include submodules in archive tarball

[wolnelektury.git] / apps / catalogue / models.py

diff --git a/apps/catalogue/models.py b/apps/catalogue/models.py
index e2b2636..d3b24d3 100644 (file)
--- a/apps/catalogue/models.py
+++ b/apps/catalogue/models.py
@@ -13,11 +13,11 @@ from django.utils.translation import get_language
 from django.core.urlresolvers import reverse
 from datetime import datetime
 
 from django.core.urlresolvers import reverse
 from datetime import datetime
 

-from newtagging.models import TagBase
+from newtagging.models import TagBase, tags_updated

 from newtagging import managers
 from catalogue.fields import JSONField
 
 from newtagging import managers
 from catalogue.fields import JSONField
 

-from librarian import html, dcparser
+from librarian import dcparser, html, epub, NoDublinCore

 from mutagen import id3
 
 
 from mutagen import id3
 
 


@@ -43,7 +43,7 @@ class TagSubcategoryManager(models.Manager):
 
 class Tag(TagBase):
     name = models.CharField(_('name'), max_length=50, db_index=True)
 
 class Tag(TagBase):
     name = models.CharField(_('name'), max_length=50, db_index=True)

-    slug = models.SlugField(_('slug'), max_length=120, unique=True, 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)
     category = models.CharField(_('category'), max_length=50, blank=False, null=False,
         db_index=True, choices=TAG_CATEGORIES)
     sort_key = models.SlugField(_('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)


@@ -51,15 +51,26 @@ class Tag(TagBase):
     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)
     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'), default=0, blank=False, null=False)
+    book_count = models.IntegerField(_('book count'), blank=False, null=True)

     death = models.IntegerField(_(u'year of death'), blank=True, null=True)
     gazeta_link = models.CharField(blank=True, max_length=240)
     wiki_link = models.CharField(blank=True, max_length=240)
 
     death = models.IntegerField(_(u'year of death'), blank=True, null=True)
     gazeta_link = models.CharField(blank=True, max_length=240)
     wiki_link = models.CharField(blank=True, max_length=240)
 

+    categories_rev = {
+        'autor': 'author',
+        'epoka': 'epoch',
+        'rodzaj': 'kind',
+        'gatunek': 'genre',
+        'motyw': 'theme',
+        'polka': 'set',
+    }
+    categories_dict = dict((item[::-1] for item in categories_rev.iteritems()))
+

     class Meta:
         ordering = ('sort_key',)
         verbose_name = _('tag')
         verbose_name_plural = _('tags')
     class Meta:
         ordering = ('sort_key',)
         verbose_name = _('tag')
         verbose_name_plural = _('tags')

+        unique_together = (("slug", "category"),)

 
     def __unicode__(self):
         return self.name
 
     def __unicode__(self):
         return self.name


@@ -69,7 +80,7 @@ class Tag(TagBase):
 
     @permalink
     def get_absolute_url(self):
 
     @permalink
     def get_absolute_url(self):

-        return ('catalogue.views.tagged_object_list', [self.slug])
+        return ('catalogue.views.tagged_object_list', [self.url_chunk])

 
     def has_description(self):
         return len(self.description) > 0
 
     def has_description(self):
         return len(self.description) > 0


@@ -87,16 +98,67 @@ class Tag(TagBase):
         """ calculates the year of public domain entry for an author """
         return self.death + 71 if self.death is not None else None
 
         """ 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 """
+
+        if self.book_count is None:
+            if self.category == 'book':
+                # never used
+                objects = Book.objects.none()
+            elif self.category == 'theme':
+                objects = Fragment.tagged.with_all((self,))
+            else:
+                objects = Book.tagged.with_all((self,)).order_by()
+                if self.category != 'set':
+                    # eliminate descendants
+                    l_tags = Tag.objects.filter(slug__in=[book.book_tag_slug() for book in objects])
+                    descendants_keys = [book.pk for book in Book.tagged.with_any(l_tags)]
+                    if descendants_keys:
+                        objects = objects.exclude(pk__in=descendants_keys)
+            self.book_count = objects.count()
+            self.save()
+        return self.book_count
+

