tornado-relayer/index.js
2019-11-08 04:25:43 +03:00

129 lines
4.2 KiB
JavaScript

const { numberToHex, toWei, toHex, toBN, toChecksumAddress } = require('web3-utils')
const { netId, rpcUrl, privateKey, mixers, defaultGasPrice } = require('./config')
const { fetchGasPrice, isValidProof, fetchDAIprice, isKnownContract } = require('./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 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('This is <a href=https://tornado.cash>tornado.cash</a> Relayer service. Check the /status for settings')
})
app.get('/status', function (req, res) {
res.json({ relayerAddress: web3.eth.defaultAccount, gasPrices, netId })
})
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 format is invalid' })
}
let currency
( { valid, currency } = isKnownContract(req.body.contract))
if (!valid) {
console.log('Contract does not exist:', req.body.contract)
return resp.status(400).json({ error: 'This relayer does not support the token' })
}
let { proof, publicSignals } = req.body.proof
const args = {
root: publicSignals[0],
nullifierHash: publicSignals[1],
recipient: toChecksumAddress(publicSignals[2]),
relayer: toChecksumAddress(publicSignals[3]),
fee: toBN(publicSignals[4]),
refund: toBN(publicSignals[5]),
}
if (args.relayer !== web3.eth.defaultAccount) {
console.log('This proof is for different relayer:', args.relayer)
return resp.status(400).json({ error: 'Relayer address is invalid' })
}
const expense = toBN(toWei(gasPrices.fast.toString(), 'gwei')).mul(toBN('1000000'))
let desiredFee
switch (currency) {
case 'eth': {
if (!args.refund.isZero()) {
return resp.status(400).json({ error: 'Cannot send refund for eth currency.' })
}
desiredFee = expense
break
}
case 'dai': {
desiredFee = expense.add(args.refund).mul(toBN(ethPriceInDai)).div(toBN(10 ** 18))
break
}
}
if (args.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 isSpent = await mixer.methods.isSpent(args.nullifierHash).call()
if (isSpent) {
return resp.status(400).json({ error: 'The note has been spent.' })
}
const isKnownRoot = await mixer.methods.isKnownRoot(args.root).call()
if (!isKnownRoot) {
return resp.status(400).json({ error: 'The merkle root is too old or invalid.' })
}
const gas = await mixer.methods.withdraw(proof, ...publicSignals).estimateGas({ value: args.refund })
const result = mixer.methods.withdraw(proof, ...publicSignals).send({
value: args.refund,
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.')
}