webapp.clj

(use 'compojure)
(use 'clojure.contrib.sql)

;;;;;;;;database

(def db {:classname   "org.hsqldb.jdbcDriver"
        :subprotocol "hsqldb"
        :subname     "file:post-db" })

(defn create-database []
 (create-table :posts
   [:key :int "IDENTITY" "PRIMARY KEY" ]
   [:text :varchar "NOT NULL" ]))

(defn ensure-database-exists []
 (try (with-connection db (create-database))
      (catch Exception e (println "Failed to create database: already
exists?"))))

(defn clear-database []
 (with-connection db (drop-table :posts))
 (with-connection db (create-database)))

(defn query-posts [q]
 (with-connection db
   (with-query-results results [q]
   (doall results))))

(defn get-posts []
 (map :text (query-posts "select text from posts")))

(defn insert-post [text]
 (with-connection db
   (insert-values :posts [:text] [text])))

;;;;;; web app


(defn link [text url] [:a {:href url} text])

(defn layout [title body]
 (html
  [:head [:title title]]
  [:body
   [:h1 title]
   body
   [:br] (link "home" "/")]))

(defn main-page []
 (layout "main page"
   [:div
    [:ul (map (fn [x] [:li (str x)]) (get-posts))]
    (form-to [:post "/add-record"]
      (text-area "text")
      (submit-button "save")
      )
    (form-to [:post "/destroy-database"]
      (submit-button "clear"))]))

;;associate actions with pages
(defroutes app
 (GET  "/" (main-page))
 (POST "/add-record" (do (insert-post (:text params)) (redirect-to
"/")))
 (POST "/destroy-database" (do (clear-database) (redirect-to "/")))
 (ANY  "*" (layout "strange request" (str params))))

(import '(java.net BindException))
(defn start-server [port]
 (try (run-server {:port port} "/*" (servlet app))
      (println (str "Server started on port " port "."))
      (catch java.net.BindException _
	 (println (str "Failed to start server on port " port ". Already
running?")))))

(ensure-database-exists)
(start-server 8080)