     @staticmethod
     def get_tag_list(tags):
         if isinstance(tags, basestring):
     @staticmethod
     def get_tag_list(tags):
         if isinstance(tags, basestring):

-            tag_slugs = tags.split('/')
-            return [Tag.objects.get(slug=slug) for slug in tag_slugs]
+            real_tags = []
+            ambiguous_slugs = []
+            category = None
+            tags_splitted = tags.split('/')
+            for index, name in enumerate(tags_splitted):
+                if name in Tag.categories_rev:
+                    category = Tag.categories_rev[name]
+                else:
+                    if category:
+                        real_tags.append(Tag.objects.get(slug=name, category=category))
+                        category = None
+                    else:
+                        try:
+                            real_tags.append(Tag.objects.exclude(category='book').get(slug=name))
+                        except Tag.MultipleObjectsReturned, e:
+                            ambiguous_slugs.append(name)
+
+            if category:
+                # something strange left off
+                raise Tag.DoesNotExist()
+            if ambiguous_slugs:
+                # some tags should be qualified
+                e = Tag.MultipleObjectsReturned()
+                e.tags = real_tags
+                e.ambiguous_slugs = ambiguous_slugs
+                raise e
+            else:
+                return real_tags

         else:
             return TagBase.get_tag_list(tags)
 
         else:
             return TagBase.get_tag_list(tags)
 

+    @property
+    def url_chunk(self):
+        return '/'.join((Tag.categories_dict[self.category], self.slug))

 
 

-# TODO: why is this hard-coded ? 
+
+# 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):
     def get_dynamic_path(book, filename):
         return 'lektura/%s.%s' % (book.slug, ext)


@@ -119,6 +181,7 @@ class Book(models.Model):
     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)
     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)
     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)


@@ -130,6 +193,9 @@ class Book(models.Model):
     tagged = managers.ModelTaggedItemManager(Tag)
     tags = managers.TagDescriptor(Tag)
 
     tagged = managers.ModelTaggedItemManager(Tag)
     tags = managers.TagDescriptor(Tag)
 

+    _tag_counter = JSONField(null=True, editable=False)
+    _theme_counter = JSONField(null=True, editable=False)
+

     class AlreadyExists(Exception):
         pass
 
     class AlreadyExists(Exception):
         pass
 


@@ -141,15 +207,19 @@ class Book(models.Model):
     def __unicode__(self):
         return self.title
 
     def __unicode__(self):
         return self.title
 

-    def save(self, force_insert=False, force_update=False, reset_short_html=True):
+    def save(self, force_insert=False, force_update=False, reset_short_html=True, refresh_mp3=True, **kwargs):

         if reset_short_html:
             # Reset _short_html during save
         if reset_short_html:
             # Reset _short_html during save

+            update = {}

             for key in filter(lambda x: x.startswith('_short_html'), self.__dict__):
             for key in filter(lambda x: x.startswith('_short_html'), self.__dict__):

+                update[key] = ''

                 self.__setattr__(key, '')
                 self.__setattr__(key, '')

+            # 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)
 
 
         book = super(Book, self).save(force_insert, force_update)
 

-        if self.mp3_file:
+        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())
             print self.mp3_file, self.mp3_file.path
             extra_info = self.get_extra_info_value()
             extra_info.update(self.get_mp3_info())


@@ -166,6 +236,18 @@ class Book(models.Model):
     def name(self):
         return self.title
 
     def name(self):
         return self.title
 

+    def book_tag_slug(self):
+        return ('l-' + self.slug)[:120]
+
+    def book_tag(self):
+        slug = self.book_tag_slug()
+        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.save()
+        return book_tag
+

     def short_html(self):
         key = '_short_html_%s' % get_language()
         short_html = getattr(self, key)
     def short_html(self):
         key = '_short_html_%s' % get_language()
         short_html = getattr(self, key)


