Use Tickets

(Requires the TicketBatch amendment )

Tickets provide a way to send transactions out of the normal order. This tutorial walks through the steps of creating a Ticket, then using it to send another transaction.

Prerequisites

This page provides JavaScript examples that use the ripple-lib (RippleAPI) library. The RippleAPI Beginners Guide describes how to get started using RippleAPI to access XRP Ledger data from JavaScript.

Since JavaScript works in the web browser, you can read along and use the interactive steps without any setup.

Tickets must be enabled. At this time, the TicketBatch amendment is only available on Devnet.

Steps

This tutorial is divided into a few phases:

  • (Steps 1-2) Setup: You need an XRP Ledger address and secret. For production, you can use the same address and secret consistently. For this tutorial, you can generate new test credentials as needed. You also need to be connected to the network.
  • (Steps 3-6) Create Tickets: Send a transaction to set aside some Tickets.
  • (Optional) Intermission: After creating Tickets, you can send various other transactions at any time before, during, and after the following steps.
  • (Steps 7-10) Use Ticket: Use one of your set-aside Tickets to send a transaction. You can repeat these steps while skipping the previous parts as long as you have at least one Ticket remaining to use.

1. Get Credentials

To transact on the XRP Ledger, you need an address and secret key, and some XRP. For development purposes, you can get these on the Devnet using the following interface:

Caution: Ripple provides the Testnet and Devnet for testing purposes only, and sometimes resets the state of these test networks along with all balances. As a precaution, do not use the same addresses on Testnet/Devnet and Mainnet.

When you're building actual production-ready software, you'll instead use an existing account, and manage your keys using a secure signing configuration.

2. Connect to Network

You must be connected to the network to submit transactions to it.

The following code uses a RippleAPI instance to connect to a public XRP Devnet server:

ripple = require('ripple-lib')

async function main() {
  api = new ripple.RippleAPI({server: 'wss://s.devnet.rippletest.net:51233'})
  await api.connect()

  // Code in the following examples continues here...
}

main()

Note: The code samples in this tutorial use JavaScript's async/await pattern . Since await needs to be used from within an async function, the remaining code samples are written to continue inside the main() function started here. You can also use Promise methods .then() and .catch() instead of async/await if you prefer.

For this tutorial, you can connect directly from your browser by pressing the following button:

3. Check Sequence Number

Before you create any Tickets, you should check what Sequence Number your account is at. You want the current Sequence number for the next step, and the Ticket Sequence numbers it sets aside start from this number.

async function get_sequence() {
  const account_info = await api.request("account_info", {
      "account": "rPT1Sjq2YGrBMTttX4GZHjKu9dyfzbpAYe"
  })
  console.log("Current sequence:", account_info.account_data.Sequence)
  return account_info.account_data.Sequence
}

let current_sequence = await get_sequence()

4. Prepare and Sign TicketCreate

Construct a TicketCreate transaction using the sequence number you determined in the previous step. Use the TicketCount field to specify how many Tickets to create. For example, to prepare a transaction that would make 10 Tickets:

let prepared = await api.prepareTransaction({
  "TransactionType": "TicketCreate",
  "Account": "rPT1Sjq2YGrBMTttX4GZHjKu9dyfzbpAYe",
  "TicketCount": 10,
  "Sequence": current_sequence
})
console.log("Prepared transaction:", prepared.txJSON)
let max_ledger = prepared.instructions.maxLedgerVersion

let signed = api.sign(prepared.txJSON, "s████████████████████████████")
console.log("Transaction hash:", signed.id)

let tx_blob = signed.signedTransaction

Record the transaction's hash and LastLedgerSequence value so you can be sure whether or not it got validated later.

5. Submit TicketCreate

Submit the signed transaction blob that you created in the previous step. Record the latest validated ledger index at the time of submission, so you can set a lower bound on what ledger versions the transaction could be validated in. For example:

let prelim_result = await api.request("submit", {"tx_blob": tx_blob})
console.log("Preliminary result:", prelim_result)
const min_ledger = prelim_result.validated_ledger_index

Warning: Be sure that you DO NOT UPDATE the min_ledger value. It is safe to submit a signed transaction blob multiple times (the transaction can only execute at most once), but when you look up the status of the transaction you should use the earliest possible ledger index that the transaction could be in, not the validated ledger index at the time of the most recent submission. Using the wrong minimum ledger value could cause you to incorrectly conclude that the transaction did not execute. For best practices, see Reliable Transaction Submission.

6. Wait for Validation

Most transactions are accepted into the next ledger version after they're submitted, which means it may take 4-7 seconds for a transaction's outcome to be final. If the XRP Ledger is busy or poor network connectivity delays a transaction from being relayed throughout the network, a transaction may take longer to be confirmed. (For information on how to set an expiration for transactions, see Reliable Transaction Submission.)

