// the find
wycats/rack-offline
A Rack and Rails plugin for building offline web applications
A Rack middleware that generates HTML5 Application Cache manifests, letting you declare which static assets should be cached for offline use. Built by Yehuda Katz around 2011 for the mobile web era. Largely irrelevant today — AppCache was deprecated in 2019 and removed from all major browsers by 2022.
The SHA-based cache-busting strategy (timestamp in dev, content hash in prod) was genuinely clever for its time. The Rails::Offline convenience wrapper made zero-config adoption fast. The README is honest about AppCache's quirks — stale-on-first-hit, atomic update model — rather than glossing over them.
AppCache is gone. Chrome, Firefox, and Safari all removed it; this gem produces manifests that browsers simply ignore. Last meaningful commit was over a decade ago. Service Workers replaced everything this does and do it better, but there's no migration path here. The test suite covers the manifest generation logic but nothing about actual offline behavior, which was always the hard part.