src/catalogue/fields.py

   1 # This file is part of Wolnelektury, licensed under GNU Affero GPLv3 or later.
   2 # Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information.
   3 #
   4 from django.conf import settings
   5 from django.core.files import File
   6 from django.core.files.storage import FileSystemStorage
   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, EBOOK_FORMATS_WITH_CHILDREN, EBOOK_FORMATS_WITHOUT_CHILDREN
  11 from catalogue.utils import absolute_url, remove_zip, truncate_html_words, gallery_path, gallery_url
  12 from celery.task import Task, task
  13 from celery.utils.log import get_task_logger
  14 from waiter.utils import clear_cache
  15
  16 task_logger = get_task_logger(__name__)
  17
  18 ETAG_SCHEDULED_SUFFIX = '-scheduled'
  19 EBOOK_BUILD_PRIORITY = 0
  20 EBOOK_REBUILD_PRIORITY = 9
  21
  22
  23 class EbookFieldFile(FieldFile):
  24     """Represents contents of an ebook file field."""
  25
  26     def build(self):
  27         """Build the ebook immediately."""
  28         return self.field.builder.build(self)
  29
  30     def build_delay(self, priority=EBOOK_BUILD_PRIORITY):
  31         """Builds the ebook in a delayed task."""
  32         self.update_etag(
  33             "".join([self.field.get_current_etag(), ETAG_SCHEDULED_SUFFIX])
  34         )
  35         return self.field.builder.apply_async(
  36             [self.instance, self.field.attname],
  37             priority=priority
  38         )
  39
  40     def get_url(self):
  41         return self.instance.media_url(self.field.attname.split('_')[0])
  42
  43     def set_readable(self, readable):
  44         import os
  45         permissions = 0o644 if readable else 0o600
  46         os.chmod(self.path, permissions)
  47
  48     def update_etag(self, etag):
  49         setattr(self.instance, self.field.etag_field_name, etag)
  50         if self.instance.pk:
  51             self.instance.save(update_fields=[self.field.etag_field_name])
  52
  53
  54 class EbookField(models.FileField):
  55     """Represents an ebook file field, attachable to a model."""
  56     attr_class = EbookFieldFile
  57     registry = []
  58
  59     def __init__(self, format_name, *args, **kwargs):
  60         super(EbookField, self).__init__(*args, **kwargs)
  61         self.format_name = format_name
  62
  63     def deconstruct(self):
  64         name, path, args, kwargs = super(EbookField, self).deconstruct()
  65         args.insert(0, self.format_name)
  66         return name, path, args, kwargs
  67
  68     @property
  69     def builder(self):
  70         """Finds a celery task suitable for the format of the field."""
  71         return BuildEbook.for_format(self.format_name)
  72
  73     def contribute_to_class(self, cls, name):
  74         super(EbookField, self).contribute_to_class(cls, name)
  75
  76         self.etag_field_name = f'{name}_etag'
  77
  78         def has(model_instance):
  79             return bool(getattr(model_instance, self.attname, None))
  80         has.__doc__ = None
  81         has.__name__ = str("has_%s" % self.attname)
  82         has.short_description = self.name
  83         has.boolean = True
  84
  85         self.registry.append(self)
  86
  87         setattr(cls, 'has_%s' % self.attname, has)
  88
  89     def get_current_etag(self):
  90         import pkg_resources
  91         librarian_version = pkg_resources.get_distribution("librarian").version
  92         return librarian_version
  93
  94     def schedule_stale(self, queryset=None):
  95         """Schedule building this format for all the books where etag is stale."""
  96         # If there is not ETag field, bail. That's true for xml file field.
  97         if not hasattr(self.model, f'{self.attname}_etag'):
  98             return
  99
 100         etag = self.get_current_etag()
 101         if queryset is None:
 102             queryset = self.model.objects.all()
 103
 104         if self.format_name in EBOOK_FORMATS_WITHOUT_CHILDREN + ['html']:
 105             queryset = queryset.filter(children=None)
 106
 107         queryset = queryset.exclude(**{
 108             f'{self.etag_field_name}__in': [
 109                 etag, f'{etag}{ETAG_SCHEDULED_SUFFIX}'
 110             ]
 111         })
 112         for obj in queryset:
 113             fieldfile = getattr(obj, self.attname)
 114             priority = EBOOK_REBUILD_PRIORITY if fieldfile else EBOOK_BUILD_PRIORITY
 115             fieldfile.build_delay(priority=priority)
 116
 117     @classmethod
 118     def schedule_all_stale(cls):
 119         """Schedules all stale ebooks of all formats to rebuild."""
 120         for field in cls.registry:
 121             field.schedule_stale()
 122
 123
 124
 125 class BuildEbook(Task):
 126     formats = {}
 127
 128     @classmethod
 129     def register(cls, format_name):
 130         """A decorator for registering subclasses for particular formats."""