@@ -181,6 +263,8 @@ class Book(models.Model):
                 formats.append(u'<a href="%s">%s</a>' % (reverse('book_text', kwargs={'slug': self.slug}), _('Read online')))
             if self.pdf_file:
                 formats.append(u'<a href="%s">PDF</a>' % self.pdf_file.url)
                 formats.append(u'<a href="%s">%s</a>' % (reverse('book_text', kwargs={'slug': self.slug}), _('Read online')))
             if self.pdf_file:
                 formats.append(u'<a href="%s">PDF</a>' % self.pdf_file.url)

+            if self.root_ancestor.epub_file:
+                formats.append(u'<a href="%s">EPUB</a>' % self.root_ancestor.epub_file.url)

             if self.odt_file:
                 formats.append(u'<a href="%s">ODT</a>' % self.odt_file.url)
             if self.txt_file:
             if self.odt_file:
                 formats.append(u'<a href="%s">ODT</a>' % self.odt_file.url)
             if self.txt_file:


@@ -198,6 +282,18 @@ class Book(models.Model):
             return mark_safe(getattr(self, key))
 
 
             return mark_safe(getattr(self, key))
 
 

+    @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 get_mp3_info(self):
         """Retrieves artist and director names from audio ID3 tags."""
         audio = id3.ID3(self.mp3_file.path)
     def get_mp3_info(self):
         """Retrieves artist and director names from audio ID3 tags."""
         audio = id3.ID3(self.mp3_file.path)


@@ -215,6 +311,11 @@ class Book(models.Model):
     has_pdf_file.short_description = 'PDF'
     has_pdf_file.boolean = True
 
     has_pdf_file.short_description = 'PDF'
     has_pdf_file.boolean = True
 

+    def has_epub_file(self):
+        return bool(self.epub_file)
+    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'
     def has_odt_file(self):
         return bool(self.odt_file)
     has_odt_file.short_description = 'ODT'


@@ -225,13 +326,59 @@ class Book(models.Model):
     has_html_file.short_description = 'HTML'
     has_html_file.boolean = True
 
     has_html_file.short_description = 'HTML'
     has_html_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, epub_file)
+            self.epub_file.save('%s.epub' % self.slug, ContentFile(epub_file.getvalue()), save=False)
+            self.save()
+            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())
+
+

     @classmethod
     def from_xml_file(cls, xml_file, overwrite=False):
         # use librarian to parse meta-data
         book_info = dcparser.parse(xml_file)
 
         if not isinstance(xml_file, File):
     @classmethod
     def from_xml_file(cls, xml_file, overwrite=False):
         # use librarian to parse meta-data
         book_info = dcparser.parse(xml_file)
 
         if not isinstance(xml_file, File):

-            xml_file = File(xml_file)
+            xml_file = File(open(xml_file))

 
         try:
             return cls.from_text_and_meta(xml_file, book_info, overwrite)
 
         try:
             return cls.from_text_and_meta(xml_file, book_info, overwrite)


@@ -243,6 +390,7 @@ class Book(models.Model):
         from tempfile import NamedTemporaryFile
         from slughifi import slughifi
         from markupstring import MarkupString
         from tempfile import NamedTemporaryFile
         from slughifi import slughifi
         from markupstring import MarkupString

+        from django.core.files.storage import default_storage

 
         # Read book metadata
         book_base, book_slug = book_info.url.rsplit('/', 1)
 
         # Read book metadata
         book_base, book_slug = book_info.url.rsplit('/', 1)


@@ -262,29 +410,27 @@ class Book(models.Model):
         book.save()
 
         book_tags = []
         book.save()
 
         book_tags = []

