code: def _get_name_from_url(self, request):
          
  
          format = request.GET.get('format', None)
          if not format:
              match = self._format_query_pattern.match(request.path)
              if match and match.group('format'):
                  format = match.group('format')
          return format
docs: Determine short name for the mapper based on the URL.
  
          Short name can be either in query string (e.g. ?format=json)
          or as an extension to the URL (e.g. myresource.json).
  
          :returns: short name of the mapper or ``None`` if not found.