'Handle the downloaded response or failure through the spider
callback/errback'

def _scrape(self, response, request, spider):

    assert isinstance(response, (Response, Failure))
    dfd = self._scrape2(response, request, spider)
    dfd.addErrback(self.handle_spider_error, request, response, spider)
    dfd.addCallback(self.handle_spider_output, request, response, spider)
    return dfd
