Offline Transaction

Sign Transaction

การสร้าง offline transaction เราสามารถ sign transaction และให้คนอื่น broadcast ไปที่ network ได้

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import {
  clusterApiUrl,
  Connection,
  Keypair,
  Transaction,
  SystemProgram,
  LAMPORTS_PER_SOL,
  Message,
} from "@solana/web3.js";
import * as nacl from "tweetnacl";
import * as bs58 from "bs58";

// to complete a offline transaction, I will seperate them into four steps
// 1. Create Transaction
// 2. Sign Transaction
// 3. Recover Transaction
// 4. Send Transaction

(async () => {
  // create connection
  const connection = new Connection(clusterApiUrl("devnet"), "confirmed");

  // create a example tx, alice transfer to bob and feePayer is `feePayer`
  // alice and feePayer are signer in this tx
  const feePayer = Keypair.generate();
  await connection.confirmTransaction(
    await connection.requestAirdrop(feePayer.publicKey, LAMPORTS_PER_SOL)
  );
  const alice = Keypair.generate();
  await connection.confirmTransaction(
    await connection.requestAirdrop(alice.publicKey, LAMPORTS_PER_SOL)
  );
  const bob = Keypair.generate();

  // 1. Create Transaction
  let tx = new Transaction().add(
    SystemProgram.transfer({
      fromPubkey: alice.publicKey,
      toPubkey: bob.publicKey,
      lamports: 0.1 * LAMPORTS_PER_SOL,
    })
  );
  tx.recentBlockhash = (await connection.getRecentBlockhash()).blockhash;
  tx.feePayer = feePayer.publicKey;
  let realDataNeedToSign = tx.serializeMessage(); // the real data singer need to sign.

  // 2. Sign Transaction
  // use any lib you like, the main idea is to use ed25519 to sign it.
  // the return signature should be 64 bytes.
  let feePayerSignature = nacl.sign.detached(
    realDataNeedToSign,
    feePayer.secretKey
  );
  let aliceSignature = nacl.sign.detached(realDataNeedToSign, alice.secretKey);

  // 3. Recover Tranasction

  // you can verify signatures before you recovering the transaction
  let verifyFeePayerSignatureResult = nacl.sign.detached.verify(
    realDataNeedToSign,
    feePayerSignature,
    feePayer.publicKey.toBytes() // you should use the raw pubkey (32 bytes) to verify
  );
  console.log(`verify feePayer signature: ${verifyFeePayerSignatureResult}`);

  let verifyAliceSignatureResult = nacl.sign.detached.verify(
    realDataNeedToSign,
    aliceSignature,
    alice.publicKey.toBytes()
  );
  console.log(`verify alice signature: ${verifyAliceSignatureResult}`);

  // there are two ways you can recover the tx
  // 3.a Recover Tranasction (use populate then addSignauture)
  {
    let recoverTx = Transaction.populate(Message.from(realDataNeedToSign));
    recoverTx.addSignature(feePayer.publicKey, Buffer.from(feePayerSignature));
    recoverTx.addSignature(alice.publicKey, Buffer.from(aliceSignature));

    // 4. Send transaction
    console.log(
      `txhash: ${await connection.sendRawTransaction(recoverTx.serialize())}`
    );
  }

  // or

  // 3.b. Recover Tranasction (use populate with signature)
  {
    let recoverTx = Transaction.populate(Message.from(realDataNeedToSign), [
      bs58.encode(feePayerSignature),
      bs58.encode(aliceSignature),
    ]);

    // 4. Send transaction
    console.log(
      `txhash: ${await connection.sendRawTransaction(recoverTx.serialize())}`
    );
  }

  // if this process takes too long, your recent blockhash will expire (after 150 blocks).
  // you can use `durable nonce` to get rid of it.
})();

Partial Sign Transaction

เมื่อ transaction ต้องการ signatures หลายอันเราสามารถแยกกัน partially sign ได้ โดย signers อื่นสามารถ sign และ broadcast ไปที่ network ได้

ตัวอย่างการใช้งาน:

  • ส่ง SPL token เพื่อกำระเงิน
  • Sign transaction เพื่อให้เราสามารถตรวจสอบความถูกต้องได้ทีหลัง
  • เรียก custom programs ใน transaction ที่ต้องการ signature ของเรา

ในตัวอย่างนี้ Bob จะส่ง SPL token ให้ Alice เพื่อเป็นการชำระเงิน:

