Default syntax for Header set Expires is:
Header set Expires "Wed, 21 May 2010 20:00:00 GMT"
and default syntax for ExpiresDefault is:
ExpiresDefault A2592000
OR
ExpiresByType image/gif A60
I want to use such a syntax for Header set Expires, that is I want to pass an expires time in seconds after access. How can I do this ?
It can’t be done directly, because RFC 2616 section 14.21 (http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.21) says:
“The format is an absolute date and time as defined by HTTP-date in section 3.3.1…”
However, if you are able to set the HTTP header programmatically during delivery of your file, you can calculate a future date based on the current server time.