':
+ file = self.file
+ extra_info = self.get_extra_info_value()
+ extra_info.update(self.get_mp3_info())
+ self.set_extra_info_value(extra_info)
+ media = super(BookMedia, self).save(force_insert, force_update)
+ return media
- parent = models.ForeignKey('self', blank=True, null=True, related_name='children')
+ def get_mp3_info(self):
+ """Retrieves artist and director names from audio ID3 tags."""
+ try:
+ audio = id3.ID3(self.file.path)
+ artist_name = ', '.join(', '.join(tag.text) for tag in audio.getall('TPE1'))
+ director_name = ', '.join(', '.join(tag.text) for tag in audio.getall('TPE3'))
+ except:
+ artist_name = director_name = ''
+ return {'artist_name': artist_name, 'director_name': director_name}
- objects = models.Manager()
- tagged = managers.ModelTaggedItemManager(Tag)
- tags = managers.TagDescriptor(Tag)
+
+class Book(models.Model):
+ title = models.CharField(_('title'), max_length=120)
+ slug = models.SlugField(_('slug'), max_length=120, unique=True, db_index=True)
+ description = models.TextField(_('description'), blank=True)
+ created_at = models.DateTimeField(_('creation date'), auto_now_add=True)
+ _short_html = models.TextField(_('short HTML'), editable=False)
+ parent_number = models.IntegerField(_('parent number'), default=0)
+ extra_info = JSONField(_('extra information'))
+ gazeta_link = models.CharField(blank=True, max_length=240)
+ wiki_link = models.CharField(blank=True, max_length=240)
+ # files generated during publication
+ xml_file = models.FileField(_('XML file'), upload_to=book_upload_path('xml'), blank=True)
+ html_file = models.FileField(_('HTML file'), upload_to=book_upload_path('html'), blank=True)
+ pdf_file = models.FileField(_('PDF file'), upload_to=book_upload_path('pdf'), blank=True)
+ epub_file = models.FileField(_('EPUB file'), upload_to=book_upload_path('epub'), blank=True)
+ txt_file = models.FileField(_('TXT file'), upload_to=book_upload_path('txt'), blank=True)
+ # other files
+ medias = models.ManyToManyField(BookMedia, blank=True)
+
+ parent = models.ForeignKey('self', blank=True, null=True, related_name='children')
+ objects = models.Manager()
+ tagged = managers.ModelTaggedItemManager(Tag)
+ tags = managers.TagDescriptor(Tag)
_tag_counter = JSONField(null=True, editable=False)
_theme_counter = JSONField(null=True, editable=False)
@@ -207,7 +243,7 @@ class Book(models.Model):
def __unicode__(self):
return self.title
- def save(self, force_insert=False, force_update=False, reset_short_html=True, refresh_mp3=True):
+ def save(self, force_insert=False, force_update=False, reset_short_html=True, **kwargs):
if reset_short_html:
# Reset _short_html during save
update = {}
@@ -217,16 +253,7 @@ class Book(models.Model):
# Fragment.short_html relies on book's tags, so reset it here too
self.fragments.all().update(**update)
- book = super(Book, self).save(force_insert, force_update)
-
- if refresh_mp3 and self.mp3_file:
- print self.mp3_file, self.mp3_file.path
- extra_info = self.get_extra_info_value()
- extra_info.update(self.get_mp3_info())
- self.set_extra_info_value(extra_info)
- book = super(Book, self).save(force_insert, force_update)
-
- return book
+ return super(Book, self).save(force_insert, force_update)
@permalink
def get_absolute_url(self):
@@ -244,10 +271,68 @@ class Book(models.Model):
book_tag, created = Tag.objects.get_or_create(slug=slug, category='book')
if created:
book_tag.name = self.title[:50]
- book_tag.sort_key = slug
+ book_tag.sort_key = self.title.lower()
book_tag.save()
return book_tag
+ def has_media(self, type):
+ if type == 'xml':
+ if self.xml_file:
+ return True
+ else:
+ return False
+ elif type == 'html':
+ if self.html_file:
+ return True
+ else:
+ return False
+ elif type == 'txt':
+ if self.txt_file:
+ return True
+ else:
+ return False
+ elif type == 'pdf':
+ if self.pdf_file:
+ return True
+ else:
+ return False
+ elif type == 'epub':
+ if self.epub_file:
+ return True
+ else:
+ return False
+ else:
