apps/catalogue/fields.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.conf import settings
   6 from django.core.files import File
   7 from django.db import models
   8 from django.db.models.fields.files import FieldFile
   9 from catalogue import app_settings
  10 from catalogue.constants import LANGUAGES_3TO2
  11 from catalogue.utils import remove_zip, truncate_html_words
  12 from celery.task import Task, task
  13 from waiter.utils import clear_cache
  14
  15
  16 class EbookFieldFile(FieldFile):
  17     """Represents contents of an ebook file field."""
  18
  19     def build(self):
  20         """Build the ebook immediately."""
  21         return self.field.builder.build(self)
  22
  23     def build_delay(self):
  24         """Builds the ebook in a delayed task."""
  25         return self.field.builder.delay(self.instance, self.field.attname)
  26
  27
  28 class EbookField(models.FileField):
  29     """Represents an ebook file field, attachable to a model."""
  30     attr_class = EbookFieldFile
  31
  32     def __init__(self, format_name, *args, **kwargs):
  33         super(EbookField, self).__init__(*args, **kwargs)
  34         self.format_name = format_name
  35
  36     @property
  37     def builder(self):
  38         """Finds a celery task suitable for the format of the field."""
  39         return BuildEbook.for_format(self.format_name)
  40
  41     def contribute_to_class(self, cls, name):
  42         super(EbookField, self).contribute_to_class(cls, name)
  43
  44         def has(model_instance):
  45             return bool(getattr(model_instance, self.attname, None))
  46         has.__doc__ = None
  47         has.__name__ = "has_%s" % self.attname
  48         has.short_description = self.name
  49         has.boolean = True
  50         setattr(cls, 'has_%s' % self.attname, has)
  51
  52
  53 class BuildEbook(Task):
  54     formats = {}
  55
  56     @classmethod
  57     def register(cls, format_name):
  58         """A decorator for registering subclasses for particular formats."""
  59         def wrapper(builder):
  60             cls.formats[format_name] = builder
  61             return builder
  62         return wrapper
  63
  64     @classmethod
  65     def for_format(cls, format_name):
  66         """Returns a celery task suitable for specified format."""
  67         return cls.formats.get(format_name, BuildEbookTask)
  68
  69     @staticmethod
  70     def transform(wldoc, fieldfile):
  71         """Transforms an librarian.WLDocument into an librarian.OutputFile.
  72
  73         By default, it just calls relevant wldoc.as_??? method.
  74
  75         """
  76         return getattr(wldoc, "as_%s" % fieldfile.field.format_name)()
  77
  78     def run(self, obj, field_name):
  79         """Just run `build` on FieldFile, can't pass it directly to Celery."""
  80         return self.build(getattr(obj, field_name))
  81
  82     def build(self, fieldfile):
  83         book = fieldfile.instance
  84         out = self.transform(book.wldocument(), fieldfile)
  85         fieldfile.save(None, File(open(out.get_filename())), save=False)
  86         if book.pk is not None:
  87             type(book).objects.filter(pk=book.pk).update(**{
  88                 fieldfile.field.attname: fieldfile
  89             })
  90         if fieldfile.field.format_name in app_settings.FORMAT_ZIPS:
  91             remove_zip(app_settings.FORMAT_ZIPS[fieldfile.field.format_name])
  92 # Don't decorate BuildEbook, because we want to subclass it.
