var http require http var URL require url var request require request

var http = require('http');
var URL = require('url');
var request = require('request');


http.createServer(onRequest).listen(3000);

function onRequest(req, res) {

  var url = URL.parse(req.url, true).pathname.substring(1);

  var bytesCopied = 0;
  var contentLength = 0;

  download(url, 0);

  function download(url, firstByte) {

    console.log('getting', url);

    request({
      url: url,
      headers: {'Range': firstByte + '-'}
    })

    .on('response', function(response) {

      contentLength = response.headers['content-length'];

      if (firstByte == 0) {
        res.writeHead(response.statusCode, response.headers);
      }

    })

    .on('error', function(e) {
      console.log('error, retrying starting with byte ' + bytesCopied);
      download(url, bytesCopied);
    })

    .on('data', function(chunk) {
      console.log('data chunk', chunk.length, 'bytes');
      res.write(chunk);
      bytesCopied += chunk.length;
    })

    .on('end', function() {
      res.end();
    });
  }

}