const EventEmitter = require('events') const EthQuery = require('ethjs-query') /* Utility class for tracking the transactions as they go from a pending state to a confirmed (mined in a block) state As well as continues broadcast while in the pending state ~config is not optional~ requires a: { provider: //, nonceTracker: //see nonce tracker, getPendingTransactions: //() a function for getting an array of transactions, publishTransaction: //(rawTx) a async function for publishing raw transactions, } */ module.exports = class PendingTransactionTracker extends EventEmitter { constructor (config) { super() this.query = new EthQuery(config.provider) this.nonceTracker = config.nonceTracker // default is one day this.retryTimePeriod = config.retryTimePeriod || 86400000 this.getPendingTransactions = config.getPendingTransactions this.getCompletedTransactions = config.getCompletedTransactions this.publishTransaction = config.publishTransaction this._checkPendingTxs() } // checks if a signed tx is in a block and // if included sets the tx status as 'confirmed' checkForTxInBlock (block) { const signedTxList = this.getPendingTransactions() if (!signedTxList.length) return signedTxList.forEach((txMeta) => { const txHash = txMeta.hash const txId = txMeta.id if (!txHash) { const noTxHashErr = new Error('We had an error while submitting this transaction, please try again.') noTxHashErr.name = 'NoTxHashError' this.emit('tx:failed', txId, noTxHashErr) return } block.transactions.forEach((tx) => { if (tx.hash === txHash) this.emit('tx:confirmed', txId) }) }) } queryPendingTxs ({ oldBlock, newBlock }) { // check pending transactions on start if (!oldBlock) { this._checkPendingTxs() return } // if we synced by more than one block, check for missed pending transactions const diff = Number.parseInt(newBlock.number, 16) - Number.parseInt(oldBlock.number, 16) if (diff > 1) this._checkPendingTxs() } resubmitPendingTxs () { const pending = this.getPendingTransactions() // only try resubmitting if their are transactions to resubmit if (!pending.length) return pending.forEach((txMeta) => this._resubmitTx(txMeta).catch((err) => { /* Dont marked as failed if the error is a "known" transaction warning "there is already a transaction with the same sender-nonce but higher/same gas price" Also don't mark as failed if it has ever been broadcast successfully. A successful broadcast means it may still be mined. */ const errorMessage = err.message.toLowerCase() const isKnownTx = ( // geth errorMessage.includes('replacement transaction underpriced') || errorMessage.includes('known transaction') // parity || errorMessage.includes('gas price too low to replace') || errorMessage.includes('transaction with the same hash was already imported') // other || errorMessage.includes('gateway timeout') || errorMessage.includes('nonce too low') ) // ignore resubmit warnings, return early if (isKnownTx) return // encountered real error - transition to error state txMeta.warning = { error: errorMessage, message: 'There was an error when resubmitting this transaction.', } this.emit('tx:warning', txMeta, err) })) } async _resubmitTx (txMeta) { if (Date.now() > txMeta.time + this.retryTimePeriod) { const hours = (this.retryTimePeriod / 3.6e+6).toFixed(1) const err = new Error(`Gave up submitting after ${hours} hours.`) return this.emit('tx:failed', txMeta.id, err) } // Only auto-submit already-signed txs: if (!('rawTx' in txMeta)) return const rawTx = txMeta.rawTx const txHash = await this.publishTransaction(rawTx) // Increment successful tries: this.emit('tx:retry', txMeta) return txHash } async _checkPendingTx (txMeta) { const txHash = txMeta.hash const txId = txMeta.id // extra check in case there was an uncaught error during the // signature and submission process if (!txHash) { const noTxHashErr = new Error('We had an error while submitting this transaction, please try again.') noTxHashErr.name = 'NoTxHashError' this.emit('tx:failed', txId, noTxHashErr) return } // If another tx with the same nonce is mined, set as failed. const taken = await this._checkIfNonceIsTaken(txMeta) if (taken) { const nonceTakenErr = new Error('Another transaction with this nonce has been mined.') nonceTakenErr.name = 'NonceTakenErr' return this.emit('tx:failed', txId, nonceTakenErr) } // get latest transaction status let txParams try { txParams = await this.query.getTransactionByHash(txHash) if (!txParams) return if (txParams.blockNumber) { this.emit('tx:confirmed', txId) } } catch (err) { txMeta.warning = { error: err.message, message: 'There was a problem loading this transaction.', } this.emit('tx:warning', txMeta, err) } } // checks the network for signed txs and // if confirmed sets the tx status as 'confirmed' async _checkPendingTxs () { const signedTxList = this.getPendingTransactions() // in order to keep the nonceTracker accurate we block it while updating pending transactions const nonceGlobalLock = await this.nonceTracker.getGlobalLock() try { await Promise.all(signedTxList.map((txMeta) => this._checkPendingTx(txMeta))) } catch (err) { console.error('PendingTransactionWatcher - Error updating pending transactions') console.error(err) } nonceGlobalLock.releaseLock() } async _checkIfNonceIsTaken (txMeta) { const completed = this.getCompletedTransactions() const sameNonce = completed.filter((otherMeta) => { return otherMeta.txParams.nonce === txMeta.txParams.nonce }) return sameNonce.length > 0 } }