  93 BuildEbookTask = task(BuildEbook, ignore_result=True)
  94
  95
  96 @BuildEbook.register('txt')
  97 @task(ignore_result=True)
  98 class BuildTxt(BuildEbook):
  99     @staticmethod
 100     def transform(wldoc, fieldfile):
 101         return wldoc.as_text()
 102
 103
 104 @BuildEbook.register('pdf')
 105 @task(ignore_result=True)
 106 class BuildPdf(BuildEbook):
 107     @staticmethod
 108     def transform(wldoc, fieldfile):
 109         return wldoc.as_pdf(morefloats=settings.LIBRARIAN_PDF_MOREFLOATS,
 110             cover=True)
 111
 112     def build(self, fieldfile):
 113         BuildEbook.build(self, fieldfile)
 114         clear_cache(fieldfile.instance.slug)
 115
 116
 117 @BuildEbook.register('epub')
 118 @task(ignore_result=True)
 119 class BuildEpub(BuildEbook):
 120     @staticmethod
 121     def transform(wldoc, fieldfile):
 122         return wldoc.as_epub(cover=True)
 123
 124
 125 @BuildEbook.register('html')
 126 @task(ignore_result=True)
 127 class BuildHtml(BuildEbook):
 128     def build(self, fieldfile):
 129         from django.core.files.base import ContentFile
 130         from fnpdjango.utils.text.slughifi import slughifi
 131         from sortify import sortify
 132         from librarian import html
 133         from catalogue.models import Fragment, Tag
 134
 135         book = fieldfile.instance
 136
 137         meta_tags = list(book.tags.filter(
 138             category__in=('author', 'epoch', 'genre', 'kind')))
 139         book_tag = book.book_tag()
 140
 141         html_output = self.transform(
 142                         book.wldocument(parse_dublincore=False),
 143                         fieldfile)
 144         lang = book.language
 145         lang = LANGUAGES_3TO2.get(lang, lang)
 146         if lang not in [ln[0] for ln in settings.LANGUAGES]:
 147             lang = None
 148
 149         if html_output:
 150             fieldfile.save(None, ContentFile(html_output.get_string()),
 151                     save=False)
 152             type(book).objects.filter(pk=book.pk).update(**{
 153                 fieldfile.field.attname: fieldfile
 154             })
 155
 156             # get ancestor l-tags for adding to new fragments
 157             ancestor_tags = []
 158             p = book.parent
 159             while p:
 160                 ancestor_tags.append(p.book_tag())
 161                 p = p.parent
 162
 163             # Delete old fragments and create them from scratch
 164             book.fragments.all().delete()
 165             # Extract fragments
 166             closed_fragments, open_fragments = html.extract_fragments(fieldfile.path)
 167             for fragment in closed_fragments.values():
 168                 try:
 169                     theme_names = [s.strip() for s in fragment.themes.split(',')]
 170                 except AttributeError:
 171                     continue
 172                 themes = []
 173                 for theme_name in theme_names:
 174                     if not theme_name:
 175                         continue
 176                     if lang == settings.LANGUAGE_CODE:
 177                         # Allow creating themes if book in default language.
 178                         tag, created = Tag.objects.get_or_create(
 179                                             slug=slughifi(theme_name),
 180                                             category='theme')
 181                         if created:
 182                             tag.name = theme_name
 183                             setattr(tag, "name_%s" % lang, theme_name)
 184                             tag.sort_key = sortify(theme_name.lower())
 185                             tag.save()
 186                         themes.append(tag)
 187                     elif lang is not None:
 188                         # Don't create unknown themes in non-default languages.
 189                         try:
 190                             tag = Tag.objects.get(category='theme',
 191                                     **{"name_%s" % lang: theme_name})
 192                         except Tag.DoesNotExist:
 193                             pass
 194                         else:
 195                             themes.append(tag)
 196                 if not themes:
 197                     continue
 198
 199                 text = fragment.to_string()
 200                 short_text = truncate_html_words(text, 15)
 201                 if text == short_text:
 202                     short_text = ''
 203                 new_fragment = Fragment.objects.create(anchor=fragment.id,
 204                         book=book, text=text, short_text=short_text)
 205
 206                 new_fragment.save()
 207                 new_fragment.tags = set(meta_tags + themes + [book_tag] + ancestor_tags)
 208             book.html_built.send(sender=book)
 209             return True
 210         return False
 211
 212
 213 class OverwritingFieldFile(FieldFile):
 214     """
 215         Deletes the old file before saving the new one.
 216     """
 217
 218     def save(self, name, content, *args, **kwargs):
 219         leave = kwargs.pop('leave', None)
 220         # delete if there's a file already and there's a new one coming
 221         if not leave and self and (not hasattr(content, 'path') or
 222                                    content.path != self.path):
 223             self.delete(save=False)
 224         return super(OverwritingFieldFile, self).save(
 225                 name, content, *args, **kwargs)
 226
 227
 228 class OverwritingFileField(models.FileField):
 229     attr_class = OverwritingFieldFile
 230
 231
 232 try:
 233     # check for south
 234     from south.modelsinspector import add_introspection_rules
 235 except ImportError:
 236     pass
 237 else:
 238     add_introspection_rules([
 239         (
 240             [EbookField],
 241             [],
 242             {'format_name': ('format_name', {})}
 243         )
 244     ], ["^catalogue\.fields\.EbookField"])
 245     add_introspection_rules([], ["^catalogue\.fields\.OverwritingFileField"])