[thelist] Is server-side browser-sniffing a bad idea?
deke
web at master.gen.in.us
Fri Dec 7 06:25:25 CST 2001
On 6 Dec 2001, at 17:37, Craig Saila posted a message which said:
> Despite the fact it cancels out the benefits of caching (i.e., faster
> download times for the user), wouldn't putting:
> <meta http-equiv="Pragma" content="no-cache">
> in the head solve these server-side issues?
That's a misuse of the "pragma" header - it's supposed to be for
sending messages *to* the server, not from the server to the client.
And the biggest single chunk of the internet is AOL, and their
caching firewall does *not* look at web pages to see if you have meta
tags. You have to have *real* headers to play in their ballpark.
Most corporate caching firewalls, as well as the MSNTV one, will not
cache a page that sets cookies in the headers, a page that is the
result of a POST operation, or pages that have an https:// URL. I
can't think of a better reason to avoid javascript cookies than that.
If you use the
Cache-Control:private
header, that tells the browser it's OK to cache the page, but firewalls
aren't supposed to save it to a shared cache. That depends on
everybody knowing and understanding HTTP/1.1, though.
deke
--------
We are the parents our people warned us about....
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