Monday, March 08, 2010
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 but that doesn't seem to work for him, although the page eventually does change, after awhile.
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 files) can only be cahced for 24 hours.
And I think that's the issue.
Dad's ISP is known to aggressively cache the web (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.