liquidity-invoice-generation

liquidity-invoice-generation

Invoice generation system compatible with Liquidity Network

IMPORTANT: Requires web3-utils and bignumber.js dependencies

Usage

const invoice: Invoice = createInvoice({
  network: 4, // Network id
  publicKey: '0xE6987CD613Dfda0995A95b3E6acBAbECecd41376', // public key of recipient
  // Generate unique id for invoice, payment by this invoice can be tracked by nonce which is derived by
  // invoice's id and amount. If id is not generated, then the invoice can be used multiple times.
  generateId: true,
  // Contract address, if not defined, on-chain invoice will be generated.
  contractAddress: '0x4FED1fC4144c223aE3C1553be203cDFcbD38C581',
  tokenAddress: '0x4FED1fC4144c223aE3C1553be203cDFcbD38C581', // Token address, if not defined, operator address applied.
  amount: '12000000000000', // Optional. BigNumber or number also can be used.
})

const encodedInvoice: string = encodeInvoice(invoice) // Used to generate QR code

const decodedInvoice: Invoice = decodeInvoice(encodedInvoice) // Decode invoice after QR code scanning

// Note: Here, decodedInvoice equals invoice

• Feed encodedInvoice into a QR code generator as plain text. (i.g: user https://www.the-qrcode-generator.com or a library) to be scanned by the user.
• Feed decodedInvoice into the sendTransfer function of the NOCUSManager.
• If no amount is specified invoice.amount will be undefined, it needs to be set before making a transfer with the nocust manager client side.
• If tokenAddress is not specified, Ether will be used.

The typical merchant needs to track the completion of payments by its customer, to do so we use generateId.

1. SERVER SIDE, generate an invoice with generateId set to true and save the nonce in the invoice object invoice.nonce in the merchant server db. It is important to be done server side otherwise the client can manipulate the value.
2. Encode the invoice with encodeInvoice function and send it to the client front-end to display the QR code
3. Wait for an incoming payment with the nocust-manager that has the correct nonce value AND amount.