I notice that the Guide omits the mention of Netscape's ignorance of
Expires: set to the same as Date: when it mentions $r->no_cache(1)
performing that function.
Currently, I'm experiencing the problem with Netscape 4.7, although I seem
to recall the same problem in earlier releases, in the case where the target
browser's clock is slow.
Of course, the server-side workaround (since we can't just fix our visitor's
clocks) is to set an Expires header that significantly in the past, for some
definition of 'significant'.
I'm going to assume that $r->no_cache(1) won't be kludged to fix Netscape's
bug, although some would argue that it should be 'fixed' in mod_perl.
As an update to /guide/correct_headers.html#2_1_3_Expires_and_Cache_Control,
I'd suggest adding the following text at the end:
[ ... works with the major browsers. ] However, Netscape clients with slow
clocks may not honor the 'immediate' timeout, cacheing pages anyway.
This can be corrected by explicitly setting an Expires header that's in
the past. How far in the past depends on how lenient you wish to be with
browsers with slow clocks.
Something between 5 and 30 minutes seems reasonable to me, but discussion
may demonstrate a different approach and/or timeframe.
Thoughts?
Randy
