123 lines
4.0 KiB
JavaScript
123 lines
4.0 KiB
JavaScript
const { numberToHex, toWei, toHex, toBN, toChecksumAddress } = require('web3-utils')
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const { netId, rpcUrl, privateKey, mixers, defaultGasPrice } = require('./config')
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const { fetchGasPrice, isValidProof, fetchDAIprice, isKnownContract } = require('./utils')
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const Web3 = require('web3')
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const express = require('express')
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const app = express()
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app.use(express.json())
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app.use((err, req, res, next) => {
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if (err) {
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console.log('Invalid Request data')
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res.send('Invalid Request data')
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} else {
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next()
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}
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})
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app.use(function(req, res, next) {
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res.header('Access-Control-Allow-Origin', '*')
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res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept')
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next()
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})
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const web3 = new Web3(rpcUrl, null, { transactionConfirmationBlocks: 1 })
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const account = web3.eth.accounts.privateKeyToAccount('0x' + privateKey)
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web3.eth.accounts.wallet.add('0x' + privateKey)
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web3.eth.defaultAccount = account.address
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const mixerABI = require('./abis/mixerABI.json')
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const gasPrices = { fast: defaultGasPrice }
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const ethPriceInDai = toWei('200')
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app.get('/', function (req, res) {
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// just for testing purposes
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res.send(`Tornado mixer relayer. Gas Price is ${JSON.stringify(gasPrices)}.
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Mixer addresses are ${JSON.stringify(mixers)}`)
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})
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app.post('/relay', async (req, resp) => {
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let { valid , reason } = isValidProof(req.body.proof)
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if (!valid) {
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console.log('Proof is invalid:', reason)
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return resp.status(400).json({ error: 'Proof is invalid' })
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}
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let currency
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( { valid, currency } = isKnownContract(req.body.contract))
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if (!valid) {
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console.log('Contract does not exist:', req.body.contract)
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return resp.status(400).json({ error: 'This relayer does not support the token' })
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}
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let { proof, publicSignals } = req.body.proof
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const relayer = toChecksumAddress(`0x${publicSignals[3].slice(26)}`)
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if (relayer !== web3.eth.defaultAccount) {
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console.log('This proof is for different relayer:', relayer)
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return resp.status(400).json({ error: 'Relayer address is invalid' })
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}
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const fee = toBN(publicSignals[4])
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const refund = toBN(publicSignals[5])
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const expense = toBN(toWei(gasPrices.fast.toString(), 'gwei')).mul(toBN('1000000'))
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let desiredFee
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switch (currency) {
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case 'eth': {
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if (!refund.isZero()) {
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return resp.status(400).json({ error: 'Cannot send refund for eth currency.' })
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}
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desiredFee = expense
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break
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}
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case 'dai': {
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desiredFee = expense.add(refund).mul(toBN(ethPriceInDai)).div(toBN(10 ** 18))
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break
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}
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}
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if (fee.lt(desiredFee)) {
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console.log('Fee is too low')
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return resp.status(400).json({ error: 'Fee is too low. Try to resend.' })
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}
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try {
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const mixer = new web3.eth.Contract(mixerABI, req.body.contract)
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const nullifier = publicSignals[1]
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const isSpent = await mixer.methods.isSpent(nullifier).call()
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if (isSpent) {
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return resp.status(400).json({ error: 'The note has been spent.' })
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}
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const root = publicSignals[0]
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const isKnownRoot = await mixer.methods.isKnownRoot(root).call()
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if (!isKnownRoot) {
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return resp.status(400).json({ error: 'The merkle root is too old or invalid.' })
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}
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const gas = await mixer.methods.withdraw(proof, publicSignals).estimateGas({ value: refund })
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const result = mixer.methods.withdraw(proof, publicSignals).send({
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value: refund,
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gas: numberToHex(gas + 50000),
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gasPrice: toHex(toWei(gasPrices.fast.toString(), 'gwei')),
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// TODO: nonce
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})
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result.once('transactionHash', function(hash){
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resp.json({ txHash: hash })
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}).on('error', function(e){
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console.log(e)
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return resp.status(400).json({ error: 'Proof is malformed.' })
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})
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} catch (e) {
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console.log(e)
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return resp.status(400).json({ error: 'Proof is malformed or spent.' })
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}
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})
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app.listen(8000)
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if (Number(netId) === 1) {
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fetchGasPrice({ gasPrices })
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fetchDAIprice({ ethPriceInDai, web3 })
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console.log('Gas price oracle started.')
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}
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