apache tutorial - How to configure caching with the mod_expires module - apache - apache web server - apache server - apache2
Using the mod_expires module
- Apache's mod_expires module enables you to define expiration intervals for different types of content on your web site.
- For example, you could use mod_expires directives to instruct browsers to cache image files for one hour, JavaScript files for two weeks, and CSS files for two months.
- The following sample .htaccess configuration demonstrates how to do this:
<IfModule mod_expires.c>
ExpiresActive On
ExpiresByType image/png "access 1 hour"
ExpiresByType image/gif "access 1 hour"
ExpiresByType image/jpeg "access 1 hour"
ExpiresByType text/javascript "access 2 weeks"
ExpiresByType text/css "access 2 months"
ExpiresByType text/html "modification 4 hours"
ExpiresDefault "access 2 days"
</IfModule>click below button to copy the code. By Apache tutorial team
- There are actually two ways to define expiration periods.
- You can specify an expiration period from the time the browser accesses the file by using the access keyword.
- Alternatively, you can specify an expiration period from the time the file was last modified on the server by using the modification keyword.
- The ExpiresDefault directive is an optional directive that specifies the expiration period for all other types of files not explicitly set in an ExpiresByType directive.
- In this example, any file that is not an image, JavaScript, or CSS file expires in two days.
- To verify your expiration settings in the .htaccess file are working correctly, you can examine the raw HTTP headers sent between the browser and web server. (To do this, use a browser plugin that displays the raw headers such as Live HTTP headers for Mozilla Firefox, or the Developer Tools feature in Google Chrome.)
- When content is marked for expiration, Apache adds the following lines to the HTTP response header (the exact values will vary based on your own .htaccess settings):
Cache-Control: max-age=86400
Expires: Thu, 02 Oct 2014 19:02:30 GMT