middleware-structure.clj

(defn middleware-fn 
  [handler-fn]
  (fn [request]
    ;; operations on the request:
    ;; to create a `new-request` 
    ;; or to simply log etc 
    (let [new-response (handler-fn new-request)]
      ;; operations on the `new-response`:
      ;; to create a `new-and-modified-response` 
      ;; or to simply log etc
      new-and-modified-response)))