# -*- coding: utf-8 -*- # # This file is part of Librarian, licensed under GNU Affero GPLv3 or later. # Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information. # from xml.parsers.expat import ExpatError from datetime import date import time from librarian import (ValidationError, NoDublinCore, ParseError, DCNS, RDFNS, WLURI) import lxml.etree as etree # ElementTree API using libxml2 from lxml.etree import XMLSyntaxError # ============== # = Converters = # ============== class Person(object): """Single person with last name and a list of first names.""" def __init__(self, last_name, *first_names): self.last_name = last_name self.first_names = first_names @classmethod def from_text(cls, text): parts = [ token.strip() for token in text.split(',') ] if len(parts) == 1: surname = parts[0] names = [] elif len(parts) != 2: raise ValueError("Invalid person name. There should be at most one comma: \"%s\"." % text) else: surname = parts[0] if len(parts[1]) == 0: # there is no non-whitespace data after the comma raise ValueError("Found a comma, but no names given: \"%s\" -> %r." % (text, parts)) names = [ name for name in parts[1].split() if len(name) ] # all non-whitespace tokens return cls(surname, *names) def readable(self): return u" ".join(self.first_names + (self.last_name,)) def __eq__(self, right): return self.last_name == right.last_name and self.first_names == right.first_names def __cmp__(self, other): return cmp((self.last_name, self.first_names), (other.last_name, other.first_names)) def __hash__(self): return hash((self.last_name, self.first_names)) def __unicode__(self): if len(self.first_names) > 0: return '%s, %s' % (self.last_name, ' '.join(self.first_names)) else: return self.last_name def __repr__(self): return 'Person(last_name=%r, first_names=*%r)' % (self.last_name, self.first_names) def as_date(text): try: try: t = time.strptime(text, '%Y-%m-%d') except ValueError: t = time.strptime(text, '%Y') return date(t[0], t[1], t[2]) except ValueError, e: raise ValueError("Unrecognized date format. Try YYYY-MM-DD or YYYY.") def as_person(text): return Person.from_text(text) def as_unicode(text): if isinstance(text, unicode): return text else: return text.decode('utf-8') def as_wluri_strict(text): return WLURI.strict(text) class Field(object): def __init__(self, uri, attr_name, validator=as_unicode, strict=None, multiple=False, salias=None, **kwargs): self.uri = uri self.name = attr_name self.validator = validator self.strict = strict self.multiple = multiple self.salias = salias self.required = kwargs.get('required', True) and not kwargs.has_key('default') self.default = kwargs.get('default', [] if multiple else [None]) def validate_value(self, val, strict=False): val = [v.strip() if v is not None else v for v in val] if strict and self.strict is not None: validator = self.strict else: validator = self.validator try: if self.multiple: if validator is None: return val return [ validator(v) if v is not None else v for v in val ] elif len(val) > 1: raise ValidationError("Multiple values not allowed for field '%s'" % self.uri) elif len(val) == 0: raise ValidationError("Field %s has no value to assign. Check your defaults." % self.uri) else: if validator is None or val[0] is None: return val[0] return validator(val[0]) except ValueError, e: raise ValidationError("Field '%s' - invald value: %s" % (self.uri, e.message)) def validate(self, fdict, fallbacks=None, strict=False): if fallbacks is None: fallbacks = {} if not fdict.has_key(self.uri): if not self.required: # Accept single value for single fields and saliases. if self.name in fallbacks: if self.multiple: f = fallbacks[self.name] else: f = [fallbacks[self.name]] elif self.salias and self.salias in fallbacks: f = [fallbacks[self.salias]] else: f = self.default else: raise ValidationError("Required field %s not found" % self.uri) else: f = fdict[self.uri] return self.validate_value(f, strict=strict) def __eq__(self, other): if isinstance(other, Field) and other.name == self.name and other.uri == self.uri: return True return False class DCInfo(type): def __new__(meta, classname, bases, class_dict): fields = list(class_dict['FIELDS']) for base in bases[::-1]: if hasattr(base, 'FIELDS'): for field in base.FIELDS[::-1]: try: fields.index(field) except ValueError: fields.insert(0, field) class_dict['FIELDS'] = tuple(fields) return super(DCInfo, meta).__new__(meta, classname, bases, class_dict) class WorkInfo(object): __metaclass__ = DCInfo FIELDS = ( Field( DCNS('creator.expert'), 'authors_expert', as_person, salias='author', required=False, multiple=True), Field( DCNS('creator.scenario'), 'authors_scenario', as_person, salias='author', required=False, multiple=True), Field( DCNS('creator.textbook'), 'authors_textbook', as_person, salias='author', required=False, multiple=True), Field( DCNS('title'), 'title'), Field( DCNS('type'), 'type', required=False), Field( DCNS('contributor.editor'), 'editors', \ as_person, salias='editor', multiple=True, default=[]), Field( DCNS('contributor.technical_editor'), 'technical_editors', as_person, salias='technical_editor', multiple=True, default=[]), Field( DCNS('date'), 'created_at', as_date), Field( DCNS('date.pd'), 'released_to_public_domain_at', as_date, required=False), Field( DCNS('publisher'), 'publisher'), Field( DCNS('subject.competence'), 'competences', multiple=True, required=False), Field( DCNS('subject.curriculum'), 'curriculum', multiple=True, required=False), Field( DCNS('language'), 'language'), Field( DCNS('description'), 'description', required=False), Field( DCNS('source'), 'source_name', required=False), Field( DCNS('source.URL'), 'source_url', required=False), Field( DCNS('identifier.url'), 