Escrevendo Programas

Como transferir SOL em um programa

Seu programa Solana pode transferir lamports de uma conta para outra sem 'invocar' o programa do Sistema. A regra fundamental é que seu programa pode transferir lamports de qualquer conta possuída pelo seu programa para qualquer outra conta.

A conta receptora não precisa ser uma conta possuída pelo seu programa.

/// Transfers lamports from one account (must be program owned)
/// to another account. The recipient can by any account
fn transfer_service_fee_lamports(
    from_account: &AccountInfo,
    to_account: &AccountInfo,
    amount_of_lamports: u64,
) -> ProgramResult {
    // Does the from account have enough lamports to transfer?
    if **from_account.try_borrow_lamports()? < amount_of_lamports {
        return Err(CustomError::InsufficientFundsForTransaction.into());
    }
    // Debit from_account and credit to_account
    **from_account.try_borrow_mut_lamports()? -= amount_of_lamports;
    **to_account.try_borrow_mut_lamports()? += amount_of_lamports;
    Ok(())
}

/// Primary function handler associated with instruction sent
/// to your program
fn instruction_handler(accounts: &[AccountInfo]) -> ProgramResult {
    // Get the 'from' and 'to' accounts
    let account_info_iter = &mut accounts.iter();
    let from_account = next_account_info(account_info_iter)?;
    let to_service_account = next_account_info(account_info_iter)?;

    // Extract a service 'fee' of 5 lamports for performing this instruction
    transfer_service_fee_lamports(from_account, to_service_account, 5u64)?;

    // Perform the primary instruction
    // ... etc.

    Ok(())
}

Como obter o relógio (clock) em um programa

Obter um relógio pode ser feito de duas maneiras:

Passando SYSVAR_CLOCK_PUBKEY em uma instrução
Acessando o relógio diretamente dentro de uma instrução

É bom saber os dois métodos, porque alguns programas legados ainda esperam que o SYSVAR_CLOCK_PUBKEY seja uma conta.

Passando o Relógio como uma conta dentro de uma instrução

Vamos criar uma instrução que recebe uma conta para inicializar e a chave pública do sysvar.

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use borsh::{BorshDeserialize, BorshSerialize};
use solana_program::{
    account_info::{next_account_info, AccountInfo},
    clock::Clock,
    entrypoint,
    entrypoint::ProgramResult,
    msg,
    pubkey::Pubkey,
    sysvar::Sysvar,
};

entrypoint!(process_instruction);

#[derive(BorshSerialize, BorshDeserialize, Debug)]
pub struct HelloState {
    is_initialized: bool,
}

// Accounts required
/// 1. [signer, writable] Payer
/// 2. [writable] Hello state account
/// 3. [] Clock sys var
pub fn process_instruction(
    _program_id: &Pubkey,
    accounts: &[AccountInfo],
    _instruction_data: &[u8],
) -> ProgramResult {
    let accounts_iter = &mut accounts.iter();
    // Payer account
    let _payer_account = next_account_info(accounts_iter)?;
    // Hello state account
    let hello_state_account = next_account_info(accounts_iter)?;
    // Clock sysvar
    let sysvar_clock_pubkey = next_account_info(accounts_iter)?;

    let mut hello_state = HelloState::try_from_slice(&hello_state_account.data.borrow())?;
    hello_state.is_initialized = true;
    hello_state.serialize(&mut &mut hello_state_account.data.borrow_mut()[..])?;
    msg!("Account initialized :)");

    // Type casting [AccountInfo] to [Clock]
    let clock = Clock::from_account_info(&sysvar_clock_pubkey)?;
    // Getting timestamp
    let current_timestamp = clock.unix_timestamp;
    msg!("Current Timestamp: {}", current_timestamp);

    Ok(())
}

Agora passamos o endereço público do sysvar do relógio por meio do cliente.

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

(async () => {
  const programId = new PublicKey(
    "77ezihTV6mTh2Uf3ggwbYF2NyGJJ5HHah1GrdowWJVD3"
  );

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

  // Airdropping 1 SOL
  const feePayer = Keypair.generate();
  await connection.confirmTransaction(
    await connection.requestAirdrop(feePayer.publicKey, LAMPORTS_PER_SOL)
  );

  // Hello state account
  const helloAccount = Keypair.generate();

  const accountSpace = 1; // because there exists just one boolean variable
  const rentRequired = await connection.getMinimumBalanceForRentExemption(
    accountSpace
  );

  // Allocating space for hello state account
  const allocateHelloAccountIx = SystemProgram.createAccount({
    fromPubkey: feePayer.publicKey,
    lamports: rentRequired,
    newAccountPubkey: helloAccount.publicKey,
    programId: programId,
    space: accountSpace,
  });

  // Passing Clock Sys Var
  const passClockIx = new TransactionInstruction({
    programId: programId,
    keys: [
      {
        isSigner: true,
        isWritable: true,
        pubkey: feePayer.publicKey,
      },
      {
        isSigner: false,
        isWritable: true,
        pubkey: helloAccount.publicKey,
      },
      {
        isSigner: false,
        isWritable: false,
        pubkey: SYSVAR_CLOCK_PUBKEY,
      },
    ],
  });

  const transaction = new Transaction();
  transaction.add(allocateHelloAccountIx, passClockIx);

  const txHash = await connection.sendTransaction(transaction, [
    feePayer,
    helloAccount,
  ]);

  console.log(`Transaction succeeded. TxHash: ${txHash}`);
})();

(async () => {
  const programId = new PublicKey(
    "77ezihTV6mTh2Uf3ggwbYF2NyGJJ5HHah1GrdowWJVD3"
  );

  // Passing Clock Sys Var
  const passClockIx = new TransactionInstruction({
    programId: programId,
    keys: [
      {
        isSigner: false,
        isWritable: true,
        pubkey: helloAccount.publicKey,
      },
      {
        is_signer: false,
        is_writable: false,
        pubkey: SYSVAR_CLOCK_PUBKEY,
      },
    ],
  });

  const transaction = new Transaction();
  transaction.add(passClockIx);

  const txHash = await connection.sendTransaction(transaction, [
    feePayer,
    helloAccount,
  ]);

  console.log(`Transaction succeeded. TxHash: ${txHash}`);
})();

Acessando o Relógio diretamente dentro de uma instrução

Vamos criar a mesma instrução, mas sem esperar o SYSVAR_CLOCK_PUBKEY do lado do cliente.

