ethereum-web-token/dist/token.js

EWT bundles Ethereum function-calls into [JWT](https://jwt.io/)-like tokens. It simplifies the use of ECDSA signatures for webapps and the development of [Smart Oracles](https://github.com/codius/codius/wiki/Smart-Oracles:-A-Simple,-Powerful-Approach-to-S

'use strict';Object.defineProperty(exports, "__esModule", { value: true });var _keys = require('babel-runtime/core-js/object/keys');var _keys2 = _interopRequireDefault(_keys);var _classCallCheck2 = require('babel-runtime/helpers/classCallCheck');var _classCallCheck3 = _interopRequireDefault(_classCallCheck2);var _createClass2 = require('babel-runtime/helpers/createClass');var _createClass3 = _interopRequireDefault(_createClass2);var _ethAbi = require('./ethAbi');var _ethAbi2 = _interopRequireDefault(_ethAbi);
var _signer = require('./signer');var _signer2 = _interopRequireDefault(_signer);
var _ethereumjsUtil = require('ethereumjs-util');var _ethereumjsUtil2 = _interopRequireDefault(_ethereumjsUtil);
var _base64url = require('base64url');var _base64url2 = _interopRequireDefault(_base64url);
var _ecdsaSigFormatter = require('ecdsa-sig-formatter');var _ecdsaSigFormatter2 = _interopRequireDefault(_ecdsaSigFormatter);
var _signature = require('./util/signature');var _signature2 = _interopRequireDefault(_signature);
var _bn = require('bn.js');var _bn2 = _interopRequireDefault(_bn);
var _types = require('./util/types');function _interopRequireDefault(obj) {return obj && obj.__esModule ? obj : { default: obj };}var

Token = function () {
  function Token(abi) {var _this = this;(0, _classCallCheck3.default)(this, Token);
    if (!abi) {
      throw new Error('Object ABI needs to be provided to Token instance');
    }

    this._abi = new _ethAbi2.default(abi);
    this._abiObj = abi;

    this._abi.functions.forEach(function (func) {
      var functionAbi;
      _this._abiObj.forEach(function (elem) {
        if (elem.name == func.name)
        functionAbi = elem;
      });
      _this[func.name] = function () {
        return new _signer2.default(arguments, functionAbi);
      }.bind(_this);
    });
  }(0, _createClass3.default)(Token, [{ key: 'functions', get: function get()

    {
      return this._functions;
    } }, { key: 'abi', get: function get()

    {
      return this._abi;
    } }], [{ key: 'concat', value: function concat(

    address, amount) {
      var addr = new Buffer(address.replace('0x', ''), 'hex');
      return Buffer.concat([addr, _ethereumjsUtil2.default.setLength(amount, 12)]);
    } }, { key: 'separate', value: function separate(

    bytes32String) {
      var val = new Buffer(bytes32String.replace('0x', ''), 'hex');
      return {
        address: '0x' + val.slice(0, 20).toString('hex'),
        amount: new _bn2.default(val.slice(21, 32)).toNumber() };

    } }, { key: 'parseToHex', value: function parseToHex(

    token) {
      //parse payload
      var tokenParts = token.split('.'),
      payload = JSON.parse(_base64url2.default.decode(tokenParts[1])),
      byteValues = [],values = [],
      abiObj = {
        type: 'function',
        name: (0, _keys2.default)(payload)[0],
        inputs: [] };


      //rebuild abi and values
      payload[abiObj.name].forEach(function (entry) {
        var input = {};
        input.type = (0, _keys2.default)(entry)[0];
        abiObj.inputs.push(input);
        values.push(entry[(0, _keys2.default)(entry)[0]]);
        byteValues.push((0, _types.checkConversion)(entry[(0, _keys2.default)(entry)[0]], input.type));
      });

      //rebuild signed data
      var abi = new _ethAbi2.default([abiObj]),
      tokens = abi.encodeTokens(abi.functions[0].inputParamTypes(), byteValues),
      encoded = new Buffer(abi.functions[0].encodeCall(tokens), 'hex');

      //parse signature
      var derSignature = _ecdsaSigFormatter2.default.joseToDer(tokenParts[2], 'ES256'),
      sig = new _signature2.default(derSignature, 'ES256'),
      r = sig.r.toBuffer('be', 32),
      s = sig.s.toBuffer('be', 32),
      v = payload.v + 27;
      return {
        rec: encoded.toString('hex'),
        sig: Buffer.concat([r, s]).toString('hex') + v.toString(16) };

    } }, { key: 'parse', value: function parse(

    token) {
      //parse payload
      var tokenParts = token.split('.'),
      payload = JSON.parse(_base64url2.default.decode(tokenParts[1])),
      byteValues = [],values = [],
      abiObj = {
        type: 'function',
        name: (0, _keys2.default)(payload)[0],
        inputs: [] };


      //rebuild abi and values
      payload[abiObj.name].forEach(function (entry) {
        var input = {};
        input.type = (0, _keys2.default)(entry)[0];
        abiObj.inputs.push(input);
        values.push(entry[(0, _keys2.default)(entry)[0]]);
        byteValues.push((0, _types.checkConversion)(entry[(0, _keys2.default)(entry)[0]], input.type));
      });

      //rebuild signed data
      var abi = new _ethAbi2.default([abiObj]),
      tokens = abi.encodeTokens(abi.functions[0].inputParamTypes(), byteValues),
      encoded = new Buffer(abi.functions[0].encodeCall(tokens), 'hex'),
      hash = _ethereumjsUtil2.default.sha3(encoded);

      //parse signature
      var derSignature = _ecdsaSigFormatter2.default.joseToDer(tokenParts[2], 'ES256'),
      sig = new _signature2.default(derSignature, 'ES256'),
      r = sig.r.toBuffer('be', 32),
      s = sig.s.toBuffer('be', 32),
      pub = _ethereumjsUtil2.default.ecrecover(hash, payload.v + 27, r, s),
      signer = '0x' + _ethereumjsUtil2.default.pubToAddress(pub).toString('hex');

      return {
        header: JSON.parse(_base64url2.default.decode(tokenParts[0])),
        abi: [abiObj],
        values: values,
        signer: signer };

    } }]);return Token;}();exports.default = Token;module.exports = exports['default'];