make cached stuff in catalogue behave before model save
[wolnelektury.git] / apps / catalogue / 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 datetime import datetime
6
7 from django.db import models
8 from django.db.models import permalink, Q
9 from django.core.cache import cache
10 from django.utils.translation import ugettext_lazy as _
11 from django.contrib.auth.models import User
12 from django.core.files import File
13 from django.template.loader import render_to_string
14 from django.utils.safestring import mark_safe
15 from django.utils.translation import get_language
16 from django.core.urlresolvers import reverse
17 from django.db.models.signals import post_save, m2m_changed, pre_delete
18
19 from django.conf import settings
20
21 from newtagging.models import TagBase, tags_updated
22 from newtagging import managers
23 from catalogue.fields import JSONField, OverwritingFileField
24 from catalogue.utils import ExistingFile
25
26 from librarian import dcparser, html, epub, NoDublinCore
27 import mutagen
28 from mutagen import id3
29 from slughifi import slughifi
30 from sortify import sortify
31
32
33 TAG_CATEGORIES = (
34     ('author', _('author')),
35     ('epoch', _('epoch')),
36     ('kind', _('kind')),
37     ('genre', _('genre')),
38     ('theme', _('theme')),
39     ('set', _('set')),
40     ('book', _('book')),
41 )
42
43 MEDIA_FORMATS = (
44     ('odt', _('ODT file')),
45     ('mp3', _('MP3 file')),
46     ('ogg', _('OGG file')),
47     ('daisy', _('DAISY file')), 
48 )
49
50 class TagSubcategoryManager(models.Manager):
51     def __init__(self, subcategory):
52         super(TagSubcategoryManager, self).__init__()
53         self.subcategory = subcategory
54
55     def get_query_set(self):
56         return super(TagSubcategoryManager, self).get_query_set().filter(category=self.subcategory)
57
58
59 class Tag(TagBase):
60     name = models.CharField(_('name'), max_length=50, db_index=True)
61     slug = models.SlugField(_('slug'), max_length=120, db_index=True)
62     sort_key = models.CharField(_('sort key'), max_length=120, db_index=True)
63     category = models.CharField(_('category'), max_length=50, blank=False, null=False,
64         db_index=True, choices=TAG_CATEGORIES)
65     description = models.TextField(_('description'), blank=True)
66     main_page = models.BooleanField(_('main page'), default=False, db_index=True, help_text=_('Show tag on main page'))
67
68     user = models.ForeignKey(User, blank=True, null=True)
69     book_count = models.IntegerField(_('book count'), blank=True, null=True)
70     gazeta_link = models.CharField(blank=True, max_length=240)
71     wiki_link = models.CharField(blank=True, max_length=240)
72
73     created_at    = models.DateTimeField(_('creation date'), auto_now_add=True, db_index=True)
74     changed_at    = models.DateTimeField(_('creation date'), auto_now=True, db_index=True)
75
76     class UrlDeprecationWarning(DeprecationWarning):
77         pass
78
79     categories_rev = {
80         'autor': 'author',
81         'epoka': 'epoch',
82         'rodzaj': 'kind',
83         'gatunek': 'genre',
84         'motyw': 'theme',
85         'polka': 'set',
86     }
87     categories_dict = dict((item[::-1] for item in categories_rev.iteritems()))
88
89     class Meta:
90         ordering = ('sort_key',)
91         verbose_name = _('tag')
92         verbose_name_plural = _('tags')
93         unique_together = (("slug", "category"),)
94
95     def __unicode__(self):
96         return self.name
97
98     def __repr__(self):
99         return "Tag(slug=%r)" % self.slug
100
101     @permalink
102     def get_absolute_url(self):
103         return ('catalogue.views.tagged_object_list', [self.url_chunk])
104
105     def has_description(self):
106         return len(self.description) > 0
107     has_description.short_description = _('description')
108     has_description.boolean = True
109
110     def get_count(self):
111         """ returns global book count for book tags, fragment count for themes """
112
113         if self.book_count is None:
114             if self.category == 'book':
115                 # never used
116                 objects = Book.objects.none()
117             elif self.category == 'theme':
118                 objects = Fragment.tagged.with_all((self,))
119             else:
120                 objects = Book.tagged.with_all((self,)).order_by()
121                 if self.category != 'set':
122                     # eliminate descendants
