102 lines
3.3 KiB
JavaScript
102 lines
3.3 KiB
JavaScript
const { numberToHex, toWei, toHex, toBN, toChecksumAddress } = require('web3-utils')
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const mixerABI = require('../abis/mixerABI.json')
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const {
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isValidProof, isValidArgs, isKnownContract, isEnoughFee
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} = require('./utils')
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const { web3, fetcher } = require('./instances')
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async function relay (req, resp) {
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const { proof, args, contract } = req.body
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const gasPrices = fetcher.gasPrices
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let { valid , reason } = isValidProof(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 format is invalid' })
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}
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({ valid , reason } = isValidArgs(args))
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if (!valid) {
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console.log('Args are invalid:', reason)
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return resp.status(400).json({ error: 'Withdraw arguments are invalid' })
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}
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let currency, amount
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( { valid, currency, amount } = isKnownContract(contract))
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if (!valid) {
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console.log('Contract does not exist:', 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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const [ root, nullifierHash, recipient, relayer, fee, refund ] = [
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args[0],
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args[1],
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toChecksumAddress(args[2]),
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toChecksumAddress(args[3]),
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toBN(args[4]),
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toBN(args[5])
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]
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console.log('fee, refund', fee.toString(), refund.toString())
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if (currency === 'eth' && !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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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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try {
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const mixer = new web3.eth.Contract(mixerABI, req.body.contract)
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const isSpent = await mixer.methods.isSpent(nullifierHash).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 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 withdrawArgs = [
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proof,
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root,
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nullifierHash,
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recipient,
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relayer,
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fee.toString(),
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refund.toString()
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]
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let gas = await mixer.methods.withdraw(...withdrawArgs).estimateGas({
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from: web3.eth.defaultAccount,
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value: refund
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})
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gas += 50000
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const ethPrices = fetcher.ethPrices
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const { isEnough, reason } = isEnoughFee({ gas, gasPrices, currency, amount, refund, ethPrices, fee })
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if (!isEnough) {
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console.log(`Wrong fee: ${reason}`)
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return resp.status(400).json({ error: reason })
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}
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const result = mixer.methods.withdraw(...withdrawArgs).send({
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from: web3.eth.defaultAccount,
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value: refund,
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gas: numberToHex(gas),
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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(txHash){
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resp.json({ txHash })
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console.log(`A new successfuly sent tx ${txHash} for the ${recipient}`)
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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.error(e.message, 'estimate gas failed')
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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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module.exports = relay |