Library for Scheduled Neon EVM Transaction

Note: this package is under development, run on neon test environment and is not ready for production use.

How to install and run tests

yarn install
cd packages/core
yarn test

How to using it in code

Node: for more details run yarn test in packages/core folder and see solana-sign.spec.ts file.

First, it is necessary to initialize all variables and providers for Solana and Neon EVM RPCs.

const result = await getProxyState(`<neon_proxy_rpc_url>`);
const token = getGasToken(result.tokensList, NeonChainId.testnetSol);
const connection = new Connection(`<solana_rpc_url>`, 'confirmed');
const provider = new JsonRpcProvider(`<neon_proxy_rpc_url>`);
const neonClientApi = new NeonClientApi(`<neon_client_api_url>`);
const neonProxyRpcApi = result.proxyApi;
const neonEvmProgram = result.evmProgramAddress;
const chainId = Number(token.gasToken.tokenChainId);
const chainTokenMint = new PublicKey(token.gasToken.tokenMint);

Next, connect a Solana wallet (in this example, a Keypair is used, but any other method for signing and sending transactions on the Solana network can also be used).

The SolanaNeonAccount class includes the Solana wallet, calculates the Neon wallet, and manages the balance account required for creating a Scheduled transaction and executing transactions on the Neon EVM.

const solanaPrivateKey = bs58.decode(`<you_private_key_base58>`);
const keypair = Keypair.fromSecretKey(solanaPrivateKey);
const solanaUser = SolanaNeonAccount.fromKeypair(keypair, neonEvmProgram, chainTokenMint, chainId);
await solanaAirdrop(connection, solanaUser.publicKey, 1e9);

We create a Scheduled transaction and send it, embedding the contract address and the method call data. Additionally, we retrieve the nonce for the Neon wallet and include this information in the Scheduled transaction.

const nonce = Number(await neonProxyRpcApi.getTransactionCount(solanaUser.neonWallet));
const maxFeePerGas = 0x77359400;

const scheduledTransaction = new ScheduledTransaction({
  nonce: toBeHex(nonce),
  payer: solanaUser.neonWallet,
  target: `<contract_address>`,
  callData: `<call_contract_data>`,
  maxFeePerGas: toBeHex(maxFeePerGas),
  chainId: toBeHex(NeonChainId.testnetSol)
});

We create a transaction for Solana, including all the previously defined data.

const transaction = await createScheduledNeonEvmTransaction({
  chainId,
  signerAddress: solanaUser.publicKey,
  tokenMintAddress: solanaUser.tokenMint,
  neonEvmProgram,
  neonWallet: solanaUser.neonWallet,
  neonWalletNonce: nonce,
  neonTransaction: scheduledTransaction.serialize()
});

It is necessary to ensure that the balance account is initialized on Solana before the Scheduled transaction is executed. If it is not, an instruction to create the balance account must be added.

const account = await connection.getAccountInfo(solanaUser.balanceAddress);

if (account === null) {
  transaction.instructions.unshift(createBalanceAccountInstruction(neonEvmProgram, solanaUser.publicKey, solanaUser.neonWallet, solanaUser.chainId));
}

Sign and send the transaction to the Solana network.

const { blockhash, lastValidBlockHeight } = await connection.getLatestBlockhash();
transaction.recentBlockhash = blockhash;
transaction.sign({ publicKey: solanaUser.publicKey, secretKey: solanaUser.keypair });
const signature = await connection.sendRawTransaction(transaction.serialize());
console.log('Transaction signature', signature);

Wait for the Scheduled transaction to execute on the Neon EVM and display the results.

const [transaction] = await neonClientApi.waitTransactionTreeExecution(solanaUser.neonWallet, nonce, 5e3);
const { status, transaction_hash, result_hash } = transaction;
console.log(`Scheduled transaction result`, transaction);
console.log(await neonProxyRpcApi.getTransactionReceipt(`0x${transaction_hash}`));