src/oai/handlers.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 oaipmh import server, common, metadata, error
   6 from catalogue.models import Book, Tag
   7 from api.models import Deleted
   8 from api.handlers import WL_BASE
   9 from librarian import WLURI
  10 from datetime import datetime
  11 from lxml import etree
  12 from django.conf import settings
  13 from django.contrib.sites.models import Site
  14 from django.utils import timezone
  15
  16
  17 def make_time_naive(d):
  18     return timezone.localtime(d).replace(tzinfo=None)
  19
  20 WL_DC_READER_XPATH = '(.|*)/rdf:RDF/rdf:Description/%s/text()'
  21 wl_dc_reader = metadata.MetadataReader(
  22     fields={
  23         'title':       ('textList', WL_DC_READER_XPATH % 'dc:title'),
  24         'creator':     ('textList', WL_DC_READER_XPATH % 'dc:creator'),
  25         'subject':     ('textList', (WL_DC_READER_XPATH + ' | ' + WL_DC_READER_XPATH + ' | ' + WL_DC_READER_XPATH) %
  26                         ('dc:subject.period', 'dc:subject.type', 'dc:subject.genre')),
  27         'description': ('textList', WL_DC_READER_XPATH % 'dc:description'),
  28         'publisher':   ('textList', WL_DC_READER_XPATH % 'dc:publisher'),
  29         'contributor': ('textList', (WL_DC_READER_XPATH + ' | ' + WL_DC_READER_XPATH + ' | ' + WL_DC_READER_XPATH) %
  30                         ('dc:contributor.editor', 'dc:contributor.translator', 'dc:contributor.technical_editor')),
  31         'date':        ('textList', WL_DC_READER_XPATH % 'dc:date'),
  32         'type':        ('textList', WL_DC_READER_XPATH % 'dc:type'),
  33         'format':      ('textList', WL_DC_READER_XPATH % 'dc:format'),
  34         'identifier':  ('textList', WL_DC_READER_XPATH % 'dc:identifier.url'),
  35         'source':      ('textList', WL_DC_READER_XPATH % 'dc:source'),
  36         'language':    ('textList', WL_DC_READER_XPATH % 'dc:language'),
  37         # 'isPartOf':    ('textList', 'rdf:RDF/rdf:Description/dc:relation.isPartOf/text()'),
  38         'hasPart':     ('textList', WL_DC_READER_XPATH % 'dc:relation.hasPart'),
  39         # 'relation':    ('textList', 'rdf:RDF/rdf:Description/dc:relation/text()'),
  40         # 'coverage':    ('textList', 'rdf:RDF/rdf:Description/dc:coverage/text()'),
  41         'rights':      ('textList', WL_DC_READER_XPATH % 'dc:rights')
  42     },
  43     namespaces={
  44         'dc': 'http://purl.org/dc/elements/1.1/',
  45         'rdf': 'http://www.w3.org/1999/02/22-rdf-syntax-ns#'}
  46     )
  47
  48
  49 NS_DCTERMS = "http://purl.org/dc/terms/"
  50
  51
  52 def nsdcterms(name):
  53     return '{%s}%s' % (NS_DCTERMS, name)
  54
  55
  56 # WTF
  57 class Catalogue(common.ResumptionOAIPMH):
  58     TAG_CATEGORIES = ['author', 'epoch', 'kind', 'genre']
  59
  60     def __init__(self, metadata_registry):
  61         super(Catalogue, self).__init__()
  62         self.metadata_registry = metadata_registry
  63
  64         self.oai_id = "oai:" + Site.objects.get_current().domain + ":%s"
  65
  66         # earliest change
  67         year_zero = timezone.make_aware(datetime(1990, 1, 1, 0, 0, 0), timezone.utc)
  68
  69         try:
  70             earliest_change = Book.objects.order_by('changed_at')[0].changed_at
  71         except IndexError:
  72             earliest_change = year_zero
  73
  74         try:
  75             earliest_delete = \
  76                 Deleted.objects.exclude(slug__exact=u'').ordery_by('deleted_at')[0].deleted_at
  77         except IndexError:
  78             earliest_delete = year_zero
  79
  80         self.earliest_datestamp = earliest_change if earliest_change <= earliest_delete else earliest_delete
  81
  82     # @staticmethod
  83     # def metadata(book):
  84     #     try:
  85     #         xml = etree.parse(book.xml_file)
  86     #     finally:
  87     #         book.xml_file.close()
  88     #     md = wl_dc_reader(xml)
  89     #     m = md.getMap()
  90     #     if book.parent:
  91     #         m['isPartOf'] = [str(WLURI.from_slug(book.parent.slug))]
  92     #     return m
  93
  94     # WTF
  95     # def record_for_book(self, book, headers_only=False):
  96     #     meta = None
  97     #     identifier = self.slug_to_identifier(book.slug)
  98     #     if isinstance(book, Book):
  99     #         # setSpec = map(self.tag_to_setspec, book.tags.filter(category__in=self.TAG_CATEGORIES))
 100     #         header = common.Header(identifier, make_time_naive(book.changed_at), [], False)
 101     #         if not headers_only:
 102     #             meta = common.Metadata(self.metadata(book))
 103     #         about = None
 104     #     elif isinstance(book, Deleted):
 105     #         header = common.Header(identifier, make_time_naive(book.deleted_at), [], True)
 106     #         if not headers_only:
 107     #             meta = common.Metadata({})
 108     #         about = None
 109     #     if headers_only:
 110     #         return header
 111     #     return header, meta, about
 112
 113     # def identify(self, **kw):
 114     #     ident = common.Identify(
 115     #         'Wolne Lektury',  # generate
 116     #         '%s/oaipmh' % unicode(WL_BASE),  # generate
 117     #         '2.0',  # version
 118     #         [m[1] for m in settings.MANAGERS],  # adminEmails
 119     #         make_time_naive(self.earliest_datestamp),  # earliest datestamp of any change
 120     #         'persistent',  # deletedRecord
 121     #         'YYYY-MM-DDThh:mm:ssZ',  # granularity
 122     #         ['identity'],  # compression
 123     #         []  # descriptions
 124     #         )
 125     #     return ident
 126
 127     # def books(self, tag, from_, until):
 128     #     if tag:
 129     #         # we do not support sets, since they are problematic for deleted books.
