Currently, no HTTP headers are set that are relevant to caching the OpenSearch XML response. In fact, since there isn't even a 'Date' header in the reponse, most caches won't even apply heuristics, let alone explicit cache directives.
We need some method for configuring HTTP response headers for the OpenSearchServlet so that the responses can play nicely with caches.
SVN 2800 & 2801. Added a new servlet filter: CacheSettingsFilter; and updated the 'web.xml' to use it.
This filter sets the 'Date' HTTP response header, and can also set 'Cache-Control: maxage=X' for some numeric value of X.
See 'web.xml' for an example.