fdb/index.html

## index.html
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <script src="https://cdn.rawgit.com/Caligatio/jsSHA/v2.2.0/src/sha256.js"></script>
  <title>S3 Post Upload Example</title>
  <style>
    body { font: 14px arial; padding: 20px; margin: 80px auto; width: 40rem; }
    input { display: block; font: 16px arial; padding: 5px; margin: 5px; width: 40rem;}
  </style>
</head>
<body>
<h1>S3 POST Uploader</h1>
<form method="post" enctype="multipart/form-data" id="form">
    <div id="hidden_fields"></div>
    <input type="file"   name="file" /> <br />
    <input type="submit" name="submit" value="Upload to Amazon S3" />
</form>

<script>

const AWS_POST_URL = 'https://enigmeta.s3.amazonaws.com/';
const AWS_ACCESS_KEY = 'YOUR_ACCESS_KEY_HERE';
const AWS_SECRET_KEY = 'YOUR_SECRET_KEY_HERE';
const AWS_REGION = 'us-east-1';
const AWS_BUCKET = 'enigmeta';

function prefixZeroes(s, length=2) {
  while (s.length < length) {
    s = '0' + s;
  }
  return s;
}

function hmacSha256(data, key, output='BYTES') {
  const shaObj = new jsSHA('SHA-256', 'BYTES');
  shaObj.setHMACKey(key, 'BYTES');
  shaObj.update(data);
  return shaObj.getHMAC(output);
}

function setHiddenFormField(name, value) {
  const $form = document.getElementById('hidden_fields');
  const $field = document.createElement('input');
  $field.setAttribute('type', 'hidden');
  $field.setAttribute('name', name);
  $field.setAttribute('value', value);
  $form.appendChild($field);
}

function dateToIso8601(d) {
  const sYear = d.getFullYear();
  const sMonth = prefixZeroes('' + (d.getMonth() + 1));
  const sDate = prefixZeroes('' + d.getDate());
  return sYear + sMonth + sDate + 'T000000Z';
}

const $form = document.getElementById('form');
$form.setAttribute('action', AWS_POST_URL);

const d = new Date();
const sYear = d.getFullYear();
const sMonth = prefixZeroes('' + (d.getMonth() + 1));
const sDate = prefixZeroes('' + d.getDate());
const sFullDate = sYear + sMonth + sDate;
const isoDate = dateToIso8601(d);
const credential = `${AWS_ACCESS_KEY}/${sFullDate}/${AWS_REGION}/s3/aws4_request`;

const MINUTES = 60 * 1000;
const HOURS = 60 * MINUTES;
const MEGABYTES = 1024 * 1024;
const expiration = new Date(Date.now() + 1 * HOURS);
const policy = {
  expiration: expiration.toISOString(),
  conditions: [
    ['starts-with', '$key', 'uploads'],
    {acl: 'public-read'},
    {bucket: AWS_BUCKET},
    ['content-length-range', 0, 1 * MEGABYTES],
    {'success_action_status': '201'},
    {'x-amz-algorithm': 'AWS4-HMAC-SHA256'},
    {'x-amz-credential': credential},
    {'x-amz-date': isoDate},
  ]
};

const stringToSign = btoa(JSON.stringify(policy));
const kDate = hmacSha256(sFullDate, 'AWS4' + AWS_SECRET_KEY);
const kRegion = hmacSha256(AWS_REGION, kDate);
const kService = hmacSha256('s3', kRegion);
const kSigning = hmacSha256('aws4_request', kService);
const signature = hmacSha256(stringToSign, kSigning, 'HEX');

setHiddenFormField('key', 'uploads/\${filename}');
setHiddenFormField('acl', 'public-read');
setHiddenFormField('success_action_status', '201');
setHiddenFormField('X-Amz-Algorithm', 'AWS4-HMAC-SHA256');
setHiddenFormField('X-Amz-Credential', credential);
setHiddenFormField('X-Amz-Date', isoDate);
setHiddenFormField('Policy', btoa(JSON.stringify(policy)));
setHiddenFormField('X-Amz-Signature', signature);

