multiple contracts

.env.example

@@ -1,4 +1,5 @@
 NET_ID=42
 RPC_URL=https://kovan.infura.io/v3/a3f4d001c1fc4a359ea70dd27fd9cb51
 PRIVATE_KEY=
-MIXER_ADDRESS=0xb2aD997a43768aB9279Cd9E72D5B75D789a09011
+ETH_MIXER_ADDRESS=0x1Cea940cA15a303A0E01B7F8589F39fF34308DB2
+DAI_MIXER_ADDRESS=0x7ed3fC8042e18db889A0466F49c438bB1410b3c7

.eslintrc.json

@@ -16,7 +16,8 @@
     "rules": {
         "indent": [
             "error",
-            2
+            2,
+            {"SwitchCase": 1}
         ],
         "linebreak-style": [
             "error",

config.js

@@ -4,7 +4,14 @@ module.exports = {
   netId: process.env.NET_ID || 42,
   rpcUrl: process.env.RPC_URL || 'https://kovan.infura.io/v3/a3f4d001c1fc4a359ea70dd27fd9cb51',
   privateKey: process.env.PRIVATE_KEY,
-  mixerAddress: process.env.MIXER_ADDRESS,
+  mixers: [ { 
+    address: process.env.ETH_MIXER_ADDRESS,
+    currency: 'eth' 
+  }, 
+  { 
+    address: process.env.DAI_MIXER_ADDRESS,
+    currency: 'dai' 
+  } ],
   defaultGasPrice: 2,
   gasOracleUrls: ['https://www.etherchain.org/api/gasPriceOracle', 'https://gasprice.poa.network/'],
   ethdaiAddress: '0x7Ef645705cb7D401C5CD91a395cfcc3Db3C93689'

index.js

@@ -20,8 +20,8 @@ app.use(function(req, res, next) {
   next()
 })
 
-const { netId, rpcUrl, privateKey, mixerAddress, defaultGasPrice } = require('./config')
-const { fetchGasPrice, isValidProof, fetchDAIprice } = require('./utils')
+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)
@@ -29,33 +29,46 @@ web3.eth.accounts.wallet.add('0x' + privateKey)
 web3.eth.defaultAccount = account.address
 
 const mixerABI = require('./abis/mixerABI.json') 
-const mixer = new web3.eth.Contract(mixerABI, mixerAddress)
 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 address is ${mixerAddress}`)
+  res.send(`Tornado mixer relayer. Gas Price is ${JSON.stringify(gasPrices)}. Mixer addresses are ${mixers}`)
 })
 
 app.post('/relay', async (req, resp) => {
-  console.log(JSON.stringify(req.body, null, 2))
-  const { valid , reason } = isValidProof(req.body)
+  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
+  let { pi_a, pi_b, pi_c, publicSignals } = req.body.proof
 
   const fee = toBN(publicSignals[3])
-  const desiredFee = toBN(toWei(gasPrices.fast.toString(), 'gwei')).mul(toBN('1000000'))
+  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) {

utils.js

@@ -1,6 +1,6 @@
 const fetch = require('node-fetch')
 const { isHexStrict, hexToNumberString } = require('web3-utils')
-const { gasOracleUrls, ethdaiAddress } = require('./config')
+const { gasOracleUrls, ethdaiAddress, mixers } = require('./config')
 const oracleABI = require('./abis/ETHDAIOracle.json')
 
 async function fetchGasPrice({ gasPrices, oracleIndex = 0 }) {
@@ -90,8 +90,17 @@ function isValidProof(proof) {
   return { valid: true }
 }
 
+function isKnownContract(contract) {
+  for (let i = 0; i < mixers.length; i++) {
+    if (mixers[i].address === contract) {
+      return { valid: true, currency: mixers[i].currency }
+    }
+  }
+  return { valid: false }
+}
+
 function sleep(ms) {
   return new Promise(resolve => setTimeout(resolve, ms))
 }
 
-module.exports = { fetchGasPrice, isValidProof, sleep, fetchDAIprice }
+module.exports = { fetchGasPrice, isValidProof, sleep, fetchDAIprice, isKnownContract }