Documentação SolanaTokens na SolanaExtensões

Tokens com rendimento de juros

Como habilitar o InterestBearingExtension

O InterestBearingMintExtension permite definir uma taxa de juros diretamente em uma mint account. Os juros são continuamente compostos com base no timestamp da rede, mas o saldo real do token armazenado em cada token account permanece inalterado. O valor total (saldo do token mais juros acumulados) é apenas um cálculo. Nenhum novo token é criado com esta extensão.

Typescript

import { getCreateAccountInstruction } from "@solana-program/system";

import {

  extension,

  getInitializeAccountInstruction,

  getInitializeMintInstruction,

  getInitializeInterestBearingMintInstruction,

  getMintSize,

  getTokenSize,

  TOKEN_2022_PROGRAM_ADDRESS

} from "@solana-program/token-2022";

import {

  airdropFactory,

  appendTransactionMessageInstructions,

  createSolanaRpc,

  createSolanaRpcSubscriptions,

  createTransactionMessage,

  generateKeyPairSigner,

  getSignatureFromTransaction,

  lamports,

  pipe,

  sendAndConfirmTransactionFactory,

  setTransactionMessageFeePayerSigner,

  setTransactionMessageLifetimeUsingBlockhash,

  signTransactionMessageWithSigners

} from "@solana/kit";



// Create Connection, local validator in this example

const rpc = createSolanaRpc("http://localhost:8899");

const rpcSubscriptions = createSolanaRpcSubscriptions("ws://localhost:8900");



// Generate the authority for the mint (also acts as fee payer)

const authority = await generateKeyPairSigner();



// Fund authority/fee payer

await airdropFactory({ rpc, rpcSubscriptions })({

  recipientAddress: authority.address,

  lamports: lamports(5_000_000_000n), // 5 SOL

  commitment: "confirmed"

});



// Generate keypair to use as address of mint

const mint = await generateKeyPairSigner();



// Define the interest bearing config extension

const interestRate = {

  rate: 500 // 5.00% annualized interest (in basis points)

};



// config for interest bearing extension

const interestBearingMintExtension = extension("InterestBearingConfig", {

  rateAuthority: authority.address,

  initializationTimestamp: BigInt(Math.floor(new Date().getTime() / 1000)),

  lastUpdateTimestamp: BigInt(Math.floor(new Date().getTime() / 1000)),

  preUpdateAverageRate: interestRate.rate,

  currentRate: interestRate.rate

});



// Get mint account size with interest bearing extension

const space = BigInt(getMintSize([interestBearingMintExtension]));



// Get minimum balance for rent exemption

const rent = await rpc.getMinimumBalanceForRentExemption(space).send();



// Get latest blockhash to include in transaction

const { value: latestBlockhash } = await rpc.getLatestBlockhash().send();



// Instruction to create new account for mint (token program)

// Invokes the system program

const createMintAccountInstruction = getCreateAccountInstruction({

  payer: authority,

  newAccount: mint,

  lamports: rent,

  space,

  programAddress: TOKEN_2022_PROGRAM_ADDRESS

});



// Instruction to initialize interest bearing config extension

const initializeInterestBearingConfigInstruction =

  getInitializeInterestBearingMintInstruction({

    mint: mint.address,

    rateAuthority: authority.address,

    rate: interestRate.rate // in basis points

  });



// Instruction to initialize mint account data

// Invokes the token22 program

const initializeMintInstruction = getInitializeMintInstruction({

  mint: mint.address,

  decimals: 6,

  mintAuthority: authority.address,

  freezeAuthority: authority.address

});



// Generate keypair to use as address of token account

const tokenAccount = await generateKeyPairSigner();



// get token account size (with extension awareness)

const tokenAccountLen = BigInt(getTokenSize());



// Get minimum balance for rent exemption

const tokenAccountRent = await rpc

  .getMinimumBalanceForRentExemption(tokenAccountLen)

  .send();



// Instruction to create new account for the token account

// Invokes the system program

const createTokenAccountInstruction = getCreateAccountInstruction({

  payer: authority,

  newAccount: tokenAccount,

  lamports: tokenAccountRent,

  space: tokenAccountLen,

  programAddress: TOKEN_2022_PROGRAM_ADDRESS

});



// Instruction to initialize the created token account

const initializeTokenAccountInstruction = getInitializeAccountInstruction({

  account: tokenAccount.address,

  mint: mint.address,

  owner: authority.address

});



console.log("token account", tokenAccount.address); // ! debug



const instructions = [

  createMintAccountInstruction,

  initializeInterestBearingConfigInstruction,

  initializeMintInstruction,

  createTokenAccountInstruction,

  initializeTokenAccountInstruction

];



