A nice feature from the commercial nginx purge package is that it lets you purge by prefix. That's a feature that I've not seen in any of the open source purge

A nice feature from the commercial nginx purge package is that it lets you purge by prefix. That's a feature that I've not seen in any of the open source purge modules. If you are hosting data for several users on the same nginx cache and you want to purge only one of them, your only options are to scan the full cache on disk and delete the files that have a key with your prefix, or fork >$1K/year per nginx box for the commercial license.