 131         def wrapper(builder):
 132             cls.formats[format_name] = builder
 133             return builder
 134         return wrapper
 135
 136     @classmethod
 137     def for_format(cls, format_name):
 138         """Returns a celery task suitable for specified format."""
 139         return cls.formats.get(format_name, BuildEbookTask)
 140
 141     @staticmethod
 142     def transform(wldoc, fieldfile):
 143         """Transforms an librarian.WLDocument into an librarian.OutputFile.
 144
 145         By default, it just calls relevant wldoc.as_??? method.
 146
 147         """
 148         return getattr(wldoc, "as_%s" % fieldfile.field.format_name)()
 149
 150     def run(self, obj, field_name):
 151         """Just run `build` on FieldFile, can't pass it directly to Celery."""
 152         fieldfile = getattr(obj, field_name)
 153
 154         # Get etag value before actually building the file.
 155         etag = fieldfile.field.get_current_etag()
 156         task_logger.info("%s -> %s@%s" % (obj.slug, field_name, etag))
 157         ret = self.build(getattr(obj, field_name))
 158         fieldfile.update_etag(etag)
 159         obj.clear_cache()
 160         return ret
 161
 162     def set_file_permissions(self, fieldfile):
 163         if fieldfile.instance.preview:
 164             fieldfile.set_readable(False)
 165
 166     def build(self, fieldfile):
 167         book = fieldfile.instance
 168         out = self.transform(book.wldocument(), fieldfile)
 169         fieldfile.save(None, File(open(out.get_filename(), 'rb')), save=False)
 170         self.set_file_permissions(fieldfile)
 171         if book.pk is not None:
 172             book.save(update_fields=[fieldfile.field.attname])
 173         if fieldfile.field.format_name in app_settings.FORMAT_ZIPS:
 174             remove_zip(app_settings.FORMAT_ZIPS[fieldfile.field.format_name])
 175 # Don't decorate BuildEbook, because we want to subclass it.
 176 BuildEbookTask = task(BuildEbook, ignore_result=True)
 177
 178
 179 @BuildEbook.register('txt')
 180 @task(ignore_result=True)
 181 class BuildTxt(BuildEbook):
 182     @staticmethod
 183     def transform(wldoc, fieldfile):
 184         return wldoc.as_text()
 185
 186
 187 @BuildEbook.register('pdf')
 188 @task(ignore_result=True)
 189 class BuildPdf(BuildEbook):
 190     @staticmethod
 191     def transform(wldoc, fieldfile):
 192         return wldoc.as_pdf(
 193             morefloats=settings.LIBRARIAN_PDF_MOREFLOATS, cover=True,
 194             base_url=absolute_url(gallery_url(wldoc.book_info.url.slug)), customizations=['notoc'])
 195
 196     def build(self, fieldfile):
 197         BuildEbook.build(self, fieldfile)
 198         clear_cache(fieldfile.instance.slug)
 199
 200
 201 @BuildEbook.register('epub')
 202 @task(ignore_result=True)
 203 class BuildEpub(BuildEbook):
 204     @staticmethod
 205     def transform(wldoc, fieldfile):
 206         return wldoc.as_epub(cover=True, base_url=absolute_url(gallery_url(wldoc.book_info.url.slug)))
 207
 208
 209 @BuildEbook.register('mobi')
 210 @task(ignore_result=True)
 211 class BuildMobi(BuildEbook):
 212     @staticmethod
 213     def transform(wldoc, fieldfile):
 214         return wldoc.as_mobi(cover=True, base_url=absolute_url(gallery_url(wldoc.book_info.url.slug)))
 215
 216
 217 @BuildEbook.register('html')
 218 @task(ignore_result=True)
 219 class BuildHtml(BuildEbook):
 220     def build(self, fieldfile):
 221         from django.core.files.base import ContentFile
 222         from slugify import slugify
 223         from sortify import sortify
 224         from librarian import html
 225         from catalogue.models import Fragment, Tag
 226
 227         book = fieldfile.instance
 228
 229         html_output = self.transform(book.wldocument(parse_dublincore=False), fieldfile)
 230
 231         # Delete old fragments, create from scratch if necessary.
 232         book.fragments.all().delete()
 233
 234         if html_output:
 235             meta_tags = list(book.tags.filter(
 236                 category__in=('author', 'epoch', 'genre', 'kind')))
 237
 238             lang = book.language
 239             lang = LANGUAGES_3TO2.get(lang, lang)
 240             if lang not in [ln[0] for ln in settings.LANGUAGES]:
 241                 lang = None
 242
 243             fieldfile.save(None, ContentFile(html_output.get_bytes()), save=False)
 244             self.set_file_permissions(fieldfile)
 245             type(book).objects.filter(pk=book.pk).update(**{
 246                 fieldfile.field.attname: fieldfile
 247             })
 248
 249             # Extract fragments
 250             closed_fragments, open_fragments = html.extract_fragments(fieldfile.path)
 251             for fragment in closed_fragments.values():
 252                 try:
 253                     theme_names = [s.strip() for s in fragment.themes.split(',')]
 254                 except AttributeError:
 255                     continue
 256                 themes = []
 257                 for theme_name in theme_names:
 258                     if not theme_name:
 259                         continue
 260                     if lang == settings.LANGUAGE_CODE:
 261                         # Allow creating themes if book in default language.