123                     l_tags = Tag.objects.filter(slug__in=[book.book_tag_slug() for book in objects])
124                     descendants_keys = [book.pk for book in Book.tagged.with_any(l_tags)]
125                     if descendants_keys:
126                         objects = objects.exclude(pk__in=descendants_keys)
127             self.book_count = objects.count()
128             self.save()
129         return self.book_count
130
131     @staticmethod
132     def get_tag_list(tags):
133         if isinstance(tags, basestring):
134             real_tags = []
135             ambiguous_slugs = []
136             category = None
137             deprecated = False
138             tags_splitted = tags.split('/')
139             for name in tags_splitted:
140                 if category:
141                     real_tags.append(Tag.objects.get(slug=name, category=category))
142                     category = None
143                 elif name in Tag.categories_rev:
144                     category = Tag.categories_rev[name]
145                 else:
146                     try:
147                         real_tags.append(Tag.objects.exclude(category='book').get(slug=name))
148                         deprecated = True 
149                     except Tag.MultipleObjectsReturned, e:
150                         ambiguous_slugs.append(name)
151
152             if category:
153                 # something strange left off
154                 raise Tag.DoesNotExist()
155             if ambiguous_slugs:
156                 # some tags should be qualified
157                 e = Tag.MultipleObjectsReturned()
158                 e.tags = real_tags
159                 e.ambiguous_slugs = ambiguous_slugs
160                 raise e
161             if deprecated:
162                 e = Tag.UrlDeprecationWarning()
163                 e.tags = real_tags
164                 raise e
165             return real_tags
166         else:
167             return TagBase.get_tag_list(tags)
168
169     @property
170     def url_chunk(self):
171         return '/'.join((Tag.categories_dict[self.category], self.slug))
172
173
174 # TODO: why is this hard-coded ?
175 def book_upload_path(ext=None, maxlen=100):
176     def get_dynamic_path(media, filename, ext=ext):
177         # how to put related book's slug here?
178         if not ext:
179             if media.type == 'daisy':
180                 ext = 'daisy.zip'
181             else:
182                 ext = media.type
183         if not media.name:
184             name = slughifi(filename.split(".")[0])
185         else:
186             name = slughifi(media.name)
187         return 'book/%s/%s.%s' % (ext, name[:maxlen-len('book/%s/.%s' % (ext, ext))-4], ext)
188     return get_dynamic_path
189
190
191 class BookMedia(models.Model):
192     type        = models.CharField(_('type'), choices=MEDIA_FORMATS, max_length="100")
193     name        = models.CharField(_('name'), max_length="100")
194     file        = OverwritingFileField(_('file'), upload_to=book_upload_path())
195     uploaded_at = models.DateTimeField(_('creation date'), auto_now_add=True, editable=False)
196     extra_info  = JSONField(_('extra information'), default='{}', editable=False)
197     book = models.ForeignKey('Book', related_name='media')
198     source_sha1 = models.CharField(null=True, blank=True, max_length=40, editable=False)
199
200     def __unicode__(self):
201         return "%s (%s)" % (self.name, self.file.name.split("/")[-1])
202
203     class Meta:
204         ordering            = ('type', 'name')
205         verbose_name        = _('book media')
206         verbose_name_plural = _('book media')
207
208     def save(self, *args, **kwargs):
209         try:
210             old = BookMedia.objects.get(pk=self.pk)
211         except BookMedia.DoesNotExist, e:
212             pass
213         else:
214             # if name changed, change the file name, too
215             if slughifi(self.name) != slughifi(old.name):
216                 self.file.save(None, ExistingFile(self.file.path), save=False, leave=True)
217
218         super(BookMedia, self).save(*args, **kwargs)
219         extra_info = self.get_extra_info_value()
220         extra_info.update(self.read_meta())
221         self.set_extra_info_value(extra_info)
222         self.source_sha1 = self.read_source_sha1(self.file.path, self.type)
223         return super(BookMedia, self).save(*args, **kwargs)
224
225     def read_meta(self):
226         """
