Scrapy - How to get duplicate request referer
<p>When I turn on <code>DUPEFILTER_DEBUG</code>, I got:</p>

<blockquote>
  <p>2016-09-21 01:48:29 [scrapy] DEBUG: Filtered duplicate request: http://www.example.org/example.html></p>
</blockquote>

<p>The problem is, I need to know the duplicate request's referrer to debug the code. How can I debug the referrer?</p>