-        for category in ('kind', 'genre', 'author', 'epoch'):
-            tag_name = getattr(book_info, category)
-            tag_sort_key = tag_name
-            if category == 'author':
-                tag_sort_key = tag_name.last_name
-                tag_name = ' '.join(tag_name.first_names) + ' ' + tag_name.last_name
-            tag, created = Tag.objects.get_or_create(slug=slughifi(tag_name))
-            if created:
-                tag.name = tag_name
-                tag.sort_key = slughifi(tag_sort_key)
-                tag.category = category
-                tag.save()
-            book_tags.append(tag)
-
-        book_tag, created = Tag.objects.get_or_create(slug=('l-' + book.slug)[:120])
-        if created:
-            book_tag.name = book.title[:50]
-            book_tag.sort_key = ('l-' + book.slug)[:120]
-            book_tag.category = 'book'
-            book_tag.save()
-        book_tags.append(book_tag)
-
-        book.tags = book_tags
+        categories = (('kinds', 'kind'), ('genres', 'genre'), ('authors', 'author'), ('epochs', 'epoch'))
+        for field_name, category in categories:
+            try:
+                tag_names = getattr(book_info, field_name)
+            except:
+                tag_names = [getattr(book_info, category)]
+            for tag_name in tag_names:
+                tag_sort_key = tag_name
+                if category == 'author':
+                    tag_sort_key = tag_name.last_name
+                    tag_name = ' '.join(tag_name.first_names) + ' ' + tag_name.last_name
+                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.save()
+                book_tags.append(tag)
+
+        book.tags = book_tags + book_shelves
+
+        book_tag = book.book_tag()

 
         if hasattr(book_info, 'parts'):
             for n, part_url in enumerate(book_info.parts):
 
         if hasattr(book_info, 'parts'):
             for n, part_url in enumerate(book_info.parts):


@@ -297,13 +443,6 @@ class Book(models.Model):
                 except Book.DoesNotExist, e:
                     raise Book.DoesNotExist(_('Book with slug = "%s" does not exist.') % slug)
 
                 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)
-            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)
 
         # Save XML and HTML files
         book.xml_file.save('%s.xml' % book.slug, raw_file, save=False)
 


@@ -313,39 +452,103 @@ class Book(models.Model):
 
             # Extract fragments
             closed_fragments, open_fragments = html.extract_fragments(book.html_file.path)
 
             # Extract fragments
             closed_fragments, open_fragments = html.extract_fragments(book.html_file.path)

-            book_themes = []

             for fragment in closed_fragments.values():
             for fragment in closed_fragments.values():

-                text = fragment.to_string()
-                short_text = ''
-                if (len(MarkupString(text)) > 240):
-                    short_text = unicode(MarkupString(text)[:160])
-                new_fragment, created = Fragment.objects.get_or_create(anchor=fragment.id, book=book,
-                    defaults={'text': text, 'short_text': short_text})
-

                 try:
                     theme_names = [s.strip() for s in fragment.themes.split(',')]
                 except AttributeError:
                     continue
                 themes = []
                 for theme_name in theme_names:
                 try:
                     theme_names = [s.strip() for s in fragment.themes.split(',')]
                 except AttributeError:
                     continue
                 themes = []
                 for theme_name in theme_names:

-                    tag, created = Tag.objects.get_or_create(slug=slughifi(theme_name))
+                    if not theme_name:
+                        continue
+                    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)
                     if created:
                         tag.name = theme_name
                         tag.sort_key = slughifi(theme_name)

-                        tag.category = 'theme'

                         tag.save()
                     themes.append(tag)
                         tag.save()
                     themes.append(tag)

+                if not themes:
+                    continue
+
+                text = fragment.to_string()
+                short_text = ''
+                if (len(MarkupString(text)) > 240):
+                    short_text = unicode(MarkupString(text)[:160])
+                new_fragment, created = Fragment.objects.get_or_create(anchor=fragment.id, book=book,
+                    defaults={'text': text, 'short_text': short_text})
+

                 new_fragment.save()
                 new_fragment.save()

-                new_fragment.tags = set(list(book.tags) + themes + [book_tag])
-                book_themes += themes
+                new_fragment.tags = set(book_tags + themes + [book_tag])
+
+        book.build_epub(remove_descendants=False)
+
+        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]
+            if child_book.has_epub_file():
+                child_book.epub_file.delete()
+            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())

