The example socket.io server, rewritten in CoffeeScript

server.coffee

http = require 'http'
url = require 'url'
fs = require 'fs'
io = require 'socket.io'
sys = require if process.binding('natives').util then 'util' else 'sys'
    
server = http.createServer (req, res) ->
  path = url.parse(req.url).pathname
  switch path
    when '/'
      res.writeHead 200, {'Content-Type': 'text/html'}
      res.write '<h1>Welcome. Try the <a href="/chat.html">chat</a> example.</h1>'
      res.end()
      
    when '/json.js', '/chat.html'
      fs.readFile __dirname + path, (err, data) ->
        if err then send404(res)
        res.writeHead 200, {'Content-Type': if path is 'json.js' then 'text/javascript' else 'text/html'}
        res.write data, 'utf8'
        res.end()
      
    else send404(res)

send404 = (res)->
  res.writeHead(404)
  res.write('404')
  res.end()

server.listen 8080


io = io.listen server
buffer = []
  
io.on 'connection', (client)->
  client.send { buffer: buffer }
  client.broadcast { announcement: client.sessionId + ' connected' }
  
  client.on 'message', (message)->
    msg = { message: [client.sessionId, message] }
    buffer.push msg
    if buffer.length > 15 then buffer.shift()
    client.broadcast msg

  client.on 'disconnect', ()->
    client.broadcast { announcement: client.sessionId + ' disconnected' }