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import {
  createTransferCheckedInstruction,
  getAssociatedTokenAddress,
  getMint,
  getOrCreateAssociatedTokenAccount,
} from "@solana/spl-token";
import {
  clusterApiUrl,
  Connection,
  Keypair,
  LAMPORTS_PER_SOL,
  PublicKey,
  SystemProgram,
  Transaction,
} from "@solana/web3.js";
import base58 from "bs58";

/* The transaction:
 * - sends 0.01 SOL from Alice to Bob
 * - sends 1 token from Bob to Alice
 * - is partially signed by Bob, so Alice can approve + send it
 */

(async () => {
  const connection = new Connection(clusterApiUrl("devnet"), "confirmed");

  const alicePublicKey = new PublicKey(
    "5YNmS1R9nNSCDzb5a7mMJ1dwK9uHeAAF4CmPEwKgVWr8"
  );
  const bobKeypair = Keypair.fromSecretKey(
    base58.decode(
      "4NMwxzmYj2uvHuq8xoqhY8RXg63KSVJM1DXkpbmkUY7YQWuoyQgFnnzn6yo3CMnqZasnNPNuAT2TLwQsCaKkUddp"
    )
  );
  const tokenAddress = new PublicKey(
    "Gh9ZwEmdLJ8DscKNTkTqPbNwLNNBjuSzaG9Vp2KGtKJr"
  );
  const bobTokenAddress = await getAssociatedTokenAddress(
    tokenAddress,
    bobKeypair.publicKey
  );

  // Alice may not have a token account, so Bob creates one if not
  const aliceTokenAccount = await getOrCreateAssociatedTokenAccount(
    connection,
    bobKeypair, // Bob pays the fee to create it
    tokenAddress, // which token the account is for
    alicePublicKey // who the token account is for
  );

  // Get the details about the token mint
  const tokenMint = await getMint(connection, tokenAddress);

  // Get a recent blockhash to include in the transaction
  const { blockhash } = await connection.getLatestBlockhash("finalized");

  const transaction = new Transaction({
    recentBlockhash: blockhash,
    // Alice pays the transaction fee
    feePayer: alicePublicKey,
  });

  // Transfer 0.01 SOL from Alice -> Bob
  transaction.add(
    SystemProgram.transfer({
      fromPubkey: alicePublicKey,
      toPubkey: bobKeypair.publicKey,
      lamports: 0.01 * LAMPORTS_PER_SOL,
    })
  );

  // Transfer 1 token from Bob -> Alice
  transaction.add(
    createTransferCheckedInstruction(
      bobTokenAddress, // source
      tokenAddress, // mint
      aliceTokenAccount.address, // destination
      bobKeypair.publicKey, // owner of source account
      1 * 10 ** tokenMint.decimals, // amount to transfer
      tokenMint.decimals // decimals of token
    )
  );

  // Partial sign as Bob
  transaction.partialSign(bobKeypair);

  // Serialize the transaction and convert to base64 to return it
  const serializedTransaction = transaction.serialize({
    // We will need Alice to deserialize and sign the transaction
    requireAllSignatures: false,
  });
  const transactionBase64 = serializedTransaction.toString("base64");
  return transactionBase64;

  // The caller of this can convert it back to a transaction object:
  const recoveredTransaction = Transaction.from(
    Buffer.from(transactionBase64, "base64")
  );
})();

Durable Nonce

RecentBlockhash เป็นค่าที่สำคัญในการทำ transaction ซึ่ง transaction จะโดนปฏิเสธ(rejected) ถ้าเราใช้ blockhash ที่หมดอายุไปแล้ว (เลย 150 blocks) เราสามารถใช้ durable nonce เพื่อหา blockhash ที่ไม่มีวันหมดอายุๆด้ โดยเราจะต้อง

  1. ใช้ nonce ที่เก็บไว้ใน nonce account แทน recent blockhash
  2. ใส่ nonce advance ใน instruction

Create Nonce Account

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import {
  clusterApiUrl,
  Connection,
  Keypair,
  Transaction,
  NONCE_ACCOUNT_LENGTH,
  SystemProgram,
  LAMPORTS_PER_SOL,
} from "@solana/web3.js";

(async () => {
  // Setup our connection and wallet
  const connection = new Connection(clusterApiUrl("devnet"), "confirmed");
  const feePayer = Keypair.generate();

