uploading to amazon S3 without AWS-SDK or any other module but native

uploadToS3.js

/* Upload to Amazon S3 without AWS-SDK or other modules
 * Alexandre Mulatinho <alex at mulatinho.net> 2016 
 *
 * You will need to change: 
 * - YOUR_FILENAME_HERE
 * - YOUR_BUCKET_HERE
 * - AWS_SECRET_KEY_HERE
 * - AWS_ACCESS_KEY_HERE */

var https = require("https");
var fs = require("fs");
var crypto = require("crypto");
var buffer = require("buffer");

var dataNow  = new Date().toUTCString().replace('GMT', '+0000')
var filename = "YOUR_FILENAME_HERE."
var remoteFile = "/YOUR_BUCKET_HERE/" + filename;
var szFilename  = fs.statSync(filename).size
var contentFile = fs.readFileSync(filename);
var md5sum = crypto.createHash('md5').update(contentFile).digest();
var base64_md5 = new Buffer(md5sum).toString('base64');

var stringToSign="PUT\n" + base64_md5 + "\napplication/octet-stream\n" + dataNow + "\nx-amz-acl:public-read\n" + remoteFile;
var sha1sum = crypto.createHmac('sha1', 'AWS_SECRET_KEY_HERE').update(stringToSign).digest();
var base64 = new Buffer(sha1sum).toString('base64');
var authorization = "AWS AWS_ACCESS_KEY_HERE:" + base64;

var options = {
  "method": "PUT",
  "hostname": "s3-us-west-2.amazonaws.com",
  "port": "443",
  "path": remoteFile,
  "headers": {
      "Host": "s3-us-west-2.amazonaws.com",
      "Date": dataNow,
      "Accept": "*/*",
      "x-amz-acl": "public-read",
      "Content-Length": szFilename,
      "Content-Type": "application/octet-stream",
      "Content-MD5": base64_md5,
      "Authorization": authorization,
      "Expect": "100-continue"
    }
};

var req = https.request(options, function (res) {
  var buffer = '';
  res.setEncoding('utf8');

  res.on("data", function (chunk) {
    buffer += chunk;
  });

  res.on("end", function () {
    console.log(res.statusCode, res.statusMessage);
    console.log(res.headers)
    console.log('https://' + options.hostname + options.path)
    console.log(buffer);
  });
});

req.write(contentFile);
req.end();

req.on('error', (e) => {
  console.error(e);
});