Synopsis

This module allows setting arbitrary HTTP headers.

Examples

  expires       24h;
  expires       modified +24h;
  expires       @15h30m;
  expires       0;
  expires       -1;
  expires       epoch;
  add_header    Cache-Control  private;

Directives

add_header

Adds headers to the HTTP response when the response code is equal to 200, 204, 301, 302 or 304.

Note that for headers other than Last-Modified, it just appends a new header entry to the output header list. So you can't use this directive to rewrite existing headers like Server. Use the headers_more module for it.

expires

Controls whether the response should be marked with an expiry time, and if so, what time that is.

• off prevents changes to the Expires and Cache-Control headers.

• epoch sets the Expires header to 1 January, 1970 00:00:01 GMT.

• max sets the Expires header to 31 December 2037 23:59:59 GMT, and the Cache-Control max-age to 10 years.

• A time without an @ prefix specifies an expiry time relative to either the response time (if the time is not preceded with "modified") or the file's modification time (when "modified" is present — available from versions 0.7.0 & 0.6.32). A negative time can be specified, which sets the Cache-Control header to no-cache.

• Times written with an @ prefix represent an absolute time-of-day expiry, written in either the form Hh or Hh:Mm, where H ranges from 0 to 24, and M ranges from 0 to 59 (available from versions 0.7.9 & 0.6.34).

A non-negative time or time-of-day sets the Cache-Control header to max-age = #, where # is the appropriate time in seconds.

Note: expires works only for 200, 204, 301, 302, and 304 responses.

References

Original Documentation

See Also

• The third-party headers_more module for adding, replacing, and clearing both input and output headers.