// Create transaction message

const transactionMessage = pipe(

  createTransactionMessage({ version: 0 }),

  (tx) => setTransactionMessageFeePayerSigner(authority, tx),

  (tx) => setTransactionMessageLifetimeUsingBlockhash(latestBlockhash, tx),

  (tx) => appendTransactionMessageInstructions(instructions, tx)

);



// Sign transaction message with all required signers

const signedTransaction =

  await signTransactionMessageWithSigners(transactionMessage);



// Send and confirm transaction

await sendAndConfirmTransactionFactory({ rpc, rpcSubscriptions })(

  signedTransaction,

  { commitment: "confirmed", skipPreflight: true }

);



// Get transaction signature

const transactionSignature = getSignatureFromTransaction(signedTransaction);



console.log(

  "Mint Address with Interest Bearing Extension:",

  mint.address.toString()

);

console.log("Token Account:", tokenAccount.address.toString());

console.log("Interest Rate: 5% APY (500 basis points)");

console.log("Rate Authority:", authority.address.toString());

console.log("Transaction Signature:", transactionSignature);
Console
Click to execute the code.

Rust

Rust
use anyhow::Result;

use solana_client::nonblocking::rpc_client::RpcClient;

use solana_commitment_config::CommitmentConfig;

use solana_sdk::{

    signature::{Keypair, Signer},

    transaction::Transaction,

};

use solana_system_interface::instruction::create_account;

use spl_token_2022_interface::{

    extension::{

        interest_bearing_mint::{

            instruction::initialize as initialize_interest_bearing_instruction,

            InterestBearingConfig,

        },

        BaseStateWithExtensions, ExtensionType, StateWithExtensions,

    },

    instruction::initialize_mint,

    state::Mint,

    ID as TOKEN_2022_PROGRAM_ID,

};



#[tokio::main]

async fn main() -> Result<()> {

    // Create connection to local validator

    let client = RpcClient::new_with_commitment(

        String::from("http://localhost:8899"),

        CommitmentConfig::confirmed(),

    );

    let latest_blockhash = client.get_latest_blockhash().await?;



    // Generate a new keypair for the fee payer

    let fee_payer = Keypair::new();



    // Airdrop 5 SOL to fee payer

    let airdrop_signature = client

        .request_airdrop(&fee_payer.pubkey(), 5_000_000_000)

        .await?;



    loop {

        let confirmed = client.confirm_transaction(&airdrop_signature).await?;

        if confirmed {

            break;

        }

    }



    // Generate keypair to use as address of mint

    let mint = Keypair::new();



    // Calculate mint account size with interest bearing extension

    let mint_space =

        ExtensionType::try_calculate_account_len::<Mint>(&[ExtensionType::InterestBearingConfig])?;



    let mint_rent = client

        .get_minimum_balance_for_rent_exemption(mint_space)

        .await?;



    // Instruction to create new account for mint (token22)

    let create_mint_account_instruction = create_account(

        &fee_payer.pubkey(),    // payer

        &mint.pubkey(),         // new account (mint)

        mint_rent,              // lamports

        mint_space as u64,      // space

        &TOKEN_2022_PROGRAM_ID, // program id

    );



    // Instruction to initialize interest bearing extension (5% APY)

    let initialize_interest_bearing_instruction = initialize_interest_bearing_instruction(

        &TOKEN_2022_PROGRAM_ID,

        &mint.pubkey(),

        Some(fee_payer.pubkey()), // rate authority

        500,                      // interest rate (basis points) = 5%

    )?;



    // Instruction to initialize mint account data

    let initialize_mint_instruction = initialize_mint(

        &TOKEN_2022_PROGRAM_ID,    // program id

        &mint.pubkey(),            // mint

        &fee_payer.pubkey(),       // mint authority

        Some(&fee_payer.pubkey()), // freeze authority

        9,                         // decimals

    )?;



    // Construct transaction with interest bearing mint extension

    let transaction = Transaction::new_signed_with_payer(

        &[

            create_mint_account_instruction,

            initialize_interest_bearing_instruction,

            initialize_mint_instruction,

        ],

        Some(&fee_payer.pubkey()),

        &[&fee_payer, &mint],

        latest_blockhash,

    );



    // Send and confirm transaction

    client.send_and_confirm_transaction(&transaction).await?;



    println!("Mint Address: {}", mint.pubkey());

    // Fetch mint account

    let mint_account = client.get_account(&mint.pubkey()).await?;

    // Deserialize the mint account with extensions

    let mint_state = StateWithExtensions::<Mint>::unpack(&mint_account.data)?;



    // Get all extension types enabled on this mint

    let mint_extension_types = mint_state.get_extension_types()?;

    println!("\nMint extensions enabled: {:?}", mint_extension_types);



    // Deserialize the InterestBearingConfig extension data

    let interest_bearing_config = mint_state.get_extension::<InterestBearingConfig>()?;

    println!("\n{:#?}", interest_bearing_config);



    Ok(())

}
Console
Click to execute the code.

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