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         html_output = self.transform(
 138                         book.wldocument(parse_dublincore=False),
 139                         fieldfile)
 140
 141         # Delete old fragments, create from scratch if necessary.
 142         book.fragments.all().delete()
 143
 144         if html_output:
 145             meta_tags = list(book.tags.filter(
 146                 category__in=('author', 'epoch', 'genre', 'kind')))
 147             book_tag = book.book_tag()
 148
 149             lang = book.language
 150             lang = LANGUAGES_3TO2.get(lang, lang)
 151             if lang not in [ln[0] for ln in settings.LANGUAGES]:
 152                 lang = None
 153
 154             fieldfile.save(None, ContentFile(html_output.get_string()),
 155                     save=False)
 156             type(book).objects.filter(pk=book.pk).update(**{
 157                 fieldfile.field.attname: fieldfile
 158             })
 159
 160             # get ancestor l-tags for adding to new fragments
 161             ancestor_tags = []
 162             p = book.parent
 163             while p:
 164                 ancestor_tags.append(p.book_tag())
 165                 p = p.parent
 166
 167             # Extract fragments
 168             closed_fragments, open_fragments = html.extract_fragments(fieldfile.path)
 169             for fragment in closed_fragments.values():
 170                 try:
 171                     theme_names = [s.strip() for s in fragment.themes.split(',')]
 172                 except AttributeError:
 173                     continue
 174                 themes = []
 175                 for theme_name in theme_names:
 176                     if not theme_name:
 177                         continue
 178                     if lang == settings.LANGUAGE_CODE:
 179                         # Allow creating themes if book in default language.
 180                         tag, created = Tag.objects.get_or_create(
 181                                             slug=slughifi(theme_name),
 182                                             category='theme')
 183                         if created:
 184                             tag.name = theme_name
 185                             setattr(tag, "name_%s" % lang, theme_name)
 186                             tag.sort_key = sortify(theme_name.lower())
 187                             tag.save()
 188                         themes.append(tag)
 189                     elif lang is not None:
 190                         # Don't create unknown themes in non-default languages.
 191                         try:
 192                             tag = Tag.objects.get(category='theme',
 193                                     **{"name_%s" % lang: theme_name})
 194                         except Tag.DoesNotExist:
 195                             pass
 196                         else:
 197                             themes.append(tag)
 198                 if not themes:
 199                     continue
 200
 201                 text = fragment.to_string()
 202                 short_text = truncate_html_words(text, 15)
 203                 if text == short_text:
 204                     short_text = ''
 205                 new_fragment = Fragment.objects.create(anchor=fragment.id,
 206                         book=book, text=text, short_text=short_text)
 207
 208                 new_fragment.save()
 209                 new_fragment.tags = set(meta_tags + themes + [book_tag] + ancestor_tags)
 210             book.fix_tree_tags()
 211             book.html_built.send(sender=book)
 212             return True
 213         book.fix_tree_tags()
 214         return False
 215
 216 @BuildEbook.register('cover_thumb')
 217 @task(ignore_result=True)
 218 class BuildCoverThumb(BuildEbook):
 219     @classmethod
 220     def transform(cls, wldoc, fieldfile):
 221         from librarian.cover import WLCover
 222         return WLCover(wldoc.book_info, height=193).output_file()
 223
 224
 225
 226 class OverwritingFieldFile(FieldFile):
 227     """
 228         Deletes the old file before saving the new one.
 229     """
 230
 231     def save(self, name, content, *args, **kwargs):
 232         leave = kwargs.pop('leave', None)
 233         # delete if there's a file already and there's a new one coming
 234         if not leave and self and (not hasattr(content, 'path') or
 235                                    content.path != self.path):
 236             self.delete(save=False)
 237         return super(OverwritingFieldFile, self).save(
 238                 name, content, *args, **kwargs)
 239
 240
 241 class OverwritingFileField(models.FileField):
 242     attr_class = OverwritingFieldFile
 243
 244
 245 try:
 246     # check for south
 247     from south.modelsinspector import add_introspection_rules
 248 except ImportError:
 249     pass
 250 else:
 251     add_introspection_rules([
 252         (
 253             [EbookField],
 254             [],
 255             {'format_name': ('format_name', {})}
 256         )
 257     ], ["^catalogue\.fields\.EbookField"])
 258     add_introspection_rules([], ["^catalogue\.fields\.OverwritingFileField"])