One of the things that Google PageSpeed uses to rate your site, and your position in the Google results, is how effectively it caches static assets. That’s thing like images, JavaScript files, etc. that don’t really change once your site’s gone live.
Look familiar?
Setting an efficient cache policy not only improves your PageSpeed score but also improves browsing for you users, which is the main goal. It tells their browser to keep a local copy of static assets for a certain amount of time, which means they’re not having to download images and stylesheets every time they visit your site – they can just use the copy they downloaded last time that’s still on their hard drive.
To set up a Google-friendly caching policy all you need to do is paste the following into your .htacess file in your website root (e.g. in the public_html folder).
You’ll need mod_deflate and mod_expires enabled in your Apache config to set this up.
On Ubuntu/Debian servers you can run
apachectl -M
to get a list of the enabled modules. If either of those two are missing, enable them using
a2enmod deflates expires
and then restart Apache
service apache2 restart
Here’s what needs to go into the .htaccess file
<ifmodule mod_deflate.c> # Compress HTML, CSS, JavaScript, Text, XML and fonts AddOutputFilterByType DEFLATE image/svg+xml AddOutputFilterByType DEFLATE application/javascript AddOutputFilterByType DEFLATE application/rss+xml AddOutputFilterByType DEFLATE application/vnd.ms-fontobject AddOutputFilterByType DEFLATE application/x-font AddOutputFilterByType DEFLATE application/x-font-opentype AddOutputFilterByType DEFLATE application/x-font-otf AddOutputFilterByType DEFLATE application/x-font-truetype AddOutputFilterByType DEFLATE application/x-font-ttf AddOutputFilterByType DEFLATE application/x-javascript AddOutputFilterByType DEFLATE application/xhtml+xml AddOutputFilterByType DEFLATE application/xml AddOutputFilterByType DEFLATE font/opentype AddOutputFilterByType DEFLATE font/otf AddOutputFilterByType DEFLATE font/ttf AddOutputFilterByType DEFLATE image/x-icon AddOutputFilterByType DEFLATE text/css AddOutputFilterByType DEFLATE text/html AddOutputFilterByType DEFLATE text/javascript AddOutputFilterByType DEFLATE text/plain AddOutputFilterByType DEFLATE text/xml # Remove browser bugs (only needed for really old browsers) BrowserMatch ^Mozilla/4 gzip-only-text/html BrowserMatch ^Mozilla/4\.0[678] no-gzip BrowserMatch \bMSIE !no-gzip !gzip-only-text/html </ifmodule>
<IfModule mod_expires.c> ExpiresActive on # Set the default expiry times. #ExpiresDefault "access plus 2 days" ExpiresByType image/jpg "access plus 1 year" ExpiresByType image/svg+xml "access plus 1 year" ExpiresByType image/gif "access plus 1 year" ExpiresByType image/jpeg "access plus 1 year" ExpiresByType image/png "access plus 1 year" ExpiresByType text/css "access plus 6 month" ExpiresByType text/javascript "access plus 6 month" ExpiresByType application/javascript "access plus 6 month" ExpiresByType image/ico "access plus 1 month" ExpiresByType image/x-icon "access plus 1 month" ExpiresByType application/vnd.ms-fontobject "access plus 1 year" ExpiresByType font/otf "access plus 1 year" ExpiresByType font/ttf "access plus 1 year" ExpiresByType font/woff "access plus 1 year" ExpiresByType font/woff2 "access plus 1 year" </IfModule>
A full list of MIME types that you can use with ExpiresByType headers is available here https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types/Common_types