Dynamic scoping simulator for ring-handlers

gistfile1.txt

(defmacro wrap-request-binding
  "Encloses the ring handler definition in a function to simulate dynamic scope
   on a request attribute via a lexical binding on the current request."
  [binding-sym ks handler-def]
  `(fn [req#]
     (let [~binding-sym (get-in req# ~ks)]
       (~handler-def req#))))