</script>
</body>
</html>
	<!DOCTYPE html>
	<html lang="en">
	<head>
	<meta charset="UTF-8">
	<script src="https://cdn.rawgit.com/Caligatio/jsSHA/v2.2.0/src/sha256.js"></script>
	<title>S3 Post Upload Example</title>
	<style>
	body { font: 14px arial; padding: 20px; margin: 80px auto; width: 40rem; }
	input { display: block; font: 16px arial; padding: 5px; margin: 5px; width: 40rem;}
	</style>
	</head>
	<body>
	<h1>S3 POST Uploader</h1>
	<form method="post" enctype="multipart/form-data" id="form">
	<div id="hidden_fields"></div>
	<input type="file" name="file" /> <br />
	<input type="submit" name="submit" value="Upload to Amazon S3" />
	</form>

	<script>

	const AWS_POST_URL = 'https://enigmeta.s3.amazonaws.com/';
	const AWS_ACCESS_KEY = 'YOUR_ACCESS_KEY_HERE';
	const AWS_SECRET_KEY = 'YOUR_SECRET_KEY_HERE';
	const AWS_REGION = 'us-east-1';
	const AWS_BUCKET = 'enigmeta';

	function prefixZeroes(s, length=2) {
	while (s.length < length) {
	s = '0' + s;
	}
	return s;
	}

	function hmacSha256(data, key, output='BYTES') {
	const shaObj = new jsSHA('SHA-256', 'BYTES');
	shaObj.setHMACKey(key, 'BYTES');
	shaObj.update(data);
	return shaObj.getHMAC(output);
	}

	function setHiddenFormField(name, value) {
	const $form = document.getElementById('hidden_fields');
	const $field = document.createElement('input');
	$field.setAttribute('type', 'hidden');
	$field.setAttribute('name', name);
	$field.setAttribute('value', value);
	$form.appendChild($field);
	}

	function dateToIso8601(d) {
	const sYear = d.getFullYear();
	const sMonth = prefixZeroes('' + (d.getMonth() + 1));
	const sDate = prefixZeroes('' + d.getDate());
	return sYear + sMonth + sDate + 'T000000Z';
	}

	const $form = document.getElementById('form');
	$form.setAttribute('action', AWS_POST_URL);

	const d = new Date();
	const sYear = d.getFullYear();
	const sMonth = prefixZeroes('' + (d.getMonth() + 1));
	const sDate = prefixZeroes('' + d.getDate());
	const sFullDate = sYear + sMonth + sDate;
	const isoDate = dateToIso8601(d);
	const credential = `${AWS_ACCESS_KEY}/${sFullDate}/${AWS_REGION}/s3/aws4_request`;

	const MINUTES = 60 * 1000;
	const HOURS = 60 * MINUTES;
	const MEGABYTES = 1024 * 1024;
	const expiration = new Date(Date.now() + 1 * HOURS);
	const policy = {
	expiration: expiration.toISOString(),
	conditions: [
	['starts-with', '$key', 'uploads'],
	{acl: 'public-read'},
	{bucket: AWS_BUCKET},
	['content-length-range', 0, 1 * MEGABYTES],
	{'success_action_status': '201'},
	{'x-amz-algorithm': 'AWS4-HMAC-SHA256'},
	{'x-amz-credential': credential},
	{'x-amz-date': isoDate},
	]
	};

	const stringToSign = btoa(JSON.stringify(policy));
	const kDate = hmacSha256(sFullDate, 'AWS4' + AWS_SECRET_KEY);
	const kRegion = hmacSha256(AWS_REGION, kDate);
	const kService = hmacSha256('s3', kRegion);
	const kSigning = hmacSha256('aws4_request', kService);
	const signature = hmacSha256(stringToSign, kSigning, 'HEX');

	setHiddenFormField('key', 'uploads/\${filename}');
	setHiddenFormField('acl', 'public-read');
	setHiddenFormField('success_action_status', '201');
	setHiddenFormField('X-Amz-Algorithm', 'AWS4-HMAC-SHA256');
	setHiddenFormField('X-Amz-Credential', credential);
	setHiddenFormField('X-Amz-Date', isoDate);
	setHiddenFormField('Policy', btoa(JSON.stringify(policy)));
	setHiddenFormField('X-Amz-Signature', signature);

	</script>
	</body>
	</html>