[whatwg] hash sum tags of binary files and code blocks?

Tab Atkins Jr. jackalmage at gmail.com
Mon Jul 13 09:55:36 PDT 2009

On Mon, Jul 13, 2009 at 11:41 AM, Aron Spohr<aron at aspohr.de> wrote:
> Hi Christian,
> have you ever considered just making the md5 (or maybe just a shorter CRC) part of the filename of the file you want to cache? Then you can send Expiry headers for 6 months or a years time for those files and you'll get the same behaviour.

FWIW, I do this.  I set far-future expiry headers on my CSS and
images.  If I need to make a change after it's gone live, I append a
query parameter with a current timestamp.  There isn't anything on the
other end which responds to the query param, but it does indicate that
it's a new resource to the browser's caching algorithm, which is
precisely what I want.  The new version will then stay cached until I
change the query param again.  Using a hash or version number instead
of a timestamp is equivalent.

(I could, of course, actually hook up a script on the server-side
which remembers the previous versions of the resource and will serve
them up as requested, but that hasn't ever been necessary so far.)


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