0ff2ca9effdc7508f9b8f21dddf1a173e5aa3dd9
[wolnelektury.git] / 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 celery.utils.log import get_task_logger
14 from waiter.utils import clear_cache
15
16 task_logger = get_task_logger(__name__)
17
18
19 class EbookFieldFile(FieldFile):
20     """Represents contents of an ebook file field."""
21
22     def build(self):
23         """Build the ebook immediately."""
24         return self.field.builder.build(self)
25
26     def build_delay(self):
27         """Builds the ebook in a delayed task."""
28         return self.field.builder.delay(self.instance, self.field.attname)
29
30
31 class EbookField(models.FileField):
32     """Represents an ebook file field, attachable to a model."""
33     attr_class = EbookFieldFile
34
35     def __init__(self, format_name, *args, **kwargs):
36         super(EbookField, self).__init__(*args, **kwargs)
37         self.format_name = format_name
38
39     def deconstruct(self):
40         name, path, args, kwargs = super(EbookField, self).deconstruct()
41         args.insert(0, self.format_name)
42         return name, path, args, kwargs
43
44     @property
45     def builder(self):
46         """Finds a celery task suitable for the format of the field."""
47         return BuildEbook.for_format(self.format_name)
48
49     def contribute_to_class(self, cls, name):
50         super(EbookField, self).contribute_to_class(cls, name)
51
52         def has(model_instance):
53             return bool(getattr(model_instance, self.attname, None))
54         has.__doc__ = None
55         has.__name__ = str("has_%s" % self.attname)
56         has.short_description = self.name
57         has.boolean = True
58         setattr(cls, 'has_%s' % self.attname, has)
59
60
61 class BuildEbook(Task):
62     formats = {}
63
64     @classmethod
65     def register(cls, format_name):
66         """A decorator for registering subclasses for particular formats."""
67         def wrapper(builder):
68             cls.formats[format_name] = builder
69             return builder
70         return wrapper
71
72     @classmethod
73     def for_format(cls, format_name):
74         """Returns a celery task suitable for specified format."""
75         return cls.formats.get(format_name, BuildEbookTask)
76
77     @staticmethod
78     def transform(wldoc, fieldfile):
79         """Transforms an librarian.WLDocument into an librarian.OutputFile.
80
81         By default, it just calls relevant wldoc.as_??? method.
82
83         """
84         return getattr(wldoc, "as_%s" % fieldfile.field.format_name)()
85
86     def run(self, obj, field_name):
87         """Just run `build` on FieldFile, can't pass it directly to Celery."""
88         task_logger.info("%s -> %s" % (obj.slug, field_name))
89         ret = self.build(getattr(obj, field_name))
90         obj.flush_includes()
91         return ret
92
93     def build(self, fieldfile):
94         book = fieldfile.instance
95         out = self.transform(book.wldocument(), fieldfile)
96         fieldfile.save(None, File(open(out.get_filename())), save=False)
97         if book.pk is not None:
98             type(book).objects.filter(pk=book.pk).update(**{
99                 fieldfile.field.attname: fieldfile
100             })
101         if fieldfile.field.format_name in app_settings.FORMAT_ZIPS:
102             remove_zip(app_settings.FORMAT_ZIPS[fieldfile.field.format_name])
103 # Don't decorate BuildEbook, because we want to subclass it.