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use borsh::{BorshDeserialize, BorshSerialize};
use solana_program::{
    account_info::{next_account_info, AccountInfo},
    clock::Clock,
    entrypoint,
    entrypoint::ProgramResult,
    msg,
    pubkey::Pubkey,
    sysvar::Sysvar,
};

entrypoint!(process_instruction);

#[derive(BorshSerialize, BorshDeserialize, Debug)]
pub struct HelloState {
    is_initialized: bool,
}

// Accounts required
/// 1. [signer, writable] Payer
/// 2. [writable] Hello state account
pub fn process_instruction(
    _program_id: &Pubkey,
    accounts: &[AccountInfo],
    _instruction_data: &[u8],
) -> ProgramResult {
    let accounts_iter = &mut accounts.iter();
    // Payer account
    let _payer_account = next_account_info(accounts_iter)?;
    // Hello state account
    let hello_state_account = next_account_info(accounts_iter)?;

    // Getting clock directly
    let clock = Clock::get()?;

    let mut hello_state = HelloState::try_from_slice(&hello_state_account.data.borrow())?;
    hello_state.is_initialized = true;
    hello_state.serialize(&mut &mut hello_state_account.data.borrow_mut()[..])?;
    msg!("Account initialized :)");

    // Getting timestamp
    let current_timestamp = clock.unix_timestamp;
    msg!("Current Timestamp: {}", current_timestamp);

    Ok(())
}

A instrução do lado do cliente agora só precisa passar as contas de estado e de pagamento.

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

(async () => {
  const programId = new PublicKey(
    "4ZEdbCtb5UyCSiAMHV5eSHfyjq3QwbG3yXb6oHD7RYjk"
  );

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

  // Airdropping 1 SOL
  const feePayer = Keypair.generate();
  await connection.confirmTransaction(
    await connection.requestAirdrop(feePayer.publicKey, LAMPORTS_PER_SOL)
  );

  // Hello state account
  const helloAccount = Keypair.generate();

  const accountSpace = 1; // because there exists just one boolean variable
  const rentRequired = await connection.getMinimumBalanceForRentExemption(
    accountSpace
  );

  // Allocating space for hello state account
  const allocateHelloAccountIx = SystemProgram.createAccount({
    fromPubkey: feePayer.publicKey,
    lamports: rentRequired,
    newAccountPubkey: helloAccount.publicKey,
    programId: programId,
    space: accountSpace,
  });

  const initIx = new TransactionInstruction({
    programId: programId,
    keys: [
      {
        isSigner: true,
        isWritable: true,
        pubkey: feePayer.publicKey,
      },
      {
        isSigner: false,
        isWritable: true,
        pubkey: helloAccount.publicKey,
      },
    ],
  });

  const transaction = new Transaction();
  transaction.add(allocateHelloAccountIx, initIx);

  const txHash = await connection.sendTransaction(transaction, [
    feePayer,
    helloAccount,
  ]);

  console.log(`Transaction succeeded. TxHash: ${txHash}`);
})();

(async () => {
  const programId = new PublicKey(
    "4ZEdbCtb5UyCSiAMHV5eSHfyjq3QwbG3yXb6oHD7RYjk"
  );

  // No more requirement to pass clock sys var key
  const initAccountIx = new TransactionInstruction({
    programId: programId,
    keys: [
      {
        isSigner: false,
        isWritable: true,
        pubkey: helloAccount.publicKey,
      },
    ],
  });

  const transaction = new Transaction();
  transaction.add(initAccountIx);

  const txHash = await connection.sendTransaction(transaction, [
    feePayer,
    helloAccount,
  ]);

  console.log(`Transaction succeeded. TxHash: ${txHash}`);
})();

Como alterar o tamanho da conta

Você pode alterar o tamanho de uma conta de propriedade do programa usando a função realloc. realloc pode redimensionar uma conta de até 10KB. Quando você usa realloc para aumentar o tamanho de uma conta, deve transferir lamports para manter essa conta isenta de aluguel.

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use {
  crate::{
      instruction::WhitelistInstruction,
      state::WhiteListData,
  },
  borsh::{BorshDeserialize, BorshSerialize},
  solana_program::{
      account_info::{next_account_info, AccountInfo},
      entrypoint::ProgramResult,
      msg,
      program::invoke_signed,
      program::invoke,
      program_error::ProgramError,
      pubkey::Pubkey,
      sysvar::Sysvar,
      sysvar::rent::Rent,
      system_instruction,
  },
  std::convert::TryInto,
};

pub fn process_instruction(
  _program_id: &Pubkey,
  accounts: &[AccountInfo],
  input: &[u8],
) -> ProgramResult {
  // Length = BOOL + VEC + Pubkey * n (n = number of keys)
  const INITIAL_ACCOUNT_LEN: usize = 1 + 4 + 0 ;
  msg!("input: {:?}", input);

  let instruction = WhitelistInstruction::try_from_slice(input)?;

  let accounts_iter = &mut accounts.iter();

  let funding_account = next_account_info(accounts_iter)?;
  let pda_account = next_account_info(accounts_iter)?;
  let system_program = next_account_info(accounts_iter)?;

  match instruction {
    WhitelistInstruction::Initialize => {
      msg!("Initialize");

      let (pda, pda_bump) = Pubkey::find_program_address(
          &[
            b"customaddress",
            &funding_account.key.to_bytes(),
          ],
          _program_id,
      );

      let signers_seeds: &[&[u8]; 3] = &[
          b"customaddress",
          &funding_account.key.to_bytes(),
          &[pda_bump],
      ];
      
      if pda.ne(&pda_account.key) {
          return Err(ProgramError::InvalidAccountData);
      }

      let lamports_required = Rent::get()?.minimum_balance(INITIAL_ACCOUNT_LEN);
      let create_pda_account_ix = system_instruction::create_account(
          &funding_account.key,
          &pda_account.key,
          lamports_required,
          INITIAL_ACCOUNT_LEN.try_into().unwrap(),
          &_program_id,
      );

      invoke_signed(
          &create_pda_account_ix,
          &[
              funding_account.clone(),
              pda_account.clone(),
              system_program.clone(),
          ],
          &[signers_seeds],
      )?;
      
