X-Git-Url: https://git.mdrn.pl/librarian.git/blobdiff_plain/07fdba2c7fe8e11b6867712d47bdd608e88c29fb..6642c1c71c5c6ce6ef3401c8c9da84cf076b018b:/librarian/dcparser.py diff --git a/librarian/dcparser.py b/librarian/dcparser.py index 557509c..830b089 100644 --- a/librarian/dcparser.py +++ b/librarian/dcparser.py @@ -3,14 +3,10 @@ from xml.parsers.expat import ExpatError from datetime import date import time -# Import ElementTree from anywhere -try: - import xml.etree.ElementTree as etree # Python >= 2.5 -except ImportError: - try: - import elementtree.ElementTree as etree # effbot's pure Python module - except ImportError: - import lxml.etree as etree # ElementTree API using libxml2 +from librarian import ValidationError, NoDublinCore + +import lxml.etree as etree # ElementTree API using libxml2 +from lxml.etree import XMLSyntaxError # ============== @@ -21,7 +17,22 @@ class Person(object): 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 __eq__(self, right): return self.last_name == right.last_name and self.first_names == right.first_names @@ -32,52 +43,71 @@ class Person(object): 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 str_to_unicode(value, previous): - return unicode(value) - +def as_person(text): + return Person.from_text(text) -def str_to_unicode_list(value, previous): - if previous is None: - previous = [] - previous.append(str_to_unicode(value, None)) - return previous +def as_unicode(text): + if isinstance(text, unicode): + return text + else: + return text.decode('utf-8') +class Field(object): + def __init__(self, uri, attr_name, type=as_unicode, multiple=False, salias=None, **kwargs): + self.uri = uri + self.name = attr_name + self.validator = type + self.multiple = multiple + self.salias = salias -def str_to_person(value, previous): - comma_count = value.count(',') - - if comma_count == 0: - last_name, first_names = value, [] - elif comma_count == 1: - last_name, first_names = value.split(',') - first_names = [name for name in first_names.split(' ') if len(name)] - else: - raise ValueError("value contains more than one comma: %r" % value) - - return Person(last_name.strip(), *first_names) + 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): + try: + if self.multiple: + if self.validator is None: + return val + return [ self.validator(v) if v is not None else v for v in val ] + elif len(val) > 1: + raise ValidationError("Mulitply 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 self.validator is None or val[0] is None: + return val[0] + return self.validator(val[0]) + except ValueError, e: + raise ValidationError("Field '%s' - invald value: %s" % (self.uri, e.message)) -def str_to_date(value, previous): - try: - t = time.strptime(value, '%Y-%m-%d') - except ValueError: - t = time.strptime(value, '%Y') - return date(t[0], t[1], t[2]) + def validate(self, fdict): + if not fdict.has_key(self.uri): + if not self.required: + f = self.default + else: + raise ValidationError("Required field %s not found" % self.uri) + else: + f = fdict[self.uri] + return self.validate_value(f) # ========== # = Parser = # ========== -class ParseError(Exception): - def __init__(self, message): - super(ParseError, self).__init__(message) - class XMLNamespace(object): '''Represents XML namespace.''' @@ -102,96 +132,175 @@ class BookInfo(object): RDF = XMLNamespace('http://www.w3.org/1999/02/22-rdf-syntax-ns#') DC = XMLNamespace('http://purl.org/dc/elements/1.1/') - mapping = { - DC('creator') : ('author', str_to_person), - DC('title') : ('title', str_to_unicode), - DC('subject.period') : ('epoch', str_to_unicode), - DC('subject.type') : ('kind', str_to_unicode), - DC('subject.genre') : ('genre', str_to_unicode), - DC('date') : ('created_at', str_to_date), - DC('date.pd') : ('released_to_public_domain_at', str_to_date), - DC('contributor.translator') : ('translator', str_to_person), - DC('contributor.technical_editor') : ('technical_editor', str_to_person), - DC('publisher') : ('publisher', str_to_unicode), - DC('source') : ('source_name', str_to_unicode), - DC('source.URL') : ('source_url', str_to_unicode), - DC('identifier.url') : ('url', str_to_unicode), - DC('relation.hasPart') : ('parts', str_to_unicode_list), - DC('rights.license') : ('license', str_to_unicode), - DC('rights') : ('license_description', str_to_unicode), - } + FIELDS = ( + Field( DC('creator'), 'author', as_person), + Field( DC('title'), 'title'), + Field( DC('subject.period'), 'epoches', salias='epoch', multiple=True), + Field( DC('subject.type'), 