htaccess - How to force the client's browser to clear the cache?

Question

For my site I have the following htaccess rules:

# BEGIN Gzip

AddOutputFilterByType DEFLATE text/text text/html text/plain tex         


        

Answer 1

Now the following wont help you with files that are already cached, but moving forward, you can use the following to easily force a request to get something new, without changing the actual filename.

# Rewrite all requests for JS and CSS files to files of the same name, without
# any numbers in them. This lets the JS and CSS be force out of cache easily
# by putting a number at the end of the filename
# e.g. a request for static/js/site-52.js will get the file static/js/site.js instead.

  RewriteEngine on
  RewriteRule ^static/(js|css)/([a-z]+)-([0-9]+)\.(js|css)$ /site/$1/$2.$4 [R=302,NC,L]

Of course, the higher up in your folder structure you do this type of approach, the more you kick things out of cache with a simple change.

So for example, if you store the entire css and javascript of your site in one main folder

/assets/js
/assets/css
/assets/...

Then you can could start referencing it as "assets-XXX" in your html, and use a rule like so to kick all assets content out of cache.

  RewriteEngine on
  RewriteRule ^assets-([a-z0-9]+)/(.*) /$2 [R=302,NC,L]
 

Note that if you do go with this, after you have it working, change the 302 to a 301, and then caching will kick in. When it's a 302 it wont cache at the browser level because it's a temporary redirect. If you do it this way, then you could bump up the expiry default time to 30 days for all assets, since you can easily kick things out of cache by simply changing the folder name in the login page.

  ExpiresActive on
  ExpiresDefault A2592000