Re: page reloads

At 1:32 PM 5/31/95, Shel Kaphan wrote:
>Kee Hinckley writes:
>        ...
>   However, even
> > that won't work with some caching servers, so you need to go one more step.
> > When the "takeorder" script redirects back to the order form, have it pass
> > a unique argument everytime (e.g.
> > http://www.somewhere.com/order.html?Defeat-Cache=3Dxxx, where xxx is the
> > result of "time(0)" or something).  The html file will ignore the argument,
> > but the presence of the argument will defeat any caching mechanism.
> >
>
>There are problems with this approach.  If you have a page A that
>contains a link in the form you suggest to document B, and you have already
>viewed page A and followed the link to B, if you "back up" to A with
>browser navigation commands, and then follow B again, you may still
>get the *old* document B (because the browser might cache B).  This is
>precisely where where browsers should respect "expires:", and where
>some current ones do not.  Moreover, if browsers did respect the
>expires header, the "cache-buster" in the URL would not be needed.

If you used the cache-buster in the URL then you could definitely have
problems like that.  However I was only recommending using it in the
redirect, where the user does not have direct access to the link (save in
browser's like Pipeline, which don't recognize redirects and display the
HTML instead (have they fixed that?))

You're right about the Expires. However in my tests using AOL's browser,
their caching server wasn't respecting it either, so until then we're stuck
with hacks.  I still think though, that it is worthwhile separating out
"don't keep in history list" from "this document has expired".

Kee Hinckley      Utopia Inc. - Cyberspace Architects    617/721-6100
nazgul@utopia.com                               http://www.utopia.com/

I'm not sure which upsets me more: that people are so unwilling to accept
responsibility for their own actions, or that they are so eager to regulate
everyone else's.

Received on Wednesday, 31 May 1995 15:24:59 UTC