tornado-relayer/index.js
2019-09-19 22:56:45 +03:00

107 lines
3.3 KiB
JavaScript

const { numberToHex, toWei, toHex, toBN } = require('web3-utils')
const Web3 = require('web3')
const express = require('express')
const app = express()
app.use(express.json())
app.use((err, req, res, next) => {
if (err) {
console.log('Invalid Request data')
res.send('Invalid Request data')
} else {
next()
}
})
app.use(function(req, res, next) {
res.header('Access-Control-Allow-Origin', '*')
res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept')
next()
})
const { netId, rpcUrl, privateKey, mixers, defaultGasPrice } = require('./config')
const { fetchGasPrice, isValidProof, fetchDAIprice, isKnownContract } = require('./utils')
const web3 = new Web3(rpcUrl, null, { transactionConfirmationBlocks: 1 })
const account = web3.eth.accounts.privateKeyToAccount('0x' + privateKey)
web3.eth.accounts.wallet.add('0x' + privateKey)
web3.eth.defaultAccount = account.address
const mixerABI = require('./abis/mixerABI.json')
const gasPrices = { fast: defaultGasPrice }
const ethPriceInDai = toWei('200')
app.get('/', function (req, res) {
// just for testing purposes
res.send(`Tornado mixer relayer. Gas Price is ${JSON.stringify(gasPrices)}. Mixer addresses are ${mixers}`)
})
app.post('/relay', async (req, resp) => {
let { valid , reason } = isValidProof(req.body.proof)
if (!valid) {
console.log('Proof is invalid:', reason)
return resp.status(400).json({ error: 'Proof is invalid' })
}
let currency
( { valid, currency } = isKnownContract(req.body.contract))
let { pi_a, pi_b, pi_c, publicSignals } = req.body.proof
const fee = toBN(publicSignals[3])
const expense = toBN(toWei(gasPrices.fast.toString(), 'gwei')).mul(toBN('1000000'))
let desiredFee
switch (currency) {
case 'eth': {
desiredFee = expense
break
}
case 'dai': {
desiredFee = expense.mul(toBN(ethPriceInDai)).div(toBN(10 ** 18))
break
}
}
if (fee.lt(desiredFee)) {
console.log('Fee is too low')
return resp.status(400).json({ error: 'Fee is too low. Try to resend.' })
}
try {
const mixer = new web3.eth.Contract(mixerABI, req.body.contract)
const nullifier = publicSignals[1]
const isSpent = await mixer.methods.isSpent(nullifier).call()
if (isSpent) {
return resp.status(400).json({ error: 'The note has been spent.' })
}
const root = publicSignals[0]
const isKnownRoot = await mixer.methods.isKnownRoot(root).call()
if (!isKnownRoot) {
return resp.status(400).json({ error: 'The merkle root is too old or invalid.' })
}
const gas = await mixer.methods.withdraw(pi_a, pi_b, pi_c, publicSignals).estimateGas()
const result = mixer.methods.withdraw(pi_a, pi_b, pi_c, publicSignals).send({
gas: numberToHex(gas + 50000),
gasPrice: toHex(toWei(gasPrices.fast.toString(), 'gwei')),
// TODO: nonce
})
result.once('transactionHash', function(hash){
resp.json({ txHash: hash })
}).on('error', function(e){
console.log(e)
return resp.status(400).json({ error: 'Proof is malformed.' })
})
} catch (e) {
console.log(e)
return resp.status(400).json({ error: 'Proof is malformed or spent.' })
}
})
app.listen(8000)
if (Number(netId) === 1) {
fetchGasPrice({ gasPrices })
fetchDAIprice({ ethPriceInDai, web3 })
console.log('Gas price oracle started.')
}