activestorage-hotcell-server

https://github.com/basecamp/hotcell

Transformations, image analysis, PDF and video previews, and media probing, written as HotCell operations so they run in an unprivileged container with no network rather than in the application. Despite the name, this gem does not load Active Storage. The name says which consumer it serves, not what it links against: a cell that loaded an application framework would have loaded its configuration and its credentials with it.