wrap-cors middleware not working with system.components - clojure

Question

I have the following system.components middleware config, in which I'm using the ring.middleware wrap-cors, to allow for redirects to an external server:
(defn config []
{:http-port (Integer. (or (env :port) 5000))
:middleware [[wrap-defaults api-defaults]
wrap-with-logger
wrap-gzip
ignore-trailing-slash
[wrap-reload {:dir "../../src"}]
[wrap-trace :header :ui]
wrap-params
wrap-keyword-params
wrap-cookies
[wrap-cors :access-control-allow-headers #{"accept"
"accept-encoding"
"accept-language"
"authorization"
"content-type"
"origin"}
:access-control-allow-origin [#"https://some-url"]
:access-control-allow-methods [:delete :get
:patch :post :put]]
]})
And this is supposed to insert headers into every response. But instead, on a request from the client which leads to a redirect to https://some-url, I get the following error in the client browser:
Access to XMLHttpRequest at 'https://someurl' (redirected from 'http://localhost:5000/some-uri') from origin 'http://localhost:5000' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.
Why aren't the correct headers in the response despite adding the middleware?
-- EDIT --
I've also tried the [jumblerg.middleware.cors] wrap-cors middleware like so:
(defn config []
{:http-port (Integer. (or (env :port) 5000))
:middleware [[wrap-defaults api-defaults]
wrap-with-logger
wrap-gzip
ignore-trailing-slash
[wrap-reload {:dir "../../src"}]
[wrap-trace :header :ui]
wrap-params
wrap-keyword-params
wrap-cookies
[wrap-cors #".*"]
]})
And have added the headers using liberator like so:
(defresource some-route [redirect-uri]
:available-media-types ["application/json"]
:allowed-methods [:post]
:post-redirect? true
:as-response (fn [d ctx]
;; added headers
(-> (as-response d ctx)
(assoc-in [:headers "Access-Control-Allow-Origin"] "*")
(assoc-in [:headers "Access-Control-Allow-Headers"] "Content-Type")
)
)
;; redirect uri
:location redirect-uri
)
But still get the ````No 'Access-Control-Allow-Origin' header is present on the requested resource.``` error

Answer 1

Try this library to (wrap-cors):
[jumblerg/ring-cors "2.0.0"]
like this:
(wrap-cors your-routes identity)
Note the third parameter is a function to determine if an origin is allowed (or a list of reg exp)
You might have to add a manual route though:
(OPTIONS "/yourendpoint" req {:headers {"Access-Control-Allow-Headers" "*"}})