A tiny Web server, written in node.js

tiny-web-server.js

// hey, everybody! it's a tiny Web server!

// instead of a bunch of foo = reqire("foo")
// list our required modules and loop through
var r = [ "fs", "http", "mime", "path", "url" ];
for (var i = 0; i < r.length; i++) { 
  global[r[i]] = require(r[i]); 
}

// some constants
var k = { 
  "port": 8000,
  "dir": "public"
};

// the main thing
var server = http.createServer( function(request, response) {

  // extract the pathname from the request URL  
  var pathname = url.parse(request.url).pathname;
  
  // add the home directory, /public or whatever  
  var filename = path.join(process.cwd(), k.dir, pathname);
  
  // if the requested path has no file extension, assume it's a directory
  // caution: if you are shipping an API, this is the wrong thing to do  
  if (!path.extname(filename)) {
    filename = filename + '/index.html';
  }
  
  // does this path exist?  
  path.exists(filename, function(gotPath) {
  
    // no, bail out    
    if (!gotPath) {
        response.writeHead(404, {"Content-Type": "text/plain"});
        response.write("404 Not Found");
        response.end();
        return;
    }

    // still here? filename is good    
    // look up the mime type by file extension
    response.writeHead(200, {'Content-Type': mime.lookup(filename)});
    
    // read and pass the file as a stream. Not really sure if this is better,
    // but it feels less block-ish than reading the whole file
    // and we get to do awesome things with listeners
    fs.createReadStream(filename, {
      'flags': 'r',
      'encoding': 'binary',
      'mode': 0666,
      'bufferSize': 4 * 1024
    }).addListener( "data", function(chunk) {
      response.write(chunk, 'binary');
    }).addListener( "close",function() {
      response.end();
    });

    /*
    // read an entire file into memory and then spit it out
    fs.readFile(filename, function(err, data){
      if (err) throw err;
      response.write(data, 'utf8');
      response.end();
    });
    */
    
  }); 
});

// fire it up
server.listen(k.port);

path.exists() has been changed to fs.exists().