aws-signing-utils/lib/index.js

Utility methods for generating AWS Signature Version 4 URLs. Works fine with react-native!

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});

var _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; };

exports.getSignedUrl = getSignedUrl;
exports.getSignature = getSignature;

var _moment = require('moment');

var _moment2 = _interopRequireDefault(_moment);

var _cryptoJs = require('crypto-js');

var _cryptoJs2 = _interopRequireDefault(_cryptoJs);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

var utils = {
  sign: function sign(key, msg) {
    var hash = _cryptoJs2.default.HmacSHA256(msg, key);
    return hash.toString(_cryptoJs2.default.enc.Hex);
  },

  sha256: function sha256(msg) {
    var hash = _cryptoJs2.default.SHA256(msg);
    return hash.toString(_cryptoJs2.default.enc.Hex);
  },

  getSignatureKey: function getSignatureKey(key, dateStamp, regionName, serviceName) {
    var kDate = _cryptoJs2.default.HmacSHA256(dateStamp, 'AWS4' + key);
    var kRegion = _cryptoJs2.default.HmacSHA256(regionName, kDate);
    var kService = _cryptoJs2.default.HmacSHA256(serviceName, kRegion);
    var kSigning = _cryptoJs2.default.HmacSHA256('aws4_request', kService);

    return kSigning;
  }
};

function getSignedUrl(options) {
  var params = getParams(options);
  var protocol = params.protocol,
      host = params.host,
      canonicalUri = params.canonicalUri;

  var signature = signString(params);

  var canonicalQuerystring = getCanonicalQueryString(params);

  canonicalQuerystring += '&X-Amz-Signature=' + signature;
  canonicalQuerystring += '&X-Amz-Security-Token=' + encodeURIComponent(params.sessionKey);

  return protocol + '://' + host + canonicalUri + '?' + canonicalQuerystring;
}

function getSignature(options) {
  var params = getParams(options);
  return signString(params);
}

function getParams(options) {
  var time = _moment2.default.utc();
  var dateStamp = time.format('YYYYMMDD');

  return _extends({}, options, {
    dateStamp: dateStamp,
    algorithm: 'AWS4-HMAC-SHA256',
    amzDate: dateStamp + 'T' + time.format('HHmmss') + 'Z'
  });
}

function getCanonicalQueryString(params) {
  var accessKey = params.accessKey,
      amzDate = params.amzDate;

  var credentialScope = getCredentialScope(params);

  var canonicalQuerystring = ['X-Amz-Algorithm=AWS4-HMAC-SHA256', 'X-Amz-Credential=' + encodeURIComponent(accessKey + '/' + credentialScope), 'X-Amz-Date=' + amzDate, 'X-Amz-Expires=86400', 'X-Amz-SignedHeaders=host'].join('&');

  return canonicalQuerystring;
}

function getCredentialScope(params) {
  var dateStamp = params.dateStamp,
      region = params.region,
      service = params.service;

  return dateStamp + '/' + region + '/' + service + '/aws4_request';
}

function getCanonicalRequest(params) {
  var canonicalQuerystring = getCanonicalQueryString(params);
  var canonicalHeaders = 'host:' + params.host;
  var payloadHash = utils.sha256('');

  return [params.method, params.canonicalUri, canonicalQuerystring, canonicalHeaders, '\nhost', payloadHash].join('\n');
}

function getStringToSign(params) {
  var algorithm = params.algorithm,
      amzDate = params.amzDate;

  var credentialScope = getCredentialScope(params);
  var canonicalRequest = getCanonicalRequest(params);

  return [algorithm, amzDate, credentialScope, utils.sha256(canonicalRequest)].join('\n');
}

function signString(params) {
  var secretKey = params.secretKey,
      dateStamp = params.dateStamp,
      region = params.region,
      service = params.service;


  var stringToSign = getStringToSign(params);
  var signingKey = utils.getSignatureKey(secretKey, dateStamp, region, service);

  return utils.sign(signingKey, stringToSign);
}