Traceback (most recent call last): File "/data/www/ecun/app.py", line 4059, in get if re.search(mobile_list, self.request.headers["User-Agent"]) and not is_mobile and self.request.headers.get('X-Requested-With') != 'cn.gove.www.ecunke': File "/usr/lib64/python2.7/site-packages/tornado/httputil.py", line 215, in __getitem__ return self._dict[_normalized_headers[name]] KeyError: 'User-Agent'