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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<T> {
[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<NetworkConfig> = {};
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<void> {
await this._dispenseOrderAsync(req, res, RequestedAssetType.WETH);
}
public async dispenseZRXOrderAsync(
req: express.Request,
res: express.Response,
next: express.NextFunction,
): Promise<void> {
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<void> {
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);
}
}
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