104 BuildEbookTask = task(BuildEbook, ignore_result=True)
105
106
107 @BuildEbook.register('txt')
108 @task(ignore_result=True)
109 class BuildTxt(BuildEbook):
110     @staticmethod
111     def transform(wldoc, fieldfile):
112         return wldoc.as_text()
113
114
115 @BuildEbook.register('pdf')
116 @task(ignore_result=True)
117 class BuildPdf(BuildEbook):
118     @staticmethod
119     def transform(wldoc, fieldfile):
120         return wldoc.as_pdf(morefloats=settings.LIBRARIAN_PDF_MOREFLOATS,
121             cover=True)
122
123     def build(self, fieldfile):
124         BuildEbook.build(self, fieldfile)
125         clear_cache(fieldfile.instance.slug)
126
127
128 @BuildEbook.register('epub')
129 @task(ignore_result=True)
130 class BuildEpub(BuildEbook):
131     @staticmethod
132     def transform(wldoc, fieldfile):
133         return wldoc.as_epub(cover=True)
134
135
136 @BuildEbook.register('html')
137 @task(ignore_result=True)
138 class BuildHtml(BuildEbook):
139     def build(self, fieldfile):
140         from django.core.files.base import ContentFile
141         from fnpdjango.utils.text.slughifi import slughifi
142         from sortify import sortify
143         from librarian import html
144         from catalogue.models import Fragment, Tag
145
146         book = fieldfile.instance
147
148         html_output = self.transform(
149                         book.wldocument(parse_dublincore=False),
150                         fieldfile)
151
152         # Delete old fragments, create from scratch if necessary.
153         book.fragments.all().delete()
154
155         if html_output:
156             meta_tags = list(book.tags.filter(
157                 category__in=('author', 'epoch', 'genre', 'kind')))
158
159             lang = book.language
160             lang = LANGUAGES_3TO2.get(lang, lang)
161             if lang not in [ln[0] for ln in settings.LANGUAGES]:
162                 lang = None
163
164             fieldfile.save(None, ContentFile(html_output.get_string()),
165                     save=False)
166             type(book).objects.filter(pk=book.pk).update(**{
167                 fieldfile.field.attname: fieldfile
168             })
169
170             # Extract fragments
171             closed_fragments, open_fragments = html.extract_fragments(fieldfile.path)
172             for fragment in closed_fragments.values():
173                 try:
174                     theme_names = [s.strip() for s in fragment.themes.split(',')]
175                 except AttributeError:
176                     continue
177                 themes = []
178                 for theme_name in theme_names:
179                     if not theme_name:
180                         continue
181                     if lang == settings.LANGUAGE_CODE:
182                         # Allow creating themes if book in default language.
183                         tag, created = Tag.objects.get_or_create(
184                                             slug=slughifi(theme_name),
185                                             category='theme')
186                         if created:
187                             tag.name = theme_name
188                             setattr(tag, "name_%s" % lang, theme_name)
189                             tag.sort_key = sortify(theme_name.lower())
190                             tag.save()
191                         themes.append(tag)
192                     elif lang is not None:
193                         # Don't create unknown themes in non-default languages.
194                         try:
195                             tag = Tag.objects.get(category='theme',
196                                     **{"name_%s" % lang: theme_name})
197                         except Tag.DoesNotExist:
198                             pass
199                         else:
200                             themes.append(tag)
201                 if not themes:
202                     continue
203
204                 text = fragment.to_string()
205                 short_text = truncate_html_words(text, 15)
206                 if text == short_text:
207                     short_text = ''
208                 new_fragment = Fragment.objects.create(anchor=fragment.id,
209                         book=book, text=text, short_text=short_text)
210
211                 new_fragment.save()
212                 new_fragment.tags = set(meta_tags + themes)
213             book.html_built.send(sender=type(self), instance=book)
214             return True
215         return False
216
217 @BuildEbook.register('cover_thumb')
218 @task(ignore_result=True)
219 class BuildCoverThumb(BuildEbook):
220     @classmethod
221     def transform(cls, wldoc, fieldfile):
222         from librarian.cover import WLCover
223         return WLCover(wldoc.book_info, height=193).output_file()
224
225
226
227 class OverwritingFieldFile(FieldFile):
228     """
229         Deletes the old file before saving the new one.
230     """
231
232     def save(self, name, content, *args, **kwargs):
233         leave = kwargs.pop('leave', None)
234         # delete if there's a file already and there's a new one coming
235         if not leave and self and (not hasattr(content, 'path') or
236                                    content.path != self.path):
237             self.delete(save=False)
238         return super(OverwritingFieldFile, self).save(
239                 name, content, *args, **kwargs)
240
241
242 class OverwritingFileField(models.FileField):
243     attr_class = OverwritingFieldFile