Cat Attack! coffeescript and node.js

kittenproxy.coffee

# to run:
# 1. npm install -g coffee-script
# 2. npm install http-proxy
# 3. coffee kittenproxy.coffee
# 4. change browser proxy settings to <thishost>:8080

httpProxy = require("http-proxy")

address   = process.argv[2] or "0.0.0.0"
port      = process.argv[3] or 8080

server = httpProxy.createServer((req, res, proxy) ->
  isImage = false
  req.headers.accept.split(",").forEach (mimetype) ->
    isImage = true  if mimetype.match(/^image\//)?

  if isImage
    res.writeHead 301,
      Location: "http://placekitten.com/200/200"

    res.end()
  else
    buffer = httpProxy.buffer(req)
    proxy.proxyRequest req, res,
      host: req.headers.host
      port: 80
      buffer: buffer
)

server.proxy.on "end", (req) ->
  console.log "Connection to " + req.headers.host +
              " URL: " + req.url

server.listen port, address
console.log "listening on %s:%d", address, port