227             Reads some metadata from the audiobook.
228         """
229
230         artist_name = director_name = project = funded_by = ''
231         if self.type == 'mp3':
232             try:
233                 audio = id3.ID3(self.file.path)
234                 artist_name = ', '.join(', '.join(tag.text) for tag in audio.getall('TPE1'))
235                 director_name = ', '.join(', '.join(tag.text) for tag in audio.getall('TPE3'))
236                 project = ", ".join([t.data for t in audio.getall('PRIV') 
237                         if t.owner=='wolnelektury.pl?project'])
238                 funded_by = ", ".join([t.data for t in audio.getall('PRIV') 
239                         if t.owner=='wolnelektury.pl?funded_by'])
240             except:
241                 pass
242         elif self.type == 'ogg':
243             try:
244                 audio = mutagen.File(self.file.path)
245                 artist_name = ', '.join(audio.get('artist', []))
246                 director_name = ', '.join(audio.get('conductor', []))
247                 project = ", ".join(audio.get('project', []))
248                 funded_by = ", ".join(audio.get('funded_by', []))
249             except:
250                 pass
251         else:
252             return {}
253         return {'artist_name': artist_name, 'director_name': director_name,
254                 'project': project, 'funded_by': funded_by}
255
256     @staticmethod
257     def read_source_sha1(filepath, filetype):
258         """
259             Reads source file SHA1 from audiobok metadata.
260         """
261
262         if filetype == 'mp3':
263             try:
264                 audio = id3.ID3(filepath)
265                 return [t.data for t in audio.getall('PRIV') 
266                         if t.owner=='wolnelektury.pl?flac_sha1'][0]
267             except:
268                 return None
269         elif filetype == 'ogg':
270             try:
271                 audio = mutagen.File(filepath)
272                 return audio.get('flac_sha1', [None])[0] 
273             except:
274                 return None
275         else:
276             return None
277
278
279 class Book(models.Model):
280     title         = models.CharField(_('title'), max_length=120)
281     sort_key = models.CharField(_('sort_key'), max_length=120, db_index=True, editable=False)
282     slug          = models.SlugField(_('slug'), max_length=120, unique=True, db_index=True)
283     description   = models.TextField(_('description'), blank=True)
284     created_at    = models.DateTimeField(_('creation date'), auto_now_add=True, db_index=True)
285     changed_at    = models.DateTimeField(_('creation date'), auto_now=True, db_index=True)
286     parent_number = models.IntegerField(_('parent number'), default=0)
287     extra_info    = JSONField(_('extra information'), default='{}')
288     gazeta_link   = models.CharField(blank=True, max_length=240)
289     wiki_link     = models.CharField(blank=True, max_length=240)
290     # files generated during publication
291     xml_file      = models.FileField(_('XML file'), upload_to=book_upload_path('xml'), blank=True)
292     html_file     = models.FileField(_('HTML file'), upload_to=book_upload_path('html'), blank=True)
293     pdf_file      = models.FileField(_('PDF file'), upload_to=book_upload_path('pdf'), blank=True)
294     epub_file     = models.FileField(_('EPUB file'), upload_to=book_upload_path('epub'), blank=True)    
295     txt_file      = models.FileField(_('TXT file'), upload_to=book_upload_path('txt'), blank=True)        
296
297     parent        = models.ForeignKey('self', blank=True, null=True, related_name='children')
298     objects  = models.Manager()
299     tagged   = managers.ModelTaggedItemManager(Tag)
300     tags     = managers.TagDescriptor(Tag)
301
302     class AlreadyExists(Exception):
303         pass
304
305     class Meta:
306         ordering = ('sort_key',)
307         verbose_name = _('book')
308         verbose_name_plural = _('books')
309
310     def __unicode__(self):
311         return self.title
312
313     def save(self, force_insert=False, force_update=False, reset_short_html=True, **kwargs):
314         self.sort_key = sortify(self.title)
315
316         if reset_short_html:
317             self.reset_short_html()
318
319         return super(Book, self).save(force_insert, force_update)
320
321     @permalink
322     def get_absolute_url(self):
323         return ('catalogue.views.book_detail', [self.slug])
