Nginx Client Caching
nginx(8) has a simplified API to managing the headers that affect client-side caching of resources.
Unit Measurements
In nginx(8) configuration files, time is measured in...
milliseconds (ms suffix)
seconds (s suffix)
minutes (m suffix)
hours (h suffix)
days (d suffix)
weeks (w suffix)
months (M suffix) (note: always equal to 30 days)
years (y suffix) (note: always equal to 365 days)
In that case that a plain integer is provided (i.e. no suffix), it is treated as a measurement in seconds.
Units can be combined as long as they are in order from greatest to least significance. A space between units is optional. For example, 2h30m and 2h 30m may be more readable than 150m.
Enabling
To cause a client device to cache all web resources for the next 30 days, try the following:
location / {
expires 30d;
}The expires directive sets the Expires and Cache-Control headers. The expiry will happen at current time plus the parameter passed on the expires directive. This can either be an integer (e.g. `expires
This is more effective when applied to a subset of resources, such as images or CSS stylesheets. Simply adjust the location block that the expires directive is used in.
Disabling
Consider one of these two options:
location / {
expires off;
}The off keyword disables adding Expires and Cache-Control headers. This is not necessarily the same as disabling client-side caching though.
location / {
expires -1;
}Passing a negative value sets the expiry to a past time, so that all resources will always be considered expired. The Cache-Control header will also be automatically set to Cache-Control: no-cache.
Tips
Take into account how the Cache-Control header will interact with compression.
See also
Module ngx_http_headers_module documentation