webserver.js

// A very basic web server in node.js
// Stolen from: Node.js for Front-End Developers by Garann Means (p. 9-10)

var port = 1337;

var http = require('http');
var path = require('path');
var fs = require('fs');

console.log('Starting web server at ' + port);

http.createServer(function(req, res) {

  var now = new Date();

  //var filename = req.url || 'index.html';
  //console.log(req.url);
  var filename = req.url;
  if (!filename || filename == '/') {
    filename = '/index.html';
  }
  var ext = path.extname(filename);
  var localPath = __dirname;
  var validExtensions = {
    '.html': 'text/html',
    '.js': 'application/javascript',
    '.css': 'text/css',
    '.txt': 'text/plain',
    '.jpg': 'image/jpeg',
    '.gif': 'image/gif',
    '.png': 'image/png',
    '.ico': 'image/ico'
  };
  var mimeType = validExtensions[ext];

  if (mimeType) {

    localPath += filename;
    path.exists(localPath, function(exists) {
      if (exists) {
        console.log('Serving file: ' + localPath);
        getFile(localPath, res, mimeType);
      } else {
        console.log('File not found: ' + localPath);
        res.writeHead(404);
        res.end();
      }
    });

  } else {
    console.log('Invalid file extension detected: ' + ext);
  }

}).listen(port);

function getFile(localPath, res, mimeType) {
  fs.readFile(localPath, function(err, contents) {
    if (!err) {
      res.setHeader('Content-Length', contents.length);
      res.setHeader('Content-Type', mimeType);
      res.statusCode = 200;
      res.end(contents);
    } else {
      res.writeHead(500);
      res.end();
    }
  });
}