      let mut pda_account_state = WhiteListData::try_from_slice(&pda_account.data.borrow())?;

      pda_account_state.is_initialized = true;
      pda_account_state.white_list = Vec::new();
      pda_account_state.serialize(&mut &mut pda_account.data.borrow_mut()[..])?;
      Ok(())
    }
    WhitelistInstruction::AddKey { key } => {
      msg!("AddKey");

      let mut pda_account_state = WhiteListData::try_from_slice(&pda_account.data.borrow())?;
      
      if !pda_account_state.is_initialized {
          return Err(ProgramError::InvalidAccountData);
      }

      let new_size = pda_account.data.borrow().len() + 32;

      let rent = Rent::get()?;
      let new_minimum_balance = rent.minimum_balance(new_size);
      
      let lamports_diff = new_minimum_balance.saturating_sub(pda_account.lamports());
      invoke(
          &system_instruction::transfer(funding_account.key, pda_account.key, lamports_diff),
          &[
              funding_account.clone(),
              pda_account.clone(),
              system_program.clone(),
          ],
      )?;

      pda_account.realloc(new_size, false)?;

      pda_account_state.white_list.push(key);
      pda_account_state.serialize(&mut &mut pda_account.data.borrow_mut()[..])?;

      Ok(())
    }
  }
}

// adding a publickey to the account
let new_size = pda_account.data.borrow().len() + 32;

let rent = Rent::get()?;
let new_minimum_balance = rent.minimum_balance(new_size);

let lamports_diff = new_minimum_balance.saturating_sub(pda_account.lamports());
invoke(
    &system_instruction::transfer(funding_account.key, pda_account.key, lamports_diff),
    &[
        funding_account.clone(),
        pda_account.clone(),
        system_program.clone(),
    ],
)?;

pda_account.realloc(new_size, false)?;

Como fazer uma Invocação de Programas Cruzados

Uma invocação de programas cruzados, em poucas palavras, é chamar a instrução de outro programa dentro do nosso programa. Um dos melhores exemplos é a funcionalidade de swap, ou troca, da Uniswap. O contrato UniswapV2Router chama a lógica necessária para a troca e chama a função de transferência do contrato ERC20 para trocar de uma pessoa para outra. Da mesma forma, podemos chamar a instrução de um programa para ter uma infinidade de propósitos.

Vamos dar uma olhada em nosso primeiro exemplo, que é a instrução de transferência do programa de tokens SPL (SPL Token Program's transfer). As contas necessárias para que ocorra uma transferência são:

A conta de token de origem (a conta na qual estamos mantendo nossos tokens)
A conta de token de destino (a conta para a qual estaremos transferindo nossos tokens)
O titular da conta de token de origem (nosso endereço de carteira pelo qual estaríamos assinando)

Press </> button to view full source

use solana_program::{
    account_info::{next_account_info, AccountInfo},
    entrypoint,
    entrypoint::ProgramResult,
    msg,
    program::invoke,
    program_error::ProgramError,
    pubkey::Pubkey,
};
use spl_token::instruction::transfer;

entrypoint!(process_instruction);

// Accounts required
/// 1. [writable] Source Token Account
/// 2. [writable] Destination Token Account
/// 3. [signer] Source Token Account holder's PubKey
/// 4. [] Token Program
pub fn process_instruction(
    _program_id: &Pubkey,
    accounts: &[AccountInfo],
    instruction_data: &[u8],
) -> ProgramResult {
    let accounts_iter = &mut accounts.iter();

    // Accounts required for token transfer

    // 1. Token account we hold
    let source_token_account = next_account_info(accounts_iter)?;
    // 2. Token account to send to
    let destination_token_account = next_account_info(accounts_iter)?;
    // 3. Our wallet address
    let source_token_account_holder = next_account_info(accounts_iter)?;
    // 4. Token Program
    let token_program = next_account_info(accounts_iter)?;

    // Parsing the token transfer amount from instruction data
    // a. Getting the 0th to 8th index of the u8 byte array
    // b. Converting the obtained non zero u8 to a proper u8 (as little endian integers)
    // c. Converting the little endian integers to a u64 number
    let token_transfer_amount = instruction_data
        .get(..8)
        .and_then(|slice| slice.try_into().ok())
        .map(u64::from_le_bytes)
        .ok_or(ProgramError::InvalidAccountData)?;

    msg!(
        "Transferring {} tokens from {} to {}",
        token_transfer_amount,
        source_token_account.key.to_string(),
        destination_token_account.key.to_string()
    );

    // Creating a new TransactionInstruction
    /*
        Internal representation of the instruction's return value (Result<Instruction, ProgramError>)

        Ok(Instruction {
            program_id: *token_program_id, // PASSED FROM USER
            accounts,
            data,
        })
    */

    let transfer_tokens_instruction = transfer(
        &token_program.key,
        &source_token_account.key,
        &destination_token_account.key,
        &source_token_account_holder.key,
        &[&source_token_account_holder.key],
        token_transfer_amount,
    )?;

    let required_accounts_for_transfer = [
        source_token_account.clone(),
        destination_token_account.clone(),
        source_token_account_holder.clone(),
    ];

    // Passing the TransactionInstruction to send
    invoke(
        &transfer_tokens_instruction,
        &required_accounts_for_transfer,
    )?;

    msg!("Transfer successful");

    Ok(())
}

let token_transfer_amount = instruction_data
    .get(..8)
    .and_then(|slice| slice.try_into().ok())
    .map(u64::from_le_bytes)
    .ok_or(ProgramError::InvalidAccountData)?;

let transfer_tokens_instruction = transfer(
    &token_program.key,
    &source_token_account.key,
    &destination_token_account.key,
    &source_token_account_holder.key,
    &[&source_token_account_holder.key],
    token_transfer_amount,
)?;

let required_accounts_for_transfer = [
    source_token_account.clone(),
    destination_token_account.clone(),
    source_token_account_holder.clone(),
];

invoke(
    &transfer_tokens_instruction,
    &required_accounts_for_transfer,
)?;

A instrução do lado do cliente correspondente seria a seguinte. Para saber as instruções de cunhagem e criação de tokens, consulte o código completo nas proximidades.

