Cache-control with Oracle ORDS - cache-control

Question

My DB gets new data only between 1pm-2pm. Users jump back and forth, often looking at the same thing multiple times, I want to use caching to cut network load. My response type is:
source_type_collection_item
Executes a SQL Query returning one row of data into a ORDS Standard JSON representation.
Available when the HTTP method is GET.
Result Format: JSON
single row SYS_REFCURSOR response with multiple nested CURSORS.
FUNCTION my_func RETURN SYS_REFCURSOR
AS
my_cursor SYS_REFCURSOR;
BEGIN
OPEN my_cursor FOR
SELECT value, CURSOR(SELECT value_2, CURSOR(SELECT ... FROM table)
...
I want to set differing cache-control based on server time:
Request at 9:30am - cache 3.5 hrs
Request at 1:30pm - cache 0 mins
Request at 3:30pm - cache 21.5 hrs
The problem is that I can't figure out how to set caching at all for an ORDS endpoint returning HTTP GET. I have one working fine for an unrelated PL/SQL service
source_type_plsql :-
Executes an anonymous PL/SQL block and transforms any OUT or IN/OUT parameters into a JSON representation.
Available only when the HTTP method is DELETE, PUT, or POST.
Result Format: JSON
using a defined parameter:
ords.define_parameter(
p_module_name => l_module_name,
p_pattern => l_pattern,
p_method => l_method,
p_name => 'Cache-Control',
p_bind_variable_name => 'cache_control',
p_source_type => 'HEADER',
p_param_type => 'STRING',
p_access_method => 'OUT',
p_comments => '');
But this won't work for the GET case because:
HTTP GET is unsupported by PL/SQL
SYS_REFCURSOR as ORDS PL/SQL out parameter unsupported
The only option I could figure out was a static cache setting in Tomcat rather than ORDS.
<filter>
<filter-name>ExpiresFilter</filter-name>
<filter-class>org.apache.catalina.filters.ExpiresFilter</filter-class>
<init-param>
<param-name>ExpiresByType application/json</param-name>
<param-value>access plus 30 minutes</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>ExpiresFilter</filter-name>
<url-pattern>/ords/*</url-pattern>
<dispatcher>REQUEST</dispatcher>
</filter-mapping>
But that's undesirable for a number of reasons:
It applies to ALL services under ORDS but caching is a bad idea for most other endpoints. I was unable to filter more precisely than this - from Tomcat's point of view it seems that ORDS is a monolith and gets one cache control setting.
It is a fixed value.