scgi_cache_valid

Sets caching time for different response codes. For example, the following directives

scgi_cache_valid 200 302 10m;
scgi_cache_valid 404      1m;

set 10 minutes of caching for responses with codes 200 and 302 and 1 minute for responses with code 404.

If only caching time is specified

scgi_cache_valid 5m;

then only 200, 301, and 302 responses are cached.

In addition, the any parameter can be specified to cache any responses:

scgi_cache_valid 200 302 10m;
scgi_cache_valid 301      1h;
scgi_cache_valid any      1m;

Parameters of caching can also be set directly in the response header. This has higher priority than setting of caching time using the directive.

• The “X-Accel-Expires” header field sets caching time of a response in seconds. The zero value disables caching for a response. If the value starts with the @ prefix, it sets an absolute time in seconds since Epoch, up to which the response may be cached.
• If the header does not include the “X-Accel-Expires” field, parameters of caching may be set in the header fields “Expires” or “Cache-Control”.
• If the header includes the “Set-Cookie” field, such a response will not be cached.
• If the header includes the “Vary” field with the special value “*”, such a response will not be cached (1.7.7). If the header includes the “Vary” field with another value, such a response will be cached taking into account the corresponding request header fields (1.7.7).

Processing of one or more of these response header fields can be disabled using the scgi_ignore_headers directive.