Press </> button to view full source

import {
  clusterApiUrl,
  Connection,
  Keypair,
  LAMPORTS_PER_SOL,
  PublicKey,
  SystemProgram,
  Transaction,
  TransactionInstruction,
} from "@solana/web3.js";
import {
  AccountLayout,
  MintLayout,
  Token,
  TOKEN_PROGRAM_ID,
  u64,
} from "@solana/spl-token";

import * as BN from "bn.js";

// Users
const PAYER_KEYPAIR = Keypair.generate();
const RECEIVER_KEYPAIR = Keypair.generate().publicKey;

// Mint and token accounts
const TOKEN_MINT_ACCOUNT = Keypair.generate();
const SOURCE_TOKEN_ACCOUNT = Keypair.generate();
const DESTINATION_TOKEN_ACCOUNT = Keypair.generate();

// Numbers
const DEFAULT_DECIMALS_COUNT = 9;
const TOKEN_TRANSFER_AMOUNT = 50 * 10 ** DEFAULT_DECIMALS_COUNT;
const TOKEN_TRANSFER_AMOUNT_BUFFER = Buffer.from(
  Uint8Array.of(...new BN(TOKEN_TRANSFER_AMOUNT).toArray("le", 8))
);

(async () => {
  const connection = new Connection(clusterApiUrl("devnet"), "confirmed");
  const programId = new PublicKey(
    "EfYK91eN3AqTwY1C34W6a33qGAtQ8HJYVhNv7cV4uMZj"
  );

  const mintDataSpace = MintLayout.span;
  const mintRentRequired = await connection.getMinimumBalanceForRentExemption(
    mintDataSpace
  );

  const tokenDataSpace = AccountLayout.span;
  const tokenRentRequired = await connection.getMinimumBalanceForRentExemption(
    tokenDataSpace
  );

  // Airdropping some SOL
  await connection.confirmTransaction(
    await connection.requestAirdrop(PAYER_KEYPAIR.publicKey, LAMPORTS_PER_SOL)
  );

  // Allocating space and rent for mint account
  const createMintAccountIx = SystemProgram.createAccount({
    fromPubkey: PAYER_KEYPAIR.publicKey,
    lamports: mintRentRequired,
    newAccountPubkey: TOKEN_MINT_ACCOUNT.publicKey,
    programId: TOKEN_PROGRAM_ID,
    space: mintDataSpace,
  });

  // Initializing mint with decimals and authority
  const initializeMintIx = Token.createInitMintInstruction(
    TOKEN_PROGRAM_ID,
    TOKEN_MINT_ACCOUNT.publicKey,
    DEFAULT_DECIMALS_COUNT,
    PAYER_KEYPAIR.publicKey, // mintAuthority
    PAYER_KEYPAIR.publicKey // freezeAuthority
  );

  // Allocating space and rent for source token account
  const createSourceTokenAccountIx = SystemProgram.createAccount({
    fromPubkey: PAYER_KEYPAIR.publicKey,
    newAccountPubkey: SOURCE_TOKEN_ACCOUNT.publicKey,
    lamports: tokenRentRequired,
    programId: TOKEN_PROGRAM_ID,
    space: tokenDataSpace,
  });

  // Initializing token account with mint and owner
  const initializeSourceTokenAccountIx = Token.createInitAccountInstruction(
    TOKEN_PROGRAM_ID,
    TOKEN_MINT_ACCOUNT.publicKey,
    SOURCE_TOKEN_ACCOUNT.publicKey,
    PAYER_KEYPAIR.publicKey
  );

  // Minting tokens to the source token account for transferring later to destination account
  const mintTokensIx = Token.createMintToInstruction(
    TOKEN_PROGRAM_ID,
    TOKEN_MINT_ACCOUNT.publicKey,
    SOURCE_TOKEN_ACCOUNT.publicKey,
    PAYER_KEYPAIR.publicKey,
    [PAYER_KEYPAIR],
    TOKEN_TRANSFER_AMOUNT
  );

  // Allocating space and rent for destination token account
  const createDestinationTokenAccountIx = SystemProgram.createAccount({
    fromPubkey: PAYER_KEYPAIR.publicKey,
    newAccountPubkey: DESTINATION_TOKEN_ACCOUNT.publicKey,
    lamports: tokenRentRequired,
    programId: TOKEN_PROGRAM_ID,
    space: tokenDataSpace,
  });

  // Initializing token account with mint and owner
  const initializeDestinationTokenAccountIx =
    Token.createInitAccountInstruction(
      TOKEN_PROGRAM_ID,
      TOKEN_MINT_ACCOUNT.publicKey,
      DESTINATION_TOKEN_ACCOUNT.publicKey,
      RECEIVER_KEYPAIR
    );

  // Our program's CPI instruction (transfer)
  const transferTokensIx = new TransactionInstruction({
    programId: programId,
    data: TOKEN_TRANSFER_AMOUNT_BUFFER,
    keys: [
      {
        isSigner: false,
        isWritable: true,
        pubkey: SOURCE_TOKEN_ACCOUNT.publicKey,
      },
      {
        isSigner: false,
        isWritable: true,
        pubkey: DESTINATION_TOKEN_ACCOUNT.publicKey,
      },
      {
        isSigner: true,
        isWritable: true,
        pubkey: PAYER_KEYPAIR.publicKey,
      },
      {
        isSigner: false,
        isWritable: false,
        pubkey: TOKEN_PROGRAM_ID,
      },
    ],
  });

  const transaction = new Transaction();
  // Adding up all the above instructions
  transaction.add(
    createMintAccountIx,
    initializeMintIx,
    createSourceTokenAccountIx,
    initializeSourceTokenAccountIx,
    mintTokensIx,
    createDestinationTokenAccountIx,
    initializeDestinationTokenAccountIx,
    transferTokensIx
  );

  const txHash = await connection.sendTransaction(transaction, [
    PAYER_KEYPAIR,
    TOKEN_MINT_ACCOUNT,
    SOURCE_TOKEN_ACCOUNT,
    DESTINATION_TOKEN_ACCOUNT,
  ]);

  console.log(`Token transfer CPI success: ${txHash}`);
})();

