a clojure webapp with ring for deploying on heroku

core.clj

(ns webdev.core
  (:require [ring.adapter.jetty :as jetty]
            [ring.middleware.reload :refer [wrap-reload]]
            [compojure.core :refer [defroutes GET]]
            [compojure.route :refer [not-found]]
            [ring.handler.dump :refer [handle-dump]]))


(defn greet [req]
  {:status 200
    :body "hi there!"
    :headers {}})


(defn goodbye [req]
  {:status 200
   :body "peace!"
   :headers {}})


(defn about [req]
  {:status 200
   :body "I'm just a little app made for clj practice"
   :headers {}})


(defn yo [req]
  {:status 200
   :body (str "Yo " (:name (:route-params req)) "!")
   :headers {}})
(def ops
  {"+" +   "-" -
   "*" *
   ":" /})


(defn calc [req]
  (let [operator (:operator (:route-params req))
        a (Integer. (:a (:route-params req)))
        b (Integer. (:b (:route-params req)))
        f (get ops op)]
    (if f
      {:status 200
       :body (str (f a b))
       :headers {}}
      {:status 404
       :body "nerp"
       :headers {}})))


(defroutes app
  (GET "/" [] greet)
  (GET "/goodbye" [] goodbye)
  (GET "/about" [] about)
  (GET "/request" [] handle-dump)
  (GET "/yo/:name" [] yo)
  (GET "/calc/:a/:operator/:b" [] calc)
  (not-found "not found, sry!!"))


(defn -main [port]
  (jetty/run-jetty app                 {:port (Integer. port)}))


; using the greet handler as a var here
; this way wrap-reload, when it refreshes the namespaces,
; will affect the value of greet
(defn -dev-main [port]
  (jetty/run-jetty (wrap-reload #'app) {:port (Integer. port)}))

Procfile

web: java $JVM_OPTS -cp target/webdev.jar clojure.main -m webdev.core $PORT

project.clj

(defproject webdev "0.1.0-SNAPSHOT"
  :description "FIXME: write description"
  :url "http://example.com/FIXME"
  :license {:name "Eclipse Public License"
            :url "http://www.eclipse.org/legal/epl-v10.html"}
  :dependencies [[org.clojure/clojure "1.7.0"]
                 [ring "1.2.1"]
                 [compojure "1.1.6"]]

  :min-lein-version "2.0.0"

  :uberjar-name "webdev.jar"

  :main webdev.core

  ; lein will automatically use this "dev profile"
  ; and this profile will call the wrap-reloaded server
  :profiles {:dev
             {:main webdev.core/-dev-main}})