gemstoclojure.clj

(ns demo.gemstoclojure
  (:use ring.adapter.jetty)
  (:use clojure.contrib.io)
  (:use clojure.contrib.classpath))

(import '(org.jruby.embed ScriptingContainer LocalContextScope))
(def c (ScriptingContainer. LocalContextScope/THREADSAFE))

(println (classpath))
(println (pwd))

;; Using $LOAD_PATH to load haml gem
;(def gempath [(str (pwd) "/src/haml-3.1.2/gem")])
;(. c setLoadPaths gempath)
;(. c runScriptlet "require 'rubygems'; require 'haml'")

;; Using classpath to load haml gem
(. c runScriptlet "require 'rubygems'; require 'haml-3.1.2/gem/haml'")

(def engineclass (. c runScriptlet "Haml::Engine"))
(def template
"%html
  %head
    %title
      Hello Clojure!
  %body
    %h2
      Hello Clojure from Haml!") 
(def engine (. c callMethod engineclass "new" template Object))

(defn app [req]
  {:status 200
   :headers {"Content-Type" "text/html"}
   :body    (. c callMethod engine "render" String)})

(defn -main []
  (let [port (Integer/parseInt (System/getenv "PORT"))]
    (run-jetty app {:port port})))

Very cool.