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(async () => {
  const connection = new Connection(clusterApiUrl("devnet"), "confirmed");
  const programId = new PublicKey(
    "EfYK91eN3AqTwY1C34W6a33qGAtQ8HJYVhNv7cV4uMZj"
  );

  const transferTokensIx = new TransactionInstruction({
    programId: programId,
    data: TOKEN_TRANSFER_AMOUNT_BUFFER,
    keys: [
      {
        isSigner: false,
        isWritable: true,
        pubkey: SOURCE_TOKEN_ACCOUNT.publicKey,
      },
      {
        isSigner: false,
        isWritable: true,
        pubkey: DESTINATION_TOKEN_ACCOUNT.publicKey,
      },
      {
        isSigner: true,
        isWritable: true,
        pubkey: PAYER_KEYPAIR.publicKey,
      },
      {
        isSigner: false,
        isWritable: false,
        pubkey: TOKEN_PROGRAM_ID,
      },
    ],
  });

  const transaction = new Transaction();
  transaction.add(transferTokensIx);

  const txHash = await connection.sendTransaction(transaction, [
    PAYER_KEYPAIR,
    TOKEN_MINT_ACCOUNT,
    SOURCE_TOKEN_ACCOUNT,
    DESTINATION_TOKEN_ACCOUNT,
  ]);

  console.log(`Token transfer CPI success: ${txHash}`);
})();

Agora vamos dar uma olhada em outro exemplo, que é a instrução de criação de conta do programa do Sistema (System Program's create_account). Há uma pequena diferença entre a instrução mencionada acima e esta. Lá, nunca foi necessário passar o token_program como uma das contas dentro da função invoke. No entanto, há exceções em que você precisa passar o program_id da instrução invocadora. Em nosso caso, seria o program_id do programa do Sistema ("11111111111111111111111111111111"). Agora as contas necessárias serão:

A conta pagadora que financia o aluguel
A conta que vai ser criada
A conta do programa do Sistema

Press </> button to view full source

use solana_program::{
    account_info::{next_account_info, AccountInfo},
    entrypoint,
    entrypoint::ProgramResult,
    msg,
    program::invoke,
    program_error::ProgramError,
    pubkey::Pubkey,
    rent::Rent,
    system_instruction::create_account,
    sysvar::Sysvar,
};

entrypoint!(process_instruction);

// Accounts required
/// 1. [signer, writable] Payer Account
/// 2. [signer, writable] General State Account
/// 3. [] System Program
pub fn process_instruction(
    program_id: &Pubkey,
    accounts: &[AccountInfo],
    instruction_data: &[u8],
) -> ProgramResult {
    let accounts_iter = &mut accounts.iter();

    // Accounts required for token transfer

    // 1. Payer account for the state account creation
    let payer_account = next_account_info(accounts_iter)?;
    // 2. Token account we hold
    let general_state_account = next_account_info(accounts_iter)?;
    // 3. System Program
    let system_program = next_account_info(accounts_iter)?;

    msg!(
        "Creating account for {}",
        general_state_account.key.to_string()
    );

    // Parsing the token transfer amount from instruction data
    // a. Getting the 0th to 8th index of the u8 byte array
    // b. Converting the obtained non zero u8 to a proper u8 (as little endian integers)
    // c. Converting the little endian integers to a u64 number
    let account_span = instruction_data
        .get(..8)
        .and_then(|slice| slice.try_into().ok())
        .map(u64::from_le_bytes)
        .ok_or(ProgramError::InvalidAccountData)?;

    let lamports_required = (Rent::get()?).minimum_balance(account_span as usize);

    // Creating a new TransactionInstruction
    /*
        Internal representation of the instruction's return value (Instruction)

        Instruction::new_with_bincode(
            system_program::id(), // NOT PASSED FROM USER
            &SystemInstruction::CreateAccount {
                lamports,
                space,
                owner: *owner,
            },
            account_metas,
        )
    */

    let create_account_instruction = create_account(
        &payer_account.key,
        &general_state_account.key,
        lamports_required,
        account_span,
        program_id,
    );

    let required_accounts_for_create = [
        payer_account.clone(),
        general_state_account.clone(),
        system_program.clone(),
    ];

    // Passing the TransactionInstruction to send (with the issused program_id)
    invoke(&create_account_instruction, &required_accounts_for_create)?;

    msg!("Transfer successful");

    Ok(())
}

let account_span = instruction_data
    .get(..8)
    .and_then(|slice| slice.try_into().ok())
    .map(u64::from_le_bytes)
    .ok_or(ProgramError::InvalidAccountData)?;

let lamports_required = (Rent::get()?).minimum_balance(account_span as usize);

let create_account_instruction = create_account(
    &payer_account.key,
    &general_state_account.key,
    lamports_required,
    account_span,
    program_id,
);

let required_accounts_for_create = [
    payer_account.clone(),
    general_state_account.clone(),
    system_program.clone(),
];

invoke(&create_account_instruction, &required_accounts_for_create)?;

O código do lado do cliente correspondente ficará assim:

Press </> button to view full source

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

import * as BN from "bn.js";

// Users
const PAYER_KEYPAIR = Keypair.generate();
const GENERAL_STATE_KEYPAIR = Keypair.generate();

const ACCOUNT_SPACE_BUFFER = Buffer.from(
  Uint8Array.of(...new BN(100).toArray("le", 8))
);

(async () => {
  const connection = new Connection(clusterApiUrl("devnet"), "confirmed");
  const programId = new PublicKey(
    "DkuQ5wsndkzXfgqDB6Lgf4sDjBi4gkLSak1dM5Mn2RuQ"
  );

  // Airdropping some SOL
  await connection.confirmTransaction(
    await connection.requestAirdrop(PAYER_KEYPAIR.publicKey, LAMPORTS_PER_SOL)
  );

  // Our program's CPI instruction (create_account)
  const createAccountIx = new TransactionInstruction({
    programId: programId,
    data: ACCOUNT_SPACE_BUFFER,
    keys: [
      {
        isSigner: true,
        isWritable: true,
        pubkey: PAYER_KEYPAIR.publicKey,
      },
      {
        isSigner: true,
        isWritable: true,
        pubkey: GENERAL_STATE_KEYPAIR.publicKey,
      },
      {
        isSigner: false,
        isWritable: false,
        pubkey: SystemProgram.programId,
      },
    ],
  });

  const transaction = new Transaction();
  // Adding up all the above instructions
  transaction.add(createAccountIx);

  const txHash = await connection.sendTransaction(transaction, [
    PAYER_KEYPAIR,
    GENERAL_STATE_KEYPAIR,
  ]);

  console.log(`Create Account CPI Success: ${txHash}`);
})();

