Creating a request using the Declarative payment network

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

Basics

Before creating a request, the 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: 'EUR', // The Declarative payment network is currency agnostic, we can use any currency supported by Request
expectedAmount: '100', // This equals 1 EUR
payee: payeeIdentity,
payer: payerIdentity,
};

Request creation with the declarative payment network

To create a request using a declarative payment network, we need to provide the payment network parameters to the request creation parameters. The parameters are paymentInfo and optionally refundInfo This value can be any Javascript object. This object should allow the payer to know how to pay the request. For example, for a European transfer, we could provide the IBAN and the BIC of the receiving bank account

const paymentNetwork: RequestNetwork.Types.Payment.IPaymentNetworkCreateParameters = {
id: RequestNetwork.Types.Payment.PAYMENT_NETWORK_ID.DECLARATIVE,
parameters: {
paymentInfo: {
IBAN: 'FR123456789123456789',
BIC: 'CE123456789',
},
},
};
const declarativeCreateParams = {
paymentNetwork,
requestInfo,
signer: payeeIdentity,
};
// Finally create the request and print its id
(async () => {
const request = await requestNetwork.createRequest(declarativeCreateParams);
console.log(`Request created with Declarative payment network: ${request.requestId}`);
})();

Declaring sent and received payments and checking balance

The Declarative payment network doesn't provide payment detection method to determine the balance of the request The balance of the request is defined by the declared payments by the payee and the declared refunds by the payer

// Import Big Number package
const BN = require('bn.js')(async () => {
const request = await requestNetwork.createRequest(declarativeCreateParams);
// Declare received payments
// The payee can declare the amount received, this amount will be added to the balance of the request
request.declareReceivedPayment('1000', 'payment received', payeeIdentity);
// The payer can declare a sent payment, this amount is not taken into account for the request balance
// But the note provided can help to solve dispute
request.declareSentPayment('1000', 'payment sent', payerIdentity);
// Declare received refunds
// The payer can declare received refunds, this amount will be subtracted from the balance of the request
request.declareReceivedPayment('900', 'refund received', payerIdentity);
// Declaring a sent refund, this amount is not taken into account for the request balance
request.declareSentPayment('900', 'received too much', payeeIdentity);
// 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 declarative 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);
})();
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