Headers#
Allows adding the "Expires" and "Cache-Control" header fields, and arbitrary fields, to a response header.
Configuration Example#
expires 24h;
expires modified +24h;
expires @24h;
expires 0;
expires -1;
expires epoch;
expires $expires;
add_header Cache-Control private;
Directives#
add_header#
Adds the specified field to a response header provided that the response code equals 200, 201, 204, 206, 301, 302, 303, 304, 307, or 308. Parameter value can contain variables.
There could be several add_header directives. These directives are inherited from the previous configuration level if and only if there are no add_header directives defined on the current level.
If the always
parameter is specified, the header field will be added regardless of the response code.
add_trailer#
Adds the specified field to the end of a response provided that the response code equals 200, 201, 206, 301, 302, 303, 307, or 308. Parameter value can contain variables.
There could be several add_trailer directives. These directives are inherited from the previous configuration level if and only if there are no add_trailer directives defined on the current level.
If the always
parameter is specified the specified field will be added regardless of the response code.
expires#
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Default |
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http, server, location, if in location |
Enables or disables adding or modifying the "Expires" and "Cache-Control" response header fields provided that the response code equals 200, 201, 204, 206, 301, 302, 303, 304, 307, or 308. The parameter can be a positive or negative time.
The time in the "Expires" field is computed as a sum of the current time and time specified in the directive. If the modified
parameter is used then the time is computed as a sum of the file's modification time and the time specified in the directive.
In addition, it is possible to specify a time of day using the "@" prefix:
expires @15h30m;
The contents of the "Cache-Control" field depends on the sign of the specified time:
time is negative — "Cache-Control: no-cache".
time is positive or zero — "Cache-Control: max-age=`t`", where t is a time specified in the directive, in seconds.
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sets "Expires" to the value "Thu, 01 Jan 1970 00:00:01 GMT", and "Cache-Control" to "no-cache". |
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sets "Expires" to the value "Thu, 31 Dec 2037 23:55:55 GMT", and "Cache-Control" to 10 years. |
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disables adding or modifying the "Expires" and "Cache-Control" response header fields. |
The last parameter value can contain variables:
map $sent_http_content_type $expires {
default off;
application/pdf 42d;
~image/ max;
}
expires $expires;