324
325     @property
326     def name(self):
327         return self.title
328
329     def book_tag_slug(self):
330         return ('l-' + self.slug)[:120]
331
332     def book_tag(self):
333         slug = self.book_tag_slug()
334         book_tag, created = Tag.objects.get_or_create(slug=slug, category='book')
335         if created:
336             book_tag.name = self.title[:50]
337             book_tag.sort_key = self.title.lower()
338             book_tag.save()
339         return book_tag
340
341     def has_media(self, type):
342         if   type == 'xml':
343             if self.xml_file:
344                 return True
345             else:
346                 return False
347         elif type == 'html':
348             if self.html_file:
349                 return True
350             else:
351                 return False        
352         elif type == 'txt':
353             if self.txt_file:
354                 return True
355             else:
356                 return False        
357         elif type == 'pdf':
358             if self.pdf_file:
359                 return True
360             else:
361                 return False  
362         elif type == 'epub':
363             if self.epub_file:
364                 return True
365             else:
366                 return False                          
367         else:
368             if self.media.filter(type=type).exists():
369                 return True
370             else:
371                 return False
372
373     def get_media(self, type):
374         if self.has_media(type):
375             if   type == "xml":
376                 return self.xml_file
377             elif type == "html":
378                 return self.html_file
379             elif type == "epub":
380                 return self.epub_file
381             elif type == "txt":
382                 return self.txt_file
383             elif type == "pdf":
384                 return self.pdf_file
385             else:                                             
386                 return self.media.filter(type=type)
387         else:
388             return None
389
390     def get_mp3(self):
391         return self.get_media("mp3")
392     def get_odt(self):
393         return self.get_media("odt")
394     def get_ogg(self):
395         return self.get_media("ogg")
396     def get_daisy(self):
397         return self.get_media("daisy")                       
398
399     def reset_short_html(self):
400         if self.id is None:
401             return
402
403         cache_key = "Book.short_html/%d/%s"
404         for lang, langname in settings.LANGUAGES:
405             cache.delete(cache_key % (self.id, lang))
406         # Fragment.short_html relies on book's tags, so reset it here too
407         for fragm in self.fragments.all():
408             fragm.reset_short_html()
409
410     def short_html(self):
411         if self.id:
412             cache_key = "Book.short_html/%d/%s" % (self.id, get_language())
413             short_html = cache.get(cache_key)
414         else:
415             short_html = None
416
417         if short_html is not None:
418             return mark_safe(short_html)
419         else:
420             tags = self.tags.filter(~Q(category__in=('set', 'theme', 'book')))
421             tags = [mark_safe(u'<a href="%s">%s</a>' % (tag.get_absolute_url(), tag.name)) for tag in tags]
422
423             formats = []
424             # files generated during publication               
425             if self.has_media("html"):
426                 formats.append(u'<a href="%s">%s</a>' % (reverse('book_text', kwargs={'slug': self.slug}), _('Read online')))
427             if self.has_media("pdf"):
428                 formats.append(u'<a href="%s">PDF</a>' % self.get_media('pdf').url)
429             if self.root_ancestor.has_media("epub"):
430                 formats.append(u'<a href="%s">EPUB</a>' % self.root_ancestor.get_media('epub').url)
431             if self.has_media("txt"):
432                 formats.append(u'<a href="%s">TXT</a>' % self.get_media('txt').url)
433             # other files
434             for m in self.media.order_by('type'):
435                 formats.append(u'<a href="%s">%s</a>' % (m.file.url, m.type.upper()))
436
437             formats = [mark_safe(format) for format in formats]
438
439             short_html = unicode(render_to_string('catalogue/book_short.html',
440                 {'book': self, 'tags': tags, 'formats': formats}))
