keyword_params.clj

(ns ring.middleware.keyword-params
  "Convert param keys to keywords.")

(defn- keyword-syntax? [s]
  (re-matches #"[A-Za-z*+!_?-][A-Za-z0-9*+!_?-]*" s))

(defn- keyify-params [target]
  (cond
    (map? target)
      (into {}
        (for [[k v] target]
          [(if (and (string? k) (keyword-syntax? k))
             (keyword k)
             k)
           (keyify-params v)]))
    (vector? target)
      (vec (map keyify-params target))
    :else
      target))

(defn wrap-keyword-params
  "Middleware that converts the string-keyed :params map to one with keyword
  keys before forwarding the request to the given handler.
  Does not alter the maps under :*-params keys; these are left with strings."
  [handler]
  (fn [req]
    (handler (update-in req [:params] keyify-params))))