Class DOMEntityResolver

Lib/xml/dom/xmlbuilder.py:212–255

class DOMEntityResolver(object):
    __slots__ = '_opener',

    def resolveEntity(self, publicId, systemId):
        assert systemId is not None
        source = DOMInputSource()
        source.publicId = publicId
        source.systemId = systemId
        source.byteStream = self._get_opener().open(systemId)

        # determine the encoding if the transport provided it
        source.encoding = self._guess_media_encoding(source)

        # determine the base URI is we can
        import posixpath, urllib.parse
        parts = urllib.parse.urlparse(systemId)
        scheme, netloc, path, params, query, fragment = parts
        # XXX should we check the scheme here as well?
        if path and not path.endswith("/"):
            path = posixpath.dirname(path) + "/"
            parts = scheme, netloc, path, params, query, fragment
            source.baseURI = urllib.parse.urlunparse(parts)

        return source

    def _get_opener(self):
        try:
            return self._opener
        except AttributeError:
            self._opener = self._create_opener()
            return self._opener

    def _create_opener(self):
        import urllib.request
        return urllib.request.build_opener()

    def _guess_media_encoding(self, source):
        info = source.byteStream.info()
        # import email.message
        # assert isinstance(info, email.message.Message)
        charset = info.get_param('charset')
        if charset is not None:
            return charset.lower()
        return None


class DOMInputSource(object):