deploy.js

  api.post('/swapper/:address', async (req, res, next) => {
    const abiPath = path.join(__dirname, '..', '..', 'contracts', 'HanwhaTokenSwapper.json');
    const abi = JSON.parse(fs.readFileSync(abiPath).toString()).abi;
    const contract = new web3.eth.Contract(abi, req.params.address);
    const from = process.env.OPERATOR_ADDRESS;
    let nonce;
    try {
      nonce = await web3.eth.getTransactionCount(from);
    } catch (err) {
      return res.status(400).json({
        code: 1,
        message: err.message,
      });
    }
    const privateKey = new Buffer(process.env.OPERATOR_PRIVATE_KEY, 'hex');
    const method = req.body.method;
    const bytecode = getBytecode(web3, abi, method, req.body.params);
    const values = Object.values(req.body.params);
    let gas;
    try {
      gas =
        await contract.methods[method](...values).estimateGas({
          from: from,
        });
    } catch (err) {
      return res.status(400).json({
        code: 1,
        message: err.message,
      });
    }

    const rawTx = {
      nonce: nonce,
      chainId: await web3.eth.net.getId(),
      to: req.params.address,
      data: bytecode,
      gasPrice: '22e9',
      gas: parseInt(gas * 1.2),
    };

    const tx = new Tx(rawTx);
    tx.sign(privateKey);
    const serializedTx = tx.serialize().toString('hex');

    try {
      web3.eth.sendSignedTransaction('0x' + serializedTx)
      .on('receipt', receipt => {
        return res.status(200).json({
          code: 0,
          message: 'success',
          response: {
            txhash: receipt.transactionHash,
          }
        });
      })
      .on('error', error => {
        return res.status(400).json({
          code: 1,
          message: error.message,
        });
      });
    } catch (err) {
      return res.status(400).json({
        code: 1,
        message: err.message,
      });
    }
  });