title: Why does extraction of gzipped sitemap fail in Scrapy 0.24.4?
body: <p>I am getting the "Not a gzipped file" exception while retrieving a gzipped sitemap xml (tested on amazon.de)</p>
  
  <p>According to the bugtrackers, there used to be a bug regarding "Not a gzipped file" </p>
  
  <p>I am using Python 2.7.3 and Scrapy 0.24.4</p>
  
  <p>Can anyone confirm this as a bug or am I overseeing something?</p>
  
  <p><strong>UPDATE</strong></p>
  
  <p>I think this is some valuable information, already posted on github as well</p>
  
  <p><strong>Possible bug:</strong>
  retrieving a gzipped sitemap xml (tested on amazon.de) fails.</p>
  
  <p><strong>Reproduce with:</strong></p>
  
  <ol>
  <li>modify /utils/gz.py gunzip method to write the incoming data to a file.</li>
  <li>gunzip the file on the command line.</li>
  <li>the unzipped file contains garbled content</li>
  <li>gunzip that file with garbled content a second time and get the correct content</li>
  </ol>
  
  <p>I suspect that the content coming from the target server is already gzip compressed and scrapy has a bug that causes the gzip http decompression to not work properly, resulting in a double compressed file arriving at the  /utils/gz.py gunzip method  </p>