snap-benchmark's pong implementation in node.js

function server (request, response) {

  var uri = url.parse(request.url).pathname;  

  if(uri=='/pong') {
    response.writeHead(200, {'Content-Type': 'text/plain'});
    response.end('PONG');
  } else if ((match = uri.match(/^\/echo\/(.*)$/)) != null) {
    response.writeHead(200, {'Content-Type': 'text/plain'});
    response.end(match[1]);
  } else {
    var filename = path.join(process.cwd(), uri);  
    path.exists(filename, pathExistsCB);  
  }
  
  function pathExistsCB (exists) {  
    if (exists) {
      fs.readFile(filename, "binary", readFileCB);
    }
    else {
      response.writeHead(404, {"Content-Type": "text/plain"});  
      response.end("404 Not Found\n");
    }  
  }
  
  function readFileCB (err, file) {  
    if (err) {  
      response.writeHead(500, {"Content-Type": "text/plain"});  
      response.end(err + "\n");  
      return;  
    }  

    response.writeHead(200);  
    response.write(file, "binary");  
    response.end();  
  }
}

http.createServer(server).listen(8124, "localhost");