'url', WLURI, strict=as_wluri_strict), Field( DCNS('rights.license'), 'license', required=False), Field( DCNS('rights'), 'license_description'), ) @classmethod def from_string(cls, xml, *args, **kwargs): from StringIO import StringIO return cls.from_file(StringIO(xml), *args, **kwargs) @classmethod def from_file(cls, xmlfile, *args, **kwargs): desc_tag = None try: iter = etree.iterparse(xmlfile, ['start', 'end']) for (event, element) in iter: if element.tag == RDFNS('RDF') and event == 'start': desc_tag = element break if desc_tag is None: raise NoDublinCore("DublinCore section not found. \ Check if there are rdf:RDF and rdf:Description tags.") # continue 'till the end of RDF section for (event, element) in iter: if element.tag == RDFNS('RDF') and event == 'end': break # if there is no end, Expat should yell at us with an ExpatError # extract data from the element and make the info return cls.from_element(desc_tag, *args, **kwargs) except XMLSyntaxError, e: raise ParseError(e) except ExpatError, e: raise ParseError(e) @classmethod def from_element(cls, rdf_tag, *args, **kwargs): # the tree is already parsed, so we don't need to worry about Expat errors field_dict = {} desc = rdf_tag.find(".//" + RDFNS('Description')) if desc is None: raise NoDublinCore("No DublinCore section found.") for e in desc.getchildren(): fv = field_dict.get(e.tag, []) fv.append(e.text) field_dict[e.tag] = fv return cls(desc.attrib, field_dict, *args, **kwargs) def __init__(self, rdf_attrs, dc_fields, fallbacks=None, strict=False): """rdf_attrs should be a dictionary-like object with any attributes of the RDF:Description. dc_fields - dictionary mapping DC fields (with namespace) to list of text values for the given field. """ self.about = rdf_attrs.get(RDFNS('about')) self.fmap = {} for field in self.FIELDS: value = field.validate(dc_fields, fallbacks=fallbacks, strict=strict) if field.multiple: value = getattr(self, 'prop_' + field.name, []) + value setattr(self, 'prop_' + field.name, value) self.fmap[field.name] = field if field.salias: self.fmap[field.salias] = field def __getattribute__(self, name): try: field = object.__getattribute__(self, 'fmap')[name] value = object.__getattribute__(self, 'prop_'+field.name) if field.name == name: return value else: # singular alias if not field.multiple: raise "OUCH!! for field %s" % name return value[0] if value else None except (KeyError, AttributeError): return object.__getattribute__(self, name) def __setattr__(self, name, newvalue): try: field = object.__getattribute__(self, 'fmap')[name] if field.name == name: object.__setattr__(self, 'prop_'+field.name, newvalue) else: # singular alias if not field.multiple: raise "OUCH! while setting field %s" % name object.__setattr__(self, 'prop_'+field.name, [newvalue]) except (KeyError, AttributeError): return object.__setattr__(self, name, newvalue) def update(self, field_dict): """Update using field_dict. Verify correctness, but don't check if all required fields are present.""" for field in self.FIELDS: if field_dict.has_key(field.name): setattr(self, field.name, field_dict[field.name]) def to_etree(self, parent = None): """XML representation of this object.""" #etree._namespace_map[str(self.RDF)] = 'rdf' #etree._namespace_map[str(self.DC)] = 'dc' if parent is None: root = etree.Element(RDFNS('RDF')) else: root = parent.makeelement(RDFNS('RDF')) description = etree.SubElement(root, RDFNS('Description')) if self.about: description.set(RDFNS('about'), self.about) for field in self.FIELDS: v = getattr(self, field.name, None) if v is not None: if field.multiple: if len(v) == 0: continue for x in v: e = etree.Element(field.uri) if x is not None: e.text = unicode(x) description.append(e) else: e = etree.Element(field.uri) e.text = unicode(v) description.append(e) return root def serialize(self): rdf = {} rdf['about'] = { 'uri': RDFNS('about'), 'value': self.about } dc = {} for field in self.FIELDS: v = getattr(self, field.name, None) if v is not None: if field.multiple: if len(v) == 0: continue v = [ unicode(x) for x in v if x is not None ] else: v = unicode(v) dc[field.name] = {'uri': field.uri, 'value': v} rdf['fields'] = dc return rdf def to_dict(self): result = {'about': self.about} for field in self.FIELDS: v = getattr(self, field.name, None) if v is not None: if field.multiple: if len(v) == 0: continue v = [ unicode(x) for x in v if x is not None ] else: v = unicode(v) result[field.name] = v if field.salias: v = getattr(self, field.salias) if v is not None: result[field.salias] = unicode(v) return result class BookInfo(WorkInfo): FIELDS = ( Field( DCNS('audience'), 'audiences', salias='audience', multiple=True, required=False), Field( DCNS('subject.period'), 'epochs', salias='epoch', multiple=True, required=False), Field( DCNS('subject.type'), 'kinds', salias='kind', multiple=True, required=False), Field( DCNS('subject.genre'), 'genres', salias='genre', multiple=True, required=False), Field( DCNS('contributor.translator'), 'translators', \ as_person, salias='translator', multiple=True, default=[]), Field( DCNS('relation.hasPart'), 'parts', WLURI, strict=as_wluri_strict, multiple=True, required=False), Field( DCNS('relation.isVariantOf'), 'variant_of', WLURI, strict=as_wluri_strict, required=False), Field( DCNS('relation'), 'relations', WLURI, strict=as_wluri_strict, multiple=True, required=False), Field( DCNS('relation.coverImage.url'), 'cover_url', required=False), Field( DCNS('relation.coverImage.attribution'), 'cover_by', required=False), Field( DCNS('relation.coverImage.source'), 'cover_source', required=False), ) def parse(file_name, cls=BookInfo): return cls.from_file(file_name)