  // Fund our wallet with 1 SOL
  const airdropSignature = await connection.requestAirdrop(
    feePayer.publicKey,
    LAMPORTS_PER_SOL
  );
  await connection.confirmTransaction(airdropSignature);

  const nonceAccountAuth = Keypair.generate();

  let nonceAccount = Keypair.generate();
  console.log(`nonce account: ${nonceAccount.publicKey.toBase58()}`);

  let tx = new Transaction().add(
    // create nonce account
    SystemProgram.createAccount({
      fromPubkey: feePayer.publicKey,
      newAccountPubkey: nonceAccount.publicKey,
      lamports: await connection.getMinimumBalanceForRentExemption(
        NONCE_ACCOUNT_LENGTH
      ),
      space: NONCE_ACCOUNT_LENGTH,
      programId: SystemProgram.programId,
    }),
    // init nonce account
    SystemProgram.nonceInitialize({
      noncePubkey: nonceAccount.publicKey, // nonce account pubkey
      authorizedPubkey: nonceAccountAuth.publicKey, // nonce account authority (for advance and close)
    })
  );

  console.log(
    `txhash: ${await connection.sendTransaction(tx, [feePayer, nonceAccount])}`
  );
})();

Get Nonce Account

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import {
  clusterApiUrl,
  Connection,
  PublicKey,
  Keypair,
  NonceAccount,
} from "@solana/web3.js";

(async () => {
  // connection
  const connection = new Connection(clusterApiUrl("devnet"), "confirmed");

  const nonceAccountPubkey = new PublicKey(
    "7H18z3v3rZEoKiwY3kh8DLn9eFT6nFCQ2m4kiC7RZ3a4"
  );

  let accountInfo = await connection.getAccountInfo(nonceAccountPubkey);
  let nonceAccount = NonceAccount.fromAccountData(accountInfo.data);
  console.log(`nonce: ${nonceAccount.nonce}`);
  console.log(`authority: ${nonceAccount.authorizedPubkey.toBase58()}`);
  console.log(`fee calculator: ${JSON.stringify(nonceAccount.feeCalculator)}`);
})();

Use Nonce Account

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import {
  clusterApiUrl,
  Connection,
  PublicKey,
  Keypair,
  Transaction,
  SystemProgram,
  NonceAccount,
  LAMPORTS_PER_SOL,
} from "@solana/web3.js";
import * as bs58 from "bs58";

(async () => {
  // Setup our connection and wallet
  const connection = new Connection(clusterApiUrl("devnet"), "confirmed");
  const feePayer = Keypair.generate();

  // Fund our wallet with 1 SOL
  const airdropSignature = await connection.requestAirdrop(
    feePayer.publicKey,
    LAMPORTS_PER_SOL
  );
  await connection.confirmTransaction(airdropSignature);

  // G2FAbFQPFa5qKXCetoFZQEvF9BVvCKbvUZvodpVidnoY
  const nonceAccountAuth = Keypair.fromSecretKey(
    bs58.decode(
      "4NMwxzmYj2uvHuq8xoqhY8RXg63KSVJM1DXkpbmkUY7YQWuoyQgFnnzn6yo3CMnqZasnNPNuAT2TLwQsCaKkUddp"
    )
  );

  const nonceAccountPubkey = new PublicKey(
    "7H18z3v3rZEoKiwY3kh8DLn9eFT6nFCQ2m4kiC7RZ3a4"
  );
  let nonceAccountInfo = await connection.getAccountInfo(nonceAccountPubkey);
  let nonceAccount = NonceAccount.fromAccountData(nonceAccountInfo.data);

  let tx = new Transaction().add(
    // nonce advance must be the first insturction
    SystemProgram.nonceAdvance({
      noncePubkey: nonceAccountPubkey,
      authorizedPubkey: nonceAccountAuth.publicKey,
    }),
    // after that, you do what you really want to do, here we append a transfer instruction as an example.
    SystemProgram.transfer({
      fromPubkey: feePayer.publicKey,
      toPubkey: nonceAccountAuth.publicKey,
      lamports: 1,
    })
  );
  // assign `nonce` as recentBlockhash
  tx.recentBlockhash = nonceAccount.nonce;
  tx.feePayer = feePayer.publicKey;
  tx.sign(
    feePayer,
    nonceAccountAuth
  ); /* fee payer + nonce account authority + ... */

  console.log(`txhash: ${await connection.sendRawTransaction(tx.serialize())}`);
})();
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Contributors: Todsaporn Banjerdkit