Reading and subscribing to Transactions

In this session, we'll demonstrate how to coordinate using the XRPL.

The XRPL is a public ledger, meaning that when you write on-chain, anyone can read it. In this session, we will demonstrate how to subscribe to events as they happen on-chain.

First, we will create a pair of accounts:

index.ts

import xrpl from "xrpl";

const serverURL = "wss://s.altnet.rippletest.net:51233"; // For testnet

const main = async () => {
  const client = new xrpl.Client(serverURL)
  await client.connect()

  // do something useful
  console.log("lets fund 2 accounts...")
  const { wallet: wallet1, balance: balance1 } = await client.fundWallet()
  const { wallet: wallet2, balance: balance2 } = await client.fundWallet()

  console.log({ wallet1, balance1 })
  console.log({ wallet2, balance2 })

  // end
  client.disconnect()
};

main()

Check the logs to find the seed for both accounts. We will use these later to reuse the accounts deterministically.

Creating a payment transaction

Here is how to generate a payment transaction between the two accounts.

Insert the seeds from the previous section in the top section.

index.ts

import xrpl from "xrpl";

const serverURL = "wss://s.altnet.rippletest.net:51233"; // For testnet

const wallet1 = xrpl.Wallet.fromSeed("s...");
const wallet2 = xrpl.Wallet.fromSeed("s...");

const main = async () => {
  const client = new xrpl.Client(serverURL);
  await client.connect();

  const tx = {
    TransactionType: "Payment",
    Account: wallet1.classicAddress,
    Destination: wallet2.classicAddress,
    Amount: "1234" // drops
  }

  const result = await client.submitAndWait(tx, {
    autofill: true,
    wallet: wallet1,
  });
  console.log(result)

  // end
  client.disconnect()
};

main()

Reading transactions

One way to retrieve transactions for a given account is to create a request for transactions. Here is an example

// ... define wallet1 before this point
const request = {
  command: 'account_tx',
  account: wallet1.classicAddress,
  ledger_index_min: -1, // To get transactions from all ledgers
  ledger_index_max: -1, // To get transactions up to the most recent ledger
  limit: 10, // Limit the number of transactions (optional)
}
const response = await client.request(request)
console.log('Account Transactions:', response.result.transactions)

Listening for transactions

Finally, we will demonstrate how to listen for transactions affecting a given account to catch all transactions.

You could use this to build a notification bot that alerts you when any activity occurs in your account.

You can subscribe to an account, to trigger on each transaction for instance. This is how you would listen to a specific account.

index.ts

import xrpl from 'xrpl';

const serverURL = 'wss://s.altnet.rippletest.net:51233'; // For testnet
const walletAddress = 'r...' // address to watch

const main = async () => {
  const client = new xrpl.Client(serverURL)
  await client.connect()

  // do something useful
    const subscriptionRequest = {
      command: 'subscribe',
      accounts: [walletAddress]
    };

    await client.request(subscriptionRequest)
    console.log(`Subscribed to transactions for account: ${walletAddress}`)

    // Event listener for incoming transactions
    client.on('transaction', (transaction) => {
      console.log('Transaction:', transaction);
    })

    // Event listener for errors
    client.on('error', (error) => {
      console.error('Error:', error);
    })

  // end
  // keep open
  console.log('all done')
}

main()
setInterval(() => {
  console.log('One second has passed!');
}, 1000)