备忘录转账扩展

Name: 使用 Web3.js 的 Token2022
Availability: InStock

MemoTranfer 扩展是一种 Token 账户扩展，它强制要求所有转入 token account 的转账都包含备忘录，从而增强交易跟踪和用户识别。

初始化 Token 账户

要在 MemoTransfer 扩展上初始化一个 Token 账户，我们需要使用 enableRequiredMemoTransfers() 函数。

以下是如何创建带有不可变所有者扩展的 token：

import { Keypair, SystemProgram, Transaction, sendAndConfirmTransaction } from "@solana/web3.js";
import {
  createInitializeAccountInstruction,
  createInitializeImmutableOwnerInstruction,
  getAccountLen,
  ExtensionType,
  TOKEN_2022_PROGRAM_ID,
} from "@solana/spl-token";

const tokenAccount = Keypair.generate();

// Calculate the size needed for a Token account with Transfer Fee extension
const accountLen = getAccountLen([ExtensionType.ImmutableOwner]);

// Calculate minimum lamports required for rent exemption
const lamports = await connection.getMinimumBalanceForRentExemption(accountLen);

// Create the account with the correct size and owner
const createAccountInstruction = SystemProgram.createAccount({
  fromPubkey: keypair.publicKey,
  newAccountPubkey: tokenAccount.publicKey,
  space: accountLen,
  lamports,
  programId: TOKEN_2022_PROGRAM_ID,
});

// Initialize the Memo Transfer extension
const enableMemoTransferInstruction = createEnableRequiredMemoTransfersInstruction(
  destinationTokenAccount.publicKey,
  destinationKeypair.publicKey,
  undefined,
  TOKEN_2022_PROGRAM_ID,
);

// Initialize the Token account itself
const initializeAccountInstruction = createInitializeAccountInstruction(
  tokenAccount.publicKey,
  mint.publicKey,
  keypair.publicKey,
  TOKEN_2022_PROGRAM_ID,
);

const transaction = new Transaction().add(
  createAccountInstruction,
  initializeAccountInstruction,
  enableMemoTransferInstruction,
);

const signature = await sendAndConfirmTransaction(
  connection,
  transaction,
  [keypair, tokenAccount],
  { skipPreflight: false },
);

console.log(
  `Token accounts created! Check out your TX here: https://explorer.solana.com/tx/${signature}?cluster=devnet`,
);

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带备忘录的 Token 转账

要在 Solana 上使用 Memo 程序，我们有两种可行路径。

构建我们自己的“原始”备忘录指令，如下所示：

const message = "Hello, Solana";

new TransactionInstruction({
    keys: [{ pubkey: keypair.publicKey, isSigner: true, isWritable: true }],
    data: Buffer.from(message, "utf-8"), // Memo message. In this case it is "Hello, Solana"
    programId: new PublicKey("MemoSq4gqABAXKb96qnH8TysNcWxMyWCqXgDLGmfcHr"), // Memo program that validates keys and memo message
}),

或者，我们可以在下载该软件包后，使用 Memo 程序的软件开发工具包，如下所示：

text

npm i @solana/spl-memo

在我们的示例中，我们将使用后者，代码如下：

const memoInstruction = createMemoInstruction("Hello, world!", [keypair.publicKey]);

const transferInstruction = createTransferCheckedInstruction(
  tokenAccount,
  mint.publicKey,
  destinationTokenAccount.publicKey,
  keypair.publicKey,
  BigInt(100e6),
  6,
  undefined,
  TOKEN_2022_PROGRAM_ID,
);

const transferTransaction = new Transaction().add(memoInstruction, transferInstruction);

const transferSignature = await sendAndConfirmTransaction(connection, transferTransaction, [
  keypair,
]);

console.log(
  `Tokens transferred with memo! Check out your TX here: https://explorer.solana.com/tx/${transferSignature}?cluster=devnet`,
);

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Disabling and Enabling the Memo

如果我们不想强制要求转账必须附带备注，可以使用 memo_transfer_disable 函数来实现，具体如下：

const disableRequiredMemoTransfersInstruction = createDisableRequiredMemoTransfersInstruction(
  destinationTokenAccount,
  destinationKeypair.publicKey,
  undefined,
  TOKEN_2022_PROGRAM_ID,
);

const transferInstruction = createTransferCheckedInstruction(
  tokenAccount,
  mint.publicKey,
  destinationTokenAccount,
  keypair.publicKey,
  BigInt(100e6),
  6,
  undefined,
  TOKEN_2022_PROGRAM_ID,
);

const transaction = new Transaction().add(
  disableRequiredMemoTransfersInstruction,
  transferInstruction,
);

const signature = await sendAndConfirmTransaction(connection, transaction, [
  keypair,
  destinationKeypair,
]);

console.log(
  `Tokens transferred and account state changed! Check out your TX here: https://explorer.solana.com/tx/${signature}?cluster=devnet`,
);

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如需恢复强制备注要求，只需调用 enableRequiredMemoTransfers() 函数，示例如下：

const enableRequiredMemoTransfersInstruction = createEnableRequiredMemoTransfersInstruction(
  destinationTokenAccount,
  destinationKeypair.publicKey,
  undefined,
  TOKEN_2022_PROGRAM_ID,
);

const transferInstruction = createTransferCheckedInstruction(
  tokenAccount,
  mint.publicKey,
  destinationTokenAccount,
  keypair.publicKey,
  BigInt(100e6),
  6,
  undefined,
  TOKEN_2022_PROGRAM_ID,
);

const transaction = new Transaction().add(
  enableRequiredMemoTransfersInstruction,
  transferInstruction,
);

const signature = await sendAndConfirmTransaction(connection, transaction, [
  keypair,
  destinationKeypair,
]);

console.log(
  `Tokens transferred and account state changed! Check out your TX here: https://explorer.solana.com/tx/${signature}?cluster=devnet`,
);

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