app.js

"use strict"

const Web3 = require('web3')
const express = require('express')
const http = require('http');
const fs = require('fs');
const coder = require('web3/lib/solidity/coder');  
const CryptoJS = require('crypto-js');

const app = express(); 

const bodyParser = require('body-parser');
app.use(bodyParser.json()); // support json encoded bodies
app.use(bodyParser.urlencoded({ extended: true })); // support encoded b

const web3 = new Web3(new Web3.providers.HttpProvider("https://ropsten.infura.io/{xxx}"));
const obj = JSON.parse(fs.readFileSync('./build/contracts/TravelHelperToken.json', 'utf8'));
const abiArray = obj.abi;
// icowhitelist contract address rinkbey testnet
const contractAddress = '0xF5131d77084E436C2C8B8f738fA5dEdaC16d8b75';
const whiteListContract =  web3.eth.contract(abiArray).at(contractAddress);
// add account address
const account = '0xa9ee36bA5BBe5c3E7C8770e1427421fa00bADd82';
const adminPass = '';
// add private key
const myPrivateKey = 'XXX';

 
var privateKey = new Buffer(myPrivateKey, 'hex') 

const Tx = require('ethereumjs-tx');

app.get('/totalWhitelisted',function countwhitelisted(req,res) {
  const total = whiteListContract.name.call();
  res.send(total);
})


app.post('/whitelist', function (req, res) {
    
    // infura doesn't support eth_sendTransaction. We don't host private keys and therefore can't sign a txn. You'll need to use eth_sendRawTransaction after signing the transaction on your side.
    //eth_sendRawTransaction

    //@TODO - req.body.addresss

    const functionName = 'whiteListAddresses';
    const types = ['address[]'];  
    const args = [['0xF24725B2aA755057Aa9cDc670b5ffC802688cB6e']];  //@idea:  replace req.body.addresss
    const fullName = functionName + '(' + types.join() + ')';
    const signature = CryptoJS.SHA3(fullName,{outputLength:256}).toString(CryptoJS.enc.Hex).slice(0, 8);
    const dataHex = signature + coder.encodeParams(types, args);
    const data = '0x'+dataHex;  

    const nonce = web3.toHex(web3.eth.getTransactionCount(account));
    const gasPrice = web3.toHex(web3.eth.gasPrice);
    const gasLimitHex = web3.toHex(600000);
    const rawTx = { 'nonce': nonce, 'gasPrice': gasPrice, 'gasLimit': gasLimitHex, 'from': account, 'to': contractAddress,data : data};  
    const tx = new Tx(rawTx);
    tx.sign(privateKey);
    const serializedTx = '0x'+tx.serialize().toString('hex');
    web3.eth.sendRawTransaction(serializedTx, function(err, txHash) {
        console.log(err, txHash); 
        if (err) { return res.send ({'error' : err})};
        res.send('https://rinkeby.etherscan.io/tx/'+txHash);
    });    

    
});

app.get('/transfer', function (req, res) {

  // infura doesn't support eth_sendTransaction. We don't host private keys and therefore can't sign a txn. You'll need to use eth_sendRawTransaction after signing the transaction on your side.
  //eth_sendRawTransaction

  //@TODO - req.body.addresss

  const functionName = 'transfer';
  const types = ['address', 'uint256'];
  const args = ['0xF7A0E08E1A02b13C40D45545355150DB66083D5c','343']; //@idea:  replace req.body.addresss
  const fullName = functionName + '(' + types.join() + ')';
  const signature = CryptoJS.SHA3(fullName, {
    outputLength: 256
  }).toString(CryptoJS.enc.Hex).slice(0, 8);
  const dataHex = signature + coder.encodeParams(types, args);
  const data = '0x' + dataHex;

  console.log(data);

  //res.send(data);

  const nonce = web3.toHex(web3.eth.getTransactionCount(account));
  const gasPrice = web3.toHex(web3.eth.gasPrice);
  const gasLimitHex = web3.toHex(600000);
  const rawTx = {
    'nonce': nonce,
    'gasPrice': gasPrice,
    'gasLimit': gasLimitHex,
    'from': account,
    'to': contractAddress,
    data: data
  };

  console.log(rawTx);

  const tx = new Tx(rawTx);
  tx.sign(privateKey);
  const serializedTx = '0x' + tx.serialize().toString('hex');
  web3.eth.sendRawTransaction(serializedTx, function (err, txHash) {
    console.log(err, txHash);
    if (err) {
      return res.send({
        'error': err
      })
    };
    res.send('https://ropsten.etherscan.io/tx/' + txHash);
  });


});

app.get('/signature', function(req,res) {

  const functionName = 'transfer';
  const types = ['address', 'uint256'];
  const fullName = functionName + '(' + types.join() + ')';
  const signature = CryptoJS.SHA3(fullName, {
    outputLength: 256
  }).toString(CryptoJS.enc.Hex).slice(0, 8);

  console.log(signature);

  res.send(signature);

});

app.get('/balance/:id', function (req, res) {
  const balance = web3.eth.getBalance(req.params.id).toNumber();
  const balanceInEth = balance / 1000000000000000000;
  res.send(balanceInEth);
})

app.get('/', function (req, res) {
  res.send('Welcome to API. Specs can be found: ');
})

var server = http.createServer(app);

server.listen(3000, function () {
  console.log('Example app listening on port 3000!')
})