Example code redeeming DOC Request

In the following example we will show how to invoke redeemDocRequest using Money on Chain contract. This method can recieve any amount of DOC to redeem, but this will be processed on the next settlement. Check the DOC redeemption section for more details.

We will use truffle and testnet network. You can find code examples into /examples dir.

First we create a new node project.

mkdir example-redeem-doc-request
cd example-redeem-doc-request
npm init

Let's add the necessary dependencies to run the project.

npm install --save web3

Example

const Web3 = require('web3');
//You must compile the smart contracts or use the official ABIs of the repository
const MoC = require('../../build/contracts/MoC.json');
const truffleConfig = require('../../truffle');
/**
 * Get a provider from truffle.js file
 * @param {String} network
 */
const getDefaultProvider = network =>
  truffleConfig.networks[network].provider || truffleConfig.networks[network].endpoint;

/**
 * Get a gasPrice from truffle.js file
 * @param {String} network
 */
const getGasPrice = network => truffleConfig.networks[network].gasPrice || 60000000;

/**
 * Get a new web3 instance from truffle.js file
 */
const getWeb3 = network => {
  const provider = getDefaultProvider(network);
  return new Web3(provider, null, {
    transactionConfirmationBlocks: 1
  });
};

const web3 = getWeb3('rskTestnet');
const gasPrice = getGasPrice('rskTestnet');

//Loading MoC address on testnet
const mocAddress = '<contract-address>';

const execute = async () => {
  web3.eth.defaultGas = 2000000;

  /**
   * Loads an specified contract
   * @param {ContractABI} abi
   * @param {String} contractAddress
   */
  const getContract = async (abi, contractAddress) => new web3.eth.Contract(abi, contractAddress);

  // Loading MoC contract
  const moc = await getContract(MoC.abi, mocAddress);
  if (!moc) {
    throw Error('Can not find MoC contract.');
  }

  const redeemDocRequest = async docAmount => {
    const [from] = await web3.eth.getAccounts();
    const weiAmount = web3.utils.toWei(docAmount, 'ether');

    console.log(`Calling redeem Doc request, account: ${from}, amount: ${weiAmount}.`);
    moc.methods
      .redeemDocRequest(weiAmount)
      .send({ from, gasPrice }, function(error, transactionHash) {
        if (error) console.log(error);
        if (transactionHash) console.log('txHash: '.concat(transactionHash));
      })
      .on('transactionHash', function(hash) {
        console.log('TxHash: '.concat(hash));
      })
      .on('receipt', function(receipt) {
        console.log(receipt);
      })
      .on('error', console.error);
  };

  const docAmount = '10000';

  // Call redeem
  await redeemDocRequest(docAmount);
};

execute()
  .then(() => console.log('Completed'))
  .catch(err => {
    console.log('Error', err);
  });