@solana/transaction-messages

@solana/transaction-messages

This package contains types and functions for creating transaction messages. It can be used standalone, but it is also exported as part of the Solana JavaScript SDK @solana/web3.js@rc.

Transaction messages are built one step at a time using the transform functions offered by this package. To make it more ergonomic to apply consecutive transforms to your transaction messages, consider using a pipelining helper like the one in @solana/functional.

import { pipe } from '@solana/functional';
import {
    appendTransactionMessageInstruction,
    createTransactionMessage,
    setTransactionMessageFeePayer,
    setTransactionMessageLifetimeUsingBlockhash,
} from '@solana/transaction-messages';

const transferTransaction = pipe(
    createTransactionMessage({ version: 0 }),
    tx => setTransactionMessageFeePayer(myAddress, tx),
    tx => setTransactionMessageLifetimeUsingBlockhash(latestBlockhash, tx),
    tx => appendTransactionMessageInstruction(createTransferInstruction(myAddress, toAddress, amountInLamports), tx),
);

Creating transaction messages

Types

TransactionVersion

As Solana transactions acquire more capabilities their version will advance. This type is a union of all possible transaction versions.

Functions

createTransactionMessage()

Given a TransactionVersion this method will return an empty transaction having the capabilities of that version.

import { createTransactionMessage } from '@solana/transaction-messages';

const tx = createTransactionMessage({ version: 0 });

Setting the fee payer

Types

ITransactionMessageWithFeePayer

This type represents a transaction message for which a fee payer has been declared. A transaction must conform to this type to be compiled and landed on the network.

Functions

setTransactionMessageFeePayer()

Given a base58-encoded address of a system account, this method will return a new transaction message having the same type as the one supplied plus the ITransactionMessageWithFeePayer type.

import { address } from '@solana/addresses';
import { setTransactionMessageFeePayer } from '@solana/transaction-messages';

const myAddress = address('mpngsFd4tmbUfzDYJayjKZwZcaR7aWb2793J6grLsGu');
const txPaidByMe = setTransactionMessageFeePayer(myAddress, tx);

Defining a transaction message's lifetime

A signed transaction can be only be landed on the network if certain conditions are met:

• It includes the hash of a recent block
• Or it includes the value of an unused nonce known to the network

These conditions define a transaction's lifetime, after which it can no longer be landed, even if signed. The lifetime must be added to the transaction message before it is compiled to be sent.

Types

TransactionMessageWithBlockhashLifetime

This type represents a transaction message whose lifetime is defined by the age of the blockhash it includes. Such a transaction can only be landed on the network if the current block height of the network is less than or equal to the value of TransactionMessageWithBlockhashLifetime['lifetimeConstraint']['lastValidBlockHeight'].

TransactionMessageWithDurableNonceLifetime

This type represents a transaction message whose lifetime is defined by the value of a nonce it includes. Such a transaction can only be landed on the network if the nonce is known to the network and has not already been used to land a different transaction.

Blockhash

This type represents a string that is particularly known to be the base58-encoded value of a block.

Nonce

This type represents a string that is particularly known to be the base58-encoded value of a nonce.

Functions

setTransactionMessageLifetimeUsingBlockhash()

Given a blockhash and the last block height at which that blockhash is considered usable to land transactions, this method will return a new transaction message having the same type as the one supplied plus the TransactionMessageWithBlockhashLifetime type.

import { setTransactionMessageLifetimeUsingBlockhash } from '@solana/transaction-messages';

const { value: latestBlockhash } = await rpc.getLatestBlockhash().send();
const txWithBlockhashLifetime = setTransactionMessageLifetimeUsingBlockhash(latestBlockhash, tx);

setTransactionMessageLifetimeUsingDurableNonce()

Given a nonce, the account where the value of the nonce is stored, and the address of the account authorized to consume that nonce, this method will return a new transaction having the same type as the one supplied plus the TransactionMessageWithDurableNonceLifetime type. In particular, this method prepends an instruction to the transaction message designed to consume (or ‘advance’) the nonce in the same transaction whose lifetime is defined by it.