441
442             if self.id:
443                 cache.set(cache_key, short_html)
444             return mark_safe(short_html)
445
446     @property
447     def root_ancestor(self):
448         """ returns the oldest ancestor """
449
450         if not hasattr(self, '_root_ancestor'):
451             book = self
452             while book.parent:
453                 book = book.parent
454             self._root_ancestor = book
455         return self._root_ancestor
456
457
458     def has_description(self):
459         return len(self.description) > 0
460     has_description.short_description = _('description')
461     has_description.boolean = True
462
463     # ugly ugly ugly
464     def has_pdf_file(self):
465         return bool(self.pdf_file)
466     has_pdf_file.short_description = 'PDF'
467     has_pdf_file.boolean = True
468
469     def has_epub_file(self):
470         return bool(self.epub_file)
471     has_epub_file.short_description = 'EPUB'
472     has_epub_file.boolean = True
473
474     def has_txt_file(self):
475         return bool(self.txt_file)
476     has_txt_file.short_description = 'HTML'
477     has_txt_file.boolean = True
478
479     def has_html_file(self):
480         return bool(self.html_file)
481     has_html_file.short_description = 'HTML'
482     has_html_file.boolean = True
483
484     def has_odt_file(self):
485         return bool(self.has_media("odt"))
486     has_odt_file.short_description = 'ODT'
487     has_odt_file.boolean = True
488
489     def has_mp3_file(self):
490         return bool(self.has_media("mp3"))
491     has_mp3_file.short_description = 'MP3'
492     has_mp3_file.boolean = True
493
494     def has_ogg_file(self):
495         return bool(self.has_media("ogg"))
496     has_ogg_file.short_description = 'OGG'
497     has_ogg_file.boolean = True
498     
499     def has_daisy_file(self):
500         return bool(self.has_media("daisy"))
501     has_daisy_file.short_description = 'DAISY'
502     has_daisy_file.boolean = True    
503     
504     def build_epub(self, remove_descendants=True):
505         """ (Re)builds the epub file.
506             If book has a parent, does nothing.
507             Unless remove_descendants is False, descendants' epubs are removed.
508         """
509     
510         from StringIO import StringIO
511         from hashlib import sha1
512         from django.core.files.base import ContentFile
513         from librarian import DocProvider
514
515         class BookImportDocProvider(DocProvider):
516             """ used for joined EPUBs """
517
518             def __init__(self, book):
519                 self.book = book
520
521             def by_slug(self, slug):
522                 if slug == self.book.slug:
523                     return self.book.xml_file
524                 else:
525                     return Book.objects.get(slug=slug).xml_file
526
527         if self.parent:
528             # don't need an epub
529             return
530
531         epub_file = StringIO()
532         try:
533             epub.transform(BookImportDocProvider(self), self.slug, output_file=epub_file)
534             self.epub_file.save('%s.epub' % self.slug, ContentFile(epub_file.getvalue()))
535             FileRecord(slug=self.slug, type='epub', sha1=sha1(epub_file.getvalue()).hexdigest()).save()
536         except NoDublinCore:
537             pass
538
539         book_descendants = list(self.children.all())
540         while len(book_descendants) > 0:
541             child_book = book_descendants.pop(0)
542             if remove_descendants and child_book.has_epub_file():
543                 child_book.epub_file.delete()
544             # save anyway, to refresh short_html
545             child_book.save()
546             book_descendants += list(child_book.children.all())
547
548     def build_txt(self):
549         from StringIO import StringIO
550         from django.core.files.base import ContentFile
551         from librarian import text
552
553         out = StringIO()
554         text.transform(open(self.xml_file.path), out)
555         self.txt_file.save('%s.txt' % self.slug, ContentFile(out.getvalue()))
556
557
558     def build_html(self):
559         from tempfile import NamedTemporaryFile
560         from markupstring import MarkupString
561
562         meta_tags = list(self.tags.filter(
563             category__in=('author', 'epoch', 'genre', 'kind')))
564         book_tag = self.book_tag()
565