(async () => {
  const connection = new Connection(clusterApiUrl("devnet"), "confirmed");
  const programId = new PublicKey(
    "DkuQ5wsndkzXfgqDB6Lgf4sDjBi4gkLSak1dM5Mn2RuQ"
  );

  // Airdropping some SOL
  await connection.confirmTransaction(
    await connection.requestAirdrop(PAYER_KEYPAIR.publicKey, LAMPORTS_PER_SOL)
  );

  // Our program's CPI instruction (create_account)
  const creataAccountIx = new TransactionInstruction({
    programId: programId,
    data: ACCOUNT_SPACE_BUFFER,
    keys: [
      {
        isSigner: true,
        isWritable: true,
        pubkey: PAYER_KEYPAIR.publicKey,
      },
      {
        isSigner: true,
        isWritable: true,
        pubkey: GENERAL_STATE_KEYPAIR.publicKey,
      },
      {
        isSigner: false,
        isWritable: false,
        pubkey: SystemProgram.programId,
      },
    ],
  });

  const transaction = new Transaction();
  // Adding up all the above instructions
  transaction.add(creataAccountIx);

  const txHash = await connection.sendTransaction(transaction, [
    PAYER_KEYPAIR,
    GENERAL_STATE_KEYPAIR,
  ]);

  console.log(`Create Account CPI Success: ${txHash}`);
})();

Como criar um PDA

Um Endereço Derivado de Programa (PDA) é simplesmente uma conta de propriedade do programa, mas que não tem uma chave privada. Em vez disso, sua assinatura é obtida por um conjunto de sementes e um bump (um nonce que garante que ele está fora da curva). "Gerar" um endereço de programa é diferente de "criá-lo". Pode-se gerar um PDA usando Pubkey::find_program_address. Criar um PDA significa essencialmente inicializar o endereço com espaço e definir o estado para ele. Uma conta de par de chaves (Keypair) normal pode ser criada fora de nosso programa e depois alimentada para inicializar seu estado. Infelizmente, para os PDAs, isso deve ser criado na cadeia, devido à natureza de não poder assinar em nome de si mesmo. Portanto, usamos invoke_signed para passar as sementes do PDA, juntamente com a assinatura da conta de financiamento, o que resulta na criação de uma conta de PDA.

Press </> button to view full source

use borsh::{BorshDeserialize, BorshSerialize};
use solana_program::{
    account_info::{next_account_info, AccountInfo},
    entrypoint,
    entrypoint::ProgramResult,
    program::invoke_signed,
    program_error::ProgramError,
    pubkey::Pubkey,
    rent::Rent,
    system_instruction,
    sysvar::Sysvar,
};

entrypoint!(process_instruction);

#[derive(BorshSerialize, BorshDeserialize, Debug)]
pub struct HelloState {
    is_initialized: bool,
}

// Accounts required
/// 1. [signer, writable] Funding account
/// 2. [writable] PDA account
/// 3. [] System Program
pub fn process_instruction(
    program_id: &Pubkey,
    accounts: &[AccountInfo],
    instruction_data: &[u8],
) -> ProgramResult {
    const ACCOUNT_DATA_LEN: usize = 1;

    let accounts_iter = &mut accounts.iter();
    // Getting required accounts
    let funding_account = next_account_info(accounts_iter)?;
    let pda_account = next_account_info(accounts_iter)?;
    let system_program = next_account_info(accounts_iter)?;

    // Getting PDA Bump from instruction data
    let (pda_bump, _) = instruction_data
        .split_first()
        .ok_or(ProgramError::InvalidInstructionData)?;

    // Checking if passed PDA and expected PDA are equal
    let signers_seeds: &[&[u8]; 3] = &[
        b"customaddress",
        &funding_account.key.to_bytes(),
        &[*pda_bump],
    ];
    let pda = Pubkey::create_program_address(signers_seeds, program_id)?;

    if pda.ne(&pda_account.key) {
        return Err(ProgramError::InvalidAccountData);
    }

    // Assessing required lamports and creating transaction instruction
    let lamports_required = Rent::get()?.minimum_balance(ACCOUNT_DATA_LEN);
    let create_pda_account_ix = system_instruction::create_account(
        &funding_account.key,
        &pda_account.key,
        lamports_required,
        ACCOUNT_DATA_LEN.try_into().unwrap(),
        &program_id,
    );
    // Invoking the instruction but with PDAs as additional signer
    invoke_signed(
        &create_pda_account_ix,
        &[
            funding_account.clone(),
            pda_account.clone(),
            system_program.clone(),
        ],
        &[signers_seeds],
    )?;

    // Setting state for PDA
    let mut pda_account_state = HelloState::try_from_slice(&pda_account.data.borrow())?;
    pda_account_state.is_initialized = true;
    pda_account_state.serialize(&mut &mut pda_account.data.borrow_mut()[..])?;

    Ok(())
}

let create_pda_account_ix = system_instruction::create_account(
    &funding_account.key,
    &pda_account.key,
    lamports_required,
    ACCOUNT_DATA_LEN.try_into().unwrap(),
    &program_id,
);

invoke_signed(
    &create_pda_account_ix,
    &[funding_account.clone(), pda_account.clone()],
    &[signers_seeds],
)?;

Podemos enviar as contas necessárias por meio do cliente da seguinte forma:

Press </> button to view full source

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

const PAYER_KEYPAIR = Keypair.generate();

(async () => {
  const connection = new Connection(clusterApiUrl("devnet"), "confirmed");
  const programId = new PublicKey(
    "6eW5nnSosr2LpkUGCdznsjRGDhVb26tLmiM1P8RV1QQp"
  );

