controller_feed
Serve /feed, /feed/:type and /feed/:type/:id with optional search arguments.
Types are atom, rss, jsonfeed and json (an alias for JSON Feed).
An id selects a visible saved query, a collection's members, or one resource.
The bare /feed uses query_feed, falling back to articles, and accepts only
pagination. On typed routes without an id, request arguments define a normal
mod_search query. Without search terms or an id, typed routes use the same
default selection as /feed; pagination alone does not change that selection. Both
bare search keys and q-prefixed keys are supported. Page length defaults to 20
and is capped at 100. Client search options are not passed to the search engine.