 262                         tag, created = Tag.objects.get_or_create(
 263                             slug=slugify(theme_name),
 264                             category='theme'
 265                         )
 266                         if created:
 267                             tag.name = theme_name
 268                             setattr(tag, "name_%s" % lang, theme_name)
 269                             tag.sort_key = sortify(theme_name.lower())
 270                             tag.for_books = True
 271                             tag.save()
 272                         themes.append(tag)
 273                     elif lang is not None:
 274                         # Don't create unknown themes in non-default languages.
 275                         try:
 276                             tag = Tag.objects.get(
 277                                 category='theme',
 278                                 **{"name_%s" % lang: theme_name}
 279                             )
 280                         except Tag.DoesNotExist:
 281                             pass
 282                         else:
 283                             themes.append(tag)
 284                 if not themes:
 285                     continue
 286
 287                 text = fragment.to_string()
 288                 short_text = truncate_html_words(text, 15)
 289                 if text == short_text:
 290                     short_text = ''
 291                 new_fragment = Fragment.objects.create(
 292                     anchor=fragment.id,
 293                     book=book,
 294                     text=text,
 295                     short_text=short_text
 296                 )
 297
 298                 new_fragment.save()
 299                 new_fragment.tags = set(meta_tags + themes)
 300                 for theme in themes:
 301                     if not theme.for_books:
 302                         theme.for_books = True
 303                         theme.save()
 304             book.html_built.send(sender=type(self), instance=book)
 305             return True
 306         return False
 307
 308     @staticmethod
 309     def transform(wldoc, fieldfile):
 310         # ugly, but we can't use wldoc.book_info here
 311         from librarian import DCNS
 312         url_elem = wldoc.edoc.getroot().find('.//' + DCNS('identifier.url'))
 313         if url_elem is None:
 314             gal_url = ''
 315             gal_path = ''
 316         else:
 317             slug = url_elem.text.rstrip('/').rsplit('/', 1)[1]
 318             gal_url = gallery_url(slug=slug)
 319             gal_path = gallery_path(slug=slug)
 320         return wldoc.as_html(gallery_path=gal_path, gallery_url=gal_url, base_url=absolute_url(gal_url))
 321
 322
 323 class BuildCover(BuildEbook):
 324     def set_file_permissions(self, fieldfile):
 325         pass
 326
 327
 328 @BuildEbook.register('cover_thumb')
 329 @task(ignore_result=True)
 330 class BuildCoverThumb(BuildCover):
 331     @classmethod
 332     def transform(cls, wldoc, fieldfile):
 333         from librarian.cover import WLCover
 334         return WLCover(wldoc.book_info, height=193).output_file()
 335
 336
 337 @BuildEbook.register('cover_api_thumb')
 338 @task(ignore_result=True)
 339 class BuildCoverApiThumb(BuildCover):
 340     @classmethod
 341     def transform(cls, wldoc, fieldfile):
 342         from librarian.cover import WLNoBoxCover
 343         return WLNoBoxCover(wldoc.book_info, height=500).output_file()
 344
 345
 346 @BuildEbook.register('simple_cover')
 347 @task(ignore_result=True)
 348 class BuildSimpleCover(BuildCover):
 349     @classmethod
 350     def transform(cls, wldoc, fieldfile):
 351         from librarian.cover import WLNoBoxCover
 352         return WLNoBoxCover(wldoc.book_info, height=1000).output_file()
 353
 354
 355 @BuildEbook.register('cover_ebookpoint')
 356 @task(ignore_result=True)
 357 class BuildCoverEbookpoint(BuildCover):
 358     @classmethod
 359     def transform(cls, wldoc, fieldfile):
 360         from librarian.cover import EbookpointCover
 361         return EbookpointCover(wldoc.book_info).output_file()
 362
 363
 364 # not used, but needed for migrations
 365 class OverwritingFieldFile(FieldFile):
 366     """
 367         Deletes the old file before saving the new one.
 368     """
 369
 370     def save(self, name, content, *args, **kwargs):
 371         leave = kwargs.pop('leave', None)
 372         # delete if there's a file already and there's a new one coming
 373         if not leave and self and (not hasattr(content, 'path') or content.path != self.path):
 374             self.delete(save=False)
 375         return super(OverwritingFieldFile, self).save(name, content, *args, **kwargs)
 376
 377
 378 class OverwritingFileField(models.FileField):
 379     attr_class = OverwritingFieldFile
 380
 381
 382 class OverwriteStorage(FileSystemStorage):
 383
 384     def get_available_name(self, name, max_length=None):
 385         self.delete(name)
 386         return name