mempool/backend/src/api/transaction-utils.ts
2024-09-28 16:34:13 +00:00

426 lines
15 KiB
TypeScript

import { TransactionExtended, MempoolTransactionExtended, TransactionMinerInfo } from '../mempool.interfaces';
import { IEsploraApi } from './bitcoin/esplora-api.interface';
import { Common } from './common';
import bitcoinApi, { bitcoinCoreApi } from './bitcoin/bitcoin-api-factory';
import * as bitcoinjs from 'bitcoinjs-lib';
import logger from '../logger';
import config from '../config';
import pLimit from '../utils/p-limit';
class TransactionUtils {
constructor() { }
public stripCoinbaseTransaction(tx: TransactionExtended): TransactionMinerInfo {
return {
vin: [{
scriptsig: tx.vin[0].scriptsig || tx.vin[0]['coinbase']
}],
vout: tx.vout
.map((vout) => ({
scriptpubkey_address: vout.scriptpubkey_address,
scriptpubkey_asm: vout.scriptpubkey_asm,
value: vout.value
}))
.filter((vout) => vout.value)
};
}
// Wrapper for $getTransactionExtended with an automatic retry direct to Core if the first API request fails.
// Propagates any error from the retry request.
public async $getTransactionExtendedRetry(txid: string, addPrevouts = false, lazyPrevouts = false, forceCore = false, addMempoolData = false): Promise<TransactionExtended> {
try {
const result = await this.$getTransactionExtended(txid, addPrevouts, lazyPrevouts, forceCore, addMempoolData);
if (result) {
return result;
} else {
logger.err(`Cannot fetch tx ${txid}. Reason: backend returned null data`);
}
} catch (e) {
logger.err(`Cannot fetch tx ${txid}. Reason: ` + (e instanceof Error ? e.message : e));
}
// retry direct from Core if first request failed
return this.$getTransactionExtended(txid, addPrevouts, lazyPrevouts, true, addMempoolData);
}
/**
* @param txId
* @param addPrevouts
* @param lazyPrevouts
* @param forceCore - See https://github.com/mempool/mempool/issues/2904
*/
public async $getTransactionExtended(txId: string, addPrevouts = false, lazyPrevouts = false, forceCore = false, addMempoolData = false): Promise<TransactionExtended> {
let transaction: IEsploraApi.Transaction;
if (forceCore === true) {
transaction = await bitcoinCoreApi.$getRawTransaction(txId, false, addPrevouts, lazyPrevouts);
} else {
transaction = await bitcoinApi.$getRawTransaction(txId, false, addPrevouts, lazyPrevouts);
}
if (Common.isLiquid()) {
if (!isFinite(Number(transaction.fee))) {
transaction.fee = Object.values(transaction.fee || {}).reduce((total, output) => total + output, 0);
}
}
if (addMempoolData || !transaction?.status?.confirmed) {
return this.extendMempoolTransaction(transaction);
} else {
return this.extendTransaction(transaction);
}
}
public async $getMempoolTransactionExtended(txId: string, addPrevouts = false, lazyPrevouts = false, forceCore = false): Promise<MempoolTransactionExtended> {
return (await this.$getTransactionExtended(txId, addPrevouts, lazyPrevouts, forceCore, true)) as MempoolTransactionExtended;
}
public async $getMempoolTransactionsExtended(txids: string[], addPrevouts = false, lazyPrevouts = false, forceCore = false): Promise<MempoolTransactionExtended[]> {
if (forceCore || config.MEMPOOL.BACKEND !== 'esplora') {
const limiter = pLimit(8); // Run 8 requests at a time
const results = await Promise.allSettled(txids.map(
txid => limiter(() => this.$getMempoolTransactionExtended(txid, addPrevouts, lazyPrevouts, forceCore))
));
