Apache Content Caching
By Lance Gliser
Published:
Heads up! This content is more than six months old. Take some time to verify everything still works as expected.
# Cache Control with .htaccess
# from http://www.askapache.com/htaccess/speed-up-sites-with-htaccess-caching.html
<FilesMatch ".(flv|gif|jpg|jpeg|png|ico|swf)$">
Header set Cache-Control "max-age=$Time"
</FilesMatch>
And list of some common times:
- 300 5 MIN
- 600 10 MIN
- 900 15 MIN
- 1800 30 MIN
- 2700 45 MIN
- 3600 1 HR
- 18000 5 HR
- 43200 12 HR
- 86400 24 HR
- 86400 1 DAY
- 172800 2 DAY
- 259200 3 DAY - This is the limit for YSlow's Far Future Restriction
- 345600 4 DAY
- 432000 5 DAY
- 518400 6 DAY
- 604800 7 DAY
- 604800 1 WEEK
- 1209600 2 WEEK
- 1814400 3 WEEK
- 2419200 4 WEEK
- 2419200 1 MONTH (FEBRUARY)
- 2505600 1 MONTH (FEBRUARY LEAP YEAR)
- 2592000 1 MONTH (APRIL, JUNE, SEPTEMBER, NOVEMBER)
- 2678400 1 MONTH (JANUARY, MARCH, MAY, JULY, AUGUST, OCTOBER, DECEMBER)
- 31536000 12 MONTH
Of course, the best policy would be to implement permanent caching of static content, then use version numbers on your content. A huge bonus of doing this is that people visiting your site get fresh files, every time you make a change, instead of telling your client to reload.
For more information on the reasoning behind doing this, you can read up on Yahoo's YSlow site.