You use the ledger event type in RippleAPI to trigger your code to run whenever there is a new validated ledger version. For example:

// signed.id is the hash we're waiting for
// min_ledger is the validated ledger index at time of first submission
// max_ledger is the transaction's LastLedgerSequence value
let tx_status = ""
api.on('ledger', async (ledger) => {
  console.log("Ledger version", ledger.ledgerVersion, "was validated.")
  if (!tx_status) {
    try {
      tx_result = await api.request("tx", {
          "transaction": signed.id,
          "min_ledger": min_ledger,
          "max_ledger": max_ledger
      })

      if (tx_result.validated) {
        console.log("Got validated result:", tx_result.meta.TransactionResult)
        tx_status = "validated"
      } else {
        // Transaction found, but not yet validated. No change.
      }
    } catch(e) {
      if (e.data.error == "txnNotFound") {
        if (e.data.searched_all) {
          console.log(`Tx not found in ledgers ${min_ledger}-${max_ledger}`)
          tx_status = "rejected"
          // This result is final if min_ledger and max_ledger are correct
        } else {
          if (max_ledger > ledger.ledgerVersion) {
            // Transaction may yet be confirmed. Keep waiting.
          } else {
            console.log("Can't get final result. Check a full history server.")
            tx_result = "unknown - check full history"
          }
        }
      } else {
        // Unknown error; pass it back up
        throw e
      }
    }
  }
})
Transaction ID: (None)
Latest Validated Ledger Index: (Not connected)
Ledger Index at Time of Submission: (Not submitted)
Transaction LastLedgerSequence: (Not prepared)

(Optional) Intermission

The power of Tickets is that you can carry on with your account's business as usual while you are getting Ticketed transactions ready. When you want to send a transaction using a Ticket, you can do that in parallel with other sending transactions, including ones using different Tickets, and submit a Ticketed transaction at any time. The only constraint is that each Ticket can only be used once.

Tip: You can come back here to send Sequenced transactions between or during any of the following steps, without interfering with the success of your Ticketed transaction.

7. Check Available Tickets

When you want to send a Ticketed transaction, you need to know what Ticket Sequence number to use for it. If you've been keeping careful track of your account, you already know which Tickets you have, but if you're not sure, you can use the account_objects method (or getAccountObjects()) to look up your available tickets. For example:

let response = await api.request("account_objects", {
    "account": "rPT1Sjq2YGrBMTttX4GZHjKu9dyfzbpAYe",
    "type": "ticket"
  })

console.log("Available Tickets:", response.account_objects)
let use_ticket = response.account_objects[0].TicketSequence

Tip: You can repeat the steps from here through the end as long as you have Tickets left to be used!

8. Prepare Ticketed Transaction

Now that you have a Ticket available, you can prepare a transaction that uses it.

This can be any type of transaction you like. The following example uses a no-op AccountSet transaction since that doesn't require any other setup in the ledger. Set the Sequence field to 0 and include a TicketSequence field with the Ticket Sequence number of one of your available Tickets.

let prepared_t = await api.prepareTransaction({
  "TransactionType": "AccountSet",
  "Account": "rPT1Sjq2YGrBMTttX4GZHjKu9dyfzbpAYe",
  "TicketSequence": use_ticket,
  "Sequence": 0
}, {
  // Adjust instructions to allow more time before submitting the transaction
  maxLedgerVersionOffset: 20
  //maxLedgerVersion: null // or, let the transaction remain valid indefinitely
})
console.log("Prepared JSON:", prepared_t.txJSON)

let signed_t = api.sign(prepared_t.txJSON,
                                   "s████████████████████████████")
console.log("Transaction hash:", signed_t.id)
let tx_blob_t = signed.signedTransaction
console.log("Signed transaction blob:", tx_blob_t)

Tip: If you don't plan to submit the TicketCreate transaction right away, you should explicitly set the instructions' maxLedgerVersionOffset to a larger number of ledgers. To create a transaction that could remain valid indefinitely, set the maxLedgerVersion to null.

9. Submit Ticketed Transaction

Submit the signed transaction blob that you created in the previous step. For example:

let prelim_result_t = await api.request("submit", {"tx_blob": tx_blob_t})
console.log("Preliminary result:", prelim_result_t)

10. Wait for Validation

Ticketed transactions go through the consensus process the same way that Sequenced transactions do.

Transaction ID: (None)
Latest Validated Ledger Index: (Not connected)
Ledger Index at Time of Submission: (Not submitted)
Transaction LastLedgerSequence: (Not prepared)

With Multi-Signing

One of the main use cases for Tickets is to be able to collect signatures for several multi-signed transactions in parallel. By using a Ticket, you can send a multi-signed transaction as soon as it is fully signed and ready to go, without worrying about which one will be ready first.

In this scenario, step 8, "Prepare Ticketed Transaction" is slightly different. Instead of preparing and signing all at once, you would follow the steps for sending any multi-signed transaction: first prepare the transaction, then circulate it among trusted signers to collect their signatures, and finally combine the signatures into the final multi-signed transaction.

You could do this in parallel for several different potential transactions as long as each one uses a different Ticket.

See Also