'kinds', salias='kind', multiple=True), + Field( DC('subject.genre'), 'genres', salias='genre', multiple=True), + Field( DC('date'), 'created_at', as_date), + Field( DC('date.pd'), 'released_to_public_domain_at', as_date, required=False), + Field( DC('contributor.editor'), 'editors', \ + as_person, salias='editor', multiple=True, default=[]), + Field( DC('contributor.translator'), 'translators', \ + as_person, salias='translator', multiple=True, default=[]), + Field( DC('contributor.technical_editor'), 'technical_editors', + as_person, salias='technical_editor', multiple=True, default=[]), + Field( DC('publisher'), 'publisher'), + Field( DC('source'), 'source_name', required=False), + Field( DC('source.URL'), 'source_url', required=False), + Field( DC('identifier.url'), 'url'), + Field( DC('relation.hasPart'), 'parts', multiple=True, required=False), + Field( DC('rights.license'), 'license', required=False), + Field( DC('rights'), 'license_description'), + ) @classmethod def from_string(cls, xml): from StringIO import StringIO return cls.from_file(StringIO(xml)) - + @classmethod - def from_file(cls, xml_file): - book_info = cls() - + def from_file(cls, xmlfile): + desc_tag = None try: - tree = etree.parse(xml_file) + iter = etree.iterparse(xmlfile, ['start', 'end']) + for (event, element) in iter: + if element.tag == cls.RDF('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 == cls.RDF('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) + except XMLSyntaxError, e: + raise ParseError(e) except ExpatError, e: raise ParseError(e) - description = tree.find('//' + book_info.RDF('Description')) - book_info.wiki_url = description.get(cls.RDF('about'), None) - - if description is None: - raise ParseError('no Description tag found in document') - - for element in description.findall('*'): - book_info.parse_element(element) + @classmethod + def from_element(cls, rdf_tag): + # the tree is already parsed, so we don't need to worry about Expat errors + field_dict = {} + desc = rdf_tag.find(".//" + cls.RDF('Description') ) - return book_info + 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 ) + + def __init__(self, rdf_attrs, dc_fields): + """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(self.RDF('about')) + self.fmap = {} + + for field in self.FIELDS: + value = field.validate( dc_fields ) + 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] + except (KeyError, AttributeError): + return object.__getattribute__(self, name) - def parse_element(self, element): + def __setattr__(self, name, newvalue): try: - attribute, converter = self.mapping[element.tag] - setattr(self, attribute, converter(element.text, getattr(self, attribute, None))) - except KeyError: - pass + 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 - def to_xml(self): + 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' + #etree._namespace_map[str(self.RDF)] = 'rdf' + #etree._namespace_map[str(self.DC)] = 'dc' - root = etree.Element(self.RDF('RDF')) + if parent is None: + root = etree.Element(self.RDF('RDF')) + else: + root = parent.makeelement(self.RDF('RDF')) + description = etree.SubElement(root, self.RDF('Description')) - if self.wiki_url: - description.set(self.RDF('about'), self.wiki_url) + if self.about: + description.set(self.RDF('about'), self.about) - for tag, (attribute, converter) in self.mapping.iteritems(): - if hasattr(self, attribute): - e = etree.Element(tag) - e.text = unicode(getattr(self, attribute)) - description.append(e) + 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) + e.text = unicode(x) + description.append(e) + else: + e = etree.Element(field.uri) + e.text = unicode(v) + description.append(e) - return unicode(etree.tostring(root, 'utf-8'), 'utf-8') + return root def to_dict(self): - etree._namespace_map[str(self.RDF)] = 'rdf' - etree._namespace_map[str(self.DC)] = 'dc' - - result = {'about': self.wiki_url} - for tag, (attribute, converter) in self.mapping.iteritems(): - if hasattr(self, attribute): - result[attribute] = unicode(getattr(self, attribute)) + 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 ] + else: + v = unicode(v) + result[field.name] = v + + if field.salias: + v = getattr(self, field.salias) + if v is not None: result[field.salias] = v return result - def parse(file_name): return BookInfo.from_file(file_name) - - -if __name__ == '__main__': - import sys - - info = parse(sys.argv[1]) - for attribute, _ in BookInfo.mapping.values(): - print '%s: %r' % (attribute, getattr(info, attribute, None)) -