+ if self.medias.filter(book=self, type=type).count() > 0:
+ return True
+ else:
+ return False
+
+ def get_media(self, type):
+ if self.has_media(type):
+ if type == "xml":
+ return self.xml_file
+ elif type == "html":
+ return self.html_file
+ elif type == "epub":
+ return self.epub_file
+ elif type == "txt":
+ return self.txt_file
+ elif type == "pdf":
+ return self.pdf_file
+ else:
+ return self.medias.filter(book=self, type=type)
+ else:
+ return None
+
+ def get_mp3(self):
+ return self.get_media("mp3")
+ def get_odt(self):
+ return self.get_media("odt")
+ def get_ogg(self):
+ return self.get_media("ogg")
+ def get_daisy(self):
+ return self.get_media("daisy")
+
def short_html(self):
key = '_short_html_%s' % get_language()
short_html = getattr(self, key)
@@ -259,20 +344,18 @@ class Book(models.Model):
tags = [mark_safe(u'%s' % (tag.get_absolute_url(), tag.name)) for tag in tags]
formats = []
- if self.html_file:
+ # files generated during publication
+ if self.has_media("html"):
formats.append(u'%s' % (reverse('book_text', kwargs={'slug': self.slug}), _('Read online')))
- if self.pdf_file:
- formats.append(u'PDF' % self.pdf_file.url)
- if self.epub_file:
- formats.append(u'EPUB' % self.epub_file.url)
- if self.odt_file:
- formats.append(u'ODT' % self.odt_file.url)
- if self.txt_file:
- formats.append(u'TXT' % self.txt_file.url)
- if self.mp3_file:
- formats.append(u'MP3' % self.mp3_file.url)
- if self.ogg_file:
- formats.append(u'OGG' % self.ogg_file.url)
+ if self.has_media("pdf"):
+ formats.append(u'PDF' % self.get_media('pdf').url)
+ if self.root_ancestor.has_media("epub"):
+ formats.append(u'EPUB' % self.root_ancestor.get_media('epub').url)
+ if self.has_media("txt"):
+ formats.append(u'TXT' % self.get_media('txt').url)
+ # other files
+ for m in self.medias.order_by('type'):
+ formats.append(u'%s' % (m.file.url, m.type.upper()))
formats = [mark_safe(format) for format in formats]
@@ -282,18 +365,24 @@ class Book(models.Model):
return mark_safe(getattr(self, key))
- def get_mp3_info(self):
- """Retrieves artist and director names from audio ID3 tags."""
- audio = id3.ID3(self.mp3_file.path)
- artist_name = ', '.join(', '.join(tag.text) for tag in audio.getall('TPE1'))
- director_name = ', '.join(', '.join(tag.text) for tag in audio.getall('TPE3'))
- return {'artist_name': artist_name, 'director_name': director_name}
+ @property
+ def root_ancestor(self):
+ """ returns the oldest ancestor """
+
+ if not hasattr(self, '_root_ancestor'):
+ book = self
+ while book.parent:
+ book = book.parent
+ self._root_ancestor = book
+ return self._root_ancestor
+
def has_description(self):
return len(self.description) > 0
has_description.short_description = _('description')
has_description.boolean = True
+ # ugly ugly ugly
def has_pdf_file(self):
return bool(self.pdf_file)
has_pdf_file.short_description = 'PDF'
@@ -304,18 +393,93 @@ class Book(models.Model):
has_epub_file.short_description = 'EPUB'
has_epub_file.boolean = True
- def has_odt_file(self):
- return bool(self.odt_file)
- has_odt_file.short_description = 'ODT'
- has_odt_file.boolean = True
+ def has_txt_file(self):
+ return bool(self.txt_file)
+ has_txt_file.short_description = 'HTML'
+ has_txt_file.boolean = True
def has_html_file(self):
return bool(self.html_file)
has_html_file.short_description = 'HTML'
has_html_file.boolean = True
+ def has_odt_file(self):
+ return bool(self.has_media("odt"))
+ has_odt_file.short_description = 'ODT'
+ has_odt_file.boolean = True
+
+ def has_mp3_file(self):
+ return bool(self.has_media("mp3"))
+ has_mp3_file.short_description = 'MP3'
+ has_mp3_file.boolean = True
+
+ def has_ogg_file(self):
+ return bool(self.has_media("ogg"))
+ has_ogg_file.short_description = 'OGG'
+ has_ogg_file.boolean = True
+
+ def has_daisy_file(self):
+ return bool(self.has_media("daisy"))
+ has_daisy_file.short_description = 'DAISY'
+ has_daisy_file.boolean = True
+
+ def build_epub(self, remove_descendants=True):
+ """ (Re)builds the epub file.