  // Airdop to Payer
  await connection.confirmTransaction(
    await connection.requestAirdrop(PAYER_KEYPAIR.publicKey, LAMPORTS_PER_SOL)
  );

  const [pda, bump] = await PublicKey.findProgramAddress(
    [Buffer.from("customaddress"), PAYER_KEYPAIR.publicKey.toBuffer()],
    programId
  );

  console.log(`PDA Pubkey: ${pda.toString()}`);

  const createPDAIx = new TransactionInstruction({
    programId: programId,
    data: Buffer.from(Uint8Array.of(bump)),
    keys: [
      {
        isSigner: true,
        isWritable: true,
        pubkey: PAYER_KEYPAIR.publicKey,
      },
      {
        isSigner: false,
        isWritable: true,
        pubkey: pda,
      },
      {
        isSigner: false,
        isWritable: false,
        pubkey: SystemProgram.programId,
      },
    ],
  });

  const transaction = new Transaction();
  transaction.add(createPDAIx);

  const txHash = await connection.sendTransaction(transaction, [PAYER_KEYPAIR]);
  console.log(`Created PDA successfully. Tx Hash: ${txHash}`);
})();

const PAYER_KEYPAIR = Keypair.generate();

(async () => {
  const connection = new Connection(clusterApiUrl("devnet"), "confirmed");
  const programId = new PublicKey(
    "6eW5nnSosr2LpkUGCdznsjRGDhVb26tLmiM1P8RV1QQp"
  );

  const [pda, bump] = await PublicKey.findProgramAddress(
    [Buffer.from("customaddress"), PAYER_KEYPAIR.publicKey.toBuffer()],
    programId
  );

  const createPDAIx = new TransactionInstruction({
    programId: programId,
    data: Buffer.from(Uint8Array.of(bump)),
    keys: [
      {
        isSigner: true,
        isWritable: true,
        pubkey: PAYER_KEYPAIR.publicKey,
      },
      {
        isSigner: false,
        isWritable: true,
        pubkey: pda,
      },
      {
        isSigner: false,
        isWritable: false,
        pubkey: SystemProgram.programId,
      },
    ],
  });

  const transaction = new Transaction();
  transaction.add(createPDAIx);

  const txHash = await connection.sendTransaction(transaction, [PAYER_KEYPAIR]);
})();

Como ler contas

Quase todas as instruções na Solana exigem pelo menos 2 a 3 contas, e elas são mencionadas nos manipuladores de instruções sobre em que ordem a instrução espera aquele conjunto de contas. É bem simples se aproveitarmos o método iter() do Rust, em vez de indicar manualmente as contas. O método next_account_info basicamente corta o primeiro índice do iterável e retorna a conta presente dentro do array de contas. Vamos ver uma instrução simples que espera um conjunto de contas e exige que cada uma delas seja analisada.

Press </> button to view full source

use borsh::{BorshDeserialize, BorshSerialize};
use solana_program::{
    account_info::{next_account_info, AccountInfo},
    entrypoint,
    entrypoint::ProgramResult,
    pubkey::Pubkey,
};

entrypoint!(process_instruction);

#[derive(BorshSerialize, BorshDeserialize, Debug)]
pub struct HelloState {
    is_initialized: bool,
}

// Accounts required
/// 1. [signer] Payer
/// 2. [writable] Hello state account
/// 3. [] Rent account
/// 4. [] System Program
pub fn process_instruction(
    _program_id: &Pubkey,
    accounts: &[AccountInfo],
    _instruction_data: &[u8],
) -> ProgramResult {
    // Fetching all the accounts as a iterator (facilitating for loops and iterations)
    let accounts_iter = &mut accounts.iter();
    // Payer account
    let payer_account = next_account_info(accounts_iter)?;
    // Hello state account
    let hello_state_account = next_account_info(accounts_iter)?;
    // Rent account
    let rent_account = next_account_info(accounts_iter)?;
    // System Program
    let system_program = next_account_info(accounts_iter)?;

    Ok(())
}

pub fn process_instruction(
    _program_id: &Pubkey,
    accounts: &[AccountInfo],
    _instruction_data: &[u8],
) -> ProgramResult {
    // Fetching all the accounts as a iterator (facilitating for loops and iterations)
    let accounts_iter = &mut accounts.iter();
    // Payer account
    let payer_account = next_account_info(accounts_iter)?;
    // Hello state account
    let hello_state_account = next_account_info(accounts_iter)?;
    // Rent account
    let rent_account = next_account_info(accounts_iter)?;
    // System Program
    let system_program = next_account_info(accounts_iter)?;

    Ok(())
}

Como verificar contas

Como os programas na Solana são sem estado, nós, como criadores de programas, temos que garantir que as contas passadas sejam validadas o máximo possível para evitar qualquer entrada maliciosa na conta. As verificações básicas que podemos fazer são:

Verificar se a conta do signatário esperado realmente assinou
Verificar se as contas de estado esperadas foram verificadas como graváveis
Verificar se o proprietário das contas de estado esperadas é o ID do programa chamado
Se estiver inicializando o estado pela primeira vez, verifique se a conta já foi inicializada ou não
Verificar se os IDs de programa cruzados passados (sempre que necessário) estão como esperado

Uma instrução básica que inicializa uma conta de estado "herói" (hero state account), mas com as verificações mencionadas acima, é definida abaixo:

Press </> button to view full source

use borsh::{BorshDeserialize, BorshSerialize};
use solana_program::{
    account_info::{next_account_info, AccountInfo},
    clock::Clock,
    entrypoint,
    entrypoint::ProgramResult,
    msg,
    program_error::ProgramError,
    pubkey::Pubkey,
    rent::Rent,
    system_program::ID as SYSTEM_PROGRAM_ID,
    sysvar::Sysvar,
};

entrypoint!(process_instruction);

#[derive(BorshSerialize, BorshDeserialize, Debug)]
pub struct HelloState {
    is_initialized: bool,
}

// Accounts required
/// 1. [signer] Payer
/// 2. [writable] Hello state account
/// 3. [] System Program
pub fn process_instruction(
    program_id: &Pubkey,
    accounts: &[AccountInfo],
    _instruction_data: &[u8],
) -> ProgramResult {
    let accounts_iter = &mut accounts.iter();
    // Payer account
    let payer_account = next_account_info(accounts_iter)?;
    // Hello state account
    let hello_state_account = next_account_info(accounts_iter)?;
    // System Program
    let system_program = next_account_info(accounts_iter)?;

    let rent = Rent::get()?;

    // Checking if payer account is the signer
    if !payer_account.is_signer {
        return Err(ProgramError::MissingRequiredSignature);
    }

