code: def serve_content(self, environ, coll='$root', url='', timemap_output='', record=False):
          
          if not self.is_valid_coll(coll):
              self.raise_not_found(environ, 'No handler for "/{0}"'.format(coll))
  
          self.setup_paths(environ, coll, record)
  
          request_uri = environ.get('REQUEST_URI')
          script_name = environ.get('SCRIPT_NAME', '') + '/'
          if request_uri and request_uri.startswith(script_name):
              wb_url_str = request_uri[len(script_name):]
  
          else:
              wb_url_str = to_native_str(url)
  
              if environ.get('QUERY_STRING'):
                  wb_url_str += '?' + environ.get('QUERY_STRING')
  
          metadata = self.get_metadata(coll)
          if record:
              metadata['type'] = 'record'
  
          if timemap_output:
              metadata['output'] = timemap_output
              # ensure that the timemap path information is not included
              wb_url_str = wb_url_str.replace('timemap/{0}/'.format(timemap_output), '')
          try:
              response = self.rewriterapp.render_content(wb_url_str, metadata, environ)
          except UpstreamException as ue:
              response = self.rewriterapp.handle_error(environ, ue)
              raise HTTPException(response=response)
          return response
docs: Serve the contents of a URL/Record rewriting the contents of the response when applicable.
  
          :param dict environ: The WSGI environment dictionary for the request
          :param str coll: The name of the collection the record is to be served from
          :param str url: The URL for the corresponding record to be served if it exists
          :param str timemap_output: The contents of the timemap included in the link header of the response
          :param bool record: Should the content being served by recorded (save to a warc). Only valid in record mode
          :return: WbResponse containing the contents of the record/URL
          :rtype: WbResponse