566         html_file = NamedTemporaryFile()
567         if html.transform(self.xml_file.path, html_file, parse_dublincore=False):
568             self.html_file.save('%s.html' % self.slug, File(html_file))
569
570             # get ancestor l-tags for adding to new fragments
571             ancestor_tags = []
572             p = self.parent
573             while p:
574                 ancestor_tags.append(p.book_tag())
575                 p = p.parent
576
577             # Delete old fragments and create them from scratch
578             self.fragments.all().delete()
579             # Extract fragments
580             closed_fragments, open_fragments = html.extract_fragments(self.html_file.path)
581             for fragment in closed_fragments.values():
582                 try:
583                     theme_names = [s.strip() for s in fragment.themes.split(',')]
584                 except AttributeError:
585                     continue
586                 themes = []
587                 for theme_name in theme_names:
588                     if not theme_name:
589                         continue
590                     tag, created = Tag.objects.get_or_create(slug=slughifi(theme_name), category='theme')
591                     if created:
592                         tag.name = theme_name
593                         tag.sort_key = theme_name.lower()
594                         tag.save()
595                     themes.append(tag)
596                 if not themes:
597                     continue
598
599                 text = fragment.to_string()
600                 short_text = ''
601                 if (len(MarkupString(text)) > 240):
602                     short_text = unicode(MarkupString(text)[:160])
603                 new_fragment = Fragment.objects.create(anchor=fragment.id, book=self,
604                     text=text, short_text=short_text)
605
606                 new_fragment.save()
607                 new_fragment.tags = set(meta_tags + themes + [book_tag] + ancestor_tags)
608             self.save()
609             return True
610         return False
611
612
613     @classmethod
614     def from_xml_file(cls, xml_file, **kwargs):
615         # use librarian to parse meta-data
616         book_info = dcparser.parse(xml_file)
617
618         if not isinstance(xml_file, File):
619             xml_file = File(open(xml_file))
620
621         try:
622             return cls.from_text_and_meta(xml_file, book_info, **kwargs)
623         finally:
624             xml_file.close()
625
626     @classmethod
627     def from_text_and_meta(cls, raw_file, book_info, overwrite=False, build_epub=True, build_txt=True):
628         import re
629
630         # check for parts before we do anything
631         children = []
632         if hasattr(book_info, 'parts'):
633             for part_url in book_info.parts:
634                 base, slug = part_url.rsplit('/', 1)
635                 try:
636                     children.append(Book.objects.get(slug=slug))
637                 except Book.DoesNotExist, e:
638                     raise Book.DoesNotExist(_('Book with slug = "%s" does not exist.') % slug)
639
640
641         # Read book metadata
642         book_base, book_slug = book_info.url.rsplit('/', 1)
643         if re.search(r'[^a-zA-Z0-9-]', book_slug):
644             raise ValueError('Invalid characters in slug')
645         book, created = Book.objects.get_or_create(slug=book_slug)
646
647         if created:
648             book_shelves = []
649         else:
650             if not overwrite:
651                 raise Book.AlreadyExists(_('Book %s already exists') % book_slug)
652             # Save shelves for this book
653             book_shelves = list(book.tags.filter(category='set'))
654
655         book.title = book_info.title
656         book.set_extra_info_value(book_info.to_dict())
657         book.save()
658
659         meta_tags = []
660         categories = (('kinds', 'kind'), ('genres', 'genre'), ('authors', 'author'), ('epochs', 'epoch'))
661         for field_name, category in categories:
662             try:
663                 tag_names = getattr(book_info, field_name)
664             except:
665                 tag_names = [getattr(book_info, category)]
666             for tag_name in tag_names:
667                 tag_sort_key = tag_name
668                 if category == 'author':
669                     tag_sort_key = tag_name.last_name
670                     tag_name = ' '.join(tag_name.first_names) + ' ' + tag_name.last_name