    // Checking if hello state account is rent exempt
    if !rent.is_exempt(hello_state_account.lamports(), 1) {
        return Err(ProgramError::AccountNotRentExempt);
    }

    // Checking if hello state account is writable
    if !hello_state_account.is_writable {
        return Err(ProgramError::InvalidAccountData);
    }

    // Checking if hello state account's owner is the current program
    if hello_state_account.owner.ne(&program_id) {
        return Err(ProgramError::IllegalOwner);
    }

    // Checking if the system program is valid
    if system_program.key.ne(&SYSTEM_PROGRAM_ID) {
        return Err(ProgramError::IncorrectProgramId);
    }

    let mut hello_state = HelloState::try_from_slice(&hello_state_account.data.borrow())?;

    // Checking if the state has already been initialized
    if hello_state.is_initialized {
        return Err(ProgramError::AccountAlreadyInitialized);
    }

    hello_state.is_initialized = true;
    hello_state.serialize(&mut &mut hello_state_account.data.borrow_mut()[..])?;
    msg!("Account initialized :)");

    Ok(())
}

pub fn process_instruction(
    program_id: &Pubkey,
    accounts: &[AccountInfo],
    _instruction_data: &[u8],
) -> ProgramResult {
    let accounts_iter = &mut accounts.iter();
    let payer_account = next_account_info(accounts_iter)?;
    let hello_state_account = next_account_info(accounts_iter)?;
    let system_program = next_account_info(accounts_iter)?;

    let rent = Rent::get()?;

    // Checking if payer account is the signer
    if !payer_account.is_signer {
        return Err(ProgramError::MissingRequiredSignature);
    }

    // Checking if hello state account is rent exempt
    if !rent.is_exempt(hello_state_account.lamports(), 1) {
        return Err(ProgramError::AccountNotRentExempt);
    }

    // Checking if hello state account is writable
    if !hello_state_account.is_writable {
        return Err(ProgramError::InvalidAccountData);
    }

    // Checking if hello state account's owner is the current program
    if hello_state_account.owner.ne(&program_id) {
        return Err(ProgramError::IllegalOwner);
    }

    // Checking if the system program is valid
    if system_program.key.ne(&SYSTEM_PROGRAM_ID) {
        return Err(ProgramError::IncorrectProgramId);
    }

    let mut hello_state = HelloState::try_from_slice(&hello_state_account.data.borrow())?;

    // Checking if the state has already been initialized
    if hello_state.is_initialized {
        return Err(ProgramError::AccountAlreadyInitialized);
    }

    hello_state.is_initialized = true;
    hello_state.serialize(&mut &mut hello_state_account.data.borrow_mut()[..])?;
    msg!("Account initialized :)");

    Ok(())
}

Como ler várias instruções de uma transação

A Solana nos permite verificar todas as instruções na transação atual. Podemos armazená-las em uma variável e iterar sobre elas. Podemos fazer muitas coisas com isso, como verificar transações suspeitas.

Press </> button to view full source

use anchor_lang::{
    prelude::*,
    solana_program::{
        sysvar,
        serialize_utils::{read_pubkey,read_u16}
    }
};


declare_id!("8DJXJRV8DBFjJDYyU9cTHBVK1F1CTCi6JUBDVfyBxqsT");

#[program]
pub mod cookbook {
    use super::*;

    pub fn read_multiple_instruction<'info>(ctx: Context<ReadMultipleInstruction>, creator_bump: u8) -> Result<()> {
        let instruction_sysvar_account = &ctx.accounts.instruction_sysvar_account;

        let instruction_sysvar_account_info = instruction_sysvar_account.to_account_info();

        let id = "8DJXJRV8DBFjJDYyU9cTHBVK1F1CTCi6JUBDVfyBxqsT";

        let instruction_sysvar = instruction_sysvar_account_info.data.borrow();

        let mut idx = 0;

        let num_instructions = read_u16(&mut idx, &instruction_sysvar)
        .map_err(|_| MyError::NoInstructionFound)?;

        for index in 0..num_instructions {
            let mut current = 2 + (index * 2) as usize;
            let start = read_u16(&mut current, &instruction_sysvar).unwrap();

            current = start as usize;
            let num_accounts = read_u16(&mut current, &instruction_sysvar).unwrap();
            current += (num_accounts as usize) * (1 + 32);
            let program_id = read_pubkey(&mut current, &instruction_sysvar).unwrap();

            if program_id != id
            {
                msg!("Transaction had ix with program id {}", program_id);
                return Err(MyError::SuspiciousTransaction.into());
            }
        }

        Ok(())
    }

}

#[derive(Accounts)]
#[instruction(creator_bump:u8)]
pub struct ReadMultipleInstruction<'info> {
    #[account(address = sysvar::instructions::id())]
    instruction_sysvar_account: UncheckedAccount<'info>
}

#[error_code]
pub enum MyError {
    #[msg("No instructions found")]
    NoInstructionFound,
    #[msg("Suspicious transaction detected")]
    SuspiciousTransaction
}

let mut idx = 0;
let num_instructions = read_u16(&mut idx, &instruction_sysvar)
.map_err(|_| MyError::NoInstructionFound)?;


for index in 0..num_instructions {
    
    let mut current = 2 + (index * 2) as usize;
    let start = read_u16(&mut current, &instruction_sysvar).unwrap();

    current = start as usize;
    let num_accounts = read_u16(&mut current, &instruction_sysvar).unwrap();
    current += (num_accounts as usize) * (1 + 32);

}

# Escrevendo Programas

# Como transferir SOL em um programa

# Como obter o relógio (clock) em um programa

# Passando o Relógio como uma conta dentro de uma instrução

# Acessando o Relógio diretamente dentro de uma instrução

# Como alterar o tamanho da conta

# Como fazer uma Invocação de Programas Cruzados

# Como criar um PDA

# Como ler contas

# Como verificar contas

# Como ler várias instruções de uma transação

Escrevendo Programas

Como transferir SOL em um programa

Como obter o relógio (clock) em um programa

Passando o Relógio como uma conta dentro de uma instrução

Acessando o Relógio diretamente dentro de uma instrução

Como alterar o tamanho da conta

Como fazer uma Invocação de Programas Cruzados

Como criar um PDA

Como ler contas

Como verificar contas

Como ler várias instruções de uma transação