+ If book has a parent, does nothing.
+ Unless remove_descendants is False, descendants' epubs are removed.
+ """
+
+ from StringIO import StringIO
+ from hashlib import sha1
+ from django.core.files.base import ContentFile
+ from librarian import DocProvider
+
+ class BookImportDocProvider(DocProvider):
+ """ used for joined EPUBs """
+
+ def __init__(self, book):
+ self.book = book
+
+ def by_slug(self, slug):
+ if slug == self.book.slug:
+ return self.book.xml_file
+ else:
+ return Book.objects.get(slug=slug).xml_file
+
+ if self.parent:
+ # don't need an epub
+ return
+
+ epub_file = StringIO()
+ try:
+ epub.transform(BookImportDocProvider(self), self.slug, output_file=epub_file)
+ self.epub_file.save('%s.epub' % self.slug, ContentFile(epub_file.getvalue()))
+ FileRecord(slug=self.slug, type='epub', sha1=sha1(epub_file.getvalue()).hexdigest()).save()
+ except NoDublinCore:
+ pass
+
+ book_descendants = list(self.children.all())
+ while len(book_descendants) > 0:
+ child_book = book_descendants.pop(0)
+ if remove_descendants and child_book.has_epub_file():
+ child_book.epub_file.delete()
+ # save anyway, to refresh short_html
+ child_book.save()
+ book_descendants += list(child_book.children.all())
+
+ def build_txt(self):
+ from StringIO import StringIO
+ from django.core.files.base import ContentFile
+ from librarian import text
+
+ out = StringIO()
+ text.transform(open(self.xml_file.path), out)
+ self.txt_file.save('%s.txt' % self.slug, ContentFile(out.getvalue()))
+ self.save()
+
+
@classmethod
- def from_xml_file(cls, xml_file, overwrite=False):
+ def from_xml_file(cls, xml_file, **kwargs):
# use librarian to parse meta-data
book_info = dcparser.parse(xml_file)
@@ -323,19 +487,27 @@ class Book(models.Model):
xml_file = File(open(xml_file))
try:
- return cls.from_text_and_meta(xml_file, book_info, overwrite)
+ return cls.from_text_and_meta(xml_file, book_info, **kwargs)
finally:
xml_file.close()
@classmethod
- def from_text_and_meta(cls, raw_file, book_info, overwrite=False):
+ def from_text_and_meta(cls, raw_file, book_info, overwrite=False, build_epub=True, build_txt=True):
from tempfile import NamedTemporaryFile
from slughifi import slughifi
from markupstring import MarkupString
- from hashlib import sha1
- from django.core.files.base import ContentFile
from django.core.files.storage import default_storage
- from StringIO import StringIO
+
+ # check for parts before we do anything
+ children = []
+ if hasattr(book_info, 'parts'):
+ for part_url in book_info.parts:
+ base, slug = part_url.rsplit('/', 1)
+ try:
+ children.append(Book.objects.get(slug=slug))
+ except Book.DoesNotExist, e:
+ raise Book.DoesNotExist(_('Book with slug = "%s" does not exist.') % slug)
+
# Read book metadata
book_base, book_slug = book_info.url.rsplit('/', 1)
@@ -369,7 +541,7 @@ class Book(models.Model):
tag, created = Tag.objects.get_or_create(slug=slughifi(tag_name), category=category)
if created:
tag.name = tag_name
- tag.sort_key = slughifi(tag_sort_key)
+ tag.sort_key = tag_sort_key.lower()
tag.save()
book_tags.append(tag)
@@ -377,41 +549,27 @@ class Book(models.Model):
book_tag = book.book_tag()
- if hasattr(book_info, 'parts'):
- for n, part_url in enumerate(book_info.parts):
- base, slug = part_url.rsplit('/', 1)
- try:
- child_book = Book.objects.get(slug=slug)
