clojure sprunge-like for GAE

sprunge-like.clj

(ns sprulj.core
  (:use compojure.core
        [appengine-magic.multipart-params :only [wrap-multipart-params]])
  (:require [appengine-magic.core :as ae]
            [appengine-magic.services.datastore :as ds]
            ))

(def VALID-CHARS
  (->>
    (concat (range 48 58)
            (range 65 91)
            (range 97 123))
    (map char)))

(def URL "http://localhost:8080")

(defn- new-id []
  (->>
    (repeatedly #(rand-nth VALID-CHARS))
    (take 4)
    (apply str)))

(ds/defentity Entry [^{:tag :key} name, data, date])


(defroutes sprulj-app-handler
  (GET "/" req
       {:status 200
        :headers {"Content-Type" "text/plain"}
        :body "hi"})
  (GET "/:id" [id]
       {:status 200
        :headers {"Content-Type" "text/plain"}
        :body
        (if-let [entry (ds/query :kind Entry :filter (= :name id))]
          (:data (first entry))
          "Not found.")})
  (POST "/" _
        (wrap-multipart-params
          (fn [req]
            (if-let [data ((req :params ) "data")]
              ; data ok ------------------------------------------------------
              (let [id (first
                         (filter
                           #(not (ds/exists? Entry %))
                           (repeatedly new-id)))
                    new-entry (Entry. id data (new java.util.Date))
                    current-count (ds/query :kind Entry :count-only? true)]
                (when (> current-count 199)
                  (ds/delete!
                    (ds/query :kind Entry
                              :sort :date
                              :limit (- current-count 199))))
                (ds/save! new-entry)
                {:status 200
                 :headers {"Content-Type" "text/plain"}
                 :body (format "%s.%s/%s\n"
                               (ae/appengine-app-id)
                               (ae/appengine-base-url)
                               id)})
              ; bad request ---------------------------------------------------
              {:status 400})))))

(ae/def-appengine-app sprulj-app #'sprulj-app-handler)