code: def _pathify(self):
          
          try:
              (path,
               query,
               self._fragment) = urisup.uri_help_split(self.path)[2:]
  
              if not path:
                  path = "/"
  
              if path[0] != "/":
                  raise urisup.InvalidURIError('path %r does not start with "/"' % path)
  
              self._path = re.sub("^/+", "/", path, 1)
  
              if query:
                  self._query_params = self.querylist_to_dict(query)
  
              return self._path
          except urisup.InvalidURIError, e:
              LOG.error("invalid URI: %s", e)
              raise self.req_error(400, str(e))
docs: rfc2616 says in 5.1.2: "all HTTP/1.1 servers MUST accept the
          absoluteURI form in requests" so if we get one, transform it
          to abs_path.
          Raises HttpReqError if the request is malformed, else returns
          (path, query, fragment)