Some macro fun.

defroute.clj

(defmacro defroute
  [routename uri meths handler]
  `(defn
     ~(with-meta routename (assoc (meta routename) :route-handler true))
    [req#]
    (let [req-meth# (:request-method req#)
          bad-meth# (nil? (some #(= req-meth# %) ~meths))
          any-meth# (= ~meths [:any])]
      (if (and (route-matches ~uri req#) (and bad-meth# (not any-meth#)))
        (method-not-allowed req-meth# (get-allowed ~meths))
        (if-let [params# (route-matches ~uri req#)]
          (~handler (assoc req# :route-params params#))
          req#)))))