buildLockProofFromBlock

Builds the BondL1LockupOutput for a lockup funding transaction from the block's ordered txid list, for callers without an Esplora /merkle-proof endpoint, such as those reading bitcoind directly. Computes the merkle branch, then calls buildLockProof. Pure computation: no network call.

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Usage

import { buildLockProofFromBlock } from '@stacks/bitcoin-staking';
import type { RegisterMetadata } from '@stacks/bitcoin-staking';

declare function rpc(method: string, params: unknown[]): Promise<any>; // your bitcoind RPC client
declare const txid: string; // funding transaction ID
declare const blockHash: string; // block that confirmed it
declare const meta: RegisterMetadata; // from buildRegisterMetadata

const block = await rpc('getblock', [blockHash, 1]);

const output = buildLockProofFromBlock({
  txHex: (await rpc('gettransaction', [txid, null, true])).hex,
  header: await rpc('getblockheader', [blockHash, false]),
  blockHeight: block.height,
  txids: block.tx,
  unlockHeight: meta.unlockHeight,
  lockScript: meta.lockScript,
});

Notes

• The transaction's position is found by hashing txHex, witness stripped, to its txid and looking it up in txids. Throws an Error whose message starts with buildLockProofFromBlock: txid if it is not there.

• txCount is txids.length. The merkle branch is computed from txids with standard Bitcoin construction: an odd row duplicates its last node.

• Output matching, witness stripping, the proof checks and their errors are those of buildLockProof.

Reference Link

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Signature

function buildLockProofFromBlock(
  input: {
    txHex: string;
    header: Uint8Array | string;
    blockHeight: number;
    txids: string[];
    unlockHeight: IntegerType;
    outputIndex?: number;
  } & ExpectedScriptInput
): BondL1LockupOutput;

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Returns

BondL1LockupOutput

A BondL1LockupOutput, as returned by buildLockProof.

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Parameters

input.txHex (required)

• Type: string

The raw funding transaction as hex. Segwit serialization is accepted.

input.header (required)

• Type: Uint8Array | string

The 80-byte header of the block that confirmed the transaction, as bytes or hex.

input.blockHeight (required)

• Type: number

The height of that block. pox-5 checks the header against the Bitcoin block at this height.

input.txids (required)

• Type: string[]

The block's txids in block order, as display-order (big-endian) hex: the tx array of getblock with verbosity 1.

input.unlockHeight (required)

• Type: IntegerType

The unlock height the lockup script commits to, the same value used to build it.

input.outputIndex (optional)

• Type: number

Which output to prove when the transaction pays the lockup script more than once. Omit when exactly one output matches.

input.outputScript or input.lockScript (required, exactly one)

• Type: Uint8Array | string

The P2WSH scriptPubKey or the witness script of the lockup. See ExpectedScriptInput.