This Gist describes how to tune HTTP browser cache expiration for static contents served by Wildfly Undertow web server, as per RFC-2616 section 13.
In order to change HTTP browser cache behavior, a "Cache-Control" HTTP header has to be added to static content HTTP responses returned by Undertow.
NOTE: "..." means existing xml config elements to be kept
<subsystem xmlns="urn:jboss:domain:undertow:1.2">
...
<server name="default-server">
...
<host name="default-host" alias="localhost">
...
<filter-ref name="custom-max-age" predicate="path-suffix['.js'] or path-suffix ['.json'] or path-suffix ['.html'] or path-suffix ['.css'] or path-suffix ['.jpg'] or path-suffix ['.jpeg'] or path-suffix ['.png'] or path-suffix ['.gif']"/>
</host>
</server>
...
<filters>
...
<response-header name="custom-max-age" header-name="Cache-Control" header-value="max-age=600, public"/>
</filters>
</subsystem>A Cache-Control header will be added to HTTP responses header for static files having extensions: ".js, .json, .html, .css, .jpg, .jpeg, .png, .gif". (Complete list of handlers predicates, such as "path-suffix", is availaible here)
This header has a "max-age=600, public" value which tells to browser to expire these static content files after 600 seconds, as described in RFC-2616 section 14.9.3. (see this other section for public value description)
- RFC-2616 - section 13, section 14.9.3 and section 14.9.1
- Predicates Attributes and Handlers