View source for HttpHeadersModule

= Synopsis =

This module allows setting arbitrary HTTP headers.

Examples
<geshi lang="nginx">
  expires       24h;
  expires       modified +24h;
  expires       @15h30m;
  expires       0;
  expires       -1;
  expires       epoch;
  add_header    Cache-Control  private;
</geshi>

= Directives =
== add_header ==
<include wikitext nopre src="http://wiki.nginx.org/nginx.org/http/ngx_http_headers_module/add_header.txt" />

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 <code>Last-Modified</code>, it just appends a new header entry to the output header list. So you can't use this directive to rewrite existing headers like <code>Server</code>. Use the [[NginxHttpHeadersMoreModule|headers_more]] module for it.

== expires ==
<include wikitext nopre src="http://wiki.nginx.org/nginx.org/http/ngx_http_headers_module/expires.txt" />

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

* <code>off</code> prevents changes to the <code>Expires</code> and <code>Cache-Control</code> headers.

* <code>epoch</code> sets the <code>Expires</code> header to 1 January, 1970 00:00:01 GMT.

* <code>max</code> sets the <code>Expires</code> header to 31 December 2037 23:59:59 GMT, and the <code>Cache-Control</code> max-age to 10 years.

* A time without an <code>@</code> 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 &mdash; available from versions 0.7.0 & 0.6.32). A negative time can be specified, which sets the <code>Cache-Control</code> header to <code>no-cache</code>.

* Times written with an <code>@</code> 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 <code>Cache-Control</code> header to <code>max-age = #</code>, where # is the appropriate time in seconds.


'''Note:''' <code>expires</code> works only for 200, 204, 301, 302, and 304 responses.

= References =
[http://nginx.org/en/docs/http/ngx_http_headers_module.html Original Documentation]

= See Also =

* The third-party [[NginxHttpHeadersMoreModule|headers_more]] module for adding, replacing, and clearing both input and output headers.