Web Cache Logs

setting Expires with web server

Expiration date can be set in web server configuration for static resources [dynamic resources can have Expires set by scripts].

Apache Expires can be set in the configuration file [httpd.conf] or with .htaccess files. In any case expires_module must be active. While .htaccess files are more flexible, allowing changes without server restart [and sometimes are the only choice available], there is a performance impact: each time a file is requested Apache must process directory's .htaccess file as well as every one that exists up to the server root.

The following example ensures that all "*-stable.pdf" files are cacheable for one year from the time they are requested. To use inside httpd.conf <Directory> or <Location> directives, or in .htaccess files:

IIS Expires can be set with IIS Manager [control panel / administrative tools]. When you set Expires for a server or directory that applies to all files under:

• Select server, directory or file properties with menus.
• In properties dialog select the HTTP headers tab.
• Select a relative [to access date] or absolute expiration time.