[brown9-2]

Is putting hash digests in filenames really easier than sending Last-Modified headers in the response, parsing If-Modified-Since headers and returning 304 when applicable, and/or using ETags?

I would have thought that most web frameworks do all these things for you automatically by now.

[jmtulloss]

Putting the hash in the filename allows the browser to not even make a request that would result in a 304 request. It also works behind badly behaved proxies and caches that don't properly respect cache headers.

[lotyrin]

It also allows for pages that were generated and cached before changes were made to still have resources, as well as other cases where you might have divergent sets of resources (split tests, rolling deployments, etc.)