Upstream {} is the same as our cache (HTTP 304)'.format(url)

[magenx]

[*] Using Mwscan rules.
[*] Fetching mwscan.yar
[*] Starting new HTTPS connection (1): mwscan.s3.amazonaws.com
[*] https://mwscan.s3.amazonaws.com:443 "GET /mwscan.yar HTTP/1.1" 304 0
Traceback (most recent call last):
  File "/usr/bin/mwscan", line 9, in <module>
    load_entry_point('mwscan==20180228.120927', 'console_scripts', 'mwscan')()
  File "/usr/lib/python2.6/site-packages/mwscan/scan.py", line 243, in main
    rules, whitelist = provider(args=args).get()
  File "/usr/lib/python2.6/site-packages/mwscan/ruleset.py", line 126, in get
    rawrules = self.get_rules()
  File "/usr/lib/python2.6/site-packages/mwscan/ruleset.py", line 46, in get_rules
    return self._recursive_fetch(self.rules_url)
  File "/usr/lib/python2.6/site-packages/mwscan/ruleset.py", line 147, in _recursive_fetch
    data = self._httpget(url)
  File "/usr/lib/python2.6/site-packages/mwscan/ruleset.py", line 114, in _httpget
    logging.debug('Upstream {} is the same as our cache (HTTP 304)'.format(url))
ValueError: zero length field name in format

[gwillem]

Thanks for reporting! Just published a new pip package.