671                 tag, created = Tag.objects.get_or_create(slug=slughifi(tag_name), category=category)
672                 if created:
673                     tag.name = tag_name
674                     tag.sort_key = sortify(tag_sort_key.lower())
675                     tag.save()
676                 meta_tags.append(tag)
677
678         book.tags = set(meta_tags + book_shelves)
679
680         book_tag = book.book_tag()
681
682         for n, child_book in enumerate(children):
683             child_book.parent = book
684             child_book.parent_number = n
685             child_book.save()
686
687         # Save XML and HTML files
688         book.xml_file.save('%s.xml' % book.slug, raw_file, save=False)
689
690         # delete old fragments when overwriting
691         book.fragments.all().delete()
692
693         if book.build_html():
694             if not settings.NO_BUILD_TXT and build_txt:
695                 book.build_txt()
696
697         if not settings.NO_BUILD_EPUB and build_epub:
698             book.root_ancestor.build_epub()
699
700         book_descendants = list(book.children.all())
701         # add l-tag to descendants and their fragments
702         # delete unnecessary EPUB files
703         while len(book_descendants) > 0:
704             child_book = book_descendants.pop(0)
705             child_book.tags = list(child_book.tags) + [book_tag]
706             child_book.save()
707             for fragment in child_book.fragments.all():
708                 fragment.tags = set(list(fragment.tags) + [book_tag])
709             book_descendants += list(child_book.children.all())
710
711         # refresh cache
712         book.reset_tag_counter()
713         book.reset_theme_counter()
714
715         book.save()
716         return book
717
718     def reset_tag_counter(self):
719         if self.id is None:
720             return
721
722         cache_key = "Book.tag_counter/%d" % self.id
723         cache.delete(cache_key)
724         if self.parent:
725             self.parent.reset_tag_counter()
726
727     @property
728     def tag_counter(self):
729         if self.id:
730             cache_key = "Book.tag_counter/%d" % self.id
731             tags = cache.get(cache_key)
732         else:
733             tags = None
734
735         if tags is None:
736             tags = {}
737             for child in self.children.all().order_by():
738                 for tag_pk, value in child.tag_counter.iteritems():
739                     tags[tag_pk] = tags.get(tag_pk, 0) + value
740             for tag in self.tags.exclude(category__in=('book', 'theme', 'set')).order_by():
741                 tags[tag.pk] = 1
742
743             if self.id:
744                 cache.set(cache_key, tags)
745         return tags
746
747     def reset_theme_counter(self):
748         if self.id is None:
749             return
750
751         cache_key = "Book.theme_counter/%d" % self.id
752         cache.delete(cache_key)
753         if self.parent:
754             self.parent.reset_theme_counter()
755
756     @property
757     def theme_counter(self):
758         if self.id:
759             cache_key = "Book.theme_counter/%d" % self.id
760             tags = cache.get(cache_key)
761         else:
762             tags = None
763
764         if tags is None:
765             tags = {}
766             for fragment in Fragment.tagged.with_any([self.book_tag()]).order_by():
767                 for tag in fragment.tags.filter(category='theme').order_by():
768                     tags[tag.pk] = tags.get(tag.pk, 0) + 1
769
770             if self.id:
771                 cache.set(cache_key, tags)
772         return tags
773
774     def pretty_title(self, html_links=False):
775         book = self
776         names = list(book.tags.filter(category='author'))
777
778         books = []
779         while book:
780             books.append(book)
781             book = book.parent
782         names.extend(reversed(books))
783
784         if html_links:
785             names = ['<a href="%s">%s</a>' % (tag.get_absolute_url(), tag.name) for tag in names]
786         else:
787             names = [tag.name for tag in names]
788
789         return ', '.join(names)
790
791     @classmethod
792     def tagged_top_level(cls, tags):
793         """ Returns top-level books tagged with `tags'.
794
795         It only returns those books which don't have ancestors which are
796         also tagged with those tags.