- child_book.parent = book
- child_book.parent_number = n
- child_book.save()
- except Book.DoesNotExist, e:
- raise Book.DoesNotExist(_('Book with slug = "%s" does not exist.') % slug)
-
- book_descendants = list(book.children.all())
- while len(book_descendants) > 0:
- child_book = book_descendants.pop(0)
- child_book.tags = list(child_book.tags) + [book_tag]
+ for n, child_book in enumerate(children):
+ child_book.parent = book
+ child_book.parent_number = n
child_book.save()
- for fragment in child_book.fragments.all():
- fragment.tags = set(list(fragment.tags) + [book_tag])
- book_descendants += list(child_book.children.all())
# Save XML and HTML files
book.xml_file.save('%s.xml' % book.slug, raw_file, save=False)
+ # delete old fragments when overwriting
+ book.fragments.all().delete()
+
html_file = NamedTemporaryFile()
if html.transform(book.xml_file.path, html_file, parse_dublincore=False):
book.html_file.save('%s.html' % book.slug, File(html_file), save=False)
- # Create EPUB
- epub_file = StringIO()
- try:
- epub.transform(book.xml_file, epub_file)
- book.epub_file.save('%s.epub' % book.slug, ContentFile(epub_file.getvalue()), save=False)
- FileRecord(slug=book.slug, type='epub', sha1=sha1(epub_file.getvalue()).hexdigest()).save()
- except NoDublinCore:
- pass
+ # get ancestor l-tags for adding to new fragments
+ ancestor_tags = []
+ p = book.parent
+ while p:
+ ancestor_tags.append(p.book_tag())
+ p = p.parent
# Extract fragments
closed_fragments, open_fragments = html.extract_fragments(book.html_file.path)
@@ -427,7 +585,7 @@ class Book(models.Model):
tag, created = Tag.objects.get_or_create(slug=slughifi(theme_name), category='theme')
if created:
tag.name = theme_name
- tag.sort_key = slughifi(theme_name)
+ tag.sort_key = theme_name.lower()
tag.save()
themes.append(tag)
if not themes:
@@ -441,11 +599,28 @@ class Book(models.Model):
defaults={'text': text, 'short_text': short_text})
new_fragment.save()
- new_fragment.tags = set(book_tags + themes + [book_tag])
+ new_fragment.tags = set(book_tags + themes + [book_tag] + ancestor_tags)
+
+ if not settings.NO_BUILD_TXT and build_txt:
+ book.build_txt()
+
+ if not settings.NO_BUILD_EPUB and build_epub:
+ book.root_ancestor.build_epub()
+
+ book_descendants = list(book.children.all())
+ # add l-tag to descendants and their fragments
+ # delete unnecessary EPUB files
+ while len(book_descendants) > 0:
+ child_book = book_descendants.pop(0)
+ child_book.tags = list(child_book.tags) + [book_tag]
+ child_book.save()
+ for fragment in child_book.fragments.all():
+ fragment.tags = set(list(fragment.tags) + [book_tag])
+ book_descendants += list(child_book.children.all())
# refresh cache
- book.tag_counter
- book.theme_counter
+ book.reset_tag_counter()
+ book.reset_theme_counter()
book.save()
return book
@@ -459,12 +634,12 @@ class Book(models.Model):
for tag in self.tags.exclude(category__in=('book', 'theme', 'set')).order_by():
tags[tag.pk] = 1
self.set__tag_counter_value(tags)
- self.save(reset_short_html=False, refresh_mp3=False)
+ self.save(reset_short_html=False)
return tags
def reset_tag_counter(self):
self._tag_counter = None
- self.save(reset_short_html=False, refresh_mp3=False)
+ self.save(reset_short_html=False)
if self.parent:
self.parent.reset_tag_counter()
@@ -480,12 +655,12 @@ class Book(models.Model):
