var http=require('http'),
   path=require('path'),
   fs=require('fs'),
   www="www",
   mimes={"jpg":"image/jpeg","webm":"video/webm"};
   errors={404:"Not found", 415:"Unsupported Media Type"};

 http.createServer(function(req, res) {
  var med=path.join(www, req.url),
   mime=mimes[path.extname(med).substring(1)];
  if (mime) {
   var rst=fs.createReadStream(med);
   rst.on("open", function() {res.writeHead(200, {'Content-Type': mime})});
   rst.on("end", function() {res.end();});
   rst.on("error", function() {error(res, 404, med)});
   rst.pipe(res);
  } else {
   error(res, 415, med);
  }
 }).listen(3001);

 function error(res, code, path) {
   res.writeHead(code, {'Content-Type': "text/html"});
   res.end("<h1>"+code+" - "+errors[code])
 }