Not able to modify response header

First, thank you for this great package.

I've been looking for a way to add a custom header to the response but I couldn't find it.
(Specifically, I want to add Access-Control-Allow-Origin: * to enable CORS)

I've also checked source but I couldn't find a way to modify header from outside of hunchentoot package, as far as I understood.

So I hope this is supported by hunchentoot. (If it's not really available at the moment)
Please let me know if there is anything I've missed.

Thanks.

https://edicl.github.io/hunchentoot/#header-out

Thanks for quick feedback.
I tried to make hunchentoot:easy-acceptor instance with custom-reply which including (:access-control-allow-origin . "*") as below:

 (setf *server*
        (make-instance 'hunchentoot:easy-acceptor
                       :port 4242
                       :reply-class *custom-reply*))

And I made *custom-reply* as below:

  (defvar *custom-reply*)
  (setf *custom-reply* (make-instance 'hunchentoot:reply))
  (setf (hunchentoot:headers-out *custom-reply*)
        (append  (hunchentoot:headers-out *custom-reply*)
                 '((:access-control-allow-origin . "*"))))

But above process didn't work but only caused an error. Is this wrong approach?
I've opened the issue actually because I couldn't modify a reply instance using header-out function.
I would appreciate it if you let me know if I'm approaching the wrong way and giving me a little hint of a proper way.

I apologize if it's just a lack of my understanding, not an issue at all.

Thanks.

@stassats Modifying custom-reply with headers-out didn't work because headers-out was not an accesor but a reader on reply.lisp, although it's an accesor on document. This was one of reasons that I thought this is an issue.

@stassats I'm sorry I just figured out there were header-out and headers-out and only headers-out was a reader.

@stassats I managed to make the *custom-reply* as below:

(setf (hunchentoot:header-out :headers *custom-reply*)
        (append  (hunchentoot:header-out :headers *custom-reply*)
                 '((:access-control-allow-origin . "*"))))

But above code still didn't work.
I thought it's because of

hunchentoot/acceptor.lisp

Line 456 in f18c0aa

(let ((*reply* (make-instance (acceptor-reply-class *acceptor*)))

I thought it should be changed as below:

  (*reply* (if (symbolp (acceptor-reply-class *acceptor*))
              (make-instance (acceptor-reply-class *acceptor*))
               (acceptor-reply-class *acceptor*)))

for the case that acceptor is provided in a way of :reply-class *custom-reply*.

Again, I would appreciate for any hint, sorry for the case of misunderstanding.
If I find out what I've done wrong, I'll leave it here for those who face similar problems like me .

Thanks.

You need to set your header-out in the handler.

@stassats Thanks a lot.

Now I can see Access-Control-Allow-Origin: * is added in response header with below code:

(hunchentoot:define-easy-handler (test :uri "/test") (word)
  (setf (hunchentoot:content-type*) "text/plain")
  (setf (hunchentoot:header-out :Access-Control-Allow-Origin hunchentoot:*reply*) "*")
  (format nil "word: ~a" word))

Thanks!