for tag in fragment.tags.filter(category='theme').order_by():
tags[tag.pk] = tags.get(tag.pk, 0) + 1
self.set__theme_counter_value(tags)
- self.save(reset_short_html=False, refresh_mp3=False)
+ self.save(reset_short_html=False)
return tags
def reset_theme_counter(self):
self._theme_counter = None
- self.save(reset_short_html=False, refresh_mp3=False)
+ self.save(reset_short_html=False)
if self.parent:
self.parent.reset_theme_counter()
@@ -495,6 +670,22 @@ class Book(models.Model):
return self.refresh_theme_counter()
return dict((int(k), v) for k, v in self.get__theme_counter_value().iteritems())
+ def pretty_title(self, html_links=False):
+ book = self
+ names = list(book.tags.filter(category='author'))
+
+ books = []
+ while book:
+ books.append(book)
+ book = book.parent
+ names.extend(reversed(books))
+
+ if html_links:
+ names = ['%s' % (tag.get_absolute_url(), tag.name) for tag in names]
+ else:
+ names = [tag.name for tag in names]
+
+ return ', '.join(names)
class Fragment(models.Model):
@@ -528,34 +719,6 @@ class Fragment(models.Model):
return mark_safe(getattr(self, key))
-class BookStub(models.Model):
- title = models.CharField(_('title'), max_length=120)
- author = models.CharField(_('author'), max_length=120)
- pd = models.IntegerField(_('goes to public domain'), null=True, blank=True)
- slug = models.SlugField(_('slug'), max_length=120, unique=True, db_index=True)
- translator = models.TextField(_('translator'), blank=True)
- translator_death = models.TextField(_('year of translator\'s death'), blank=True)
-
- class Meta:
- ordering = ('title',)
- verbose_name = _('book stub')
- verbose_name_plural = _('book stubs')
-
- def __unicode__(self):
- return self.title
-
- @permalink
- def get_absolute_url(self):
- return ('catalogue.views.book_detail', [self.slug])
-
- def in_pd(self):
- return self.pd is not None and self.pd <= datetime.now().year
-
- @property
- def name(self):
- return self.title
-
-
class FileRecord(models.Model):
slug = models.SlugField(_('slug'), max_length=120, db_index=True)
type = models.CharField(_('type'), max_length=20, db_index=True)
@@ -570,6 +733,12 @@ class FileRecord(models.Model):
def __unicode__(self):
return "%s %s.%s" % (self.sha1, self.slug, self.type)
+###########
+#
+# SIGNALS
+#
+###########
+
def _tags_updated_handler(sender, affected_tags, **kwargs):
# reset tag global counter
@@ -587,3 +756,24 @@ def _tags_updated_handler(sender, affected_tags, **kwargs):
sender.book.reset_theme_counter()
tags_updated.connect(_tags_updated_handler)
+
+def _m2m_changed_handler(sender, instance, action, reverse, pk_set, **kwargs):
+ """ refresh all the short_html stuff on BookMedia delete """
+ if sender == Book.medias.through and reverse and action == 'pre_clear':
+ for book in instance.book_set.all():
+ book.save()
+m2m_changed.connect(_m2m_changed_handler)
+
+def _pre_delete_handler(sender, instance, **kwargs):
+ """ explicitly clear m2m, so that Books can be refreshed """
+ if sender == BookMedia:
+ instance.book_set.clear()
+pre_delete.connect(_pre_delete_handler)
+
+def _post_save_handler(sender, instance, **kwargs):
+ """ refresh all the short_html stuff on BookMedia update """
+ if sender == BookMedia:
+ for book in instance.book_set.all():
+ book.save()
+post_save.connect(_post_save_handler)
+