simplecache.clj

(defn epoch
  []
  (quot (System/currentTimeMillis) 1000))

(let [cache (atom {})]
  (defn add-key
    [k v expire]
    (swap! cache assoc k {:v v, :e expire, :c (epoch)}))

  (defn del-key
    [k]
    (swap! cache dissoc k))

  (defn get-key
    [k]
    (get @cache k))

   (defn get-keys
    []
    (keys @cache)))

(defn remove-expired
  []
  (loop []
    (do
      (doseq [k (get-keys)]
        (let [now (epoch)
              {e :e, c :c} (get-key k)]
          (if (> now (+ e c))
            (del-key k))))
      (Thread/sleep 1000)
      (recur))))

(def expire-handler (future (remove-expired)))