Fan-out باستخدام Durable Nonce لـ SWQoS

import {
  Connection,
  Keypair,
  SystemProgram,
  NONCE_ACCOUNT_LENGTH,
} from '@solana/web3.js'

const connection = new Connection('https://<primary-rpc-endpoint>', 'confirmed')

const nonceAuthority = Keypair.fromSecretKey(/* secret key */)

const nonceAccount = Keypair.generate()

const lamports =
  await connection.getMinimumBalanceForRentExemption(NONCE_ACCOUNT_LENGTH)

import { Transaction } from '@solana/web3.js'

const tx = new Transaction()

tx.add(
  SystemProgram.createAccount({
    fromPubkey: nonceAuthority.publicKey,
    newAccountPubkey: nonceAccount.publicKey,
    lamports,
    space: NONCE_ACCOUNT_LENGTH,
    programId: SystemProgram.programId,
  }),
  SystemProgram.nonceInitialize({
    noncePubkey: nonceAccount.publicKey,
    authorizedPubkey: nonceAuthority.publicKey,
  }),
)

// fee payer is the nonce authority
tx.feePayer = nonceAuthority.publicKey

// use a normal blockhash for initialization
const { blockhash, lastValidBlockHeight } =
  await connection.getLatestBlockhash('confirmed')

tx.recentBlockhash = blockhash

// sign with both the new account and the authority
tx.sign(nonceAccount, nonceAuthority)

const signature = await connection.sendRawTransaction(tx.serialize())
await connection.confirmTransaction(
  { signature, blockhash, lastValidBlockHeight },
  'confirmed',
)

import { NonceAccount } from '@solana/web3.js'

const { value, context } = await connection.getAccountInfoAndContext(
  nonceAccount.publicKey,
  'confirmed',
)

if (!value) {
  throw new Error('Nonce account not found')
}

const nonce = NonceAccount.fromAccountData(value.data).nonce
const minContextSlot = context.slot

import { TransactionMessage, VersionedTransaction } from '@solana/web3.js'

const instructions = [
  SystemProgram.nonceAdvance({
    noncePubkey: nonceAccount.publicKey,
    authorizedPubkey: nonceAuthority.publicKey,
  }),
  // add your real instructions after this
]

const message = new TransactionMessage({
  payerKey: nonceAuthority.publicKey,
  recentBlockhash: nonce,
  instructions,
}).compileToV0Message()

const tx = new VersionedTransaction(message)
tx.sign([nonceAuthority /* + other signers */])

const rawTx = tx.serialize()

const endpoints = [
  'https://swqos-fra2.erpc.global?api-key=YOUR_API_KEY',
  'https://swqos-ams1.erpc.global?api-key=YOUR_API_KEY',
  'https://<backup-rpc-1>',
]

const results = await Promise.allSettled(
  endpoints.map((url) =>
    new Connection(url, 'confirmed').sendRawTransaction(rawTx, {
      skipPreflight: true,
      minContextSlot,
    }),
  ),
)

const success = results.find(
  (r): r is PromiseFulfilledResult<string> => r.status === 'fulfilled',
)

if (!success) {
  throw new Error('All sends failed')
}

const signature = success.value

await connection.confirmTransaction(
  {
    signature,
    nonceAccountPubkey: nonceAccount.publicKey,
    nonceValue: nonce,
    minContextSlot,
  },
  'confirmed',
)