Mint Close Authority 扩展

MintCloseAuthority 扩展是一个 Mint 扩展，允许权限方关闭并从当前供应量为 0 的 Mint 账户中取回租金。

此扩展对于清理未使用的铸币账户并回收用于支付账户租金豁免的 SOL 非常有用。只有在没有代币流通时，铸币账户才能被关闭。

初始化铸币账户

要在 Mint 账户上初始化 MintCloseAuthority 扩展，我们需要使用 initializeMintCloseAuthority() 函数。

以下是如何创建带有 Mint Close 扩展的铸币账户：

import {
    Keypair,
    SystemProgram,
    Transaction,
    sendAndConfirmTransaction,
} from '@solana/web3.js';
import {
    createInitializeMintInstruction,
    createInitializeMintCloseAuthorityInstruction,
    getMintLen,
    ExtensionType,
    TOKEN_2022_PROGRAM_ID,
} from '@solana/spl-token';
 
const mint = Keypair.generate();
 
// Calculate the size needed for a Mint account with Transfer Fee extension
const mintLen = getMintLen([ExtensionType.MintCloseAuthority]);
 
// Calculate minimum lamports required for rent exemption
const lamports = await connection.getMinimumBalanceForRentExemption(mintLen);
 
// Create the account with the correct size and owner
const createAccountInstruction = SystemProgram.createAccount({
    fromPubkey: keypair.publicKey,
    newAccountPubkey: mint.publicKey,
    space: mintLen,
    lamports,
    programId: TOKEN_2022_PROGRAM_ID,
});
 
// Initialize the Mint Close Authority extension
const initializeMintCloseAuthority = createInitializeMintCloseAuthorityInstruction(
    mint.publicKey,
    keypair.publicKey,
    TOKEN_2022_PROGRAM_ID,
);
 
// Initialize the mint itself
const initializeMintInstruction = createInitializeMintInstruction(
    mint.publicKey,
    6,
    keypair.publicKey,
    null,
    TOKEN_2022_PROGRAM_ID,
);
 
// Combine all instructions in the correct order
const transaction = new Transaction().add(
    createAccountInstruction,
    initializeMintCloseAuthority,
    initializeMintInstruction,
);
 
const signature = await sendAndConfirmTransaction(connection, transaction, [keypair, mint]);
 
console.log(`Mint created! Check out your TX here: https://explorer.solana.com/tx/${signature}?cluster=devnet`);

关闭铸币账户

如果 Mint 账户的供应量为零，CloseMint Authority 可以通过使用 closeAccount 指令来回收该账户的租金，如下所示：

const closeMintInstruction = createCloseAccountInstruction(
    mint.publicKey,
    keypair.publicKey,
    keypair.publicKey,
    [],
    TOKEN_2022_PROGRAM_ID,
);
 
const transaction = new Transaction().add(closeMintInstruction);
 
const signature = await sendAndConfirmTransaction(connection, transaction, [keypair], {skipPreflight: false});
 
console.log(`Mint closed! Check out your TX here: https://explorer.solana.com/tx/${signature}?cluster=devnet`);

使用 Web3.js 的 Token2022

Mint Close Authority 扩展

初始化铸币账户

关闭铸币账户