Problems with :cookies-setattr!

[Mortimer Cladwell]

Hi,

Using the following controller I can set a cookie "prjid"

----BEGIN----------------------------------------------
(plateset-define cset
(options #:cookies '(names prjid sid))
(lambda (rc)
  (let* ((result "sometext")
 (dummy (:cookies-set! rc 'prjid "prjid" result))
 (cookies (rc-cookie rc)))
    (view-render "test" (the-environment)))))
----END------------------------------------------------

In the Firefox console I see:

Name: prjid
Value: sometext
Domain: 127.0.0.1
Path: /plateset
Expires: Thu, 28 Jan 2021 15:25:19 GMT  (this is one hour in the future)
Size: 13
HttpOnly: true
Secure: false
SameSite: none

I want to modify the Expires to 6 hours (21600 sec) into the future

----BEGIN----------------------------------------------
(plateset-define update
(options #:cookies '(names prjid sid))
(lambda (rc)
  (let* (
   (result (:cookies-setattr! rc 'prjid #:expires 21600 #:domain #f #:path #f #:secure #f #:http-only #f))
  (cookies (rc-cookie rc))
  (view-render "test" (the-environment)))))
----END------------------------------------------------


Doesn't work.  I have tried matching some/all of the other parameters to the existing cookie without effect. I can:

(:cookies-setattr! rc 'prjid #:expires 21600 #:domain #f #:path "/junk" #:secure #f #:http-only #f)

To get:

Name: <blank>
Value: <blank>
Domain: 127.0.0.1
Path: /junk
Expires: Thu, 28 Jan 2021 20:39:24 GMT  (6 hours into the future)
Size: 0
HttpOnly: true
Secure: false
SameSite: none

So here the path and expires are correct but no name - i.e. does not affect the existing cookie but creates a new blank cookie.

I assume :cookies-setattr! will only work on existing cookies, is that correct?
In addition to changing the expiration time I would like to change the path from "/plateset" to "/" so the cookie is available sitewide - should that be possible?
When setting a parameter to #f e.g. #:secure #f - does that mean change that parameter to #f or "don't modify that parameter"?  Seems like all parameters are required.
What am I doing wrong?
Thanks
Mortimer