* * * * *
                                        
                              Cache flow problems
                                        
“I keep getting these notifications that you've updated your site,” said Dad,
“but when I check, I keep seeing the same page over and over again.” This was
about the fourth or fifth time this topic has come up over the past few
months. And each time I tell Dad to shift-reload [1] but that doesn't seem to
work for him, although the page eventually does change, after awhile.

Sigh.

I suspect I know the problem. Sometime in the past year I changed the
configuration of my webserver to allow browsers and web proxies to better
cache the content here:

> ExpiresActive  On
> ExpiresDefault "access plus 1 day"
> ExpiresByType  image/jpeg "access plus 1 month"
> ExpiresByType  image/gif  "access plus 1 month"
> ExpiresByType  image/png  "access plus 1 month"
> ExpiresByType  text/css   "access plus 1 month"
> ExpiresByType  text/plain "access plus 1 month"
> 

Images, style sheets, plain text files, all can be cached for a month (heck,
they can probably be cached indefinitely for my blog—the content has never
really changed all that much), but the web pages (in addition to the various
feed [2] files [3]) can only be cahced for 24 hours.

And I think that's the issue.

Dad's ISP (Internet Service Provider) is known to aggressively cache the web
[4] (I won't name names, but it's initials are 'A', 'O' and 'L') so I may
need to adjust my methods for caching values.

[1] http://www.hbuhsd.k12.ca.us/Bulletins/Bulletin_1999-08-04.htm
[2] https://boston.conman.org/bostondiaries.rss
[3] https://boston.conman.org/index.atom
[4] http://webmaster.info.aol.com/caching.html

Email Sean Conner at sean@conman.org

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