First qiita_pet exception type
Bold preprocessing status indicators
Use basename instead of os.path.split(...)[-1]
Grace-fail if user downloads from server w/o nginx

The file will download but will contain a (somewhat) helpful message
Display download links conditionally

If the request is coming from localhost, then do not display the link (instead,
display the filepath); if it is coming from elsewhere, provide links that
use the download handler