[thelist] Server Proxy Cache Conundrum

Hershel Robinson hershelsr at yahoo.com
Wed Aug 1 14:13:50 CDT 2001


My ISP has a proxy cache.  This is problematic because I am a web developer.
They have not succeeded in removing my web sites from the cache (but they
are very cheap and have a fast connection so I am staying with them for now)
so I have used other methods.

Namely, I use the nocache pragma so my pages aren't cached.  I have noticed,
however, that if I use a JavaScript include file, then that file itself IS
cached and if I update that file, I do not get the new version right away.
There is no nocache pragma (of which I am aware) for a JS include file, so
it therefore gets cached.  (Using Shift-Refresh does not overcome this
problem.)

I can of course just put the JS into the page itself, but we do have several
pages which share JS include files and so we want to leave them as JS
include files.

We can foresee a day that there may be an actual user also behind a proxy
cache who gets a page two minutes before we update it's JS include file.  We
update and then he refreshes or comes back to the page in 5 minutes.  He
gets the new HTML, but if the HTML in the new page itself depends on the new
JS file, then this user is going to have problems.

My question is, do people agree this could be a problem and are there any
solutions?  I myself am not in the US and I don't know how common caches
like this are there.  The vast majority of our users are in the US, however.

I suppose we could take out the nocache pragma once we finish developing,
but then how can we actually guarantee that the cache will expire at the
same time on the HTML and the JS?  It could be that the HTML page could be
'older' in the cache than the JS because the JS is used by multiple pages
and was therefore requested again by the user since the HTML.  When he again
requests the HTML, he will get new HTML with old JS.

Strange problem, I think, but interesting.

Thanks,
Hershel


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