Barry Pollard
2016-06-12 04:21:47
The absence of a cache-control header does not mean a resource cannot be cached - it's up to the client (i.e. the web browser) to decide how to handle this undefined state.
Caching it (whether in memory or in disk) and only using that cached version if ETag validates seems a perfectly reasonable implementation to me.
If you don't want a resource cached then you should explicitly say this with a cache-control header of "max-age=0, no-store, no-cache, must-revalidate".
Are all these values required? Seems like quite a verbose header to not cache something. I think a common scenario for needing to ensure that a file is never cached would be the
service-worker.jsfile for many single page apps.