Creating an ERC20 request

This is an example of creating a request using an erc20 payment network The request will be stored in memory and cleared as soon as the script is finished running.

Basics#

For both erc20 payment networks, Request Client must be initialized.

Imports#

First we import the 2 packages we will need to create the request:

// The signature provider allows us to sign the request
import { EthereumPrivateKeySignatureProvider } from '@requestnetwork/epk-signature';
// RequestNetwork is the interface we will use to interact with the Request network
import * as RequestNetwork from '@requestnetwork/request-client.js';

Identity#

To create a request we need to declare the identities of the parties involved. Identities are the unique identifier of a request user. They are generally different from payment addresses but can be the same. They identify an entity like a person or business.

// Here we declare the payee identity, with the payee identity ethereum address
const payeeIdentity = {
  type: RequestNetwork.Types.Identity.TYPE.ETHEREUM_ADDRESS,
  value: '0x627306090abab3a6e1400e9345bc60c78a8bef57',
};
// Here we declare the (optional, but recommended) payer identity address.
const payerIdentity = {
  type: RequestNetwork.Types.Identity.TYPE.ETHEREUM_ADDRESS,
  value: '0xF317BedAA5c389F2C6f469FcF25e0752C7228Ba6',
};

Signature Provider#

The Ethereum private key signature provider allows a user to pass in their private Ethereum key to sign a request. The signer is either the payee or the payer. The signature is proof of who created the request and of its integrity (that no data changed after it was signed). This process is similar to the signature of an Ethereum transaction.

// The signature info requires the request creator private key.
// For this demo purposes, we hard-coded the private key. Please be careful with how you store and handle your private key since it's a very sensitive piece of data.
const payeeSignatureInfo = {
  method: RequestNetwork.Types.Signature.METHOD.ECDSA,
  privateKey: '0xc87509a1c067bbde78beb793e6fa76530b6382a4c0241e5e4a9ec0a0f44dc0d3',
};
const signatureProvider = new EthereumPrivateKeySignatureProvider(payeeSignatureInfo);
// We can initialize the RequestNetwork class with the signature provider and inform we will be using the mock storage.
const requestNetwork = new RequestNetwork.RequestNetwork({
  signatureProvider,
  useMockStorage: true,
});

Request Information#

In the next section of code we declare the request information.

// The main request info, with the currency, amount (in the smallest denominator), payee identity and payer identity
const requestInfo: RequestNetwork.Types.IRequestInfo = {
  currency: 'REQ',
  expectedAmount: '1000000000000000000', // 1 REQ
  payee: payeeIdentity,
  payer: payerIdentity,
};

Request creation with the proxy contract payment network#

To create a request using erc20 proxy contract payment network, we need to provide the payment network parameters to the request creation parameters. Proxy contract payment network parameters are the same as the address-based payment network: the payment and eventually the refund address.

const paymentNetwork: RequestNetwork.Types.Payment.PaymentNetworkCreateParameters = {
  id: RequestNetwork.Types.Extension.PAYMENT_NETWORK_ID.ERC20_PROXY_CONTRACT,
  parameters: {
    paymentAddress: '0x92FC764853A9A0287b7587E59aDa47165b3B2675',
  },
};
const proxyContractCreateParams = {
  paymentNetwork,
  requestInfo,
  signer: payeeIdentity,
};
// Finally create the request and print its id
(async () => {
  const request = await requestNetwork.createRequest(proxyContractCreateParams);
  console.log(`Request created with erc20 proxy contract payment network: ${request.requestId}`);
})();

Request creation with address-based payment network#

To create a request using the erc20 address-based payment network, we need to provide the payment network parameters to the request creation parameters.

const addressBasedPaymentNetwork: RequestNetwork.Types.Payment.PaymentNetworkCreateParameters = {
  id: RequestNetwork.Types.Extension.PAYMENT_NETWORK_ID.ERC20_ADDRESS_BASED,
  parameters: {
    paymentAddress: '0x92FC764853A9A0287b7587E59aDa47165b3B2675',
  },
};
const addressBasedCreateParams = {
  addressBasedPaymentNetwork,
  requestInfo,
  signer: payeeIdentity,
};
// Finally create the request and print its id
(async () => {
  const request = await requestNetwork.createRequest(addressBasedCreateParams);
  console.log('Request created with erc20 address based payment network:');
  console.log(request.requestId);
})();

Checking the balance of an erc20 request#

The function getData() of a request provides its balance This function is available independently of the payment network used

// Import Big Number package
const BN = require('bn.js');
(async () => {
  // Use a proxy contract request for example
  const request = await requestNetwork.createRequest(proxyContractCreateParams);
  // Check the balance of the request
  const requestData = request.getData();
  const balanceObject = requestData.balance;
  if (!balanceObject) {
    console.error('balance no set');
    return;
  }
  if (balanceObject.error) {
    console.error(balanceObject.error.message);
    return;
  }
  console.log(`Balance of the erc20 proxy contract request: ${balanceObject.balance}`);
  // Check if the request has been paid
  // Convert the balance to big number type for comparison
  const expectedAmount = new BN(requestData.expectedAmount);
  const balanceBigNumber = new BN(balanceObject.balance);
  // Check if balanceBigNumber is greater or equal to expectedAmount
  const paid = balanceBigNumber.gte(expectedAmount);
})();