return results.filter(reply => reply.status === 'fulfilled')
.map(r => (r as PromiseFulfilledResult<MempoolTransactionExtended>).value);
} else {
const transactions = await bitcoinApi.$getMempoolTransactions(txids);
return transactions.map(transaction => {
if (Common.isLiquid()) {
if (!isFinite(Number(transaction.fee))) {
transaction.fee = Object.values(transaction.fee || {}).reduce((total, output) => total + output, 0);
}
}
return this.extendMempoolTransaction(transaction);
});
}
}
public extendTransaction(transaction: IEsploraApi.Transaction): TransactionExtended {
// @ts-ignore
if (transaction.vsize) {
// @ts-ignore
return transaction;
}
const feePerVbytes = (transaction.fee || 0) / (transaction.weight / 4);
const transactionExtended: TransactionExtended = Object.assign({
vsize: transaction.weight / 4,
feePerVsize: feePerVbytes,
effectiveFeePerVsize: feePerVbytes,
}, transaction);
if (!transaction?.status?.confirmed && !transactionExtended.firstSeen) {
transactionExtended.firstSeen = Math.round((Date.now() / 1000));
}
return transactionExtended;
}
public extendMempoolTransaction(transaction: IEsploraApi.Transaction): MempoolTransactionExtended {
const vsize = Math.ceil(transaction.weight / 4);
const fractionalVsize = (transaction.weight / 4);
let sigops = Common.isLiquid() ? 0 : (transaction.sigops != null ? transaction.sigops : this.countSigops(transaction));
// https://github.com/bitcoin/bitcoin/blob/e9262ea32a6e1d364fb7974844fadc36f931f8c6/src/policy/policy.cpp#L295-L298
const adjustedVsize = Math.max(fractionalVsize, sigops * 5); // adjusted vsize = Max(weight, sigops * bytes_per_sigop) / witness_scale_factor
const feePerVbytes = (transaction.fee || 0) / fractionalVsize;
const adjustedFeePerVsize = (transaction.fee || 0) / adjustedVsize;
const effectiveFeePerVsize = transaction['effectiveFeePerVsize'] || adjustedFeePerVsize || feePerVbytes;
const transactionExtended: MempoolTransactionExtended = Object.assign(transaction, {
order: this.txidToOrdering(transaction.txid),
vsize,
adjustedVsize,
sigops,
feePerVsize: feePerVbytes,
adjustedFeePerVsize: adjustedFeePerVsize,
effectiveFeePerVsize: effectiveFeePerVsize,
});
if (!transactionExtended?.status?.confirmed && !transactionExtended.firstSeen) {
transactionExtended.firstSeen = Math.round((Date.now() / 1000));
}
return transactionExtended;
}
public hex2ascii(hex: string) {
let str = '';
for (let i = 0; i < hex.length; i += 2) {
str += String.fromCharCode(parseInt(hex.substr(i, 2), 16));
}
return str;
}
public countScriptSigops(script: string, isRawScript: boolean = false, witness: boolean = false): number {
if (!script?.length) {
return 0;
}
let sigops = 0;
// count OP_CHECKSIG and OP_CHECKSIGVERIFY
sigops += (script.match(/OP_CHECKSIG/g)?.length || 0);
// count OP_CHECKMULTISIG and OP_CHECKMULTISIGVERIFY
if (isRawScript) {
// in scriptPubKey or scriptSig, always worth 20
sigops += 20 * (script.match(/OP_CHECKMULTISIG/g)?.length || 0);
} else {
// in redeem scripts and witnesses, worth N if preceded by OP_N, 20 otherwise
const matches = script.matchAll(/(?:OP_(?:PUSHNUM_)?(\d+))? OP_CHECKMULTISIG/g);
for (const match of matches) {
const n = parseInt(match[1]);
if (Number.isInteger(n)) {
sigops += n;
} else {
sigops += 20;
}
}
}
return witness ? sigops : (sigops * 4);
}
public countSigops(transaction: IEsploraApi.Transaction): number {
let sigops = 0;
for (const input of transaction.vin) {