import { setTransactionMessageLifetimeUsingDurableNonce } from '@solana/transactions';

const NONCE_VALUE_OFFSET =
    4 + // version(u32)
    4 + // state(u32)
    32; // nonce authority(pubkey)
// Then comes the nonce value.

const nonceAccountAddress = address('EGtMh4yvXswwHhwVhyPxGrVV2TkLTgUqGodbATEPvojZ');
const nonceAuthorityAddress = address('4KD1Rdrd89NG7XbzW3xsX9Aqnx2EExJvExiNme6g9iAT');
const { value: nonceAccount } = await rpc
    .getAccountInfo(nonceAccountAddress, {
        dataSlice: { length: 32, offset: NONCE_VALUE_OFFSET },
        encoding: 'base58',
    })
    .send();
const nonce =
    // This works because we asked for the exact slice of data representing the nonce
    // value, and furthermore asked for it in `base58` encoding.
    nonceAccount!.data[0] as unknown as Nonce;

const durableNonceTransactionMessage = setTransactionMessageLifetimeUsingDurableNonce(
    { nonce, nonceAccountAddress, nonceAuthorityAddress },
    tx,
);

assertIsBlockhash()

Client applications primarily deal with blockhashes in the form of base58-encoded strings. Blockhashes returned from the RPC API conform to the type Blockhash. You can use a value of that type wherever a blockhash is expected.

From time to time you might acquire a string, that you expect to validate as a blockhash, from an untrusted network API or user input. To assert that such an arbitrary string is a base58-encoded blockhash, use the assertIsBlockhash function.

import { assertIsBlockhash } from '@solana/transaction-messages';

// Imagine a function that asserts whether a user-supplied blockhash is valid or not.
function handleSubmit() {
    // We know only that what the user typed conforms to the `string` type.
    const blockhash: string = blockhashInput.value;
    try {
        // If this type assertion function doesn't throw, then
        // Typescript will upcast `blockhash` to `Blockhash`.
        assertIsBlockhash(blockhash);
        // At this point, `blockhash` is a `Blockhash` that can be used with the RPC.
        const blockhashIsValid = await rpc.isBlockhashValid(blockhash).send();
    } catch (e) {
        // `blockhash` turned out not to be a base58-encoded blockhash
    }
}

assertIsDurableNonceTransactionMessage()

From time to time you might acquire a transaction message that you expect to be a durable nonce transaction, from an untrusted network API or user input. To assert that such an arbitrary transaction is in fact a durable nonce transaction, use the assertIsDurableNonceTransactionMessage function.

See assertIsBlockhash() for an example of how to use an assertion function.

Adding instructions to a transaction message

Types

IInstruction

This type represents an instruction to be issued to a program. Objects that conform to this type have a programAddress property that is the base58-encoded address of the program in question.

IInstructionWithAccounts

This type represents an instruction that specifies a list of accounts that a program may read from, write to, or require be signers of the transaction itself. Objects that conform to this type have an accounts property that is an array of IAccountMeta | IAccountLookupMeta in the order the instruction requires.

IInstructionWithData

This type represents an instruction that supplies some data as input to the program. Objects that conform to this type have a data property that can be any type of Uint8Array.

Functions

appendTransactionMessageInstruction()

Given an instruction, this method will return a new transaction message with that instruction having been added to the end of the list of existing instructions.

import { address } from '@solana/addresses';
import { appendTransactionMessageInstruction } from '@solana/transaction-messages';

const memoTransaction = appendTransactionMessageInstruction(
    {
        data: new TextEncoder().encode('Hello world!'),
        programAddress: address('MemoSq4gqABAXKb96qnH8TysNcWxMyWCqXgDLGmfcHr'),
    },
    tx,
);

If you'd like to add multiple instructions to a transaction message at once, you may use the appendTransactionInstructions function instead which accepts an array of instructions.

prependTransactionMessageInstruction()

Given an instruction, this method will return a new transaction message with that instruction having been added to the beginning of the list of existing instructions.

If you'd like to prepend multiple instructions to a transaction message at once, you may use the prependTransactionMessageInstructions function instead which accepts an array of instructions.

See appendTransactionMessageInstruction() for an example of how to use this function.