qbert.clj

(ns alandipert.qbert 
  (:use [clojure.contrib.duck-streams :only (reader writer read-lines spit)]
        [clojure.contrib.str-utils :only (re-split str-join)])
  (:import (java.net ServerSocket Socket InetAddress URLDecoder)
           (java.io File)))

(def status {200 "HTTP/1.0 200 OK" 404 "HTTP/1.0 404 Not Found" })
(def content {"css" "Content-type: text/css" "jpg" "Content-type: image/jpeg" "html" "Content-type: text/html" "txt" "Content-type: text/plain" })
(def error {404 "The file was not found."})
(def doc-root "/Users/alan/Sites")

(defn build-headers [& headers]
  "Build a header string and end it with two spaces"
  (str (str-join "\r\n" headers) "\r\n\r\n"))

(defn get-ext [abspath]
  (last (re-split #"\." abspath)))

(defn deliver-resource [sock uri]
  "Figure out if the resource exists, and send it back"
  (let [os (.. sock getOutputStream)
        file (File. (str doc-root (URLDecoder/decode uri)))
        path (.. file getAbsolutePath)
        ext (get-ext path)]
    (with-open [wrt (writer os)]
      (if (.. file exists)
        (do
          (spit wrt (str (build-headers (status 200) (content ext "txt"))))
          (.. os write (to-byte-array file) 0 (.. file length)))
        (spit wrt (str (build-headers (status 404) (content "txt")) "File not found."))))
    (.. sock close)))

(defn handle-request [sock]
  "Parse out the URI from the request pass it on"
  (let [is (.. sock getInputStream)]
    (with-open [rdr (reader is)]
      (deliver-resource sock (second (re-split #"\s+" (first (line-seq rdr))))))))

(defmulti http-listen class)

(defmethod http-listen ServerSocket [socket]
  "Bind to a socket and keep listening"
  (let [client-socket (.. socket accept)]
    (handle-request client-socket))
  (recur socket))

(defmethod http-listen Integer [port]
  "Takes a port number to listen on"
  (http-listen (ServerSocket. port)))

(http-listen 8081)