librarian/parser.py

   1 # -*- coding: utf-8 -*-
   2 #
   3 # This file is part of Librarian, licensed under GNU Affero GPLv3 or later.
   4 # Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information.
   5 #
   6 from librarian import ValidationError, NoDublinCore,  ParseError
   7 from librarian import RDFNS
   8 from librarian import dcparser
   9
  10 from xml.parsers.expat import ExpatError
  11 from lxml import etree
  12 from lxml.etree import XMLSyntaxError, XSLTApplyError
  13
  14 import re
  15 from StringIO import StringIO
  16
  17 class WLDocument(object):
  18     LINE_SWAP_EXPR = re.compile(r'/\s', re.MULTILINE | re.UNICODE);
  19
  20     def __init__(self, edoc, parse_dublincore=True):
  21         self.edoc = edoc
  22
  23         root_elem = edoc.getroot()
  24
  25         dc_path = './/' + RDFNS('RDF')
  26
  27         if root_elem.tag != 'utwor':
  28             raise ValidationError("Invalid root element. Found '%s', should be 'utwor'" % root_elem.tag)
  29
  30         if parse_dublincore:
  31             self.rdf_elem = root_elem.find(dc_path)
  32
  33             if self.rdf_elem is None:
  34                 raise NoDublinCore('Document has no DublinCore - which is required.')
  35
  36             self.book_info = dcparser.BookInfo.from_element(self.rdf_elem)
  37         else:
  38             self.book_info = None
  39
  40     @classmethod
  41     def from_string(cls, xml, *args, **kwargs):
  42         return cls.from_file(StringIO(xml), *args, **kwargs)
  43
  44     @classmethod
  45     def from_file(cls, xmlfile, swap_endlines=False, parse_dublincore=True, preserve_lines=True):
  46
  47         # first, prepare for parsing
  48         if isinstance(xmlfile, basestring):
  49             file = open(xmlfile, 'rb')
  50             try:
  51                 data = file.read()
  52             finally:
  53                 file.close()
  54         else:
  55             data = xmlfile.read()
  56
  57         if not isinstance(data, unicode):
  58             data = data.decode('utf-8')
  59
  60         if swap_endlines:
  61             sub = u'<br/>'
  62             if preserve_lines:
  63                 sub += u'\n'
  64             data = cls.LINE_SWAP_EXPR.sub(sub, data)
  65
  66         try:
  67             parser = etree.XMLParser(remove_blank_text=False)
  68             return cls(etree.parse(StringIO(data), parser), parse_dublincore=parse_dublincore)
  69         except (ExpatError, XMLSyntaxError, XSLTApplyError), e:
  70             raise ParseError(e)
  71
  72     def chunk(self, path):
  73         # convert the path to XPath
  74         expr = self.path_to_xpath(path)
  75         elems = self.edoc.xpath(expr)
  76
  77         if len(elems) == 0:
  78             return None
  79         else:
  80             return elems[0]
  81
  82     def path_to_xpath(self, path):
  83         parts = []
  84
  85         for part in path.split('/'):
  86             match = re.match(r'([^\[]+)\[(\d+)\]', part)
  87             if not match:
  88                 parts.append(part)
  89             else:
  90                 tag, n = match.groups()
  91                 parts.append("*[%d][name() = '%s']" % (int(n)+1, tag) )
  92
  93         if parts[0] == '.':
  94             parts[0] = ''
  95
  96         return '/'.join(parts)
  97
  98     def transform(self, stylesheet, **options):
  99         return self.edoc.xslt(stylesheet, **options)
 100
 101     def update_dc(self):
 102         if self.book_info:
 103             parent = self.rdf_elem.getparent()
 104             parent.replace( self.rdf_elem, self.book_info.to_etree(parent) )
 105
 106     def serialize(self):
 107         self.update_dc()
 108         return etree.tostring(self.edoc, encoding=unicode, pretty_print=True)
 109
 110     def merge_chunks(self, chunk_dict):
 111         unmerged = []
 112
 113         for key, data in chunk_dict.iteritems():
 114             try:
 115                 xpath = self.path_to_xpath(key)
 116                 node = self.edoc.xpath(xpath)[0]
 117                 repl = etree.fromstring(u"<%s>%s</%s>" %(node.tag, data, node.tag) )
 118                 node.getparent().replace(node, repl);
 119             except Exception, e:
 120                 unmerged.append( repr( (key, xpath, e) ) )
 121
 122         return unmerged