 
 

-            book_themes = set(book_themes)
-            book.tags = list(book.tags) + list(book_themes) + book_shelves
+        # refresh cache
+        book.tag_counter
+        book.theme_counter

 
         book.save()
         return book
 
 
 
         book.save()
         return book
 
 

+    def refresh_tag_counter(self):
+        tags = {}
+        for child in self.children.all().order_by():
+            for tag_pk, value in child.tag_counter.iteritems():
+                tags[tag_pk] = tags.get(tag_pk, 0) + value
+        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)
+        return tags
+
+    def reset_tag_counter(self):
+        self._tag_counter = None
+        self.save(reset_short_html=False, refresh_mp3=False)
+        if self.parent:
+            self.parent.reset_tag_counter()
+
+    @property
+    def tag_counter(self):
+        if self._tag_counter is None:
+            return self.refresh_tag_counter()
+        return dict((int(k), v) for k, v in self.get__tag_counter_value().iteritems())
+
+    def refresh_theme_counter(self):
+        tags = {}
+        for fragment in Fragment.tagged.with_any([self.book_tag()]).order_by():
+            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)
+        return tags
+
+    def reset_theme_counter(self):
+        self._theme_counter = None
+        self.save(reset_short_html=False, refresh_mp3=False)
+        if self.parent:
+            self.parent.reset_theme_counter()
+
+    @property
+    def theme_counter(self):
+        if self._theme_counter is None:
+            return self.refresh_theme_counter()
+        return dict((int(k), v) for k, v in self.get__theme_counter_value().iteritems())
+
+
+

 class Fragment(models.Model):
     text = models.TextField()
     short_text = models.TextField(editable=False)
 class Fragment(models.Model):
     text = models.TextField()
     short_text = models.TextField(editable=False)


@@ -371,11 +574,8 @@ class Fragment(models.Model):
         if short_html and len(short_html):
             return mark_safe(short_html)
         else:
         if short_html and len(short_html):
             return mark_safe(short_html)
         else:

-            book_authors = [mark_safe(u'<a href="%s">%s</a>' % (tag.get_absolute_url(), tag.name))
-                for tag in self.book.tags if tag.category == 'author']
-

             setattr(self, key, unicode(render_to_string('catalogue/fragment_short.html',
             setattr(self, key, unicode(render_to_string('catalogue/fragment_short.html',

-                {'fragment': self, 'book': self.book, 'book_authors': book_authors})))
+                {'fragment': self})))

             self.save()
             return mark_safe(getattr(self, key))
 
             self.save()
             return mark_safe(getattr(self, key))
 


@@ -408,3 +608,34 @@ class BookStub(models.Model):
         return self.title
 
 
         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)
+    sha1 = models.CharField(_('sha-1 hash'), max_length=40)
+    time = models.DateTimeField(_('time'), auto_now_add=True)
+
+    class Meta:
+        ordering = ('-time','-slug', '-type')
+        verbose_name = _('file record')
+        verbose_name_plural = _('file records')
+
+    def __unicode__(self):
+        return "%s %s.%s" % (self.sha1,  self.slug, self.type)
+
+
+def _tags_updated_handler(sender, affected_tags, **kwargs):
+    # reset tag global counter
+    Tag.objects.filter(pk__in=[tag.pk for tag in affected_tags]).update(book_count=None)
+
+    # if book tags changed, reset book tag counter
+    if isinstance(sender, Book) and \
+                Tag.objects.filter(pk__in=(tag.pk for tag in affected_tags)).\
+                    exclude(category__in=('book', 'theme', 'set')).count():
+        sender.reset_tag_counter()
+    # if fragment theme changed, reset book theme counter
+    elif isinstance(sender, Fragment) and \
+                Tag.objects.filter(pk__in=(tag.pk for tag in affected_tags)).\
+                    filter(category='theme').count():
+        sender.book.reset_theme_counter()
+tags_updated.connect(_tags_updated_handler)
+