+
+
+class BuildError(Exception):
+ pass
+
+
+class EmptyNamespace(XMLNamespace):
+ def __init__(self):
+ super(EmptyNamespace, self).__init__('')
+
+ def __call__(self, tag):
+ return tag
+
+# some common namespaces we use
+RDFNS = XMLNamespace('http://www.w3.org/1999/02/22-rdf-syntax-ns#')
+DCNS = XMLNamespace('http://purl.org/dc/elements/1.1/')
+XINS = XMLNamespace("http://www.w3.org/2001/XInclude")
+XHTMLNS = XMLNamespace("http://www.w3.org/1999/xhtml")
+NCXNS = XMLNamespace("http://www.daisy.org/z3986/2005/ncx/")
+OPFNS = XMLNamespace("http://www.idpf.org/2007/opf")
+
+SSTNS = XMLNamespace('http://nowoczesnapolska.org.pl/sst#')
+
+
+class WLURI(object):
+ """Represents a WL URI. Extracts slug from it."""
+ slug = None
+
+ example = 'http://wolnelektury.pl/katalog/lektura/template/'
+ _re_wl_uri = re.compile(r'http://(www\.)?wolnelektury.pl/katalog/lektura/(?P<slug>[-a-z0-9]+)/?$')
+
+ def __init__(self, uri):
+ uri = unicode(uri)
+ self.uri = uri
+ self.slug = uri.rstrip('/').rsplit('/', 1)[-1]
+
+ @classmethod
+ def strict(cls, uri):
+ match = cls._re_wl_uri.match(uri)
+ if not match:
+ raise ValidationError(u'Invalid URI (%s). Should match: %s' % (
+ uri, cls._re_wl_uri.pattern))
+ return cls(uri)
+
+ @classmethod
+ def from_slug(cls, slug):
+ """Contructs an URI from slug.
+
+ >>> WLURI.from_slug('a-slug').uri
+ u'http://wolnelektury.pl/katalog/lektura/a-slug/'
+
+ """
+ uri = 'http://wolnelektury.pl/katalog/lektura/%s/' % slug
+ return cls(uri)
+
+ def __unicode__(self):
+ return self.uri
+
+ def __str__(self):
+ return self.uri
+
+ def __eq__(self, other):
+ return self.slug == other.slug
+
+
+class URLOpener(urllib.FancyURLopener):
+ version = 'FNP Librarian (http://git.nowoczesnapolska.org.pl/?p=librarian.git)'
+urllib._urlopener = URLOpener()