Re: cache-busting and query-string versioning

On Mon, Jun 27, 2016 at 2:41 PM, Amos Jeffries <squid3@treenet.co.nz> wrote:

> On 27/06/2016 9:37 a.m., Raphaël D wrote:
> > On Wed, 22 Jun 2016 13:39:39 +0200 Alcides Viamontes wrote:
> >
> >> Yes, this is related to caching in general. And it is the reason
> >> people have to add query strings for doing cache busting. This problem
> is a
> >> separate issue, but it interacts with cache digests in that old version
> >> of assets are kept in the cache and  therefore in the cache digest and
> the
> >> origin have no way of removing it. The origin can only create a new URL
> >> (say, via a new query string) that gets added to the cache and the cache
> >> digest.
> >
> > (email subject renamed to avoid polluting the "Cache Digests for HTTP/2"
> >  mailing-list thread)
> >
> > Hi,
> >
> > I read this incidentally meanwhile trying to understand what alternative
> > to cache-busting exists.
> > I'm stretching my head to find which overlooked IETF-http or W3C concept
> matches.
> >
> >
> > Nowadays most CMS, javascript/css-frameworks feature cache-busting
> > (usually using query-string) which is considered as the unavoidable
> > answer to the "can't forcefully refresh browser cache" issue (and web
> > traffic pattern).
> >
> >
> > Among the facts/reasons given are:
> >
> > 1) web-applications support the fact that some webserver set far-future
> >    Expires times for assets (css, js, fonts)
>
> The existing Best Practice is for redesigns to change the names of their
> objects slightly *iff* the object has changed enough to warrant it.
> Enough to do cache busting without query-string, but also to retain
> backward compatibility with older versions of the application requesting
> old assets.
>

I do think that having to change the names of modified assets is a bit sad.
Wouldn't it be nice if etag validators were enough? On the other hand, if a
bug needs to be fixed in say "login.js", one would certainly want to
propagate those changes instantaneously. As it is now, I can not have my
pie and eat it :-(