import { Order, SignedOrder, ZeroEx } from '0x.js'; import { BigNumber, logUtils } from '@0xproject/utils'; import { Provider } from 'ethereum-types'; import * as express from 'express'; import * as _ from 'lodash'; import * as Web3 from 'web3'; // HACK: web3 injects XMLHttpRequest into the global scope and ProviderEngine checks XMLHttpRequest // to know whether it is running in a browser or node environment. We need it to be undefined since // we are not running in a browser env. // Filed issue: https://github.com/ethereum/web3.js/issues/844 (global as any).XMLHttpRequest = undefined; import { NonceTrackerSubprovider, PrivateKeyWalletSubprovider } from '@0xproject/subproviders'; import ProviderEngine = require('web3-provider-engine'); import RpcSubprovider = require('web3-provider-engine/subproviders/rpc'); import { configs } from './configs'; import { constants } from './constants'; import { DispatchQueue } from './dispatch_queue'; import { dispenseAssetTasks } from './dispense_asset_tasks'; import { rpcUrls } from './rpc_urls'; interface NetworkConfig { dispatchQueue: DispatchQueue; web3: Web3; zeroEx: ZeroEx; } interface ItemByNetworkId { [networkId: string]: T; } enum RequestedAssetType { ETH = 'ETH', WETH = 'WETH', ZRX = 'ZRX', } const FIVE_DAYS_IN_MS = 4.32e8; // TODO: make this configurable export class Handler { private _networkConfigByNetworkId: ItemByNetworkId = {}; private static _createProviderEngine(rpcUrl: string): Provider { if (_.isUndefined(configs.DISPENSER_PRIVATE_KEY)) { throw new Error('Dispenser Private key not found'); } const engine = new ProviderEngine(); engine.addProvider(new NonceTrackerSubprovider()); engine.addProvider(new PrivateKeyWalletSubprovider(configs.DISPENSER_PRIVATE_KEY)); engine.addProvider( new RpcSubprovider({ rpcUrl, }), ); engine.start(); return engine; } constructor() { _.forIn(rpcUrls, (rpcUrl: string, networkId: string) => { const providerObj = Handler._createProviderEngine(rpcUrl); const web3 = new Web3(providerObj); const zeroExConfig = { networkId: +networkId, }; const zeroEx = new ZeroEx(web3.currentProvider, zeroExConfig); const dispatchQueue = new DispatchQueue(); this._networkConfigByNetworkId[networkId] = { dispatchQueue, web3, zeroEx, }; }); } public getQueueInfo(req: express.Request, res: express.Response): void { res.setHeader('Content-Type', 'application/json'); const queueInfo = _.mapValues(rpcUrls, (rpcUrl: string, networkId: string) => { const dispatchQueue = this._networkConfigByNetworkId[networkId].dispatchQueue; return { full: dispatchQueue.isFull(), size: dispatchQueue.size(), }; }); const payload = JSON.stringify(queueInfo); res.status(constants.SUCCESS_STATUS).send(payload); } public dispenseEther(req: express.Request, res: express.Response): void { this._dispenseAsset(req, res, RequestedAssetType.ETH); } public dispenseZRX(req: express.Request, res: express.Response): void { this._dispenseAsset(req, res, RequestedAssetType.ZRX); } public async dispenseWETHOrderAsync(req: express.Request, res: express.Response): Promise { await this._dispenseOrderAsync(req, res, RequestedAssetType.WETH); } public async dispenseZRXOrderAsync( req: express.Request, res: express.Response, next: express.NextFunction, ): Promise { await this._dispenseOrderAsync(req, res, RequestedAssetType.ZRX); } private _dispenseAsset(req: express.Request, res: express.Response, requestedAssetType: RequestedAssetType): void { const networkId = req.params.networkId; const recipient = req.params.recipient; const networkConfig = this._networkConfigByNetworkId[networkId]; let dispenserTask; switch (requestedAssetType) { case RequestedAssetType.ETH: dispenserTask = dispenseAssetTasks.dispenseEtherTask(recipient, networkConfig.web3); break; case RequestedAssetType.WETH: case RequestedAssetType.ZRX: dispenserTask = dispenseAssetTasks.dispenseTokenTask( recipient, requestedAssetType, networkConfig.zeroEx, ); break; default: throw new Error(`Unsupported asset type: ${requestedAssetType}`); } const didAddToQueue = networkConfig.dispatchQueue.add(dispenserTask); if (!didAddToQueue) { res.status(constants.SERVICE_UNAVAILABLE_STATUS).send('QUEUE_IS_FULL'); return; } logUtils.log(`Added ${recipient} to queue: ${requestedAssetType} networkId: ${networkId}`); res.status(constants.SUCCESS_STATUS).end(); } private async _dispenseOrderAsync( req: express.Request, res: express.Response, requestedAssetType: RequestedAssetType, ): Promise { const networkConfig = _.get(this._networkConfigByNetworkId, req.params.networkId); if (_.isUndefined(networkConfig)) { res.status(constants.BAD_REQUEST_STATUS).send('UNSUPPORTED_NETWORK_ID'); return; } const zeroEx = networkConfig.zeroEx; res.setHeader('Content-Type', 'application/json'); const makerToken = await zeroEx.tokenRegistry.getTokenBySymbolIfExistsAsync(requestedAssetType); if (_.isUndefined(makerToken)) { throw new Error(`Unsupported asset type: ${requestedAssetType}`); } const takerTokenSymbol = requestedAssetType === RequestedAssetType.WETH ? RequestedAssetType.ZRX : RequestedAssetType.WETH; const takerToken = await zeroEx.tokenRegistry.getTokenBySymbolIfExistsAsync(takerTokenSymbol); if (_.isUndefined(takerToken)) { throw new Error(`Unsupported asset type: ${requestedAssetType}`); } const makerTokenAmount = ZeroEx.toBaseUnitAmount(new BigNumber(0.1), makerToken.decimals); const takerTokenAmount = ZeroEx.toBaseUnitAmount(new BigNumber(0.1), takerToken.decimals); const order: Order = { maker: configs.DISPENSER_ADDRESS, taker: req.params.recipient, makerFee: new BigNumber(0), takerFee: new BigNumber(0), makerTokenAmount, takerTokenAmount, makerTokenAddress: makerToken.address, takerTokenAddress: takerToken.address, salt: ZeroEx.generatePseudoRandomSalt(), exchangeContractAddress: zeroEx.exchange.getContractAddress(), feeRecipient: ZeroEx.NULL_ADDRESS, expirationUnixTimestampSec: new BigNumber(Date.now() + FIVE_DAYS_IN_MS), }; const orderHash = ZeroEx.getOrderHashHex(order); const signature = await zeroEx.signOrderHashAsync(orderHash, configs.DISPENSER_ADDRESS, false); const signedOrder = { ...order, ecSignature: signature, }; const signedOrderHash = ZeroEx.getOrderHashHex(signedOrder); const payload = JSON.stringify(signedOrder); logUtils.log(`Dispensed signed order: ${payload}`); res.status(constants.SUCCESS_STATUS).send(payload); } }