if (input.scriptsig_asm) {
sigops += this.countScriptSigops(input.scriptsig_asm, true);
}
if (input.prevout) {
switch (true) {
case input.prevout.scriptpubkey_type === 'p2sh' && input.witness?.length === 2 && input.scriptsig && input.scriptsig.startsWith('160014'):
case input.prevout.scriptpubkey_type === 'v0_p2wpkh':
sigops += 1;
break;
case input.prevout?.scriptpubkey_type === 'p2sh' && input.witness?.length && input.scriptsig && input.scriptsig.startsWith('220020'):
case input.prevout.scriptpubkey_type === 'v0_p2wsh':
if (input.witness?.length) {
sigops += this.countScriptSigops(bitcoinjs.script.toASM(Buffer.from(input.witness[input.witness.length - 1], 'hex')), false, true);
}
break;
case input.prevout.scriptpubkey_type === 'p2sh':
if (input.inner_redeemscript_asm) {
sigops += this.countScriptSigops(input.inner_redeemscript_asm);
}
break;
}
}
}
for (const output of transaction.vout) {
if (output.scriptpubkey_asm) {
sigops += this.countScriptSigops(output.scriptpubkey_asm, true);
}
}
return sigops;
}
// returns the most significant 4 bytes of the txid as an integer
public txidToOrdering(txid: string): number {
return parseInt(
txid.substr(62, 2) +
txid.substr(60, 2) +
txid.substr(58, 2) +
txid.substr(56, 2),
16
);
}
public addInnerScriptsToVin(vin: IEsploraApi.Vin): void {
if (!vin.prevout) {
return;
}
if (vin.prevout.scriptpubkey_type === 'p2sh') {
const redeemScript = vin.scriptsig_asm.split(' ').reverse()[0];
vin.inner_redeemscript_asm = this.convertScriptSigAsm(redeemScript);
if (vin.witness && vin.witness.length > 2) {
const witnessScript = vin.witness[vin.witness.length - 1];
vin.inner_witnessscript_asm = this.convertScriptSigAsm(witnessScript);
}
}
if (vin.prevout.scriptpubkey_type === 'v0_p2wsh' && vin.witness) {
const witnessScript = vin.witness[vin.witness.length - 1];
vin.inner_witnessscript_asm = this.convertScriptSigAsm(witnessScript);
}
if (vin.prevout.scriptpubkey_type === 'v1_p2tr' && vin.witness) {
const witnessScript = this.witnessToP2TRScript(vin.witness);
if (witnessScript !== null) {
vin.inner_witnessscript_asm = this.convertScriptSigAsm(witnessScript);
}
}
}
public convertScriptSigAsm(hex: string): string {
const buf = Buffer.from(hex, 'hex');
const b: string[] = [];
let i = 0;
while (i < buf.length) {
const op = buf[i];
if (op >= 0x01 && op <= 0x4e) {
i++;
let push: number;
if (op === 0x4c) {
push = buf.readUInt8(i);
b.push('OP_PUSHDATA1');
i += 1;
} else if (op === 0x4d) {
push = buf.readUInt16LE(i);
b.push('OP_PUSHDATA2');
i += 2;
} else if (op === 0x4e) {
push = buf.readUInt32LE(i);
b.push('OP_PUSHDATA4');
i += 4;
} else {
push = op;
b.push('OP_PUSHBYTES_' + push);
}
const data = buf.slice(i, i + push);
if (data.length !== push) {
break;
}
b.push(data.toString('hex'));
i += data.length;
} else {
if (op === 0x00) {
b.push('OP_0');
} else if (op === 0x4f) {
b.push('OP_PUSHNUM_NEG1');
} else if (op === 0xb1) {
b.push('OP_CLTV');
} else if (op === 0xb2) {
b.push('OP_CSV');
} else if (op === 0xba) {
b.push('OP_CHECKSIGADD');
} else {
const opcode = bitcoinjs.script.toASM([ op ]);
if (opcode && op < 0xfd) {
if (/^OP_(\d+)$/.test(opcode)) {
b.push(opcode.replace(/^OP_(\d+)$/, 'OP_PUSHNUM_$1'));
} else {
b.push(opcode);
}
} else {
b.push('OP_RETURN_' + op);
}
}
i += 1;
}
}
return b.join(' ');
}
/**
* This function must only be called when we know the witness we are parsing
* is a taproot witness.