797
798         """
799         # get relevant books and their tags
800         objects = cls.tagged.with_all(tags)
801         # eliminate descendants
802         l_tags = Tag.objects.filter(category='book', slug__in=[book.book_tag_slug() for book in objects])
803         descendants_keys = [book.pk for book in cls.tagged.with_any(l_tags)]
804         if descendants_keys:
805             objects = objects.exclude(pk__in=descendants_keys)
806
807         return objects
808
809
810 class Fragment(models.Model):
811     text = models.TextField()
812     short_text = models.TextField(editable=False)
813     anchor = models.CharField(max_length=120)
814     book = models.ForeignKey(Book, related_name='fragments')
815
816     objects = models.Manager()
817     tagged = managers.ModelTaggedItemManager(Tag)
818     tags = managers.TagDescriptor(Tag)
819
820     class Meta:
821         ordering = ('book', 'anchor',)
822         verbose_name = _('fragment')
823         verbose_name_plural = _('fragments')
824
825     def get_absolute_url(self):
826         return '%s#m%s' % (reverse('book_text', kwargs={'slug': self.book.slug}), self.anchor)
827
828     def reset_short_html(self):
829         if self.id is None:
830             return
831
832         cache_key = "Fragment.short_html/%d/%s"
833         for lang, langname in settings.LANGUAGES:
834             cache.delete(cache_key % (self.id, lang))
835
836     def short_html(self):
837         if self.id:
838             cache_key = "Fragment.short_html/%d/%s" % (self.id, get_language())
839             short_html = cache.get(cache_key)
840         else:
841             short_html = None
842
843         if short_html is not None:
844             return mark_safe(short_html)
845         else:
846             short_html = unicode(render_to_string('catalogue/fragment_short.html',
847                 {'fragment': self}))
848             if self.id:
849                 cache.set(cache_key, short_html)
850             return mark_safe(short_html)
851
852
853 class FileRecord(models.Model):
854     slug = models.SlugField(_('slug'), max_length=120, db_index=True)
855     type = models.CharField(_('type'), max_length=20, db_index=True)
856     sha1 = models.CharField(_('sha-1 hash'), max_length=40)
857     time = models.DateTimeField(_('time'), auto_now_add=True)
858
859     class Meta:
860         ordering = ('-time','-slug', '-type')
861         verbose_name = _('file record')
862         verbose_name_plural = _('file records')
863
864     def __unicode__(self):
865         return "%s %s.%s" % (self.sha1,  self.slug, self.type)
866
867 ###########
868 #
869 # SIGNALS
870 #
871 ###########
872
873
874 def _tags_updated_handler(sender, affected_tags, **kwargs):
875     # reset tag global counter
876     # we want Tag.changed_at updated for API to know the tag was touched
877     Tag.objects.filter(pk__in=[tag.pk for tag in affected_tags]).update(book_count=None, changed_at=datetime.now())
878
879     # if book tags changed, reset book tag counter
880     if isinstance(sender, Book) and \
881                 Tag.objects.filter(pk__in=(tag.pk for tag in affected_tags)).\
882                     exclude(category__in=('book', 'theme', 'set')).count():
883         sender.reset_tag_counter()
884     # if fragment theme changed, reset book theme counter
885     elif isinstance(sender, Fragment) and \
886                 Tag.objects.filter(pk__in=(tag.pk for tag in affected_tags)).\
887                     filter(category='theme').count():
888         sender.book.reset_theme_counter()
889 tags_updated.connect(_tags_updated_handler)
890
891
892 def _pre_delete_handler(sender, instance, **kwargs):
893     """ refresh Book on BookMedia delete """
894     if sender == BookMedia:
895         instance.book.save()
896 pre_delete.connect(_pre_delete_handler)
897
898 def _post_save_handler(sender, instance, **kwargs):
899     """ refresh all the short_html stuff on BookMedia update """
900     if sender == BookMedia:
901         instance.book.save()
902 post_save.connect(_post_save_handler)