json.clj

(defn json-request?
  [request]
  (when-let [type (:content-type request)]
    (= type "application/json")))


(defn wrap-json-params
  [handler]
  (fn [request]
    (if-let [body (and (json-request? request) (:body request))]
      (let [[json msg] (try
                         [(json/read-str (slurp body) :key-fn keyword) nil]
                         (catch Exception e
                           [nil (.getMessage e)]))]
        (if (not msg)
          (-> request
              (update-in [:json-params] merge json)
              (update-in [:params] merge json)
              handler)
          {:status 400 :body (str "invalid JSON body: " msg)}))
      (handler request))))