 130     #         raise error.NoSetHierarchyError("Wolne Lektury does not support sets.")
 131     #         # books = Book.tagged.with_all([tag])
 132     #     else:
 133     #         books = Book.objects.all()
 134     #     deleted = Deleted.objects.exclude(slug__exact=u'')
 135     #
 136     #     books = books.order_by('changed_at')
 137     #     deleted = deleted.order_by('deleted_at')
 138     #     if from_:
 139     #         books = books.filter(changed_at__gte=from_)
 140     #         deleted = deleted.filter(deleted_at__gte=from_)
 141     #     if until:
 142     #         books = books.filter(changed_at__lte=until)
 143     #         deleted = deleted.filter(deleted_at__lte=until)
 144     #     return list(books) + list(deleted)
 145
 146     # @staticmethod
 147     # def tag_to_setspec(tag):
 148     #     return "%s:%s" % (tag.category, tag.slug)
 149
 150     # @staticmethod
 151     # def setspec_to_tag(s):
 152     #     if not s: return None
 153     #     cs = s.split(':')
 154     #     if len(cs) == 2:
 155     #         if not cs[0] in Catalogue.TAG_CATEGORIES:
 156     #             raise error.NoSetHierarchyError("No category part in set")
 157     #         tag = Tag.objects.get(slug=cs[1], category=cs[0])
 158     #         return tag
 159     #     raise error.NoSetHierarchyError("Setspec should have two components: category:slug")
 160
 161     # def getRecord(self, **kw):
 162     #     """Returns (header, metadata, about) for given record."""
 163     #     slug = self.identifier_to_slug(kw['identifier'])
 164     #     try:
 165     #         book = Book.objects.get(slug=slug)
 166     #         return self.record_for_book(book)
 167     #     except Book.DoesNotExist:
 168     #         book_type = ContentType.objects.get_for_model(Book)
 169     #         try:
 170     #             deleted_book = Deleted.objects.get(content_type=book_type,
 171     #                                               slug=slug)
 172     #         except:
 173     #             raise error.IdDoesNotExistError("No item for this identifier")
 174     #         return self.record_for_book(deleted_book)
 175
 176     # def validate_kw(self, kw):
 177     #     if 'resumptionToken' in kw:
 178     #         raise error.BadResumptionTokenError("No resumption token support at this point")
 179     #     if 'metadataPrefix' in kw and not self.metadata_registry.hasWriter(kw['metadataPrefix']):
 180     #         raise error.CannotDisseminateFormatError("This format is not supported")
 181
 182     # def identifier_to_slug(self, ident):
 183     #     return ident.split(':')[-1]
 184
 185     # def slug_to_identifier(self, slug):
 186     #     return self.oai_id % slug
 187
 188     # def listIdentifiers(self, **kw):
 189     #     self.validate_kw(kw)
 190     #     records = [self.record_for_book(book, headers_only=True) for
 191     #                book in self.books(None,
 192     #                        kw.get('from_', None),
 193     #                        kw.get('until', None))]
 194     #     return records, None
 195
 196     # def listRecords(self, **kw):
 197     #     """
 198     #         can get a resumptionToken kw.
 199     #         returns result, token
 200     #     """
 201     #     self.validate_kw(kw)
 202     #     records = [self.record_for_book(book) for
 203     #                book in self.books(None,
 204     #                        kw.get('from_', None),
 205     #                        kw.get('until', None))]
 206     #
 207     #     return records, None
 208
 209     # def listMetadataFormats(self, **kw):
 210     #     formats = [
 211     #         ('oai_dc',
 212     #          'http://www.openarchives.org/OAI/2.0/oai_dc.xsd',
 213     #          server.NS_OAIDC),
 214     #         ('qdc',
 215     #          'http://dublincore.org/schemas/xmls/qdc/2006/01/06/dcterms.xsd',
 216     #          NS_DCTERMS)]
 217     #     if 'identifier' in kw:
 218     #         slug = self.identifier_to_slug(kw['identifier'])
 219     #         try:
 220     #             b = Book.objects.get(slug=slug)
 221     #             return formats
 222     #         except:
 223     #             try:
 224     #                 d = Deleted.objects.get(slug=slug)
 225     #                 return []
 226     #             except:
 227     #                 raise error.IdDoesNotExistError("This id does not exist")
 228     #     else:
 229     #         return formats
 230
 231     # def listSets(self, **kw):
 232     #     raise error.NoSetHierarchyError("Wolne Lektury does not support sets.")
 233     #     # tags = []
 234     #     # for category in Catalogue.TAG_CATEGORIES:
 235     #     #     for tag in Tag.objects.filter(category=category):
 236     #     #         tags.append(("%s:%s" % (tag.category, tag.slug),
 237     #     #                      tag.name,
 238     #     #                      tag.description))
 239     #     # return tags, None