e6fdeb1ce08dd962c00c5fc16ca54daf4523ce98
[librarian.git] / 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, swap_endlines=False, parse_dublincore=True):
42         return cls.from_file(StringIO(xml), swap_endlines, parse_dublincore=parse_dublincore)
43
44     @classmethod
45     def from_file(cls, xmlfile, swap_endlines=False, parse_dublincore=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             data = cls.LINE_SWAP_EXPR.sub(u'<br />\n', data)
62     
63         try:
64             parser = etree.XMLParser(remove_blank_text=False)
65             return cls(etree.parse(StringIO(data), parser), parse_dublincore=parse_dublincore)
66         except (ExpatError, XMLSyntaxError, XSLTApplyError), e:
67             raise ParseError(e)                  
68
69     def chunk(self, path):
70         # convert the path to XPath        
71         expr = self.path_to_xpath(path)
72         elems = self.edoc.xpath(expr)
73
74         if len(elems) == 0:
75             return None
76         else:        
77             return elems[0]
78
79     def path_to_xpath(self, path):
80         parts = []
81
82         for part in path.split('/'):
83             match = re.match(r'([^\[]+)\[(\d+)\]', part)
84             if not match:
85                 parts.append(part)
86             else:
87                 tag, n = match.groups()
88                 parts.append("*[%d][name() = '%s']" % (int(n)+1, tag) )
89
90         if parts[0] == '.':
91             parts[0] = ''
92
93         return '/'.join(parts)
94
95     def transform(self, stylesheet, **options):
96         return self.edoc.xslt(stylesheet, **options)
97
98     def update_dc(self):
99         if self.book_info:
100             parent = self.rdf_elem.getparent()
101             parent.replace( self.rdf_elem, self.book_info.to_etree(parent) )
102
103     def serialize(self):
104         self.update_dc()
105         return etree.tostring(self.edoc, encoding=unicode, pretty_print=True)
106
107     def merge_chunks(self, chunk_dict):
108         unmerged = []
109
110         for key, data in chunk_dict.iteritems():
111             try:
112                 xpath = self.path_to_xpath(key)
113                 node = self.edoc.xpath(xpath)[0]
114                 repl = etree.fromstring(u"<%s>%s</%s>" %(node.tag, data, node.tag) )
115                 node.getparent().replace(node, repl);
116             except Exception, e:
117                 unmerged.append( repr( (key, xpath, e) ) )
118
119         return unmerged