* @param witness An array of hex strings that represents the witness stack of
* the input.
* @returns null if the witness is not a script spend, and the hex string of
* the script item if it is a script spend.
*/
public witnessToP2TRScript(witness: string[]): string | null {
if (witness.length < 2) return null;
// Note: see BIP341 for parsing details of witness stack
// If there are at least two witness elements, and the first byte of the
// last element is 0x50, this last element is called annex a and
// is removed from the witness stack.
const hasAnnex = witness[witness.length - 1].substring(0, 2) === '50';
// If there are at least two witness elements left, script path spending is used.
// Call the second-to-last stack element s, the script.
// (Note: this phrasing from BIP341 assumes we've *removed* the annex from the stack)
if (hasAnnex && witness.length < 3) return null;
const positionOfScript = hasAnnex ? witness.length - 3 : witness.length - 2;
return witness[positionOfScript];
}
// calculate the most parsimonious set of prioritizations given a list of block transactions
// (i.e. the most likely prioritizations and deprioritizations)
public identifyPrioritizedTransactions(transactions: any[], rateKey: string): { prioritized: string[], deprioritized: string[] } {
// find the longest increasing subsequence of transactions
// (adapted from https://en.wikipedia.org/wiki/Longest_increasing_subsequence#Efficient_algorithms)
// should be O(n log n)
const X = transactions.slice(1).reverse().map((tx) => ({ txid: tx.txid, rate: tx[rateKey] })); // standard block order is by *decreasing* effective fee rate, but we want to iterate in increasing order (and skip the coinbase)
if (X.length < 2) {
return { prioritized: [], deprioritized: [] };
}
const N = X.length;
const P: number[] = new Array(N);
const M: number[] = new Array(N + 1);
M[0] = -1; // undefined so can be set to any value
let L = 0;
for (let i = 0; i < N; i++) {
// Binary search for the smallest positive l ≤ L
// such that X[M[l]].effectiveFeePerVsize > X[i].effectiveFeePerVsize
let lo = 1;
let hi = L + 1;
while (lo < hi) {
const mid = lo + Math.floor((hi - lo) / 2); // lo <= mid < hi
if (X[M[mid]].rate > X[i].rate) {
hi = mid;
} else { // if X[M[mid]].effectiveFeePerVsize < X[i].effectiveFeePerVsize
lo = mid + 1;
}
}
// After searching, lo == hi is 1 greater than the
// length of the longest prefix of X[i]
const newL = lo;
// The predecessor of X[i] is the last index of
// the subsequence of length newL-1
P[i] = M[newL - 1];
M[newL] = i;
if (newL > L) {
// If we found a subsequence longer than any we've
// found yet, update L
L = newL;
}
}
// Reconstruct the longest increasing subsequence
// It consists of the values of X at the L indices:
// ..., P[P[M[L]]], P[M[L]], M[L]
const LIS: any[] = new Array(L);
let k = M[L];
for (let j = L - 1; j >= 0; j--) {
LIS[j] = X[k];
k = P[k];
}
const lisMap = new Map<string, number>();
LIS.forEach((tx, index) => lisMap.set(tx.txid, index));
const prioritized: string[] = [];
const deprioritized: string[] = [];
let lastRate = X[0].rate;
for (const tx of X) {
if (lisMap.has(tx.txid)) {
lastRate = tx.rate;
} else {
if (Math.abs(tx.rate - lastRate) < 0.1) {
// skip if the rate is almost the same as the previous transaction
} else if (tx.rate <= lastRate) {
prioritized.push(tx.txid);
} else {
deprioritized.push(tx.txid);
}
}
}
return { prioritized, deprioritized };
}
}
export default new TransactionUtils();